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WORKING DRAWINGS HANDBOOK This page intentionally left blank WORKING DRAWINGS HANDBOOK Fourth Edition Keith Styles and Andrew Bichard Architectural Press An imprint of Elsevier Linacre House, Jordan Hill, Oxford OX2 8DP 30 Corporate Drive, Burlington, MA 01803 First published 1982 Second edition 1986 Third edition 1995 Reprinted 1998, 2000, 2002, 2003 Fourth edition 2004 Copyright © 2004, Keith Styles and Andrew Bichard. All rights reserved The right of Keith Styles and Andrew Bichard to be identified as the authors of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1T 4LP. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone: (⫹44) 1865 843830, fax: (⫹44) 1865 853333, e-mail: permissions@elsevier.co.uk. You may also complete your request on-line via the Elsevier homepage (http://www.elsevier.com), by selecting ‘Customer Support’ and then ‘Obtaining Permissions’ British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloguing in Publication Data A catalogue record for this book is available from the Library of Congress ISBN 0 7506 6372 3 For information on all Architectural Press publications visit our website at www.architecturalpress.com Typeset by Newgen Imaging Systems (P) Ltd., Chennai, India Printed and bound in Great Britain by Biddles Ltd, King's Lynn, Norfolk Working together to grow libraries in developing countries www.elsevier.com | www.bookaid.org | www.sabre.org Contents Introduction 1 1 The structure of information 2 2 The general arrangement drawing 35 3 Component, sub-component and assembly drawings 61 4 Drawing the set 88 5 Working drawing management 113 Appendix 1 Building elements and external features 145 Appendix 2 Conventions for doors and windows 148 Appendix 3 Symbols indicating materials 150 Appendix 4 Electrical, telecommunications and fire protection symbols 152 Appendix 5 Non-active lines and symbols 156 Appendix 6 Glossary of CAD terms 158 Index 161 v This page intentionally left blank Introduction This book had its origins in the series of articles of the It had been hoped at the outset to illustrate the book with same name published in the Architects’ Journal in 1976 actual drawings taken from live projects, but for various and 1977. My thanks are due therefore to my fellow reasons this proved to be impracticable. Invariably the contributors to that series, Patricia Tutt, Chris Daltry scale was wrong, or the drawing was too big, or was too and David Crawshaw, for many stimulating discussions profusely covered with detail irrelevant to the immediate during its production, and to the Architects’ Journal for purpose. In the event the drawings in the book have allowing me to reproduce material from it. The text of been drawn for it especially, or have been redrawn for it the first edition, however, was completely rewritten, from source material provided by others. My thanks for and responsibility for the views expressed and providing such material are due to Messrs Oscar Garry recommendations made therein were mine and Partners, the Department of Health and Social alone. Security, Messrs Kenchington Little and Partners, Autodesk Ltd and the Property Services Agency. Thanks The development of CAD since publication of the are also due to The British Standards Institution, The third edition has led to a major revision and up-dating Royal Institute of British Architects, and the Construction to include details of the application of the latest Project Information Committee for permission to use CAD techniques to the whole field of production material for which they hold the copyright. drawings. This has led to the introduction as collaborator of Andrew Bichard, the well-known A final caveat: the illustrations have been selected – architect and writer on CAD topics, who is an indeed, in many instances devised – solely for their acknowledged leader in the field. He has written the function in illustrating points made in the text, and are sections on CAD, and in particular all the CAD not presented as working details to be used for any drawings have been produced by him. other purpose. 1 CHAPTER The structure of information No one who has delivered drawings to site and overhead 1 ● the foreman’s jocular reference to a ‘fresh set of comics having arrived’ will deny that the quality of architects’ working drawings in general is capable of improvement. omissions—items of information accidentally missing ● poor presentation—(i.e. the drawing or set of drawings was complete but confusing to read). In some measure we have all of us suffered more or less justifiable accusations of inaccuracy, inadequacy and incomprehensibility; and yet drawings are prepared and issued with the best of intentions. Few offices deliberately skimp the job, despite economic pressures and time constraints, for the consequences of inadequate or incorrect information being passed to the builder loom frighteningly behind every contract. We do our genuine best, and still things go wrong which might have been avoided; still information is found to be missing, or vague, or incorrect (1.1). The UK Building Research Establishment paper ‘Working Drawings in use’ lists a depressing number of defects which the authors found giving rise to site queries. Those defects included: Analysis of this list suggests that the defects spring from different causes—some from an inadequate understanding of the user’s needs, some from an undisciplined approach to the problems of presenting a complex package of information, and some from faulty project management procedures. That the problems seem to arise more frequently in relation to architects’ drawings than to those of other disciplines merely illustrates how the difficulty is compounded by the complicated nature of the architect’s work and the diversity of the information they have to provide. The structural engineer need only adopt a simple crossreferencing system to enable him to link any structural member back to a general arrangement drawing; but for an architect economically to give precise and simply uncoordinated drawings—(i.e. information from understood directions about, say, a door set—involving a different sources found to be in conflict) range of variables which include door, frame, architrave, ● errors—items of information incorrect finishes, materials and ironmongery—a communications ● failures in transmission—(i.e. information produced method of some complexity will be required. Where is and available but not put in the right hands) such a method to be found (1.2)? ● 2 The structure of information 1.1 Hellman’s view of the problem Problems of communication ● comprehensive and sufficiently detailed for its purpose The Handbook of Architectural Practice and Management (published by the Royal Institute of British ● easily retrievable from the mass of other information with which, inevitably, it will be combined. Architects) points out, ‘As with all technical communication, the user’s needs are the primary It is the purpose of this book to consider these four consideration’. Whoever the user is—and the users of a requirements in detail and hopefully to propose set of drawings will be many and various—he has the techniques for satisfying them. right to expect that the information given to him will be: There is a fifth and fundamental requirement, of course. ● an accurate record of the designer’s intentions The information conveyed must be technically sound; ● clearly expressed and easily understood if this is not the case then all the careful draughting and 3 Working Drawings Handbook 1.2 House at Gerrards Cross by A. Jessop Hardwick, c. 1905. A typical working drawing of its era, in both its draughting techniques and its obsessive use of every inch of the drawing sheet (RIBA Drawings Collection) 4 The structure of information cross-referencing will not be sufficient to prevent disaster. ● a source for the preparation of other documents This aspect, however, lies outside the scope of the present ● a statement of intent for the purpose of obtaining book which must concern itself only with the adequate documentation of technical decisions made at an earlier statutory consents ● stage. In RIBA Plan of Work terminology, the decisions belong to stage E; their documentation belongs to stage F. The plan of work a framework for establishing nominated subcontractors or suppliers ● a source for the preparation of shop drawings ● a shopping list for the ordering of materials ● a construction manual ● a model for developing the construction programme ● a supervising document Since what we shall be looking at is in effect a series of ● a record of variations from the contract disciplines, and since the plan of work is the overriding ● a base document for measurement of the completed discipline into which the working drawing process is works and preparation of the final accounts integrated, it is probably worthwhile reminding ourselves ● a base document for defects liability inspection of it at the outset. Table I of the outline plan of work is ● a record of the completed structure given here in its entirety. ● a source of feedback. Frequent reference to the plan of work will be made in this book, for it is important that stage F production drawings should be seen in the context of the whole architectural process, forming the vital link between the designer’s intention and the builder’s execution of it. The successful implementation of many of the techniques to be dealt with here will depend upon proper procedures having been carried out at earlier stages, whilst the whole raison d’ être of the drawing set lies in the stages following its production. It will be noted that the majority of these uses involve the contractor and clearly his needs are paramount, if only for the purely legal reason that it is he who will be contractually committed to the employer to build what the architect tells him to. They may be separated into three main activities and any drawing method must satisfy all three if it is to prove viable. Activity 1: The procurement of all necessary materials and components. For this the contractor will need the following information in a form in which it can be The users There are many users of a set of drawings and each may put it to more than one use. Unless the set is to be redrawn expensively to suit the ideal requirements of each, priorities must be established and compromises accepted. Consider the following functions of a set of drawings (the list is by no means exhaustive). identified readily and extracted for ordering purposes: A specification of the materials to be used, which can be referred back simply to the drawings and the bills of quantities. Drawings and schedules of all components which he is to provide (doors, windows, etc.) and which constitute measured items in the bills of quantities. Drawings and schedules from which outside It forms for different people and at different times: manufacturers’ products may be ordered and which provide design criteria against which manufacturers’ ● a basis for tendering (‘bidding’ in USA) ● a contractual commitment shop drawings may be checked. 5 Working Drawings Handbook Table I The RIBA Plan of Work Feasibility A Appraisal Identification of client’s requirements and of possible constraints on development. Preparation of studies to enable the client to decide whether to proceed and to select the probable procurement method. B Strategic Briefing Preparation of Strategic Brief by or on behalf of the client confirming key requirements and constraints. Identification of procedures, organisational structure and range of consultants and others to be engaged for the project. Pre-construction period C Outline Proposals Commence development of Strategic Brief into full Project Brief. Preparation of Outline Proposals and estimate of cost. Review of procurement route. D Detailed Proposals Complete development of the Project Brief. Preparation of Detailed Proposals. Application for full Development Control approval. E Final Proposals Preparation of Final Proposals for the project sufficient for coordination of all components and elements of the project. F Production Information F1 Preparation of production information in sufficient detail to enable a tender or tenders to be obtained. Application for statutory approvals. F2 Preparation of further production information required under the building contract. G Tender documentation Preparation and collation of tender documentation in sufficient detail to enable a tender or tenders to be obtained for the construction of the project. H Tender Action Identification and evaluation of potential contractors and/or specialists for the construction of the project. Obtaining and appraising tenders and submission of recommendations to the client. Construction period J Mobilisation Letting the building contract, appointing the contractor. Issuing of production information to the contractor. Arranging site hand-over to the contractor. K Construction to Practical Completion Administration of the building contract up to and including practical completion. Provision to the contractor of further information as and when reasonably required. L After Practical Completion Administration of the building contract after practical completion. Making final inspections and settling the final account. The Work Stages into which the process of designing building projects and administering building contracts may be divided. (Some variations to the Work Stages apply for design and build procurement.) Published by RIBA 1998. By permission of RIBA 6 The structure of information Activity 2: The deployment of plant and labour. For this moving between different offices. Nothing is more he will need: disruptive for architect, estimator and contract manager alike than to have to switch constantly from one working Drawings showing the extent of each trade’s involvement. method to another. A ‘construction manual’ describing, by means of annotated drawings, the way in which each trade is to operate and It was with this in mind that the Project Information which is explicit enough to ensure that no local querying Group (commonly known by its somewhat unfortunate or decision-making will be necessary. acronym) was set up to identify more precisely the An objective and realistic description of the quality standards required and the methods to be employed. Activity 3: The preparation of a programme and decision on a method of operation. For this he will need: reasons for the inadequacies in building information previously noted. In the course of time the Group became transmuted into the Construction Project Information Committee, upon which the main building professional and contracting organisations are represented and which in 2003 Drawings giving an overall picture of his commitment. published a sequence of Co-ordinated Project Information Comprehensive information about the constraints of site, (CPI) documents. These represent what is to date the access and programme. A summary of his contractual obligations. most comprehensive statement of intent regarding the achievement of better production information. Among other aspects they acknowledge the concept of The need for a unified system drawings, specifications and bills of quantities, together forming the complete information package, and despite What we are looking for is a complete information the existence of ingenious alternative methods which system which will satisfy these different user have been devised for particular situations it is not the requirements and which will be at the same time: intention of this book to disturb that long-standing tripartite relationship. ● reasonably simple and economical to produce ● simple to understand and to use at all levels Consideration will be given in a later chapter to what ● flexible enough to embrace information produced by information sometimes given on drawings may be more various offices—structural, M & E, etc. appropriate to the specification; but other than that this capable of application to both small and large book will concern itself solely with drawings, regarding projects them as the base documents in the information package appropriate for use in both small and large producing which it is the role of the specification to amplify, the bills offices. to quantify (1.3). ● ● The importance of the two latter points tends to be underestimated. Given a standard method of procedure The structure of working drawings a common experience is gradually built up, not only among contractors but among assistants moving from Every set of working drawings consisting of more than one project to another within the office, or indeed one sheet is structured, for it represents a more or 7 Working Drawings Handbook 1.3 Drawings, specification and bills of quantities. Each has a clearly defined role in the building package less conscious decision on the part of the Regulations for the erection of a garage is likely to draughtsman to put certain information on one sheet contain a small-scale plan showing the site in relation to of paper and certain other information on others. the surrounding neighbourhood as well as a Even were the reason for doing so simply that there dimensioned plan of the building itself. This in effect is insufficient space on a single sheet of paper, a acknowledges the existence of some informational selection has still to be made of what to put on each hierarchy within which certain different aspects of sheet and a sensible basis for that division has to be instruction about the building may sensibly be given in determined. different places and in different ways (1.4). Indeed, the simplest of single sheet applications to a In the following pages we shall be not so much seeking local authority for approval under the Building to impose a method of doing this as seeking out the 8 The structure of information 1.4 Detail from an early example of elementalisation. Drainage plan by James Adam, c.1775 (RIBA Drawing Collection) structure inherent in the whole concept of building information, and trying to reflect it in the form that the information package will take. What, where and how? The information that an operative needs to know about each element of the building he is called upon to construct may be classified into three distinct types: Let us start our search at the point where the ultimate end product of the entire communications exercise is to be found—the building site. 1 He needs to know what it is that he has to install or erect. Whether it be a window frame, brick or cubic 9 Working Drawings Handbook metre of concrete, he needs to know certain informa- The amount of information required so that the description tion about its nature and physical dimensions. of any aspect of the building will be unambiguous must 2 He needs to know where it is to be placed. This always be a matter for intelligent consideration. The demands pictorial and dimensional information strength and density of bricks forming footings below regarding its relationship to the building as a whole. ground level, for instance, will be fit subjects for precise 3 He needs to know how it is to be placed or fixed in description, whereas their colour will not. relation to its immediate neighbouring elements. But two fundamental principles emerge which will be Clearly, these three questions—what, where and how— are fundamental to the business of building communications, and demand a variety of replies in practice if they are to be answered satisfactorily and without ambiguity. It may be useful to reflect for a moment on the degree of depth and comprehensiveness that may be required of these answers. If the designer has devised a precise solution to the building problem set him by his client, then the information to be conveyed to the builder must be of sufficient detail to enable the unique nature of that solution to be appreciated and converted into physical building terms by a variety of people, most of whom will be unfamiliar with the original problem and unaware of the chain of thought processes which has given rise to its solution. So if we are dealing with a window, the single question— What window?—may proliferate into a large and varied found to hold good at all times. 1 All building information may be classified into three basic categories, depending upon which of the three basic questions—how, where and what—it purports to answer. 2 All building information is hierarchic in its nature and proceeds from the general to the particular. This latter observation requires some discussion, because the sequence in which the three questions which were posed at the start of this section emerge may suggest that the seeker after information starts with the component and its nature and then works outwards to a consideration of where and how to install it. This sequence is in fact occasionally true—the window manufacturer, for example, would tend to consider the type of window he was being called upon to make before determining how many of them were in the building and how they were distributed throughout it. series: what are its overall dimensions; what does it look But in general terms the reverse is true. Almost every user like; what material is it made from; what is its glass of the information package will wish to know that there is a thickness; what furniture does it have; what are its wall of finite dimensions with windows in it which forms the finishes? These and many other questions will arise outer boundary of the building, before seeking to from consideration of the nature of a single component. determine the various forms that the windows might take or the precise nature of the bricks and their pointing. Similarly we need to know where in the building it is to be installed, implying the need for dimensional Since this is also the manner in which the designer will information in three planes; and how it is to be logically work, there is little difficulty, and every installed—how it sits in relation to the lintel above it, how advantage, in devising a system in which the search for it relates to the vertical DPCs in the adjacent wall information starts with the question Where? The answer cavities, how many fixing points are required and what is to this question indicates where the answers may be the nature of their fixing. And so on. found to the supplementary questions What? and How? 10 The structure of information Primary structuring—by information type What has been outlined is a method of primary ● Component information, answering the question: what is the component like? ● Assembly information, answering the question: how structuring of information according to its type, and are the various components to be related one to which may be summarised and named as follows: another—how are they to be assembled? This type of structure and the search pattern it ● Location information, answering the questions: where generates is illustrated in (1.5). It is to be noted that the are components to be built or installed and where CPI recommendations adopt a similar method of further information about them may be found? classification, the only difference being that location 1.5 The fundamental search pattern generated by the questions What?, Where? and How? 11 Working Drawings Handbook drawings are termed ‘general arrangement drawings’. Nevertheless, they have a role to play and used sensibly The term ‘location drawing’ has long been established and with forethought they form an essential element in within the architectural profession and the mnemonic the information package. SLAC (schedule, location, assembly, component) is in common use. Nevertheless, it seems likely that the CPI Some principles affecting scheduling terminology will become increasingly known and used. The term ‘general arrangement’ has in any case long Their primary function is to identify and list components been used in the engineering disciplines and has possessing common characteristics—e.g. windows, therefore been used throughout the remainder of doors, manhole covers, etc. this book. They should not attempt to provide comprehensive information about the component; they should serve Into this neatly classified system must now be rather as an index to where the relevant information introduced that somewhat hybrid creature, the may be found. schedule. It must be made clear at the outset that the term ‘schedule’ here referred to is confined to basic lists of information—primarily about components—which are more readily set out in this manner than on the drawings. (The Schedule of Works, as envisaged in the CPI documents for smaller projects, has a different function, more akin to the bills of quantities.) They should initiate a simple search pattern for the retrieval of component, sub-component and assembly information. They are only worth providing if the component in question has more than one variable. For instance, if you have windows of three different sizes which are identical in every other respect, then size is the only variable and you may as well write ‘Window Type 1’ on the general arrangement plan as ‘Window no. 1’. But if each window size may be fixed into either a brick wall or The idea of using written schedules, or lists of a pre-cast concrete panel then the assembly information information, exists in most information systems and has required is a second variable. its source in a variety of motives, not all of them Window Type 1 may be combined with jamb detail type 1 necessarily valid. It is assumed that they are economical or type 2, and it is for this greater degree of complexity of drawing office time; that quantity surveyors, that it is preferable to prepare a schedule. contractors and suppliers alike all welcome them; and that they provide a ready check that the information conveyed is comprehensive. The great virtue of the schedule is that it can direct you to a vast amount of information about a given These reasons do not always stand up to close component in a way that would be impossible by any examination. Schedules are only economical if they are system of direct referencing from a general arrangement simpler than the drawings they replace; the architect drawing. Consider a window—thirty-seventh, shall we should not necessarily be doing other people’s jobs for say, of fifty-one on the second floor of a multi-storey them; suppliers more often than not produce their own block of offices. The method chosen for giving it a schedules because the architect’s schedule is not in a unique reference is unimportant for the moment—W2/37 form which they find usable; and some schedules is as good a piece of shorthand as any for the attempt to provide so much information in so purpose—but it is obvious that this simple means of complicated a form that mistakes and omissions identification may be shown equally on a drawing or a readily occur. schedule (1.6). 12 The structure of information Thus, there are two ways of providing a catalogue of the windows on the job, in which W2/37 is seen to take its place between W2/36 and W2/38. But if we were now to add to the drawing a fuller description of what W2/37 in fact consists of, then we should meet an immediate difficulty—there is just not space to do it (1.7). Consequently, when it is considered that the information given only scratches the surface of what the recipient really needs to know and that similar information will need to be provided about W2/1 to W2/50—to name but the windows on the second floor—it becomes apparent that not only will there be insufficient room on the 1.6 Simple identification of components may be recorded on either a schedule or general arrangement plan drawing to make this method feasible but there will be insufficient drawing office time and money available to make it an economic starter. The schedule does it so much better (1.8). Given the presence of schedules in the package, the search pattern given in (1.5) becomes simpler and more directly focused. The general arrangement drawing is still the starting point but now the searcher is directed from it to the schedule and from there to the various sources of assembly and component information (1.9). Further consideration will be given later to the most suitable format for schedules and 1.7 The general arrangement plan is an inappropriate medium for to the areas of information which lend recording the diverse characteristics of each component. Detail of this themselves most readily to scheduling. order can only be given elsewhere—in a specification or in other All that remains to be settled for the moment drawings to which the schedule points the way is what sort of an animal this hybrid most resembles. Is it a drawing or some other form of document? If a drawing, then what type of drawing is it? 13 Working Drawings Handbook 1.8 The schedule provides a simple and economical index to a variety of information towards assembly drawing, general arrangement drawing, specification, trade literature and, possibly, the bills of quantities. If considered as a drawing then it clearly possesses all the directive qualities of a general arrangement drawing. But it will inevitably be of a different nature—and indeed size—from the other general arrangement drawings in the package, and its status as such puts it in an anomalous situation when used in conjunction with other documents—as an adjunct to the bills of quantities, for example. Maximum flexibility in use is therefore achieved by acknowledging the hybrid nature of the schedule for what it is and by treating it as an independent form of document in its own right, capable equally of being bound into a set of drawings or into a specification. The package is nearly complete. However, it requires two further categories of drawing to render it entirely 1.9 The fundamental search pattern of 1.5 now comprehensive. They may be dealt with quite quickly. runs through the schedule In practice it does not really matter provided that all the implications of your choice have been fully considered and that having made your decision you are consistent in sticking to it. Sub-component drawings: First, it will become desirable at times to illustrate how a component itself is made. The frame sections of a timber window, for example, are often better shown separately from the drawing showing the window itself, for they may well be applicable to a The schedule’s function is primarily that of an index and number of windows whose overall sizes and as such it will at different times direct the searcher appearances are widely different. Yet to term the drawing 14 The structure of information The complete primary structure: The complete primary structure is summarised in (1.12). It is worth noting that this complete drawing package, which has to be all things to all men, is now capable of sub-division into smaller packages, each of which is tailored to suit the needs of the individual recipient. The bricklayer needs to know the position and size of the window he has to install, but has no interest in the manner in which it is made in the joiner’s shop. Similarly, the local authority will not require the complete set of drawings for approval (even though the extravagant demands of certain Building Control officers in this respect may induce in frustrated practitioners a somewhat cynical smile at this statement). With occasional exceptions, however, the drawing set 1.10 The sub-component drawing illustrates how the may be used as shown here, with attendant advantages component itself is made of order and economy. The focal position of the schedule is well demonstrated. showing these sections a ‘component drawing’ is Secondary structuring inaccurate, as well as being potentially confusing. In the The good old-fashioned working drawing floor plan— hierarchy of information it is clearly one step lower and ancestor of the general arrangement plan and aimed at more detailed. embracing every piece of information necessary for the erection of the building—still survives in places but its It is, in fact, a sub-component drawing and there is a defects are now so generally recognised that it is place for it as such in the set (1.10). possibly unnecessary to spend much time in demonstrating them. Figure 1.13, taken almost at Information drawings: Second, there is a class of random from such a drawing, shows the disadvantages. drawing which conveys information, not so much about the building and its elements as about the building’s The sheet is cluttered with information, making it background. Such matters as the site survey, records of extremely difficult to read. The notes and references fill adjoining buildings, light envelope diagrams, bore hole every available corner, and in an attempt to crowd too analyses, all fall into this category. They have this much information into too small a compass the feature in common, which distinguishes them from the draughtsman has had to resort to a lettering style of other drawings in the package, that they convey microscopic dimensions. Any alteration to it would be information without giving instructions (1.11). (It should difficult both to achieve and to identify. (Figure 1.2 also be noted that a cross-section of the building such as is illustrates the defects inherent in the ‘one drawing’ shown in (3.16) in Chapter 3, and condemned there as approach.) conveying little constructional direction to the builder, might nevertheless form a useful information drawing for This is a case of one drawing attempting to do the work anyone planning a building programme.) of several, and simplicity, legibility and common sense 15 Working Drawings Handbook 1.11 Typical information drawing—this record of bore hole findings provides the contractor with useful background information but gives no instructions about the building would all be better served if there were several drawings an overstretched profession and building industry, and a to replace it. Let us consider the various ways in which growing awareness of the inefficiency and waste of time the crowded information might be distributed. on building sites being caused by inadequate documentation. Not all these systems were at that time The Department of the Environment Report, ‘Structuring sufficiently well tested to allow a genuine evaluation of Project Information’ lists no fewer than nine separate their merits. non-traditional systems that include in their make-up some degree of information structuring. The 1970s and Now, some twenty years later, we are in a better position 1980s saw a widespread and largely uncoordinated to obtain a proper perspective of the field, and the experimentation in building communications techniques, problem becomes somewhat clearer. Some of the generated by an increasing demand on the resources of communications systems then presenting themselves for 16 The structure of information different materials. To some extent the specification does just that, describing with precision the type of sand, the type of cement and the size of aggregate to be used, as well as describing their admixture into concrete (the point at which the bills of quantities take an interest). You may look at it, on the other hand, as a series of different trade activities, in which case you would tend to regard as one package of information all work done by the carpenter and as another package all work done by the plumber. Bills of quantities have traditionally been structured on these lines, the concept lying at the heart of the Standard Method of Measurement. It 1.12 The complete primary structure of building drawings information has been one of the primary tasks of the Construction Project Information Committee in its development of the Common Arrangement of Work consideration are now seen to be so closely associated Sections to seek out a rational with the requirements of specific organisations or method of terminology for building constructional systems that they lack universal operations that would be acceptable applicability. Others, reliant upon a more radical to all the building disciplines. refashioning of the bills of quantities than is envisaged here, offer possible pointers to the future and are In drawing terms, however, neither discussed later. the materials-based nor the activitybased sub-division relates very All accept the primary structuring of drawn information happily to the architectural realities. represented in this book by the general arrangement/ To the quantity surveyor one cubic assembly/component format. Where they tend to diverge metre of concrete may be very like is in their approach to secondary structuring and their another but when one forms part of methods of identifying and coding it. the foundations and another part of the roof slab, it is over-simplistic to The building operation and indeed the completed suggest that both should form part of building, may be considered in a number of ways. You a series of ‘concrete’ or ‘concretor’ may regard it, for example, as an assemblage of drawings. 17 Working Drawings Handbook 1.13 Drawing attempting to show everything ends up by showing nothing very clearly (original scale 1:50) 18 The structure of information Drawings are by definition concerned with the perceived It should be noted that the drawings illustrating this have form of the building and if we are to sub-divide them been prepared using CAD. In most offices the decision then a breakdown into the different elements of their on whether small drawings such as these are drawn by form is more logical than an attempt to classify them by hand or by computer will hinge, as here, on the either material or trade sub-divisions. (A criticism that complexity, longevity and distribution of the information may be levelled at the Uniclass Table G—Elements for to be conveyed, and the number of CAD seats available buildings—is that it is too much oriented towards in the office. In practice, the illustrations shown here, materials and procedures; a defect that is largely while small in themselves, show part of a much larger avoided in the simpler provisions of CI/SfB Table I). complex and the question of drawing them manually never really arose. Both systems of classification co-exist in the profession at the present time and are dealt with later in this chapter. Structuring by building element In the meantime let us return to the cluttered example Within the framework of a primary structuring by shown in (1.13) and separate it into three elements information type, the information to be shown is sub- chosen at random, collecting information about the walls divided by building element and this constitutes the on one drawing, floor finishes on another and the doors secondary structuring of the drawing set. on a third (1.14, 1.15 and 1.16). To establish the possible means of achieving this we At once we can see what we are doing. The notes and should start by looking at the various ways in which the references to other drawings are relatively few and building fabric may be regarded. Consider the diagram sparsely distributed, so that they catch the eye, and in (1.19). plenty of space is left for further annotation should this become desirable during the course of the project. Furthermore, to anyone who knows how this particular set of drawings is sub-divided the search pattern for any aspect of the building is straightforward. If someone wants to know about windows they can go straight to the general arrangement drawing dealing with windows, from which point the search pattern described previously can proceed within the narrow confines of window information. The general search pattern, shown diagrammatically in (1.17) now follows a series of paths, each related to a specific aspect of the building (1.18). It is difficult to visualise any space-enclosing structure, no matter how primitive, which does not possess elements falling within one or other of the four categories shown. A little thought, however, will suggest that this is an oversimplification, and that a minimal subdivision of elements would look much more like (1.20). The elements here have one common feature—they are all structural. We may introduce other elements but it is apparent that then we are setting up another hierarchy of information analogous to the hierarchy established when considering types of information (1.21). Coding the set The advantages of this are two-fold. In the first place the It is one thing to recognise the existence of this designer now has a framework upon which to display his hierarchy and another thing altogether to set it down in information; in the second place the user has an simple and universally acceptable terms. The trouble authoritative guide through the informational labyrinth. with hierarchic systems—in building communications as 19 Working Drawings Handbook 1.14 Elemental version of 1.13 dealing with walls—(21) 20 The structure of information 1.15 Elemental version of 1.13 dealing with floor finishes—(43) 21 Working Drawings Handbook 1.16 Elemental version of 1.13 dealing with doors and windows—(31) 22 The structure of information 1.19 The simplest possible division of building 1.17 The fundamental search pattern structure 1.20 Sub-division of building into structural elements 1.18 Search pattern running through different building elements most appropriate to his purpose. So we are looking for a method of elementalising the building which fulfils the in politics—is that they tend to be complex, difficult to following requirements: understand and self-defeating when applied too rigidly. Their great advantage—in building communications at ● It should be simple to understand any rate—is that they offer the user access at the level ● It should be universally applicable 23 Working Drawings Handbook Uniclass Table G This is the system set out in the 2003 CPI Code of Procedure, and as such has the advantage of being consistent in its terminology with the Common Arrangement of Work Sections. (The National Building Specification operates under the Common Arrangement.) Having said that, it should be pointed out that the Uniclass headings relate to building elements, while the Common Arrangement is specifically materials-oriented. Uniclass Table G (Table II) is an attempt to reconcile these divergent objectives, but in essence is simply a tabulation and naming of the elements forming the secondary structure of a set of drawings. 1.21 Further sub-division of the fabric leads to increasing complexity You will note that the table is broken down into the following primary elements: ● It should operate on a number of levels, permitting G1 Site preparation greater or less sub-division of information depending G2 Fabric: complete elements upon the size and complexity of the building in G3 Fabric: parts of elements question. G4 Fittings/furniture/equipment (FFE) G5 Services: complete elements Home-made systems G6 Services: parts of elements G7 External/site works It is not difficult to devise your own systems to meet these requirements. Indeed, in practice many offices do, varying the method each time to suit the complexity of the job in hand. Within the primary general arrangement/assembly/component framework, for instance, it is possible to divide the drawings on a These generic headings clearly require sub-division if they are to be of use in coding the drawings. Consequently, there is a second level of headings, of which the 57 main sub-headings are broken down into further sub-divisions. To take two instances at random: small project into, say, brickwork (series B), windows (series W), doors (series D), etc. The precise method of G251 External walls is seen to break down into: sub-division and of coding is of less importance than recognising the existence of an inherent primary and secondary structure. G311 Core fabric G312 Coverings/external finishes to external walls There are two generally accepted methods, however, which despite certain defects will, if adopted, fulfil most of the requirements enumerated above. 24 G321 External windows G322 External doors G333 Internal finishes to external walls The structure of information Table II Uniclass Table G Elements for buildings G G1 Site preparation G11 Site clearance G12 Ground contouring G13 Stabilisation G2 Fabric: complete G21 :G311 Foundations elements (foundations consist entirely of core fabric) G22 Floors G221 Lowest floors :G311 Core fabric :G331 Floor finish to lowest floors 1 Direct 2 Raised floor G222 Upper floors :G311 Core fabric :G331 Floor finish to upper floors 1 Direct 2 Raised floor :G332 Ceillings/soffit finishes to upper floors 1 Direct 2 Suspended G23 Stairs Balustrades are at G251 and G252. However, if preferred, balustrades to stairs/ramps may be included here. :G311 Core fabric :G33 Stair finish 11 Top 21 Soffit G24 Roofs :G311 Core fabric :G312 Roof coverings :G321 Roof lights :G332 Roof soffit finishes/ceilings to roofs 1 Direct 2 Suspended :G34 Roof edges Includes parapets, gutters, etc. Rainwater downpipes are at G5812. :G25 G251 External walls Walls Includes external balustrades. :G311 Core fabric :G312 Coverings/external finishes to external walls :G321 External windows 25 Working Drawings Handbook Table II (continued) Elements for buildings G :G322 External doors :G333 Internal finish to external walls G252 Internal walls and partitions Includes internal balustrades. :G311 Core fabric :G321 Internal windows :G322 Internal doors :G333 Internal finish to internal walls G26 Frame/isolated structural members :G311 Core fabric :G334 Frame finish Where separate from ceiling and wall finishes. G3 Fabric: parts of elements G311 Core fabric G31 Carcass/structure/fabric :G21 Foundations (foundations consist entirely of core fabric) :G221 Core fabric of lowest floors :G222 Core fabric of upper floors :G23 Core fabric of stairs :G24 Core fabric of roofs :G251 Core fabric of external walls :G252 Core fabric of internal walls G312 Coverings/external finishes :G26 Core fabric of frame :G24 Coverings of roofs :G251 Coverings/external finishes to external walls G321 Windows G32 Openings :G24 Roof lights :G251 External windows :G252 Internal windows G322 Doors :G251 External doors :G252 Internal doors G33 G331 Floor finishes Internal finishes 1 Floor finishes, direct :G221 To lowest floors :G222 To upper floors :G23 To stairs 2 Floor finishes, raised :G221 To lowest floors :G222 To upper floors G332 Ceilings/soffit finishes 1 Ceilings/soffit finishes, direct :G222 To upper floors :G23 To stairs :G24 To roofs 2 Ceilings/soffit finishes, suspended 26 The structure of information Table II (continued) Elements for buildings G :G222 To upper floors :G24 G333 Wall internal finishes To roofs :G251 To external walls :G252 To internal walls G334 Other internal finishes :G26 Frame finishes Where separate from ceiling and wall finishes. G34 Other parts of fabric :G24 elements Roof edges Includes parapets, gutters, etc. Rainwater downpipes are at G5812. G4 Fittings/furniture/ equipment (FFE) G41 Circulation FFE G42 Rest, work FFE G43 Culinary FFE G44 Sanitary, hygiene FFE G45 Cleaning, maintenance FFE G46 Storage, screening FFE G47 Works of art, soft furnishings 1 Works of art G48 Special activity FFE Classify with reference to 2 Soft furnishings Table D Facilities. G49 Other FFE G5 Services: complete G50 Water supply elements For mains water supply see G751. Classify parts with reference to Section G6, e.g.: G50:G61 Energy generation/ storage/conversion for water supply G50:502:G632 Pipework for water supply G502:G632 Pipework for hot water supply 1 Cold water 2 Hot water 9 for special activity Classify with reference to Table D Facilities. G51 Gas supply For mains gas supply see G754. Classify parts with reference to Section G6, e.g.: G51:G632 Pipework for gas supply G52 Heating/ventilation/air conditioning (HVAC) Classify parts with reference to Section G6, e.g.: G52:G61 Energy generation/ storage/conversion for HVAC 27 Working Drawings Handbook Table II (continued) Elements for buildings G G52:G631 Ductwork for HVAC 1 Heating 2 Heating ⫹ non-cooling air conditioning 3 Heating ⫹ cooling air conditioning 4 Ventilation 1 Supply and extract ventilation 2 Extract ventilation For smoke extraction/control see G5723 9 For special activity Classify with reference to Table D Facilities, e.g.: G529:D73 Special HVAC services for laboratories G53 Electric power For electric mains see G755. Classify parts with reference to Section G6, e.g.: G53:G61 Energy generation/ storage/conversion for electric power 1 General purpose outlets 2 Supply to service installations 9 For special activity Classify with reference to Table D Facilities. G54 Lighting For outdoor lighting see G761. Classify parts with reference to Section G6. 1 General lighting 2 Emergency lighting 9 For special activity Classify with reference to Table D Facilities G55 Communications Classify parts with reference to Section G6 1 Public address 2 Visual display 3 Radio 4 TV 5 Telephones 6 Computer networks 9 For special activity Classify with reference to Table D Facilities, e.g.: G559:D 14 Special communications services for air transport 28 The structure of information Table II (continued) Elements for buildings G G56 Transport Classify parts with references to Section G6. 1 Lifts/hoists 2 Escalators 3 Conveyors 4 Travelling cradles 9 For special activity Classify with reference to Table D Facilities, e.g.: G569:D284 Special transport services for industrial warehouses (including mechanical handling systems) G57 Protection Classify parts with reference to Section G6. 1 Security 1 Entrance controls 2 Intruder/security alarms 2 Fire 1 Fire/smoke alarms 2 Fire fighting and sprinkler installations 3 Smoke extraction/control installations 3 Other protection 1 Lightning protection 9 For special activity Classify with reference to Table D Facilities. G58 Removal/disposal Classify parts with reference to Section G6. 1 Drainage 1 Foul drainage 2 Surface water drainage Includes rainwater downpipes. Gutters are at G24:G34. 2 Refuse disposal 9 For special activity Classify with reference to Table D Facilities. G59 Other services elements G6 Services: parts of elements For mains supply see G75. Classify sound attenuation for services elements with the appropriate part in the list below. 29 Working Drawings Handbook Table II (continued) Elements for buildings G For example classify sound attenuation for distribution elements at G63. G61 Energy generation/storage/ conversion Classify the complete elements to which these parts belong with reference to Section G5, e.g.: G61:G50 Energy generation/ storage/conversion for water supply G61:G52 Energy generation/ storage/conversion for HVAC G61:G53 Energy generation/ storage/conversion for electric power 1 Heat output 1 Heat generation i.e. boilers (including fuel storage), solar collectors. 2 Heat conversion i.e. calorifiers, heat exchangers, 2 Electricity output 1 Electricity generation i.e generators, turbines, photovoltaic cells. 2 Electricity conversion i.e. transformers, convertors. 3 Cooling output 4 Combined heat/power/cooling G62 Non-energy treatment/ storage Classify the complete elements to which these parts belong with reference to Section G5. G63 Distribution Classify the complete elements to which these parts belong with reference to Section G5, e.g.: G631:G52 Ductwork for HVAC G632:G50 Pipework for water supply G632:G51 Pipework for gas supply 1 Ductwork 2 Pipework 3 Cables 4 Pumps 5 Fans G64 Terminals Classify the complete elements to which these parts belong with reference to Section G5. 30 The structure of information Table II (continued) Elements for buildings G G65 Package units Classify the complete elements to which these parts belong with reference to Section G5. G66 Monitoring and control Classify the complete elements to which these parts belong with reference to Section G5. G69 Other parts of services elements G7 External/site works G71 Surface treatment 1 Hard surfaces 2 Landscaping G72 Enclosure/division 1 Fencing/walling/hedges 2 Retaining walls G73 Special purpose works 1 Water features, pools 2 Shelters, minor buildings 3 Bridges, underpasses 9 Other G74 Fittings/furniture/equipment G75 Mains supply 1 Water mains 2 Fire mains 3 Hot water/steam mains 4 Gas mains 5 Electric mains 6 Communications cable mains G76 External distributed 1 Lighting services 2 Other G77 Site/underground drainage In this table the combined codes under each main element have been abbreviated for the sake of clarity of presentation. For example, at G24 Roofs, the entry ‘:G312 Roof coverings’ is an abbreviation for ‘G24:G312 Roof coverings’. The full codes should be used when quoting Uniclass codes. G252 Internal walls and partitions is seen to break classification of drawings unnecessarily complex. It will down into: no doubt be modified in the future, as its defects become tested in practice and found wanting. At the moment G311 Core fabric however it is possible to rationalise our approach to it: G321 Internal windows G322 Internal doors G333 Internal finishes to internal walls 1 The only possible justification for structuring a set of drawings is that it makes life easier for everybody to do so. The moment this ceases to be the case (and Clearly, the Uniclass system, in endeavouring to it would have to be a pretty small project for this to embrace the conflicting needs of draughtsman, specifier happen) the system becomes self-defeating and and quantity surveyor, renders its use for the you would be better off without it. 31 Working Drawings Handbook 2 When we talk of elementalising the drawings we are Such a division will probably be adequate for coding all in effect talking almost exclusively of the general but the very largest and most complicated projects. If it arrangement drawings. These are the only drawings should be found desirable however to deal separately which will be drawn elementally in the sense that the with, for example, doors and windows, the further sub- same floor plan, for example, may be shown several divisions G321 and G322 are available. times—either by CAD or manually—to illustrate the various elements contained within it. All other CI/SfB categories of drawing—assembly, component, An alternative method is in existence which fulfils most of sub-component, schedule—may well fall within one the requirements of an elemental structuring system and or other of the elemental sub-divisions; but they will which has the advantage of being already well established be drawn uniquely and will appear only once in the within both the profession and the industry. This is the drawing set. CI/SfB method of classification, and while it has its 3 Although all the facets of Uniclass Table G are detractors, who legitimately point to certain weaknesses in available, like so many pigeon-holes, to receive the detail, it has so many advantages in logic and flexibility various drawings prepared, there is no particular that on balance it must be recommended. The CPI virtue in trying to use them all. In practice a very few documents accept it as a viable alternative to Uniclass will suffice, even for the larger projects. Never forget Table G, and consequently it will form the basis of most of the two-fold objective of this secondary structuring, the drawings illustrated in subsequent chapters. which is to provide both a disciplined framework for the draughtsman and a simple retrieval method for the seeker after information. A drawing set containing Its virtues are: ● a couple of drawings in each of some thirty elemental sub-divisions assists the achievement of neither. It is currently the most widely known and used of available classification methods. ● 4 Given a true understanding of the objectives It is comprehensive in its scope, offering opportunities for uniting the output of different common sense is the paramount consideration. disciplines into a common package. ● With this in mind Table G might well be simplified into: It is capable of operation at various levels of sophistication, making it suitable for both large and small projects. G1 Site preparation ● G21 Foundations G22 Floors G24 Roofs It is fully compatible with the Co-ordinated Project Information elementalised concept. ● It is compatible with the use of computer-aided draughting. G25 Walls G26 Frame The complete CI/SfB system is undoubtedly complex G32 Openings (though considerably less so than Uniclass Table G), G33 Internal finishes and some tend to shy away from it, frightened at the G4 Fittings/furniture/equipment prospect of having such a sophisticated sledge-hammer G5 Services G52 Heating/ventilation/air conditioning G54 Lighting G7 External works. to crack such small nuts as are the mainstay of the average practice. This is a pity, for that aspect of CI/SfB which is of greatest relevance to the drawing office is in fact of a disarming simplicity. (It is certainly less 32 Table III CI/SfB Table 1 (—)Project in general (1–) (2–) (3–) (4–) (5–) (6–) (7–) (8–) (9–) Substructure, Primary elements Secondary elements Finishes Services Services, Fittings Loose furniture External, piped, ducted electrical equipment other elements (50) (60) ground (10) (20) (30) (40) (70) (80) (90) External works (11) (21) (31) (41) Ground Walls, External Wall finishes, external walls wall openings external (22) (32) (42) (52) (62) (72) (82) Internal walls, Internal Wall finishes, Waste disposal, Power Rest, work Rest, work (12) (51) (61) (71) (81) Electrial Circulation Circulation, loose fittings equipment partitions wall openings internal drainage fittings loose equipment (13) (23) (33) (43) (53) (63) (73) (83) Floor beds Floors, galleries Floor openings Floor finishes Liquids supply Lighting Culinary Culinary loose fittings equipment (14) (24) (34) (44) (54) (64) (74) (84) Stairs, ramps Balustrades Stair finishes Gases supply Communications Sanitary, hygiene Sanitary, hygiene fittings loose equipment (25) (35) (45) (55) (65) Suspended ceilings Ceiling finishes Space cooling (15) (75) (85) Cleaning, Cleaning, maintenance fittings (91) (92) (93) (94) (95) maintenance loose equipment (16) (26) (36) (46) Retaining walls, (56) (66) (76) (86) Space heating Transport Storage, screening Storage, screening fittings loose equipment (67) foundations (17) (27) (37) (47) (57) Pile foundations Roofs Roof openings Roof finishes Air-conditioning, (18) (28) (38) (48) (58) (68) Other sub- Building frames, Other secondary Other finishes Other piped, Security, control, structure other primary elements to structure ducted services other services elements elements ventilation (96) (77) (87) Special activity Special activity (97) fittings loose equipment (78) (88) (98) Other fittings Other equipment Other elements (19) (29) (39) (49) (59) (69) (79) (89) (99) Parts of Parts of Parts of Parts of Parts of Parts of Parts of Parts of Parts of (11) to (19), (21) to (29), (31) to (39), (41) to (49), (51) to (59), (61) to (69), (71) to (79), (81) to (89), (91) to (99), cost summary cost summary cost summary cost summary cost summary cost summary cost summary cost summary cost summary 33 Working Drawings Handbook complicated than some home-made systems one has The codes are always bracketed, in the form (24), (27), encountered over the years.) (45), etc. Before looking at this aspect in detail, however, let us CI/SfB Table 1 is here given in its entirety (Table III): look briefly and without going into superfluous detail, at the whole range of the CI/SfB system of classification. The hierarchic structure is immediately apparent. There are five tables in the complete CI/SfB matrix: Within it each building element may be considered at any of three levels, the level selected being determined Table 0 deals with building types and its codes are always of the nature B1. Table 2 deals primarily with manufactured components. by the complexity of the project in question and the need to break down the conveyed information into categories of a manageable size. Any element within the Typical examples would be blockwork—blocks (code F), building—a lavatory basin, for example—may clearly be tubes and pipes (code I), or thin coatings (code V). The regarded as forming part of ‘The project in general (—)’. codes are always as shown, consisting of a single But it may also be considered as coming within the upper case letter. category of ‘Fittings (7-)’ (the seventh of the main Table 3 deals with basic materials, such as clay, dried sections into which the table is divided). Finally, it may fired (code g2), gypsum (code r2), or flame-retardant be regarded as coming within the quite specific grouping materials (code u4). It will be seen that when used of ‘Sanitary, hygiene fittings (74)’, the fourth sub-division with the codes of Table 2 they provide a method of of section (7-). shorthand for quite specific descriptions of components—such as blocks in lightweight aggregate Windows, in similar fashion, may be seen as coming Fp3, clay tiles Ng2, or plywood Ri4. within the (—), (3-) or (31) headings, terrazzo flooring as Table 4 deals with the various techniques involved in the (—), (4-) or (43). And so on. physical process of building, such as testing (Aq) or demolition (D2). The primary and secondary information structure is therefore complete and we are ready to move on to In terms of classification for drawing purposes however, detailed consideration of what each drawing should we need consider only Table 1 dealing with building contain and what it should attempt to convey to the elements—stairs, roofs, ceiling finishes, etc. recipient. 34 CHAPTER The general arrangement drawing The types of drawing which make up the complete 2 The general arrangement drawing set having now been identified, the following two chapters look at them in sequence to see the sort of The drawings falling into this category will normally information that each should contain. A brief reference include: must be made here, however, to the means of ● floor plans at all levels ● reflected ceiling plan at all levels ● roof plan ● foundation plan 1 Drawing them manually, by means of ink or pencil ● external elevations on tracing paper. Until relatively recently this was the ● general sections and/or sectional elevations only available method. ● site plan. producing them. There are two methods: 2 Drawing them electronically on a computer screen using a mouse and printing the result. This is Floor plans Computer-Aided Draughting which has so many There are three situations to consider: advantages that it is now in almost universal use in all but the smallest architects’ offices. ● General arrangement (location) drawing designed to show a single building element and what it should contain. Both techniques are dealt with in detail in Chapter 4. It is worth noting here, however, that the basic principles of ● The general arrangement drawing designed to be elementalising and organising the drawing set are complete in itself—i.e. a drawing which in CI/SfB virtually identical for each method. Table 1 terminology would be described as 35 Working Drawings Handbook 2.1 36 The basic plan from which the elemental drawings shown in Chapter 1 were produced (1.14, 1.15 and 1.16) The general arrangement drawing ● ‘The project in general’ and coded (--). (Clearly this items which more often than not get added to the type of drawing would only arise on the smallest and original needlessly and superfluously, to the subsequent simplest of projects.) inconvenience of everyone. The basic general arrangement drawing—the drawing which provides the fundamental and minimal To be included: information which will appear as the framework for each individual elemental plan. The basic drawing, in ● Walls fact, from which future drawings containing elemental ● Main openings in walls (i.e. doors and windows) information will be taken. ● Partitions ● Main openings in partitions (doors) Since the latter has a substantial bearing on the other ● Door swings two, it will be dealt with first. ● Room names and numbers ● Grid references (when applicable) ● Stairs (in outline) ● Fixed furniture (including loose furniture where its The basic floor plan Let us assume that you are to prepare a set of working drawings for a building project and that, by means of techniques to be discussed in a disposition in a room is in practice predetermined— later chapter, you have decided that the floor plans will e.g. desks set out on a modular grid, etc.) be divided into five elements in the following manner: (2-) Primary elements ● Sanitary fittings ● Cupboards ● North point. (3-) Secondary elements (5-) Services (piped and ducted) Items which tend to be included but should not be: (6-) Services (Electrical) (7-) Fittings. ● Dimensions ● Annotations The basic plan from which these elemental drawings will ● Details of construction—e.g. cavity wall construction be produced is shown (produced by CAD) in 2.1. ● Hatching or shading ● Loose furniture where its disposition is not General arrangement plans Whether the elemental plans are to be drawn by CAD or manually, you must predetermined ● Section indications. first consider what common features of the plan will need to appear in all five elementalised plans. It is The basic plan (2.1) gives an idea of what should be clearly important that the information carried by the base aimed at. Note that a uniform line thickness is used negative, (manual) or layers common to all drawings in a throughout and that this is the middle of the three line CAD set shall be (like the amount of lather specified in thicknesses to be recommended in Chapter 4. the old shaving soap advertisement), not too little, not too much, but just right. See below for a check list of The elemental floor plan what the basic plan should contain and a list of those project needs to be dealt with elementally then it will Generally speaking, if a 37 Working Drawings Handbook need to be separated into most or all of the following: (31) external openings are unlikely to conflict with (32) internal openings and both may appear on the *(2-) Primary elements (walls, frames, etc.) same drawing under the generic coding of (3-). (3-) Secondary elements—possibly sub-divided into: (31) secondary elements to external walls (windows, etc.) (32) secondary elements to internal walls (doors, etc.) (35) suspended ceilings Refer back to 1.14, 1.15 and 1.16 in Chapter 1, where the basic plan illustrated in 2.1 has been utilised as the framework for various elemental plans—in this case primary elements, floor finishes and secondary elements. (4-) Finishes—possibly sub-divided into: (42) internal finishes (43) floor finishes (45) ceiling finishes *(5-) Services—possibly sub-divided into any or all of the various constituent services *(6-) Installations—possibly sub-divided into: The project of which these drawings form part was a two million pound office and workshop complex with a reinforced concrete frame. In practice both the reinforced concrete structure and the electrics would have been carried out by other consultants, as in 2.2 and 2.3. (62) power (63) lighting This project will be used throughout the book to illustrate (64) communications various aspects of working drawing practice. (7-) Fittings—possibly sub-divided into: (74) sanitary, hygiene fittings (WCs, sinks, basins) Finishes (76) storage, cleaning fittings (shelving, window of laboriously covering the floor plan with descriptive rails, etc.) (8-) Loose equipment. * May well be produced by other than the architect. With regard to finishes generally, the practice wall, floor and ceiling finishes on a room-by-room basis is not to be recommended. It is impossible for the plan to give detailed enough information without exhaustive (and exhausting) annotation. (See attempt made to convey this information about room 1/9 in 2.4.) A system In other words, the breakdown is into the primary facets of coded reference back to a written schedule is a more of CI/SfB Table 1, and only in one or two instances is it practical alternative, as shown in room 1/18 in the same sometimes necessary to go any deeper. The reasons for illustration. The references A/7, B/3 and B/2 relate to a this are apparent from a common-sense appraisal of the vocabulary of finishes given separately in written form, reason for elementalising the general arrangement floor where the repetitive nature of the relatively few types of plan in the first place—the desire to produce simple finish involved makes it possible to record them in detail uncluttered drawings upon which different types of without too much time-consuming room-by-room information will not be laid unidentifiably and confusingly annotation. one upon the other. If you consider the possible sub-divisions of the primary element facet it will be Non-graphical room-by-room scheduling is a more apparent that any drawn or annotated information about satisfactory alternative. It is easy to produce and to refer (21) external walls is unlikely to conflict with information to, and a lot of information may be conveyed by it. It has about (22) internal walls or (23) floor construction. The its disadvantages, the main one being the difficulty of different elements are physically separated on the relating the written description to an actual wall area drawing and complete legibility may be maintained even or door surface, but on the whole it is a reasonably though they share the same sheet of paper. Similarly, effective method (2.5). 38 The general arrangement drawing 2.2 Elemental structural layout (28) based on 2.1 39 Working Drawings Handbook 2.3 Elemental electrical layout—(63) based on 2.1 Of course, a description such as ‘Two coats of emulsion’ a concise answer (let alone the possibility of explaining is helpful only to the estimator. Ultimately somebody is that you want the chimney breast in a different colour from going to ask ‘what colour?’ and a method of the rest of the room) is an ill-considered one. So while documentation which does not offer facilities for providing there is a case to be made for including in the set a plan 40 The general arrangement drawing 2.4 Coded system of finishes in room 1/18 compares favourably with over-elaborate annotation of finishes for room 1/9 coded (43) and dealing solely with floor finishes, which are apt to make an unexpected and unwelcome visual will serve as a base drawing for dealing with nominated impact during a site visit late in the contract. suppliers, finishes pertaining to walls and their ancillaries for any room other than the most simply decorated are Specific problems arise when we come to ceilings, best dealt with by a series of internal elevation sheets services and finishes. Some consideration must be given covering the whole project on a room-by-room basis. to the best method of documenting these, for boundaries tend to overlap and clear thinking is essential. Figure 2.6 shows a workable format for this and demonstrates its use in positioning accurately those Ceiling Finishes Ceiling finishes complete the room miscellaneous items which if otherwise uncoordinated but before simply opting for a (45) coded reflected 41 Working Drawings Handbook 2.5 Finishes given in schedule form. Strong on descriptive detail, though weak on actual location, it nevertheless offers a simple and effective method 42 The general arrangement drawing ceiling plan the implications must be considered of any suspended ceilings (which CI/SfB Table 1 would have us code (35)) and of the lighting and air conditioning layouts, both of which will normally have a bearing on the ceilings. Let us be clear about what we are trying to achieve. There will be a general arrangement plan of airconditioning trunking—no doubt prepared by the M & E engineer—and coded (assuming other consultants are working within the CI/SfB format), G(57). There will also be a lighting layout, a sprinkler layout, etc. and each will also be a general arrangement drawing of the appropriate coded reference. Should a drawing be produced to consolidate these various services, to ensure that they can co-exist satisfactorily in the same ceiling void, then it might be thought to be an assembly drawing and sensibly coded A(5-), since the services as a whole are its primary concern. But at the end of the day the architect’s drawing must be of the ceiling per se, so that the precise positioning of diffusers, lighting fittings, sprinkler heads, etc. may be visually acceptable and may be taken to represent the ‘picture on the lid’ for all concerned with the construction of it. This is in every 2.6 Internal elevations on a room-by-room basis is the most flexible method for conveying information on finishes (cont.) 43 Working Drawings Handbook 2.6 (continued) 2.7 Electrical layout at ceiling level 2.8 Air conditioning layout in ceiling void sense a general arrangement drawing and a finishes Figures 2.7, 2.8 and 2.9 show how the various disciplines drawing and it will be coded G(45). It completes the sixth concerned have dealt with their respective layouts for a side of the cube for every room on that particular floor particular area and how the G(45) ceiling finishes level. drawing (2.10) serves as a picture of the finished product, as well as providing a useful vehicle for This principle holds good whether the information is information about applied finishes which it would have conveyed by CAD or manually. been difficult to provide in any other way. 44 The general arrangement drawing Roof plans Roofs—particularly if they are flat roofs—are essentially just another floor and it might be thought pedantic to introduce separate codes for them. Admittedly quantity surveyors and others concerned with elemental cost analysis require the distinction, but drawing codes do not always help here. Is (2.11) a roof plan of the factory, for example, or is it a floor plan of the tank room? It should be treated as a floor plan and coded accordingly as ‘level number . . .’ . This method of referring to all plans as ‘levels’ has the inbuilt (and on a very large project, the important) advantage that every plan level lies in a 2.9 Sprinkler layout at ceiling level numerical sequence and that in consequence (if care is taken), general arrangement plans of any one level, no matter what their elemental subject, will possess the same number. The elementalised general arrangement plans of level 3, for example, would be numbered: G(2-) 003 G(3-) 003 G(42) 003 G(43) 003 G(45) 003, etc. On a large project this is of immense practical advantage to users of the drawing package because it offers them two ready sortations of the information. It is only necessary to assemble all the G(43) drawings, for example, to have the complete general arrangement 2.10 Architect’s general arrangement drawing of information on floor finishes for the entire project. the ceiling finishes provides coordinating layout for Assembling all general arrangement drawings whose everyone involved sequential number is 003, on the other hand, provides every elementalised general arrangement plan for level 3. It should be noted here how much easier this It should be noted that in CAD, levels are effectively correlation becomes with the use of CAD, where all treated as horizontal sections. In fact, some automated the facets of information shown may be simply CAD programs that generate plans, elevations and combined into one drawing file, as well as existing in sections automatically from the ‘model’ can only work in their own right. this way. 45 Working Drawings Handbook 2.11 Floor plan or roof plan? The problem is avoided if all plans are treated as ‘levels’ Some examples It has been noted that even the most complex of General arrangement plans—primary elements projects is unlikely to engage more than a handful of the available elemental sub-divisions. By the same token, it would be a very simple project indeed that did not Note that CI/SfB Table 1 offers the following choice within the general summary code (2-): benefit from a degree of elementalisation. Two examples are given here: (21) Walls, external walls ● Project A—a multi-storeyed building of some two million pounds contract value (part of which has been used already in 2.1, 2.2 and 2.3, as well as 1.14, 1.15 and 1.16 in Chapter 1). ● 46 Project B—a small house. (22) Internal walls, partitions (23) Floors, galleries (24) Stairs, ramps (27) Roofs (28) Building frames, other primary elements. The general arrangement drawing In the larger of the two buildings—Project A—the arrangement drawings, are identified by being decision was made to confine the architect’s information emphasised in a heavier line than that used for the rest about primary elements to a single (2-) drawing. A of the drawing. decision was made at about the same time in relation to the smaller and simpler Project B to sub-divide the The comparable (2-) drawing for the smaller of the two primary elements to a greater degree. Since the reasons projects had obvious points of similarity but the for arriving at these decisions were different in each reasoning behind its production was somewhat different. case, they serve to illustrate the importance of thinking The building was of simple two-storeyed load-bearing about what you are trying to achieve before actually brick construction, with simply supported timber roof and starting to draw. floor joists and timber staircase. There was no structural engineer, so the design and detailing of these structural On Project A, which had a reinforced concrete frame elements devolved upon the architect. and floor slabs, and which enjoyed the services of a structural consultant, it was deemed unnecessary, Two primary elements drawings were therefore not to say inadvisable, for the architect’s drawings to produced—a generic (--) drawing covering both give constructional information about structural external walls and internal partitions and a (27) drawing elements which were clearly the responsibility of the covering the roof construction. Both are shown in 2.12 structural engineer. So floors (23), stairs (24), roofs and 2.13. (27) and frames (28), whilst appearing on the architect’s primary element drawing (2-), nevertheless, It is worth making a point about the way in which the remain in outline only. Against each of these brickwork was described in each case because it elements appears a reference to the fact that the illustrates the fundamentally common sense way in appropriate structural engineer’s drawing should be which all such decisions should be handled (2.14). In the consulted, thus satisfying the second of the two basic larger building there were four different types of functions of a general arrangement plan—either to brickwork involved. These were: locate the element it deals with or to state where it may be found. 1 A Class II engineering brick in cement mortar, used in Of the other primary elements—and in this particular 2 A common brick to BS 3921 Part II, laid in a 1:1:6 manholes and certain works below ground. instance the walls and partitions are the primary consideration—the information given about them mortar mix and used generally for all backings. 3 A sand–lime facing to BS 187, laid in 1:1:6 mortar to consists of statements as to where they are to be placed a Flemish bond and used generally as a facing brick (i.e. dimensions from known reference points—sensibly, to wall panels. in this instance the structural grid); what they consist of 4 A hand-made fired clay facing brick, used in certain (i.e. notes on their materials or reference back to more featured areas on the entrance facade and laid to a detailed specification information); and where further decorative pattern. information about them may be found (i.e. coded references to relevant assembly details). The primary A schedule of brickwork types formed part of the elements dealt with on this particular drawing, as distinct specification, in which each type was fully identified and from primary elements dealt with on other general described. The reference Fg1/3 on the drawing would 47 Working Drawings Handbook 2.12 Both primary and secondary elements are combined in this small building under the code (--) The Project in General. The simple nature of the building and the large scale of the drawing, made possible by its modest size, makes this feasible 48 The general arrangement drawing 2.13 For clarity the roof construction layout is separated and coded (27) 49 Working Drawings Handbook 2.14 Elevations as a guide to external finishes not readily described in detail by other means indicate that it is the third type of brickwork in that specification has fulfilled its proper descriptive function— schedule, which given that the project included the was perfectly adequate. full CI/SfB nomenclature as part of its documentation would be found in the Fg (bricks and blocks) section of In neither case is it likely that the routine of the drawing that specification. The intricacies of full CI/SfB coding is office was disrupted a year later by someone of course unnecessary unless so desired. ‘Brickwork telephoning from site to ask ‘which brick goes here?’ Type 3’ would have been an equally specific identification, provided it were so described in the Figure 2.15 shows the virtues of secondary structuring of specification. drawings and the inherent flexibility of elementalisation when used with common sense and imagination. The In the smaller project, however, only two types of brick project in question was one of a number dealing with a were used—a common brick and a facing brick. So in similar building type, each of which involved the this instance the description ‘facing brick’—assuming the appointment of a nominated sub-contractor for various 50 The general arrangement drawing 2.15 Elementalisation used flexibly in practice. The general arrangement plan gives a clear exposition of the responsibilities of one sub-contractor—in this case the shopfitter shopfitting works. With certain elements—doors, pelmets main contractor appeared on separate general and skirtings, for example—being carried out by the arrangement plans covering (2-) primary elements, main contractor in some areas and by the shopfitter in (3-) secondary elements and (4-) finishes. Assembly others, it was important that the method of drawings involving the work of both main contractor and documentation employed should be capable of defining shopfitter were referenced from all the relevant general satisfactorily the limits of responsibility for each. It was arrangement plans and were included in both packages also desirable that it should provide for separate of information. packages of information being available upon which each could tender. General arrangement plans—format With very small buildings it is perhaps pedantic to ask The method adopted in practice was to treat all the that each of (two) plan levels be presented on a work of the shopfitter as a (7-) fittings element, separate piece of paper when both fit happily one above regardless of rigid CI/SfB definitions and to record it on the other on a single A2 sheet. In general, however, it is a (7-) general arrangement plan, while the work of the desirable that each sheet should be devoted to one plan 51 Working Drawings Handbook level only, the size of the building and the appropriate and of the building’s relationship with the immediately scale determining the basic size of sheet for the whole surrounding terrain or pavings. project. We have mentioned sectional elevations and we may as Leave plenty of space on the sheet. Apart from the fact well deal here with general sections also, for in this context that this tends to get filled up with notes, etc. during the they serve the same purpose as the elevations, in that course of the drawing’s production (the addition of three they present a general picture of the building without strings of dimensions on each face alone adds necessarily providing any specific information from which it considerably to the original plan area of the drawing), it can be built. They are of particular value to the contractor must be remembered that the drawing’s various users when he is planning the sequence of his operations on will in all probability wish to add their own notes to the site, and for this reason those items of particular relevance prints in their possession. to this function—the relationship of floor levels to one another and of the building to the ground are obvious General arrangement elevations—external Given the plan view and sufficient sections through an object, it is arguable that it is unnecessary to show it in elevation for the object to be fully comprehended. That so much often goes wrong on a building site, even with the benefit of elevations, is an illustration of the fact that the construction process often has little connection with formal logic; in practice, to erect a building without a set of elevations is like trying to assemble a jigsaw puzzle without the picture on the lid to refer to from time to time. Nevertheless, it is as well to remember that the instances—must be shown adequately. Elevations too should carry grid lines and finished floor levels. Other than that they should be simply drawn, with all visible features included but not unduly elaborated. Windows in particular tend to be overdrawn; there is really no point in elaborating glazing bars and beads when these aspects are going to be covered much more fully on the appropriate components drawings. Brick courses merely confuse the eye. We are not dealing here with an artistic pictorial simulation of the building but with a schematic factual representation. elevation’s function is primarily informative rather than instructive, and that in consequence it should not be There are four areas where elementalisation of the made to carry information more sensibly conveyed by elevations should be considered, particularly on larger other means. projects: If elevations are to be of relevance they must be 1 They may be used to locate external openings and complete and this means not just the four views—front, this can be a helpful means of cross-reference back back and two sides—that sometimes suffice, but to the external openings schedule. All that is sectional elevations covering re-entrant points in the necessary is for the opening reference—(31)007, plan shape and the elevations of courtyards. (31)029—to be given on the appropriate opening in the elevation. The practice, sometimes attempted, of Remember too that the building consists of more than using the elevation as the actual external openings that which can be seen above ground. One of the more schedule, is not to be recommended. More needs to useful aspects of a properly produced set of elevations be said about the average window than can sensibly is that an indication can be given of the sub-structure be carried in a small box on a 1:100 elevation. 52 The general arrangement drawing Such references are useful in relating a point on the 3 They may be used as both location drawings elevation with its corresponding position on the plan, and schedule for cladding panels or ashlar but the elevation should never be regarded as the facings (2.17). primary source of reference for these components. 4 They may be used to convey information about Regardless of whether or not they appear on the external plumbing and drainage services above elevations, it is essential that the references appear ground level (2.18). on the appropriate general arrangement plans. The references in 2.16 are to the external openings schedule. 2 They may be used to identify the type and extent of General arrangement sections General arrangement plans in effect constitute a series of horizontal cross-sections through the external finishes; this is a useful device, for it is not building, spaced out so that one is taken at every floor easy by any other means to indicate such things as level. This spacing is reasonable, since in practice the patterned brickwork, the change from one type appearance of the horizontal section is most likely to of bond or pointing to another, or soldier courses differ from floor to floor and unlikely to differ between (see preceding 2.14). floor and ceiling. 2.16 Elevation as a secondary reference to window components. The reference S/31 leads back to the external seconday elements schedule, where the components are listed and classified 53 Working Drawings Handbook 2.17 With a limited range of panel types and with each panel’s component drawing giving full information about it, the elevation itself forms an adequate schedule 2.18 Elevation giving information about external plumbing If a comparable series of vertical cuts were to be made conveyed, yet their number must be limited to through the building, again taking a fresh one whenever manageable proportions. the appearance of the section changed, the result would be a very large number of sections indeed. Such vertical Fortunately, a large number of the possible sections sections constitute a vital aspect of the information to be tell us very little about the building. Figure 2.19 which 54 The general arrangement drawing 2.19 Diagrammatic cross-section through a multi-storeyed building. Virtually all the information it gives may be conveyed more fully and intelligibly by other means. The frame will be built from the structural engineer’s drawings; the doors will be manufactured from information to which the joiner is directed from the appropriate schedule; they will be installed in positions located on the floor plans; the construction of the external walls will be found on strip sections amplified as necessary by larger scale details. A section such as that shown has its functions but they are more likely to be advisory—i.e. letting the contractor see the sort of building he is embarking upon, rather than directly instructing him what to build and where to build it reduces the cross-section through a multi-storeyed shown the positions of doors in those walls but building to a diagrammatic simplicity, will explain why. these are shown, and indeed dimensioned, much more comprehensively on the respective floor plans. Most of it is irrelevant to our understanding. The internal elevations of those rooms which are exposed The heights of internal door frames may be derived by the section cut are not a very suitable medium whenever the section line passes through an internal for describing, for example, wall finishes, since the wall coincident with a door opening, but the height of other three walls are not shown. It is true that we are the frame may be obtained more readily from the 55 Working Drawings Handbook component drawing of the doorset of which it will form part. The only pieces of information it carries which are not readily obtainable from other sources in fact, are the height of the window sill, the height of the parapet, the relative floor levels and the thickness of the floor construction. Each of these items of information would be conveyed just as effectively if the section were confined to the narrow strip running through the external walls (2.20). On a large project it is arguable that one such general section is useful to the contractor in describing generally the type of building upon which he is embarking. If provided, its purpose should be limited to this and the drawing regarded (and coded) solely as an information drawing. Since the number of potentially different wall sections will be limited, the vast number of separate crosssectional cuts through the building at first envisaged is reduced to manageable proportions. Such strip sections may also be used as a reference point for the detailed construction information which needs to be given about window head, window sill, parapet, footings and the junctions of floors with walls, and as such they may be regarded as forming part of the general arrangement information for the project. There is little point in attempting to use the strip sections in themselves to convey this detailed information unless the building is so small, or so simple in its design, that a few such sections tell all that needs to be conveyed about the construction. In most instances the scale of the 2.20 Sectional cut confined to perimeter of the building section and the number of times it will change around the building, will make it more sensible to treat the general arrangement section in almost diagrammatic terms. Note that the floor levels are given and that the vertical dimensions (for example, to window sills) are given from 56 The general arrangement drawing 2.21 General arrangement plans give references to general sections G(--) and strip section G(21). The former will be of the type shown in 2.19. The latter will be similar in scope and function to 2.20 those floor levels to a datum which is readily achievable The points around the building at which the strip on site (for example, to the top of the last course of sections are taken will, of course, be indicated on the bricks), and to which the more comprehensive general arrangement plans (2.21). dimensioning contained in the subsequent assembly details may be referred. Site plans There is no advantage in elementalising the general arrangement sections, although if CI/SfB coding is being used there is some logic in regarding them as G(2-) The functions of the site plan are to show: ● drawings, thus differentiating them from the G(--) general sections previously described and which fulfil a different purpose in the set. The location of the building or buildings in relation to their surroundings. ● The topography of the site, with both existing and finished levels. 57 Working Drawings Handbook 2.22 A typical site plan. Information is given about new and existing levels as well as directions as to where other information may be found. (The information about levels is given here because the plan is to a sufficiently large scale and the small amount of earth moving makes it unlikely to form a separate contract—a good example of common sense prevailing over a more rigidly doctrinaire approach) 58 The general arrangement drawing ● Buildings to be demolished or removed. on to different drawings. The problem with site plans, ● The extent of earthworks, including cutting and filling, however, is that these functions are closely interrelated. and the provision of banks and retaining walls. Incoming services may well share duct runs, which in turn ● Roads, footpaths, hardstandings and paved areas. will probably be related to the road or footpath systems; ● Planting. manhole covers will need to be related to paving layouts if ● The layout of external service runs, including an untidy and unplanned appearance is not to result. drainage, water, gas, electricity, telephone, etc. ● The layout of external lighting. There is a case for recording demolitions and earth ● Fencing, walls and gates. movement on separate drawings. These are after all ● The location of miscellaneous external self-contained activities which will precede the other site components—bollards, litter bins, etc. (2.22). works. Indeed, they may well form the subject of separate contracts and will often be carried out before These are multifarious functions and some consideration other aspects of the site works have been finalised. has to be given to the desirability of elementalising them Similarly, pavings are a finishing element which may 2.23 Site plan with inset assembly details is not to be recommended. Such details form no part of what is essentially a general arrangement drawing 59 Working Drawings Handbook benefit from separation into a drawing associated with what should be regarded solely as a general service runs (and more particularly any manholes or arrangement drawing, and it is interesting to speculate inspection chambers within them). on the reasoning that led to its being there. In most cases it appears for one of two reasons. The first is that When CAD is being used, of course, the problem is the detail was an afterthought, and since no provision simplified into a question of layering the information. had been made for its inclusion elsewhere in the set, it When the set is being drawn manually, however, the seemed providential that the site plan had this bit of remaining site works are best recorded on a single space in one corner. The second arises in the belief drawing. If problems of clarity and legibility seem likely to that it helps the builder to have everything on the one arise by virtue of the work being unduly complicated, sheet. then common sense will dictate either further elementalisation or producing the drawing at an This latter misconception extends over a much wider appropriately generous scale. field of building communications than the site plan and it cannot be refuted too strongly. No single document can Most site plans that are unduly cluttered and difficult to ever be made to hold all the information necessary to read suffer from two faults: define a single building element, let alone a single building. If to place the assembly section of the road on 1 They are at too small a scale for the information they are required to carry. 2 They attempt to include detailed information— the same sheet as its plan layout was deemed to be helpful in this instance, then why not the specification of the asphalt and the dimensions of the concrete kerb as large-scale sections of road construction are a frequent well? The road cannot be constructed, or indeed priced example—which apart from crowding the sheet would by the estimator, without them. The essential art in more logically appear separately among the assembly building documentation is not the pursuit of a information of which they clearly form part. demonstrably mythical complete and perfect drawing, but the provision of a logical search pattern which will Figure 2.23 is a good example of how not to do it. There enable the user to find and assemble all the relevant is no room for the extraneous assembly information on information rapidly and comprehensively. 60 CHAPTER Component, sub-component and assembly drawings Component drawings 3 2 There is the special item requiring fabrication—the non-standard timber window, the reception desk, the A component may be defined as any item used in a pre-cast concrete cladding panel—and in order that building which emanates from a single source of supply someone may make it as required, it is necessary for and which arrives on site as a complete and self- the architect to define quite precisely what it is he contained unit, whose incorporation into the building wants and (in many instances) how he wants it to requires only its fixing to another component or be made. components. Thus, a window is clearly a component, as is a manhole cover, a door, a section of pre-cast Clearly it is the latter category that is of most concern at concrete coping, a mirror. So, for that matter, is a brick. the drawing stage. (A brick wall would be an assembly.) In both categories, however, a basic principle holds Two types of component should be distinguished: good. The component should always be defined as the largest single recognisable unit within the supply of a 1 There is the manufacturer’s product, available off the builders’ merchant’s shelf, for which no descriptive particular manufacturer or tradesman. An example will make this clear. drawing need be prepared. Such items as standard windows, sanitary fittings and proprietary kitchen units Figure 3.1 shows an elevation of a row of fixed and may be described uniquely by the quotation of a cata- opening lights, contained within a pre-cast concrete logue reference. If they are to be drawn at all then their frame and separated from each other by either a brick draughting will be in the simplest terms, more for the panel or a pressed metal mullion. How many window avoidance of doubt in the minds of architect and con- components are there? We may look at this in various tractor than for any other reason. Certainly any detail as ways, and all of them would have some logical force to their method of construction will be at best redun- behind them. We could say, for example, that there were dant, and at worst highly amusing to the manufacturer. six window components, of which four were of type A 61 Working Drawings Handbook and two were of type B (3.2). There is an attractive The correct procedure, however, simplicity about this view. will be to regard the whole assembly as consisting of two window It could be argued with equal justification, that we had in components (3.4). fact a single component, consisting of an assemblage of fixed lights, opening lights, coupling mullions and brick The key determining factor here is the infill panels. The component, in fact, is everything held supply of the component. It is within the overall pre-cast concrete frame (3.3). This reasonable to make the window approach too has its attractions. manufacturer responsible for supplying the pressed metal mullions, but not for supplying the brick panel—and if he is to provide the coupling mullions, then it is rash and unnecessarily intrusive for the architect (inexperienced in this field) to take responsibility for the assembly junction between light and mullion. One of the problems associated with an increasingly factory-oriented building technology is ensuring a satisfactory fit when two components of different manufacture come together on site. Treating the component as embracing the coupling mullions at least puts one 3.1 How many window components in this assembly? aspect of the problem squarely on the shoulders of the manufacturer, who is best equipped to deal with it. This principle may be extended with advantage. If doors and frames are treated as two separate components the responsibility becomes that of the architect to ensure that the door meets the frame with the correct tolerances. If, however, the component is regarded as the complete doorset, then dimensional considerations apply only to the overall size of the frame and it is the joiner who ensures that door and frame fit one another. This is not 3.2 62 Six window components? passing the buck. Rather, it is putting Component, sub-component and assembly drawings he must have the basic technical knowledge of joinery to ensure that he does not ask for a frame size which involves a third of the timber ending up as shavings on the joinery shop floor simply because the finished section was just too large to allow it to be run from a more economically sized sawn baulk. Refinements in documentation method may simplify the process of building communications, but they 3.3 One window component? cannot serve as substitutes for fundamental technical knowledge. (See also the notes on coordinating dimensions and work sizes in Chapter 4.) Component drawings lend themselves to reuse within the office more than do other categories of drawing. One of the advantages of a comprehensive communications system is the facility it offers of standardising the format of such details, and hence enabling them to be used direct from one project to another. The resultant benefits in economy and consistency are obvious (3.5). For this reason a standard 3.4 This assembly is most sensibly regarded as having two window components format should be considered and the drawing size will probably be smaller than that used for the rest of the project. (However, see the comments back in the right hands a buck which the architect on this in Chapter 4.) should never have picked up in the first place. CAD of course lends itself well to this It is, of course, part of the architect’s professional technique of storing details for reuse, responsibility to ensure that he does not specify overall the relevant details being held on disk doorset sizes complete with frame dimensions which until required. The ease with which involve expensive non-standard doorleaf sizes. Similarly, details may be amended means that 63 Working Drawings Handbook 3.5 Useful format for a door component drawing assembly drawings as well can benefit from this segregated may be relaxed with advantage in the case technique. of components, particularly when (for example 3.8), they form part of a standard office library. Figures 3.6, 3.7 and 3.8 show three typical examples of component drawing. It should be noted that the general Note also that in 3.7 the term ‘component’ has been rule whereby drawing and specification information are extended to embrace the method of fixing as well as the 64 Component, sub-component and assembly drawings this nature is required throughout even the largest project. Sub-component drawings These have a limited use and often the information they convey will be better shown on the component drawing. There are instances, however—particularly when a range of components is being dealt with of which the sizes and appearance differ but the basic construction remains constant—when it may be more economical to present details of the construction on a separate drawing. For example, 3.9 shows two doorsets of different sizes and types. The basic sections from which they are fabricated are similar however and that fact has been acknowledged in this instance by the production of a sub-component drawing 3.10 to which the various components drawings refer. The method is really best suited to large projects, or to those offices which have produced their own standard ranges of component details. 3.6 External works components such as this lend themselves to standardisation. Illustration from Landscape Detailing by Michael Littlewood, Architectural Press, London, 1984 The assembly drawing The juxtaposition of two or more description of what is to be fixed. It is only common components constitutes an assembly, and sense to treat such drawings as components rather than depending on the complexity of the assemblies. Furthermore, the alternative fixing methods arrangement and on how far it may be shown and the references back to the general thought to be self-evident from other arrangement drawing for overall sizes, make this one information contained elsewhere in the set, small detail of universal applicability when shelving of it will need to be drawn at an appropriate 65 Working Drawings Handbook 3.7 Shelving treated as a component rather than as an assembly. An example of common sense overriding too rigid theories of classification 66 Component, sub-component and assembly drawings 3.8 Component detail of concrete sill 67 Working Drawings Handbook 3.9 Component drawing of different doorsets all cross-referenced back to standard sub-component drawing 3.10 scale for the benefit of the assembler. Figure 3.11, taken With the assembly drawing we come to the very heart of from the UK Department of the Environment’s PSA the information package. If the general arrangement Library of Standard Details, is an assembly drawing. drawing is in many ways simply an ordered confirmation Figure 3.12, part of Foster Associates’ highly of planning decisions made long before, and the sophisticated detailing for the Willis, Faber and Dumas components drawing is frequently a documentation of head office building in Ipswich, is another. A world of the architect’s judicious selection, the assembly drawing technology lies between them, but each drawing has in poses that most searching of all our questions, ‘How is it common that it defines how a number of component going to be built?’ Before attempting to document his parts are to be put together. answer in a manner which is going to be acceptable to 68 Component, sub-component and assembly drawings 3.10 Sub-component drawing illustrating details of the component itself. (Original scale full size) the users of the document, the detailer must not only be ● Does the range of detailing anticipate adequately confident that he knows the answer but also be aware of all the constructional problems that will be the full implications of the question. encountered by someone trying to erect the building? It was stated at the outset that this book is not intended as a textbook on building construction but it would be futile to pretend that the preparation of a set of working drawings can be regarded as an academic exercise, to be undertaken without reference to its content. Clearly, form and content interact, and the point is raised now because it is precisely here, in the area of assembly detailing, that the really fundamental questions of adequacy emerge: Check lists are of limited value. There is really no substitute for the complete involvement of the detailer in his task, for an intelligent anticipation of the possible difficulties, and for an alert awareness of the total problem while individual aspects of it are being dealt with. Nevertheless, it is useful at times to review one’s work formally, if only because to do so concentrates the ● Will the construction function adequately? mind wonderfully. Since two distinct aspects of detailing ● Is the method of presentation adequate? are involved, two lists may be formulated. 69 Working Drawings Handbook 3.11 Assembly detail taken from PSA Standard Library. Its simplicity contrasts sharply with the complexity of the detail illustrated in 3.12. What they have in common is that each conveys clearly and precisely the information needed by the operative carrying out the operation 70 Component, sub-component and assembly drawings detail happens to show a plan view?) 5 Is the result going to be acceptable visually, both inside and outside? 6 Does the information concerned give rise to any possible ambiguity or conflict with other information given elsewhere? These questions are self-evident and the conscientious detailer should have them constantly in mind from the outset of the detailing. They are noted here because it is probably better to pose them once more, formally, on completion of the series of details, than to have to worry about them at random in the small hours of the morning at some later date. The second check list, aimed at determining the completeness of assembly detailing throughout the building, is more capable of precise definition. The 3.12 Assembly detail from Willis Faber and Dumas objective is to cover the building comprehensively, Head Office Building. (Architects Foster Associates) identifying those aspects which merit the provision of assembly information about them. A logical progression is essential and a suitable vehicle is readily to hand in The first, aimed at establishing the adequacy of the CI/SfB Table 1 (see Chapter 1), for not only does this individual assembly detail, is a series of questions: provide an analysis of the building in elemental form but it also affords a framework within which the necessary 1 Is the chosen method of construction sound, particu- details, once they are identified, may be presented. larly with regard to: ● possible movement It should be noted here that almost all the assembly ● water or damp penetration detailing with which the architect will be concerned is ● condensation confined to the primary and secondary elements, ● cold bridging. sections (2-) and (3-) of CI/SfB Table 1. (The range of 2 Has it been adequately researched, particularly if built-up fittings inherent in section (7-) should in general non-traditional methods or the use of proprietary be regarded as components rather than assemblies.) products, are involved? Nevertheless, the exercise should be undertaken 3 Is it reasonable to ask someone to construct it? comprehensively. Figure 3.13—taken from a real but anonymous detail and calling for an improbably dexterous plasterer—is The important things to note about assembly drawings an example of the sort of thing that can occur when are these: this question isn’t asked. 4 What happens to the construction in plan (if the detail happens to be a sectional view) or in section (if the 1 The scale must be appropriate to the complexity of the construction being detailed. In practice this will 71 Working Drawings Handbook 3.13 Not an easy task for any plasterer 72 Component, sub-component and assembly drawings it is necessary to convey. Note that the damp course in 3.14, being a simple layer of lead-cored bituminous felt, can be shown adequately at the smaller scale, whereas the damp course in 3.15 is a much more complex piece of work, with all sorts of hazards should it be installed incorrectly and so justifies its more expansive 1 : 5 treatment. With CAD of course, where the details will generally be created full size, the same degree of detail will exist on the drawing file, to be reproduced at any scale deemed appropriate. 2 The information given should be limited. Perhaps concentrated is the better word. For it is more helpful to produce twenty assembly sections, each covering limited portions of the structure, than to attempt an elaborate constructional cross-section through the entire building purporting to give detailed information about almost everything. 3.14 Relatively simple detailing adequately conveyed at a scale of 1 : 20 Figure 3.16, reduced here from its original scale of 1 : 20, is a good example of how not to do it. All that has been achieved is a very large sheet of paper, consisting involve a scale of 1 : 20 being used for a wide variety of of an internal elevation at an inappropriately large scale constructions, with a scale of 1 : 5 being used where surrounded by a margin of detailing which through greater detailed explanation is required—e.g. where the necessity has been portrayed at a smaller scale than exact positioning of relatively small components such as would have been desirable. The drawing has clearly bricks or tiles is a vital part of the information to be taken a considerable time to produce. This in itself may conveyed. well have led to some frustration on the part of the builder or the quantity surveyor, who needed urgently to The level of draughting ability may well be a deciding know the damp course detailing in the bottom left-hand factor when details are drawn manually. But don’t be over- corner but had to wait for the gutter flashing at the top optimistic, the mere fact of drawing to a larger scale will right-hand corner to be finalised before the drawing force you into consideration of problems which might could be issued to him. have been glossed over at a smaller scale. It is the operative ultimately who will be asking the questions and At the end of the day we have been shown in some requiring the drawn answer. And he will be building full detail what happens to the construction along a more or size. (In CAD, of course, the drawing files are created full less arbitrary knife cut through the building at one point. size, and the ultimate scale is only applied when printing.) It is to be hoped that the detailing is consistent right round the perimeter, because the manual detailer is not Figures 3.14 and 3.15 at scales of 1 : 20 and 1 : 5, going to be anxious to repeat the exercise whenever the respectively, are appropriate examples of the information construction changes. Were he to do so he would find 73 Working Drawings Handbook 3.15 Scale of 1 : 5 is necessary to show this detailing adequately himself redrawing 80 per cent of the information time section on general arrangement drawings. The relevant and again in order that changes in the other 20 per cent information would then be cross-referenced on the lines could be properly recorded. The use of CAD makes this of 3.17 and 3.18. process a lot easier and more rapid but it is still a somewhat pointless exercise. 3 The assembly drawing should not be used to convey unnecessarily detailed information about the components The more sensible way to deal with providing this sort of from which it is to be produced. Consider the assembly information is to prepare the assembly details in section shown in 3.19. The window frame is a standard conjunction with, and related back to, the series of section and will be bought in from a supplier ready for sections described and advocated in the previous fixing into the structural opening. There was no need 74 Component, sub-component and assembly drawings 3.16 Old-fashioned section through entire building. Far too detailed for its role of conveying information about the form and nature of the building; insufficient for anyone to build from it with confidence therefore to detail so lovingly and so explicitly the profiles The detail might have been produced more simply and of the frame and sub-frame, right down to the glazing speedily as shown in 3.20. beads and the throatings—they are matters of moment to the manufacturer in his workshop, not the erector on 4 The information conveyed should be both site. (The matter of prime importance to the erector, the comprehensive and, within the limits already defined for method of fixing, is not mentioned at all—let us charitably an assembly drawing, exhaustive. It should be assume that the point had been covered in the comprehensive in the sense that the individual detail specification.) The only piece of information this must contain all that the operative is going to need when assembly detail need convey about the window is its he comes to that point on site. The detail may have been relationship to the surrounding components. produced primarily to show the detailing of the window 75 76 3.17 General arrangement sections provide references to where more detailed assembly information may be found Component, sub-component and assembly drawings 3.19 Unnecessary elaboration wastes time and helps nobody Coding assembly drawings A complete system for coding the drawing 3.18 Assembly sections derived from 3.17 package is discussed in Chapter 5 but a note here on the coding of the drawings illustrated sill at a particular junction but if it purports to show this in 3.17, 3.18 and 3.20 may be helpful. junction then others will expect to use it for their own purposes and it is no use being explicit about the The general arrangement sections (3.17) window sill and vague about the wall finish beneath it. are coded G for general arrangement; (2-) An assembly drawing is, by definition, a correlation of all for primary elements (see notes on general the elements and trades involved. arrangement sections earlier for the reasoning on this); and 017, 018 and 019 So too the information should be exhaustive in the because that is their sequence in that sense that no aspect of the construction, no variant on a particular series. basic detail, should be ambiguous or left to the discretion of the operative. ‘Typical details’ are just not The references in the circles are to external good enough. wall details or to external wall opening 77 Working Drawings Handbook It is not unreasonable to give a (21) coding to the section shown in 3.18, for it clarifies the construction of an external wall. But then so does the section illustrated in 3.20. Why not code that (21) also? The answer is that it would be perfectly in order to do so and if you elected to produce a series of details devoted to the assembly problems encountered in constructing the external walls, then you would code A(21)001, etc. accordingly. But it is more likely that in commencing a series of details showing the junctions of two elements—for example, the junction of external openings with the external walls within which they sit— you would find it more convenient, and a better guarantee that you had covered the subject comprehensively, to produce a series of external openings assembly details—and these would naturally fall into the A(31) series. The examples of assembly details illustrated have consisted of vertical sections through a particular construction but of course the plan section also requires illustration and enlargement at certain key points—door 3.20 Simplified version of 3.19 gives and window jambs, for example. adequate information to all concerned Where this is the case and where space allows, it is details (i.e. to windows) and are therefore coded, respectively: A for assembly, (21) for external walls, followed by their number in the sequence of such details; and A for assembly, (31) for external openings, followed by their number in the sequence of such details. better to group plans and sections together by their common element rather than to produce a series of plan details on one sheet and a series of section details on another. Everyone on site concerned with forming the window opening and with fixing the window into it, will then have the relevant information readily to hand. The assembly section shown in 3.18 is coded: A for assembly; (21) for external walls; and 021 because that is its number in the series. The schedule The assembly section shown in 3.20 is coded: A for (See also the section on schedules in Chapter 1.) assembly; (31) for external openings; and 001 because it is the first in that series. 78 There are two distinct types of schedule. Component, sub-component and assembly drawings There is the straightforward list of items, complete in same pattern, for it enables information to be included in itself, which adds nothing to information which may be the schedule both about openings which are filled by no obtained elsewhere in the drawings or the specification. component—an arched opening, for example, or an What it does is present this information in a more unsealed serving hatch—and about openings filled by disciplined and readily retrievable form. A list of lighting components which are neither doors nor windows— fittings, collected on a room-by-room basis, is an ventilator grilles, for example. example, providing a convenient document for the electrical contractor who has to order the fittings and a A form of schedule best avoided is what might be useful check list with which the architect can reassure termed the ‘vocabulary schedule’. An example is shown himself that none has been overlooked. in 3.22. The basis of this type of schedule is the vertical tabulation of a list of components or rooms, and the Schedules of manholes, of sanitary fittings and of horizontal tabulation of an exhaustive list of ancillaries. ironmongery are others of this type, as indeed is the The disadvantages of this method are two-fold. It is not drawing schedule. always easy to be exhaustive in assessing at the outset the range of possible ancillaries, with the result that the Such schedules, carrying descriptive rather than subsequent introduction of another item disrupts the graphical information, are better typed than drawn and tabulation. And the use of dots or crosses to indicate their natural home is more likely to be within the covers which ancillary is required is visually confusing and of the specification or bills of quantities than the prone to error. drawing set. A more rational way of dealing with this ironmongery The other type of schedule is also component-oriented schedule would be to collect the individual items of but in addition to being a list it provides an essential link ironmongery into a series of sets and to indicate which in the search pattern information by giving pointers as set is required against the individual door or window to where other information is to be found. Such component in the openings schedule illustrated in 3.21. schedules are of the type envisaged in 1.9 and The listing of ironmongery sets would then be as shown commented upon in Chapter 1. A useful format is in 3.23, and the addition to the schedule would appear shown in 3.21. as in the ‘Ancillaries’ column in 3.24. Note that what is shown is neither a door schedule nor a window schedule but an ‘openings schedule’. It is Pictorial views important to maintain this concept if the drawing set is being structured using CI/SfB, because CI/SfB The use of perspective sketches, axonometric and acknowledges only ‘openings in external walls’, exploded views should not be overlooked as a means of ‘openings in internal walls’, ‘openings in floors’ and conveying information which might be difficult to ‘openings in roofs’. All components filling such openings document in more conventional forms. (The ability of require to be treated as part of the opening and hence CAD to produce three-dimensional information is of are scheduled accordingly. obvious benefit here.) Nor should the value of pictorial elevations, perspectives, photo montages and models Even if use is made of some other elemental form of be discounted as an aid to the contractor. Photographs coding, however, it is still of advantage to follow the of existing buildings are invaluable to an estimator when 79 Working Drawings Handbook 3.21 Useful format for an openings schedule pricing demolition or rehabilitation work and a model, or CAD programs printing raster printers (inkjets and a photograph of one, will often demonstrate site lasers) will allow photographs to be incorporated into the management problems to the contractor’s planning rest of the drawings. Such pictorial aids should be team more succinctly than a collection of plans and clearly defined as being for informational purposes only sections. and not possessing any contractual significance. 80 Component, sub-component and assembly drawings Specification should trespass upon the other’s territory. If the drawing calls for roofing felt then it need describe it simply as The function of the specification in relation to a that—‘roofing felt’, or ‘built-up felt roofing’. If only one competent and comprehensive set of drawings may be type of built-up roofing felt construction is to be used on defined quite simply. It is to set out quality standards for the project then that simple description suffices. If more materials and workmanship in respect of building than one, then ‘built-up felt roofing type 1’ will be a elements whose geometry, location and relationships to sufficient indication of intent. To the specification will one another have been described by means of the then fall the task of describing in detail just what ‘built-up drawings. roofing felt type 1’ is to consist of. It follows therefore that in a properly structured Conversely, the specification is no place for instructions information package neither specification nor drawings such as ‘Cover the roof of the boiler house in three 3.22 ‘Vocabulary’ type of schedule. It is dangerously easy to get a dot in the wrong place 81 Working Drawings Handbook 3.23 Lists of ironmongery collected into sets layers of built-up felt roofing.’ If a specific roof surface is Conversion, alteration and rehabilitation to be so covered, then it is the function of the drawings to tell everybody so, when the full extent of the covering It is now necessary to look at the methods described and the possible operational problems in achieving it previously and to see how far they are applicable to the may be clearly and simply described. description of work to existing buildings. This simple differentiation between the roles of drawings To dispose of the simple matters first, straightforward and specification will enable each to fulfil its true extensions to buildings present no problem. They are in function properly. every respect new pieces of building and there is no 82 Component, sub-component and assembly drawings 3.24 The openings schedule shown in 3.21 extended to give information about ironmongery sets reason why the methods adopted for any other new Whenever any demolition of existing structures is building and the conditions relating to their use should involved, no matter how modest, it is preferable to show not apply. it on a separate drawing—to regard it, in fact, as one more element in the elementalised set. The expression Where information needs to be given about work to ‘demolitions’ is to be interpreted widely in this existing structures, two additional aspects need connection, including such items as forming an opening consideration which are not present in entirely new in an existing wall as well as more major demolitions work. One is the question of demolitions, particularly involving entire sections of the building. The correct way demolitions within a structure. The other is the question to deal with an opening to be cut in an existing brick wall of repairing and making good. to take a new door and frame is shown in 3.25. The 83 Working Drawings Handbook 3.25 Demolition drawing covering formation of new opening in an existing wall drawing deals with the forming of the opening as a carefully separated from the new work which is to single activity, including the insertion of the new lintel replace them (3.28), as well as from the alterations to over. It could hardly be dealt with otherwise by the internal partitions, etc. which are covered on another builder. The drawing showing the new work 3.26 refers sequence of drawings. only to the new door and frame, inserted in what is by then an existing opening. Simple items of making good, such as the replacement of areas of plaster, or the overhauling and repair of Note that it would be wrong for the drawing showing new windows, are often most simply covered by scheduling works to make reference to the opening having been on a room-to-room basis. If only two square metres of formed under the same contract. To do so would invite plaster are to be replaced in a given room, it is the possibility of the estimator including the item twice. presumably obvious enough to all concerned which Neither is the routine note ‘make good to plaster and two square metres are referred to, without the necessity finishes’ included on either drawing. Such a general of precisely locating them on an internal elevation. instruction, which will presumably apply to a number of Written description, in fact, is often better than such door openings throughout the project, is more graphical instruction in much rehabilitation work. appropriate to the specification or schedule of works. If CI/SfB coding is being adopted for the set then Generally speaking, a single demolition plan for each demolition drawings will normally be given a (—) ‘project floor will suffice, but if there are complexities of a special in general’ code, leaving the more detailed code nature to be covered then the mode of conveying the references for application to the new works. information may need to be more elaborate. Figure 3.27, for example, shows the demolition drawing of a reflected One extremely important point is often overlooked in ceiling plan, where the fact that certain suspended drawings of alteration work, with unfortunate consequent ceiling tiles and light fittings were to be removed is effects. It is absolutely vital that everyone should be clear 84 Component, sub-component and assembly drawings 3.26 Drawing covering installation of door and frame in the opening formed in 3.25 3.27 Demolition drawing of reflected ceiling plan 85 Working Drawings Handbook 3.28 Drawing showing new works replacing demolitions shown in 3.27 from the drawings as to what is new work and what is alterations, was an instance of an activity-oriented existing. Basic structure is not too difficult to distinguish approach to the provision of building information. (shading in existing walls and showing the details of Activity 1, involving the cutting of the opening and construction on new walls will avoid confusion in this insertion of the lintel, was rightly regarded as being respect) but it is the little things—manholes, rainwater distinct and of a different nature from activity 2, which pipes, sanitary fittings—often appearing as left-overs embraces the fixing of a new door and frame. The two from the survey drawing, which need specific annotation. activities were separate and complete in themselves; they were potentially capable of being carried out by It is, of course, helpful to issue the survey drawings as different people or groups of people; and they might part of the set. well have been (and indeed probably were) separated from each other by a significant period of time, during which no work of any kind was being done to either the Activity drawings opening or the door. It was possible, therefore, and on the face of it reasonable, to convey the necessary The provision of a new door in the existing brick wall, information to the builder in the form of two separate given as an example in the section on conversions and instructions. 86 Component, sub-component and assembly drawings Whilst this approach to building communications is clearly advantage that remeasurement, when necessary, would sensible in the very limited context of alteration work, it is be restricted to small and readily identifiable sections of possible to apply it to the whole spectrum of building the work rather than entire trade sections, and that operations. Hitherto in this book a building has been valuations for interim certificates and final account would looked upon as consisting of an assembly of individual be greatly simplified. (It would not be a matter of elements. It may equally well be regarded as the result of agreeing how many metres of brickwork had, in fact, a sequence of different and separately identifiable been erected. It would be a matter of common activities. Such a concept lay behind the development in observation how many activities had been completed.) the 1970s and 1980s of activity and operational bills of quantities. The theory behind them is simple. The The method has not become so widely established as contractor’s main problem lies in the organisation of his had at one time seemed likely but it is there, readily resources, both material and human. His bricks have to available and consideration should be given as to arrive on site at the right time, his bricklaying force has to whether any adjustment of working drawing technique is be sufficient to optimise the length of time his scaffolding desirable to accompany it. is on hire; it must be re-deployed smoothly and economically when the work is finished, either to some The method starts with the establishment of a notional other part of the project, or to another project. Success list of building activities which, while not binding on the lies in careful and accurate programming. contractor, is nevertheless intended as a realistic attempt to put the work into a correct order. A typical sequence Conventional bills of quantities do little to assist in this for a piece of brick walling, for example, might run thus: task. To tell the contractor that he is to erect a total of x m2 of brick wall will enable him to put an overall price 1 Strip top soil on the total brickwork/bricklayer section. It will not 2 Excavate for strip footings necessarily point out to him that the last brick will be laid 3 Lay concrete some eighteen months after the first; nor that it will be 4 Lay engineering bricks to DPC level laid on an entirely different part of the site; nor that the 5 Lay DPC nature of the construction involves the total bricklaying 6 Build 275 mm cavity wall to wall plate level, etc. operation being split into three separate stints, with substantial gaps of time between them. It is not possible for drawings to show activities, only the completed event. There is no reason, however, why an Such information may well be deducible from an elementalised set of general arrangement drawings such intelligent examination of the drawings, but the bill of as has been discussed in the previous pages should not quantities is, after all, the document he has to price, and form a perfectly satisfactory adjunct to an operational were it to be presented in a form which showed the true bill. In the example given, activities 1 to 3 would all be nature of his work there would be inestimable benefits all covered on the foundation plan and the remaining three round. The contractor would have at his disposal not only on the primary elements plan. To each drawing would be a more accurate basis for his estimating, but a flexible added a note saying which numbered activities were management tool which could be used for, among other shown on it (or were shown on other drawings to which things, the programming of material deliveries, the that drawing referred). Against each activity in the list deployment of site labour and the forecasting of cash would be set the number of the general arrangement flow for the project. The quantity surveyor would have the drawing which would initiate the search pattern. 87 CHAPTER Drawing the set 4 We have covered the structure of a set of working lines, circles and text, each file being an electronic drawings, the hierarchic progression of location, image of the paper drawing that will be created from it. assembly, component, sub-component drawings and Individual lines and circles are assigned a pen width, a schedules. We now have to look at how the drawings colour and a linetype of dashes and dots but little more themselves are to be prepared, in a form that will be than that. At the other end of the spectrum some CAD economical of drawing time and will enable multiple (Computer-Aided Design) programs aim to provide all copies to be taken for the use of the contractor, the tools necessary to design the project, whilst all sub-contractors, quantity surveyor and others. necessary construction drawings are generated automatically. There are two primary methods for producing the originals: 1 They may be created on a computer using a CAD program before being sent to a printer or plotter 2 They may be drawn manually, using pen or pencil techniques, which until a few years ago were the only options available. A drawing file created by CAD has the potential to be far more than just a collection of paper drawings stored on computer. Used properly, it can be a database describing a building in its entirety as a 3D model, from which plans, elevations and sections can be generated as and when needed, at any scale, and showing any sub-set of information. The drawing file would be created Since CAD is the predominant method now in use we from walls and windows rather than lines and circles, shall deal with it first. and these walls and windows might have their size, weight, cost, materials and manufacturer details attached. The same drawing file might also be used to Computer-Aided Draughting generate isometric or axonometric diagrams, or photorealistic coloured perspectives. The same file might be At its simplest CAD is little more than an electronic used at all stages of design and construction, from initial drawing board. Individual drawing files are created from proposals and discussions with the client through 88 Drawing the set production information and on to ‘as built’ information. As Most offices now use large format inkjet plotters capable the project progressed through these stages information of printing A1 or A0 drawings. Smaller offices might would constantly be added to the drawing files. The send small drawings and check plots to the same A4 client might also use them for facilities management laser printer as is used for general correspondence and (sometimes called asset management) once the building send larger drawing files direct to plotting agencies over was handed over. the Internet. CAD possesses many advantages over manual drawing, With regard to the actual creation of the drawing files, even for a small practice. A computer takes up far less two methods are currently in use, the first being both the space than a drawing board, so you don’t need as large most common and the less sophisticated. an office. It can double up for writing specifications, getting information from manufacturers over the Internet or from CDs, sending and receiving messages, and even doing your accounts. You don’t have to keep pens clean and pencils sharp. A drawing created on a computer doesn’t need to be built up sequentially. Mistakes can be corrected easily without starting afresh, and revisions and repetitions are easy to make. You can start on a computerised drawing even if you don’t have all the information to hand to complete it, because you can come back later, make corrections and fill in details. At this level CAD has done for drawings what word processors did for text. A good CAD package will also let you automate difficult or repetitive tasks, so that whole sections of drawings can be completed with just a couple of clicks on a button. It should either have all the necessary ‘hooks’ to allow links with third-party applications when you decide to add them, or have a file format compatible with architectural design packages, to make it easier to upgrade later. Some ancillary equipment is useful. A CD or better still a DVD writer enables back up copies to be made of valuable data and copies sent through the post. An A4 flat bed scanner enables site location plans or manufacturers’ trade literature to be scanned into CAD drawings. A 4 megapixel digital camera can provide a Drawing overlay method The basic concept is simple. Each element of the design is drawn on its own unique ‘layer’ within the computer file, walls on one layer, dimensions on a second, electrics on a third, radiators on a fourth, and so on. Layers can be turned on or off as needed. During the design process both electric and radiator layouts might be turned on, enabling electric sockets behind radiators to be spotted. The concept of layering is common to all CAD programs. Different programs might use different terminology but the underlying principle is the same. All programs will have tools to help you manipulate your layers, by way of wild carding or through grouping layers. Likewise, layer names might be preassigned by a high-end fully automated architectural CAD program, whereas you may have to devise your own layer naming conventions with a simpler program. (See Chapter 5 for section on Layer Naming Conventions.) However, if in doubt, use more layers than fewer. It is much easier to combine layers to simplify the drawing file’s structure than it is to separate drawn entities into two or more layers later. Model exchange method photographic record of existing buildings and When drawings are produced by CAD it is probable that topography, saving a return trip to site. during the design process several different designers will 89 Working Drawings Handbook work on the project at different times and on different The use of copy negatives is really only applicable to computers. It is also possible that on more complex general arrangement drawings. Even in situations where projects creation of the production information set will be an assembly or component drawing has been given an shared between different professionals working in elemental CI/SfB coded number it is unlikely to have separate offices. The traditional method of exchanging benefited from the superimposition of additional layers of data and coordinating various aspects of a project would information and might as well have been produced as a have been to send marked up prints back and forth single sheet, drawn once only. through the post, with separate sets of drawings being produced as the final design emerged. Paper size is of less consequence here than in the other methods discussed, for the production of the negative is In model exchange, where all the professionals are limited only by the size of the drawing board available using CAD to produce their drawings (ideally but not and the cost implications of using large drawings are not necessarily the same CAD program), it is the ‘model’ so great as they are with more sophisticated methods. that is sent back and forth on disk, CD or by email rather Nevertheless, the same general comments regarding than pieces of paper through the post. Hopefully, the paper sizes which were made earlier still apply with final scheme is better coordinated, with fewer errors, manual draughting. No one is going to think kindly of omissions and conflicts. Management procedures must you while trying to consult an A0-sized drawing flapping be in place to ensure that everyone is working from the about in a gale on an exposed building site. same version of the CAD model, but in theory at least, a better set of production information should be created, As to the medium upon which manual drawing may be with far less duplication of effort. carried out, there is a wide range, coupled with a range of pens and pencils. Manual drawing Materials for manual draughting This has now been largely superseded by CAD. The and, because it offers a semi-opaque background, most recent RIBA survey indicates, however, that 15 per pleasant and satisfying to draw on, particularly in pencil. cent of small practices still draw the bulk of their work It is best suited to the preparation of drafts for manually, and it seems desirable therefore that some subsequent tracing into final drawings, where the notes be included covering the method of elementalising original sheet may be expected to have a limited life, drawings manually. and where any prints taken from it will be for internal Detail paper has the great advantage of being cheap exchange of information among team members, and The method is very similar in essence to the CAD drawing also for rapidly produced pencil details (accompanying overlay method described previously. A basic floor plan is architects’ instructions, for example). drawn (see the section entitled ‘the basic floor plan’ in Chapter 2) and from it are taken the requisite number of Tracing paper is the most common medium in use today. copy negatives (normally by dyeline reproduction on some A smooth finish is desirable, especially for pencil work, translucent medium which will take manual drawing on its where the more abrasive surfaces of the matt and semi- top surface). The elemental information is then added to matt finishes tend to wear down pencil points rapidly each copy negative, which is then coded elementally and and are more difficult to keep clean during the printed for inclusion in the drawing set. preparation of the drawing. A weight of 90 g/m2 is 90 Drawing the set probably the most common in general use but it is arguable that 112 g/m2 justifies its extra cost, being dimensionally more stable and less liable to go brittle with age. Draughting film is expensive but it is dimensionally stable, takes ink and pencil well and both may be erased easily. However, it is hard on the normal technical pen and it is desirable to use a range with specially hardened tips. Ink and pencil are the two available media for drawing lines and the choice rests to some extent with the individual. Many find pencil the more sympathetic medium, with its wide range of line inflexions. The function of a working drawing, however, is the unambiguous conveyance of drawn information, and aesthetic considerations must remain secondary. Line thickness Line thicknesses offered by the manufacturers of technical pens cover a wide range. Figure 4.1 shows them at full size. It will be noted that there are two ranges available, Range One being the most common and Range Two based on German DIN standards. With Range Two each size doubles the thickness alternately preceding it, with the result that alterations may be 4.1 The range of line thicknesses available with the use of technical pens carried out to an enlarged or reduced copy negative in a similar weight of line to that appearing on the original. (This applies equally when manual alterations to CAD printed drawings is being carried out.) legibility and uniformity of reproduction are to be maintained. But for the normal production of working It is of course undesirable to mix the ranges on any drawing negatives, where reproduction may be expected given drawing. For 1:2 reduction of negatives the to be at a 1:1 ratio, there is no reason why a thickness minimum recommended line thickness for use on the of 0.18 or 0.2 should not be selected for the thinnest original drawing is 0.25 mm, allowing the use of the line used. minimum size 0.13 mm pen for any alterations. Three different line thicknesses will suffice for most In any process of reduction the minimum line thickness drawings. If we term them (a), (b) and (c), with (a) on the final print should not be less than 0.13 mm if being the thinnest and (c) the thickest, the various 91 Working Drawings Handbook parts of a drawing may be grouped within them as used in the office will conform to its requirements. It follows: originates in the ingenious concept of a rectangle having an area of 1 m2, the length of whose sides are in the proportion 1:√2 (4.4). (a) grid lines centre lines The dimensions of this rectangle will be found to be dimension lines leader lines 1189 ⫻ 841 mm and by progressively halving the larger incidental furniture, where relevant dimension each time, a reducing series of rectangles is hatching produced, in which the proportions of the original (b) all other lines, with the exception of: rectangle remain unchanged, and in which the area of (c) those lines, particularly on an elementalised drawing, each rectangle is half that of its predecessor in the which it is desired to emphasise, either because they series (4.5). define the element which is the subject of the drawing, or in the general interest of clarity. The range of ‘A’ sizes available to the drawing office is as follows: The values to be set against the three categories will vary with the scale and nature of the drawing and with the range of pen sizes selected. A0: 1189 ⫻ 841 mm A1: 841 ⫻ 594 mm A2: 594 ⫻ 520 mm A3: 420 ⫻ 297 mm Recommended pen sizes are as follows: 1 Drawings to a (a) (b) A4: 297 ⫻ 210 mm (c) scale of 1:50 CAD uses these paper sizes, with the addition on larger and less drawings of a gripping margin for the printer or plotter. 2 Drawings to a (a) (b) (c) scale of 1:20 The large differential between A0 and A1 has led to the to 1:5 3 Drawings to a (a) (b) (c) introduction in some offices of a bastard-sized sheet to reduce the gap, but the use of intermediate sizes is not scale larger desirable. They have to be cut from paper of a larger than 1:5 Pen size Range 1 0.2 0.3 0.4 0.5 0.7 size, and their non-standard proportions lead to Pen size Range 2 0.18 0.25 0.35 0.5 0.7 difficulties in both storage and photographic reproduction. Figures 4.2 and 4.3, taken from parts of drawings of various scales, have been redrawn using both pen size ranges for comparison. Drawing sheet size Indeed, both these and the A0 sheet should be avoided wherever possible. The A0 sheet is incredibly cumbersome both in the drawing office and on site, and on the whole it would seem to be preferable to set the A1 sheet as an upper limit in all but the most The international ‘A’ series of paper sizes is now exceptional circumstances. The site plan for even the universally accepted, and all drawing and printed sheets largest of projects can always be illustrated at the 92 Drawing the set 4.2 Parts of three drawings using the Range 1 line thicknesses appropriate scale on a number of marginally of the size of the job and of the appropriate scale for the overlapping sheets, with, if necessary, a key sheet general arrangement plans will probably establish the drawn more simply at a smaller scale to show the whole format for the complete set of such drawings; normally extent of the site (4.6). it is not difficult to contrive that the assemblies and the ranges of component drawings should also be Where an area is sub-divided in this fashion a small key drawn on sheets of that size. The majority of the plan should always form part of the title block to indicate drawings in the average set therefore will appear in the relationship of that particular drawing to the overall either A1 or A2 format, depending upon the size of the plan (4.7). project. Apart from this upper limitation it is clearly sensible to The nature of sub-component drawings and schedules restrict as far as possible the number of different sized however, tends to make a smaller format more suitable drawings issued on any one project. An early appraisal for them, and there will always be, in addition, a number 93 Working Drawings Handbook 4.3 The drawing shown in 4.2 redrawn using the recommended Range 2 line thicknesses of small details on any project which it would be A4 or A3? It may be helpful to set out the pros and pointless to draw in one corner of an A1 sheet and cons. The advantages of the A4 format are: which it would be confusing to attempt to collect together on a single sheet (the ‘miscellaneous details’ ● approach which has been condemned earlier). A substantial amount of the project information is already in A4 format—specification, bills of quantities, architect’s instructions, Where the format for the other drawings is A2 it is probably worth wasting a little paper for the sake of correspondence, etc. ● Trade literature is normally A4 and if you wish to obtaining a manageable set of consistent size. Where include manufacturers’ catalogues as part of your set the general size is A1 however, a smaller sheet (and why not?) then they are more readily absorbed becomes necessary and whether this should be A4 or into the structure of the set if you already have an A4 A3 is a matter for some debate. category. 94 Drawing the set ● Architects’ instructions are frequently accompanied by a sketch detail and the A4 format simplifies filing and retrieval. ● A bound set of A4 drawings is suitable for shelf storage. A3s are an inconvenient size to store, whether on a shelf, in a plan chest drawer, or in a vertifile. ● A4s can be carried around easily. The disadvantages of the A4 format are: ● The drawing area is altogether too small. One is constantly being forced into the position of limiting what is shown because there is just not room on the 4.4 paper, or of selecting an inappropriately small scale. Derivation of the rectangle A0, with a surface area of 1 m 2 ● There is no room to record amendments adequately, or for that matter to incorporate a reasonably informative title panel. ● Builders don’t like them. The choice is not easy but on the whole the authors are inclined to favour A3 as the smallest sheet of a set, if only for the pragmatic reason that you can, at a pinch, hang them landscape in a vertifile; that you can, at a pinch, bind them into a specification or a bill of quantities 4.5 ‘A’ sizes retain the same proportions (1:√2). Each sheet is half the size of its predecessor and fold them double; that you can, at a pinch, copy them in two halves on an electro-static copier and sellotape the two halves together; and that wasting paper ● Most users—both producer and recipient—will is, in the last resort, cheaper than redrawing a detail possess or have access to an A4 photocopier with which in the end just would not quite go on the sheet. the facility that this offers to, for example, the ● contractor who wishes to get alternative quotes for a Drawing conventions particular item and can rapidly produce his own In the same way that line thickness is influenced by copies of the particular drawing. The A3 copier is still considerations of scale and the relative importance of something of an expensive rarity (though their use in the objects delineated, so too is the degree of detail by contractors’ and professional offices is becoming which various elements are represented. The manner in more common). which a door or a window is shown on a 1:20 assembly The restricted size of sheet makes it more suitable drawing is not necessarily appropriate to their for producing standard drawings, where it is representation on a 1:100 general arrangement plan. necessary to limit the amount and extent of the information shown in order to preserve its As always, common sense and absolute clarity of ‘neutrality’. expression are the criteria. If a door frame is detailed 95 Working Drawings Handbook 4.6 Overlapping smaller sheets allow the appropriate scale to be used for the plan of a large area without recourse to unwieldy A0 sheets elsewhere in the set at a scale large enough for the Handing and opening intricacies of its moulding to be described accurately, the side on which a door is hung are many and varied. then it is a waste of time and a possible source of These are sometimes ambiguous, at worst contradictory, confusion if an attempt is made to reproduce the and few areas where precise description is vital suffer so mouldings on a 1:20 assembly drawing whose real much in practice from imprecision as this one. The conventions for describing function is to indicate the frame’s position in relation to the wall in which it sits. Possibly the simplest and most easily remembered convention is this: that the hand of an opening is the Some conventional methods of representation which are side on which the hinges may be seen. (BSI’s ‘clockwise generally speaking appropriate for a range of elements closing’ and ‘anti-clockwise closing’ cut across long at various scales are given in Appendix 1. engrained terminology.) 96 Drawing the set requirements for off-site hanging of casements and a consequent clear system for describing the handing. The normally accepted convention is that the window is drawn as viewed from the outside. Conventional representations for both door and window openings are given in Appendix 2. Hatching The use of hatching of various kinds to give a graphical indication of different materials was first developed as a readily reproducible alternative to the laborious colouring of opaque originals which had preceded it. The existing ranges of conventions are based on building techniques of a previous century, and were they to be brought fully up to date an enormous expansion of conventions would be necessary. Such concepts as loose-fill insulation, for example, fibre-glass mouldings, or glass-reinforced cement would all require consideration. One should first question the necessity, or indeed the desirability, of hatching in the first place. It should only be used when confusion is likely to occur in the interpretation of drawings, and in most cases such potential confusion may be avoided by other means. 4.7 Key to sub-divided plan forms part of the title block Building elements shown in section, for example, may be distinguished from lines in elevation or grid lines by affording each their proper line thickness, without The use of this convention provides a ready mental recourse to hatching. Different materials are less likely to reference for checking the handing of any component be confused with one another when drawings are and for providing instructions to others. Like any other elementalised; and in any case, the mere differentiation convention, however, it is of little use to the recipient between, say, brickwork and blockwork, which is possible unless they are in on the secret. So they must be told, with hatching, is not normally sufficiently precise for preferably by a simple statement at the start of the present-day purposes. We want to know if the bricks are component schedules. commons, or engineering quality, or facings. We want to know if the blockwork is lightweight for insulating The conventions determining window openings are in purposes or dense and load-bearing. Such subtleties can more general use, presumably through the early only be covered by proper annotation and such development of the metal window industry with its annotation will often render other methods redundant. 97 Working Drawings Handbook Where hatching is used it should be kept simple in convention. Often a simple diagonal hatching, with the diagonals running in different directions, will suffice to illustrate the function of two components of the same material, without requiring that the user look up some vast code book to see what the material is. This is clarified in the accompanying notes. Non-active lines Lines on a drawing which delineate the actual building fabric are termed ‘active lines’. Those lines which are essential to our understanding of the drawing, such as grid lines, dimension lines, direction arrows, etc. are termed ‘non-active’ lines. Recommended conventions for non-active lines are Gridded hatching, where the grid is parallel to the given in Appendix 5. axes of the element being hatched, is confusing to interpret. The foregoing comments apply equally to hatching applied during CAD draughting, even though such hatching is simple and rapid to apply. Some conventions in common use, simplified from their original sources, are given in Appendix 3 but their use should be very much conditioned by the comments above. Templates Various plastic cut-out templates are on the market, covering many of the symbols given in the appendices. Templates are also available for the production of circles and ellipses and for drawing sanitary fittings. Such templates are a time-saving aid, even though one of the corollaries of Murphy’s law ensures that the symbol you really need is missing from that particular template. A word of warning should be added about the indiscriminate use of templates for sanitary fittings, Electrical symbols where it is dangerously easy to fool yourself about The architect frequently becomes involved in the dimensions. Some manufacturers of sanitary fittings production of electrical layout drawings, particularly on produce their own templates, and these of course give smaller projects where no M & E consultant is engaged, an accurate representation of the particular fitting and Appendix 4 gives some of the more commonly used specified. However, in their absence it is safer to draw symbols in general practice. the fitting to its true overall dimensions taken from the manufacturer’s catalogue than to rely on a standard Two points may usefully be made about the method of template which may deceive you into a situation where showing wiring links between switch and fitting. In the the toilet door fouls the lavatory basin which arrived on first place, of course, any such representation on site larger than you had drawn it. Figure 4.8 gives an the drawing is purely diagrammatic; no attempt need be example of a typical template. made to indicate the precise route the wiring should take. (If ducted provision has been made the fact should Block libraries (templates) be noted on the drawing and the ducting shown on the The CAD equivalent of drawing templates is the block appropriate builder’s work drawing.) library. In the second place, the links are far better drawn Dedicated architectural CAD programs will come curved than in straight lines which are liable to conflict complete with their own 2D and 3D block and symbol with other building elements (see 2.7 in Chapter 2). libraries. These programs will allow you to select 98 Drawing the set 4.8 Examples of plastic cut-out templates available commercially symbols or component drawings from menus and insert The final source of block and component libraries is to them in your drawings where needed. The more create your own. A not inconsiderable advantage of sophisticated programs will add the inserted creating your own libraries is that quality is ensured. components to automatically generated schedules. A disadvantage with some low cost libraries is that they were produced, seemingly, by very junior staff and not Several generic block and symbol libraries are available checked thoroughly before distribution. At least you for sale, some with CAD versions of diagrams from know your own libraries are perfect. books that you can insert straight into your drawing files. These are designed to give you some of the It is not necessarily an onerous task to create these benefits of dedicated architectural packages at a much libraries. They can be built up over the years by ‘writing out’ lower cost (4.9). parts of drawings you create for use later on other projects. One long-term aim of the building industry is that Dimensioning manufacturers start to provide libraries of intelligent That this is a more complex subject than may appear at ‘objects’ rather than simple blocks. The task is immense first sight may be illustrated by a simple example. and although the dedicated architectural CAD programs already use ‘objects’ it seems unlikely that we shall see Consider a timber window set in a prepared opening in any substantial number of ‘object’ libraries in the near an external wall. Unless the wall is to be built up around future. the window frame, in which case the frame itself will 99 Working Drawings Handbook 4.9 The conventions shown are contained in computer software and may be selected as required for the drawing being undertaken. (Reproduced by courtesy of Autodesk Ltd) serve as a template for the opening, the architect will be daunting prospect of trying to represent a series of faced with making the brick opening larger all round than 15 mm differences on a general arrangement plan at a the overall dimensions of the frame which is to be fitted scale of 1:100, the problem is compounded by into it; for otherwise it will be impossible, in practical inaccuracies which are bound to occur in both the terms, to insert the one into the other. It would seem that fabrication of the frames and the erection of the the joiner will need to work to one set of dimensions and brickwork, to say nothing of the difficulty of inserting one the bricklayer to another if a satisfactory fit is to be centrally into the other. achieved. How, simply, is each to be instructed? The solution lies in the concept of the coordinating To answer ‘dimension the frame 15 mm all round smaller dimension, which may be defined as the distance than the opening’ is unduly simplistic. Apart from the between two hypothetical planes of reference—known 100 Drawing the set 4.10 The coordinating dimension as coordinating planes—representing the theoretical boundary between adjoining building elements. A diagrammatic indication of the window in the wall will clarify this definition (4.10). The coordinating dimension is the one which will be shown on the general arrangement and assembly drawings, and is the nominal dimension to which both the bricklayer and joiner will work. If that dimension is 4.11 The work size 1500 mm, then we may speak quite properly of a ‘1500 opening’ and of a ‘1500 window’. The nominal size related to the nature of the materials in which each is of the frames will be reduced by the manufacturer to a working. It may be assumed that the bricklayer will set up size which is smaller all round by 10 mm, this being the a temporary timber framework as a simple template to dimension laid down by the British Woodworking which this brickwork may be built to form the opening. For Manufacturers’ Association as an appropriate reduction for the bricklayer therefore, an opening which varies in size timber products in order to produce a final or ‘work size’. between x ⫹ 5 mm and x ⫺ 0 mm with x being the coordinating dimension may be considered reasonable. We now have a situation which may be shown In the timber component however, it will be reasonable to diagrammatically as in 4.11. accept variation in size between y ⫹ 5 mm and y ⫺ 5 mm where y is the laid down work size of the component. It must be borne in mind, however, that neither the bricklayer nor the joiner is likely to achieve 100 per cent The final assembly of window and brickwork may dimensional accuracy and the best that can be done is therefore have two extreme dimensional situations, with to specify the degree of inaccuracy that will be regarded a range of intermediate possibilities (4.12). as acceptable. The selected method of sealing the gap between In the present example two trades are involved, and the component and opening must take account of these degree of precision to be demanded must be realistically variables if it is to work in all situations. The sizing of 101 Working Drawings Handbook 4.13 Opening on plan defined by its coordinating dimension 4.12 Dimensional possibilities of window/wall assemblies components and the establishment of their work sizes and permitted deviations is an entire field for study in its own right. An obvious instance is that of pre-cast concrete cladding panels with a compressible extruded plastic section providing the weathertight seal between them 4.14 Component destined to fill the opening shown where, unless the greatest care is taken, the maximum in 4.13 is also defined by its coordinating dimension permitted gap between panels may be too great to hold the plastic section in compression, while the minimum The assembly of window and wall will be dimensioned on permitted gap is too small for it to be inserted. The UK the general arrangement plan as in 4.13, and if he is wise, Building Research Establishment’s paper on ‘Tolerance the architect will similarly designate the coordinating and Fit’ is important reading in this connection, as is BSI’s dimensions on the component drawing (4.14). 1999 publication BS EN ISO 6284. It will be prudent to note in the drawing set that this The above discussion is intended as the most basic of method has been adopted. A note on the component introductions to a complex subject. But it may be seen schedule or component drawing stating that ‘Dimensions how the whole of dimensioning practice becomes given for components are coordinating dimensions. The simplified by the concept of the coordinating dimension. manufacturer is to make his own reductions to give the 102 Drawing the set work size of the component’ should avoid the possibility The following comments may be helpful in establishing of error. the correct approach to dimensioning such diverse drawings as the site plan, primary element general arrangement plans, general arrangement and assembly Definitions sections, and component and sub-component details. It may be helpful at this point to summarise some of the To set out a building it is necessary to establish a datum terms referred to in a list of definitions and to add to parallel to one of the building’s axes. The criteria by them others in common use: which this datum is selected will vary. Where there is an improvement line required for the site, or an established Coordinating plane: Line representing the hypothetical boundary between two adjoining building elements. Coordinating dimension: The distance between two coordinating planes. Controlling dimension: The key dimension—normally between coordinating planes—which is the crucial determining dimension in an assembly and which must remain sacrosanct while intermediate dimensions may be permitted some tolerance. Work size: The actual finished size of a component. building line, these will obviously be important starting points. If the site is relatively uncluttered then existing physical features—boundary fencing, adjoining buildings, etc.—will be used. In certain specialised structures orientation may well be the overriding factor. The important thing is that the chosen starting points should be unambiguous and clearly recognisable on site. It is better to establish the datum some distance from the perimeter of the new building so that it may be pegged in as a permanent record during construction. Permitted deviation (sometimes known as The building may then be set out from it by offsets. A manufacturer’s tolerance): The amount (plus or minus) datum which coincides with one of the new building’s by which the finished size of a component may vary faces will be obliterated as soon as excavation starts. from its stated work size and still be acceptable. Where the construction is load-bearing the setting-out Dimension line: The line drawn between two planes with dimensions from the datum should be given to the a view to showing the dimension between them. outside face of the wall. Where the structure is framed this dimension should be to grid centre-lines. Extension line: The line drawn from a plane which is to be dimensioned and intersecting the dimension line. The dimensioning of the plan shown in 4.15 is largely self-explanatory. Note the three strips of dimensions Leader line: The line joining a note with the object which along the external walls, the string picking up the grid is the subject of that note. being the outermost line of the three. Overall dimensions Some examples are included, partly as an arithmetical check for the dimensioner, partly to aid the estimator. Appendix 5, dealing with non-active lines, gives examples of the types of dimension line recommended Generally speaking, internal setting out is effected by for different purposes. judiciously selected strings of dimensions. Where the 103 Working Drawings Handbook 4.15 Typical dimensioning of general arrangement primary elements plan. (The other general arrangement plans in the set will not need to record these dimensions) positioning of a given element is critical however (where, The only comment that needs to be made about for example, it must be a precise distance from a certain components and sub-components is the general one, wall face), it will be dimensioned from that face alone, to that they should be dimensioned to their finished sizes. ensure that the setter-out works in a similar fashion. When it is critical that a feature be in the centre of a wall This is particularly relevant when the material involved is face an ‘equal/equal’ indication should be given from its timber. A note to the effect that the finished section is to centre line. be ‘ex 150 ⫻ 150’ is too imprecise for a constructional world of off-site fabrication. Economy requires that the Figures 4.16 and 4.17 show the role of the controlling finished section should realistically be obtainable from dimension in vertical setting out. The salient levels one of the standard sawn sections. To give a finished dimensioned from the relevant datum (in this case the size of 150 ⫻ 150, for example, would result in the client finished floor level) in the assembly section appear paying for a large quantity of wood-shavings and again as reference planes in the larger scale detail. sawdust. 104 Drawing the set The superimposition of grids presents no problem with CAD, as they can be assigned their own unique layering that can be turned on and off at will. When drawn manually grids may be combined with the use of pre-printed sheets. A half-tone is usually adopted for the printing of the grid itself, appearing on the finished print in a fainter line than those used for the rest of the drawing. In practical terms, the use of grids is limited to general arrangement plans and they are of the greatest benefit in projects where rationalisation of the design has restricted the size and position of the elements. In 4.18 for example, where the use of a grid of 6 mm squares has allowed each square to represent a 300 mm module at a scale of 1:50, the placing of the 100 mm partition has been limited to one of three conditions. It is either centred on a grid line, centred on a line midway between grid lines or has one face coinciding with a grid line. Similarly, the door frame, with a coordinating dimension of 900 mm, is always situated so that it occupies three entire grids. No dimensions are needed to locate such elements if the discipline for positioning them is established from the outset and is known to everyone using the drawings. A word of warning however. It is not realistic to expect the man on site to set out a wall by counting grids and 4.16 The controlling dimension doing his own calculations. Dimensions should always be added to the grid for key setting-out positions, overall lengths and controlling dimensions. Grids The use of shadow grids has been around for a long Title panels time, particularly among the manufacturers of building The title panel should be at the bottom right hand corner systems, where components tend to be modular and of the sheet, so that when the drawing is folded properly, junctions simple and standardised. They are applicable the title and number are always clearly visible. A to traditional building as well however, whenever a possible exception to this is when A2, A3 and A4 sheets modular discipline exists, and when used with discretion are being used, where the title panel might be reduced can speed up the production of drawings and reduce the in height and spread across the full paper width to need for elaborate dimensioning. provide a more useable drawing area. 105 Working Drawings Handbook The panel may carry further optional information, such as the name of the project architect, the names of the persons preparing and checking the drawing, office job reference, etc. Figure 4.20 shows a suitable format; however, many are available. Title panels when drawings are prepared manually are best pre-printed on to standard drawing sheets. When the drawings are CAD-produced however, the panel is prepared electronically. It should be defined as a CAD block and inserted into each drawing sheet, which can then in turn be inserted into every drawing on the computer. If your practice logo uses a specific 4.17 Vertical location of elements in the assembly section is given by references to the planes established in 4.16 font it is probably best to create a bitmap image of that logo (.tif or .bmp) and insert that into your title panel. Figure 4.19 shows the recommended method of folding various ‘A’-sized sheets. (See Glossary of CAD terms.) That way the logo will not change if the computer used for plotting the drawing The format of the panel will vary but it must make (such as a plotting agency) does not provision for the following (minimum) information to be have that font installed. displayed: Depending on your CAD program it Name and address of the project may be possible to link the text items in Name, address, telephone number and email address of the title panel into a database or to the issuing office Title of the drawing Scale of the drawing Coded number of the drawing (status of issuing office— e.g. architect, structural engineer, etc.; nature of drawing—e.g. general arrangement, assembly, etc.; CAD software to maintain a drawing register automatically and keep track of revisions and drawing issue (see additional notes on managing the set in Chapter 5.) CI/SfB code, and unique number in that series Date of first issue Reference, description and dates of subsequent revisions. When drawings are prepared manually trimming lines and margins is unnecessary when standard ‘A’ size 106 Drawing the set 4.18 Modular discipline eliminates the need for complicated dimensioning by limiting the location of elements to certain standard situations. (Scale of original 1:50) sheets are used. It is useful however, if the line marking In CAD usage each drawing sheet should include a the left-hand of the title panel continues up for the full border so that you can see where the edges of your extent of the sheet, since this reserves a strip along the paper will be when creating the drawing in the computer. side of the sheet for the addition of notes, revisions, etc. (If the border is on its own layer it can be turned off 107 Working Drawings Handbook 4.19 Recommended method of folding ‘A’-sized sheets always keeps the title panel visible before printing if you prefer.) But many printers and We are told, in sequence, that the drawing is prepared plotters need margins at the edges to hold the paper by the architect; that it is a general arrangement; that it firm as it passes through the machine, so the borders is a plan taken at level one; and because this is an should be placed to take account of these. If you are elementalised set of drawings, we are told the element using a plotting agency don’t forget to set up sheets to which the drawing shows, i.e. primary element dealing suit their plotter too. with walls. 027 is the drawing number in that series. When completing the title panel it is most important that The identical title will appear in the drawing register (see the drawing title be stated simply and consistently, giving Chapter 5). the casual searcher a brief but accurate and informative statement about the drawing’s content: Annotation of the drawing Adding text to a drawing presents few problems when Arch/ G/ level 1/ (21)/ 027 108 working with CAD. Modern CAD programs, connected to Drawing the set 4.20 Example of drawing title panel 109 Working Drawings Handbook laser printers or inkjet printers, will have access to all the fonts installed on the operating system. There is a huge choice of styles, any of which might be used for text notes in the drawing. But remember that the aim of text is to convey information clearly and concisely. Don’t go overboard with too wild a font style and do use a size that is big enough to read on site. Imagine that a bricklayer with dirty hands is trying to read the drawing in the rain before the paper tears. Use one of the more common fonts, so that the text looks the same whatever computer you use for plotting. (If the font used to create text in the drawing isn’t installed on the computer that is used for plotting, the computer will attempt to substitute its best guess of close match for you, with sometimes surprising results!) Arial is a simple and legible font and is widely used. Text on CAD-produced drawings in this book has been annotated in Arial. Hand lettering With the pre-eminence of CAD this tends to be a dying skill. But even in the fully automated office there is from time to time the need for a manually prepared and lettered drawing, if only to provide the site office with an urgently needed detail. Such occasions demand a lettering style which is both rapid and legible. Figure 4.21 shows a recommended sequence of strokes in the formation of individual upper case letters. Increasing fluency and self-confidence (each generates the other) will enable this stroke-making procedure to be 4.21 Formation of the upper case alphabet simplified in due course into an acceptable and rapidly produced individual style. Horizontal guide lines are beneficial and if they are in blue pencil they will not lower case. The spacing between lines of upper case appear on the subsequently produced dyeline print. letters should not be less than the lettering itself. With lower case lettering the space should be somewhat Lettering for general annotation should be a minimum greater than the lettering to allow for upstanding stems of 2 mm in height for upper case letters and 1.5 mm for and tails. 110 4.22 A well-annotated plan (original scale 1:20) 111 Working Drawings Handbook The line should be either 0.3 mm or 0.25 mm, upstanding stems from one line coming into contact with depending on which range of pen sizes is being used. the tails from the line above. Most lettering will normally run from left to right of the drawing, parallel to the bottom edge of the sheet. Should it become necessary for lettering to run vertically it should always run from the bottom upwards. (This applies equally to dimensions.) Figure 4.22, prepared manually, is an example of wellspaced out lettering on a quite complex detail (actually a (52) general arrangement plan showing the drainage services). Note how a little forethought at all stages in the production of this plan has helped to ensure that With lower case lettering the spacing should be notes, dimensions and coded references do not clash somewhat greater than the lettering size to avoid with each other or with the building. 112 CHAPTER 5 Working drawing management The objective experience and ability, and during which only the most routine and undemanding of technical problems should Prior to this chapter production information has been the remain for resolution. In order to achieve this it is primary concern. It is this information—both drawings important that a more or less rigid adherence to the plan and specification—which represents the final of work is maintained. commitment to the building project of planning and constructional decisions arrived at during the earlier stages. This documentation is inevitably a time- The plan of work consuming process and if it is to be carried through smoothly and economically it is important that all the The RIBA Plan of Work was illustrated in Chapter 1 as necessary decisions should have been taken before its constituting the basic discipline within which the manifold commencement. activities of the architect are contained. Against each stage were noted the major aspects of work dealt with at It is also true to say that of all the aspects of an that stage which will have a bearing on the working architect’s work it is this final documentation that lends drawing process or which will be influenced by it. itself best to the deployment of a team. On very few projects will there be the time available to allow the The plan of work is sometimes criticised as being working drawings to be prepared by a single individual doctrinarian and unrelated to the harsh facts of and in practice quite small buildings will involve more professional life. Certainly, in practice there are constant than one person at this stage. pressures to do things out of sequence because there is a short-term benefit to be gained by doing so. It is very The objective therefore, is the achievement of a rapid, tempting when struggling with knotty problems of detailing well-programmed set of drawings, in which the or seemingly lethargic fellow consultants, to take the view information to be documented by each member of the that a premature start on the final drawings will in some team is allocated in advance with due reference to his way have a cathartic effect on the enterprise. 113 Working Drawings Handbook The increasing use of CAD, of course, has blurred the separation of the various work stages described in the plan of work. In the same way that word processing has transformed writing, CAD has transformed the process of designing buildings and describing them through applicable trade literature library of standard details drawing register design team network drawing office programme working drawings. The process is no longer a strictly linear one. We don’t necessarily have to finish the design before we start on the production information (though we may well be unwise to do so.) CAD forces the designer into making some decisions far These items are dealt with in detail below. Final design set (stage D) earlier than might otherwise have been the case. Even It will always be necessary to produce a set of drawings at outline stage it is possible for the walls to be drawn showing the final design, and if subsequent changes are with absolute accuracy, taking account of brick, block called for, no matter how minor, it is sensible to record and cavity thicknesses; openings may be drawn to these on the drawings or CAD files themselves in conform with coordinated brick dimensions. The layout addition to any other form, so that at any one time there might change as the design evolves but at any given exists an up-to-date record and confirmation of what has moment in time the ‘model’ is accurate. been agreed with the client. Nevertheless, a proper laying of the groundwork will Obviously these will be presentation drawings, prepared help to avoid those drawing office crises, destructive in the manner best calculated to obtain the client’s alike of morale and financial budgeting, when a team of approval. Nevertheless, before the trees and the several people is brought to a standstill by the sudden shadows are added, it is prudent to take a set from the realisation of some unresolved problem. So from the unadorned master files, for then definitive plans and standpoint of stage F let us look back to the preceding elevations will be available which may be issued stages, where a little forethought will make life in the immediately to other consultants on commencement of subsequent stages a great deal easier. stage E, and the rather fruitless business often encountered of ‘draft working drawings’ once design approval has been obtained may be eliminated, with Pre-requisites for stage F benefit to both office economics and programme. There is a basic minimum of information which needs to This implies, of course, that the scales and draughting be available before embarking on stage F and this techniques should be compatible with use for both should certainly include the following: purposes but this is quite feasible if their subsequent use is borne in mind from the outset (5.1 and 5.2). final set of design drawings (stage D) record of statutory approvals (stages D and E) key detailing in draught (stage E) room data sheets (stages C to E) outline specification The use of CAD, of course, renders the whole process much simpler and of even more economic benefit. The final design plans, denuded of their extraneous trees and shadows, will serve directly as the basic file for subsequent elementalisation, with the decorative 114 Working drawing management 5.1 Final design drawing as issued to the client for approval. Presentation techniques are designed to display the scheme attractively and to assist a layman’s understanding of it 115 Working Drawings Handbook 5.2 Copy taken from 5.1 before the blandishments were added. Scale and simple draughting make it suitable for issue to consultants for preparation of their own scheme drawings (or to nominated sub-contractors when CAD is not being used) 116 Working drawing management presentation features possibly remaining as an invisible It should be noted in particular how one draft assembly layer in the set. section generates a whole series of detailed statements about various aspects of the building. In the past it might Statutory approvals A chicken and egg situation this one—you can’t get approval until you’ve submitted the drawing: it’s pointless preparing the drawing until you’ve got approval. But visits to the fire officer and the building inspector in the early stages of the scheme will not only set up lines of communication which will be invaluable for the future but will establish principles for incorporation in subsequent detailing. It is a firming-up process. It is essential to know at the start of stage C the spacing of escape stairs the fire officer will demand have been thought adequate to issue the section as a final drawing, a ‘typical section’ from which the operative might be expected to infer detailed variations to suit differing but basically similar situations throughout the building. In today’s very different conditions this is just not adequate. It is, however, reasonable to expect a drawing office assistant to apply the principles involved to other aspects of the building, which they will either identify or which will be identified for them by others with greater experience or knowledge of the particular building. and by the end of it their widths. It is essential to know This approach to detailing, whereby the basic principles before the end of stage E the required fire rating of all of construction are established by the principal or the doors. Nobody should need to raise such questions in project architect but are translated into detailed practice the middle of stage F. by an assistant, lends itself to considerable drawing office economies. By defining the necessary drawing office The decisions and agreements must be recorded, of tasks at the outset of the programme (a subject which will course, and it is obviously more helpful to give someone be dealt with in detail later) the appropriate level of a marked-up drawing to work from than a bulky file to responsibility may be set for all members of the team. read. The final design drawings referred to above as being issued to consultants form an obvious basis for the recording of this sort of information (5.3). Key detailing in draft (stage E) Room data sheets The advantages of room-by-room scheduling as a medium for conveying information about internal finishes and fittings have been noted earlier. The gradual At the completion of stage E there should be a carefully collection during stage E of such information into a thought out solution available for every construction source document of comparable format will clearly assist problem that can be envisaged; this will involve the in the preparation of such schedules at stage F. Whether production of a sheaf of draft details in which the this is done on a copy of the floor plan or on a series of principles of these solutions are established. individual sheets representing each room or room type, is a decision which will be made in the light of the size The drafts will not be elaborated into final drawings. and complexity of the individual project. At the end of the They will remain as source documents and the decisions day there will exist, hopefully, a complete record of each they embody will be fed out into various stage F room’s requirements, with indications where applicable drawings—or computer files if CAD is being used for as to the authority for those requirements, serving alike detailing. General arrangement sections, assemblies and as a detailed record of client instructions and a briefing component details, as well as the specification, will manual and check list when the final document is being come into this category. prepared (5.3). 117 Working Drawings Handbook 5.3 118 Copy taken from 5.2 and marked up as a briefing guide to the drawing office at stage E Working drawing management Outline specification The case is argued elsewhere in this handbook for a by the drawing office junior at the last minute because time was short and nobody had told him any better. specification which is an integral part of the production documentation rather than the afterthought which puzzled Trade literature site staff often assume it to have been. If drawings are to The rationalised drawing structure provides a convenient be freed of the detailed written descriptions they are framework on which to hang manufacturers’ literature. frequently made to carry, it is implicit that this information There is no virtue in redrawing the builders’ work details must be conveyed to the contractor by other means. printed in Bloggs & Company’s catalogue when a Indeed, the philosophy of the National Building photocopy or scanned image suitably overcoded with Specification is reliant upon the geometry of the building the job and drawing number will convey the information and of its component parts being covered by the drawings, more cheaply and accurately. (Bloggs & Company are with selection from alternative materials and definition of not likely to object to the resultant wider distribution of quality standards being covered by the specification. their literature.) Indeed, a number of manufacturers will provide the architect with CDs of their products, for It should be noted that some CAD programs specifically incorporation into their CAD drawings. tailored for architects will provide links to NBS specifications. It can also be helpful to have both a CAD drawing and NBS text file open at the same time on a computer, with the designer preparing the specification in parallel with the drawings. It is desirable therefore that both drawings and specification should draw their information from a common source document and that this document should be Manufacturers’ trade literature should always be reproduced with caution. If there is an error in the manufacturers’ literature and this is reproduced in the architect’s own drawing, who is responsible if a manufacturer corrects an error in a data-sheet but the architect does not update his drawing based on that data-sheet – who is liable? produced before the stage F programme gets under way. However, in any case the literature which it is known will The outline specification is a useful format for this be required, if only as source documents for one’s own document, partly because something approaching it will drawings, should be assembled early in the day. It can have been needed by the quantity surveyor for his final be frustrating to interrupt work on a detail to telephone design stage cost check to have any validity. for urgently needed trade literature and then wait two or three days for its arrival (5.4). It consists basically of a check list (CI/SfB elemental order is a convenient framework) upon which decisions Library of standard details of construction and materials may be noted as they are made. Many practices attempt, at some point in their existence, to crystallise the accumulated wisdom and experience of Formalising these decisions into such a document at an the practice into a set of standard details, only to find with early stage ensures that they are made at the proper level increasing disillusionment as they proceed, that not nearly of experience. Readers of The Honeywood File will recall so much is really standard as was at first supposed, and Ridoppo, the wonder paint that crept off the walls and out that the very existence of a standard drawing which is of the house. We have all had our Ridoppos but at least it nearly (but not quite) applicable to the project in hand is a ought to be possible to ensure that they are not selected dangerous inducement to compromise. 119 Working Drawings Handbook 5.4 Manufacturer’s catalogue gives precise fixing details. It is pointless to redraw this information when the catalogue can be issued to the contractor as an instruction 120 Working drawing management On the other hand, it is frustrating to realise that the detail being worked out laboriously in one room on project A is not going to end up significantly different from the detail simultaneously being worked up across the corridor for project B. There should be room somewhere for a common-sense approach which does not attempt too much. In practice, few assembly details can be drawn so ‘neutrally’ as to render them directly reusable on more than one project. The best that can be achieved in this field is to collect together drawings for various projects which embody solutions to recurring problems of principle, making them available for reference rather than direct reuse. The ease with which details drawn with CAD from another project can be altered and reused makes them ideal candidates for an office’s standard vocabulary. Component drawings are another matter, however, and provided that the office is using a structured drawing Design team programme It is essential for the work of the entire design team to be integrated into a comprehensive programme, and unless a specialist programmer forms part of the team (and this is almost a sine qua non for any very large or complex project) then the management role of team coordinator falls to the architect. Of all the consultant team an architect is probably best fitted by virtue of his training and other duties to exercise the skills required, and should take advantage of his position as team leader to establish the appropriate procedures at the outset (see the section Design team meeting). In setting down the programme on paper, it will be found that a simple network is the best format, where the dependencies of the various team members upon each other may need to be shown. The format suggested in an early (but still valid) edition of the RIBA Management Handbook Guide on Resource Control is a good way to do it (5.5). method it should be possible for each project to contribute its quota of contractor-made components Its complexity may be unnecessarily daunting for the (there is no point in redrawing proprietary items) to a small- to medium-sized project however, particularly central library. Such components as doorsets, shelving, when a non-technical client is involved (the method is cupboard fitments and external works items—bollards, best suited to computer analysis and critical path fencing, etc.—are suitable subjects for treatment. method which may not always be available). A simplified version on which a time scale has been superimposed The details, once selected for a standard library, will serve the same purpose in most cases (5.6). should sensibly be renumbered to ensure that when reused on new projects they do not conflict with the The point to be re-iterated is that every job, no matter numbering sequence for that project. C(32)501, for how small, benefits from thoughtful programming, and example, might well be the first drawing in a library of the things to watch which are common to any method internal joinery components, and would not conflict with you use are: component details specific to the project and numbered C(32)001, etc. Restrict the network to as few activities as you reasonably can, paying particular attention to those activities whose The use of CAD raises other issues. The ease with completion is a prerequisite for subsequent action by which details stored electronically may be altered means others. The purpose of the network is to provide each that assembly drawings too may more frequently form member of the team with basic management information. part of a standard vocabulary. (Each team member may well wish to develop, for their 121 Dates Major activities Client Architect design function Architect management function Quantity surveyor Structural engineer Services engineer Contractor or sub-contractor 5.5 Precedence diagram (taken from an early edition of the RIBA Management Handbook). It has the advantage that it offers a rapid assessment of the consequences of any programme’s change, by its compatibility with computer analysis Working drawing management 5.6 A less sophisticated network, with the advantage that the time scale is immediately apparent. More readily understandable by the average client (and architect?) than a computer print out own purposes, a more detailed network of their own Involve the client. Many of the client’s activities are activities within the team management’s framework.) critical ones, particularly his formal approvals at various stages in the design, and he must be made aware of Make it simple. Its value as a document is that it can his responsibilities at the outset, along with the respond rapidly to a changed situation, and it must other members of the design team. In so far as his always be a realistic statement of the current position if it approval may be conditional on consideration by is to retain its credibility. It is no use having a programme committees within his own organisation adequate drawn so beautifully and in so much detail that no one time for decision-making must be built into the has the heart to redraw it when it becomes out of date. programme. 123 Working Drawings Handbook Planning the set involved, and that the decision has been made to produce 1:100 general arrangement plans, elementalised for clarity. The structure of the final production set of drawings is central to both the smooth running of the project on site Assuming that the set is to be produced by CAD, the and the economics of the office producing it. It must first allocation of files will be to general arrangement therefore be considered in some detail. plans, one for each plan level. They will be coded G(— —) i.e. ‘The project in general’, because they are the basis General arrangement plans Given that the set is to be structured in the manner recommended in the earlier chapters the first decision to be made (and as noted earlier it will have been sensible to make it before preparation of the final design from which the subsequent elementalised layers will be produced. (As has been noted in Chapter 4, numbering of the plans by floor levels is a refinement which, apart from possessing a certain elegance for the systemminded, offers eventual benefits to the site staff). drawings) relates to sheet size and scale of the general arrangement plans. Basically the choice lies between a scale of 1:50, permitting a relatively large amount of information to be conveyed on a single sheet, or 1:100 where a greater degree of elementalisation will be required if the sheet is to remain uncluttered and legible, and where its main purpose is to provide a ready The basic plans having been established it is necessary to consider what elemental plans should spring from them. The CI/SfB project manual offers a sensible method for identifying these. The complete range of elements in CI/SfB Table 1 is available and offers a useful check list (see Chapter 1). indication of where other and more detailed information is to be found. Generally speaking, however, few projects—and then only those containing problems of a specialised A number of considerations will determine this decision, nature—will need to go beyond the much more limited but they will centre around the size and complexity of range shown in Table IV. the project. Housing and conversions are normally best carried out at the larger scale. Larger projects are often Other general arrangement drawings better suited to an elementalised set of general Site plan, elevations and basic sections complete the arrangement plans. general arrangement set. The complexity of the external works will influence the decision on whether or not to put Most CAD programmes work at 1:1. This means that the all general arrangement information on a single drawing. CAD ‘model’ is created full size, and that only later will This is an area where coordination of information is of views of this ‘model’ be created, and only then that the paramount importance and this may outweigh the other drawings will be assigned their plotted scale. It is advantages inherent in the elemental approach. obviously important that every drawing be presented at a recognisable scale in general use in the building industry. General arrangement sections In the discussion that follows it will be assumed that a These are best identified from the final design drawings. single multi-storeyed building of some £2 000 000 contract The external envelope of the building will generate the value is being dealt with (the building, in fact, parts of majority and the most important of these, so the which have been used previously in Chapters 1 and 2), approach illustrated in 5.7 is useful. Bearing in mind that a drawing team of three or four people will be that the approach initially is in terms of strictly limited 124 Working drawing management Table IV A typical range of CI/SfB codes used on a large project This band will normally be used for The location drawings and a large project number of the assembly drawings on (– –) small projects; for basic location plans (i.e. before process negatives are taken) on large projects. (2–) (3–) primary secondary (4–) elements elements (5–) finishes drainage (7–) (8–) fixtures loose This band will normally cover the elementalised location plans on most equipment projects. It will also be used for assembly and component coding on small projects. (30) (31) (32) (35) (82) (87) special site ext int suspended general secondary wall wall ceilings room loose loose equipment elements openings openings equipment This band will normally cover assembly and component details and schedules on most projects, but may well be found unnecessarily detailed (20) (21) (24) (27) site external stairs roofs primary walls elements for small projects. (70) site fixtures (72) (74) general sanitary room fixtures fixtures strip sections rather than the traditional ‘section through the building’, work systematically round the building, marking on a print the necessity for a fresh section every time the condition changes. You will finish with a series of G(21) details—desirably at a scale of 1:50— whose function will be to establish all important vertical dimensions and to provide references to larger scale (and largely repetitive) assembly details of head, sill and eaves, etc. The drawing register The drawing register is a key document in the proper organisation of a working drawing project and as such needs to be something rather more than the loose sheet of paper with a scribbled list of drawing numbers and titles which sometimes suffices. After all, it serves a multitude of purposes, being at various times a declaration of intent, a record of performance and, in the event of dispute on abandonment of the project after commencement of the working drawings, possibly a The general arrangement drawings are listed in Table V legal document. as they would appear in the drawing register. In any case, it will have a relatively long and hard life, so Assemblies, components and schedules it should be housed in a hardback folder or file, The assembly drawings, component drawings and preferably of a colour striking enough to make it easily schedules appropriate to a project of this nature are identifiable in the drawing office (it is essential that it be listed in Table VI. to hand immediately whenever a drawing is completed) 125 Working Drawings Handbook 5.7 A print of the elevation has been used to identify every section through the external walls where the construction changes and in a loose leaf format so that sheets may be each CI/SfB element used. In consequence, there will removed and inserted easily. A4 is the obvious size, be a relatively large number of sheets in the register, and 5.8 illustrates a useful format. but the advantage will be that the bones of the drawing structure are laid out for all to see, in strict numerical It is strongly recommended that the register be sequence, and that if subsequently the need for a prepared at the beginning of the working drawing fresh drawing is identified (and the initial identification programme, immediately the approximate list of is unlikely to be accurate to within 5 per cent) then it required drawings has been identified. Its sequence of may be entered without disruption either of the entries, therefore, will be similar to that of the drawing numbering sequence or of the register’s own hypothetical list of drawings and schedules given in page order. Tables V and VI; that is to say, it will be divided into general arrangement, assembly, component and Within this framework the make-up of the individual schedule categories, and a single sheet will be given to register sheet may vary, but the information it should 126 Working drawing management Table V General arrangement drawings listed as they would appear in the drawing register Drawing number Scale Title Comments G(— —)001 1:100 Plan at level 1—Basic These are the basic floor plans from which copy 002 2— ,, negatives will be taken for development by the 003 3— ,, architect and other consultants into elemental 004 4— ,, plans. Numbering of plans by levels 005 5— ,, aids retrieval of elementalised information and offers a useful framework for identifying scheduled components, e.g. (31)2/11, identifies external (window) opening no. 11 on level 2. These plans in their basic form will not be issued for construction purposes. G(— —)006—009 1:100 Elevations 6,7,8,9 — Basic Similar basic drawings of elevations and sections. 010—013 1:100 Sections 10,11,12,13— Basic Composite drawing numbering, e.g. 006–009, enables unique identification of each of several drawings on the same sheet. E.g. the second elevation may be referred to simply as G (— —) 007, rather than ‘detail no. 2 on drawing G (— —) 006’. Sections are skeletal only and confined to giving a datum for each of the plan levels and giving a general picture only to the contractor. G(— —)014 1:200 Site plan The site plan is the only G (— —) drawing to contain elemental information and to be issued for construction purposes, although the G(— —) elevation and sections will be issued for the contractor’s background information. G(2— )001 1:100 Plan at level 1—Primary elements The key set of plans giving dimensioned 002 2— ,, setting out information about the building. Note 003 3— ,, that while it would have been quite possible and 004 4— ,, perfectly in accordance with CI/SfB logic to split 005 5— ,, the information carried on these (2–) plans into (21) external walls, (22)—internal walls, (23)—floors, (24)—stairs, (27)—roof and (28)—frame, common sense and the straightforward nature of the project suggested that a single (2–) grouping of these elements would suffice. G(2— )015—020 1:50 General arrangement The key a sections described earlier. sections—External walls They could equally well be coded (21) since they deal specifically with the external walls, but in either case their numbering commences at 15 to preserve the integrity of the numbering system. Again, ‘Drawing G(2–) 015–020’ provides a unique identification for each section. 127 Working Drawings Handbook Table V (continued) Drawing number Scale Title Comments G(3–)001 1:100 Plan at level 1—Secondary elements This series is used in this particular set as a 002 2— ,, means of locating, and uniquely identifying for 003 3— ,, scheduling purposes, internal doors, roof lights, 004 4— ,, gulleys and balustrades. While the plans group all 005 5— ,, this information under the (3–) code, nevertheless the referencing of individual components will be more G(3–)006–009 1:00 Elevations 6,7,8,9—Secondary specific, e.g. plans G(3–), will locate and identify elements both (32) 2/007 (internal opening, i.e. door number 7 on level 2) and (34) 003 (balustrade number 3). External openings, i.e. windows, external doors, ventilation grilles, etc. are located and numbered on these elevations. Note that while suspended ceiling (35) may also be included on the G(3–) series if required it may be less confusing to give them a separate (35) series of plans. Again common sense will dictate the approach. G(4–)001 1:100 Plan at level 1—Finishes There are many ways of indicating the finishes 002 you want. You may tabulate them into a purely 003 descriptive schedule. You may code them into a form 004 of shorthand (e.g. F3 ⫽ Floor finish type 3) and refer 005 them back from the plans to a vocabulary of finishes. (This is the method assumed in this G(4–)006–009 1:100 finishes Elevations 6,7,8,9—External set. It has the advantage that a drawn vehicle for the information already exists, i.e. the basic plans, and the elemental method allows decisions on finishes to be deferred without detriment to other more urgent information being conveyed to the contractor at the right time.) Or you may use the room data sheets already referred to, with the advantage that this approach is more consistent with the room-by-room way in which finishing tradesmen actually work. The elevations are an obvious medium for conveying information about external finishes, and their representation may vary from Letratone to laboriously drawn brick coursing. NBS offers a more precise and less onerous alternative with its system of coded references tied back to comprehensive specification descriptions, F11/1 for example will be uniquely designated in the specifications as ‘the selected facing brick laid in 1:1:6 cement-lime-sand mortar in Flemish Bond and with flush pointing’ and the coding F11/1 on the elevation will delineate the areas to which this description applies. 128 Working drawing management Table V (continued) Drawing number Scale Title Comments G(7–)001 1:100 Plan at level 1—Fixtures Self-explanatory, although it might be questioned what 002 2— ,, fixtures would appear on level 5 (roof). In this case, 003 3— ,, the (7–) coding was used to cover window cleaning 004 4— ,, track. And a flag pole. 005 5— ,, G(8–)001 1:100 Plan at level 1—Loose equipment This coding seems to cover a multitude of omissions 002 2— ,, in practice. Mirrors, notice boards, fire exit signs, fire 003 3— ,, extinguishers—all tend to get added late in the life of 004 4— ,, a project. Rather than re-issuing cluttered-up and 005 5— ,, dog-earned amended copies of other plans, it is preferable to reserve an (8–) set of copy negatives for eventual use. provide will consist of, at the minimum: the second place, there is really very little to be gained from such a record. A check on drawing issues should 1 Drawing category : i.e. general arrangement, assembly, component or schedule. be possible from other in-built procedures, such as standard drawing circulation lists or drawing issue sheets. 2 Drawing element : its CI/SfB number, or other coded reference. 3 Drawing number : its unique identification within the A CAD user would almost certainly maintain the drawing register in electronic format as a computer file. category and element. 4 Revision suffix. 5 Scale : not essential to the record but can be helpful. 6 Size of sheet : because A4 and A1 drawings are unlikely to be stored in the same container, and the searcher must be told where to look. One test of the effectiveness of a drawing retrieval system is that it should always be quicker to locate the given drawing in the register and then go to it straight away than to leaf hopefully through the vertifile. The date of completion and the dates of any revisions Status coding As has been noted earlier, many drawings perform different functions at different stages in their life, and some system of identifying their function at a given moment is a useful adjunct to a coding system. One such method is to use the letter reference of the appropriate RIBA stage of work in conjunction with the drawing number, as follows: are not included, for they will be recorded on the E: Detail design drawing. Any working drawing up to the drawings themselves. Neither is it desirable to use the time it is frozen for issue to the quantity surveyor, when drawing register as a record of drawing issues. In the it becomes: first place this practice imposes an administrative strain upon the drawing office, which is likely to act G: Drawing reconciled with bills of quantities. That is the unfavourably to seemingly bureaucratic procedures. In stage at which the drawings form part of a tender set. 129 Working Drawings Handbook Table VI Assembly drawings, component drawings and schedules listed as they would appear in the drawing register Scale Title 1:5 External wall details Comments Drawing number A (21) 001–020 Assembly details illustrating the entire range of different external wall conditions to be found on the project, including door and window heads and sills, and, in this instance, the footing, and ground floor junctions. It would have been equally possible to code these latter conditions A(16)—Foundations, or A (23)—Floors, but these were only two variants on this particular project and common sense prompted their inclusion in the A(21) series rather than a pointless further extension of the elementalisation. A (27) 001–003 1:5 Eaves details A (27) 501 1:5 Parapet detail Parapet and eaves details, however, are covered separately under an A(27)—Roof series, largely because the office possessed a standard parapet assembly drawing which it wished to use on this project, and which was already coded as A(27). It is numbered 501 because it is desirable to keep the sequence of standard drawing numbers well clear of numbers used for specific project purposes. The gaps in numbers which thus appear may be criticised as leading to confusion and doubts on site as to whether they are in possession of the complete set. It is felt, however, that the advantages outweigh these possible objections, and that the objections themselves largely disappear if the drawing register procedures discussed elsewhere are adopted. A (31) 001–010 1:5 External wall opening assemblies—Sheet 1 A (31) 011–018 1:5 External wall opening assemblies—Sheet 2 The A(21) series will have covered a number of assemblies which also convey information about secondary elements —e.g. a lot of the head and sill conditions for windows and external doors. The process of filling in external openings schedules in the format recommended previously will automatically throw up a number of conditions not taken care of in this series and these, together with the jamb conditions, form the subject of the A(31) assemblies. A (32) 001–006 1:5 Internal wall opening assemblies—Sheet 1 A (32) 007–012 1:5 Internal wall opening assemblies—Sheet 2 A similar series covering internal openings. Two A1 sheets have been assumed, but the details might equally well have been carried out on a larger number of A4 or A3 sheets. Note that this series conveys assembly information only about the openings themselves —head, jambs and sills where appropriate. Information about what goes in the openings—e.g. internal doorsets—is given elsewhere in a series of C(32) component drawings. Here again, the necessity for a particular detail will be made apparent by the openings schedule. A (35) 001–004 1:5 Suspended ceiling Manufacturers’ drawings will often be sufficient for describing the fixing assemblies of suspended ceilings. In the present case the drawing covered the timber framework for bulkheads at changes in the ceiling level. A (37) 001–003 1:5 Rooflight assemblies With the limited elementalisation applied to this set, it may be argued that this drawing could have been grouped under (27) —Roofs, a category which already exists for other purposes. 130 Working drawing management Table VI (continued) Scale Title Comments Component and sub-component drawings* Drawing number C (31) 001—008 1:20 External openings component 1 to 8 The windows and external doors in this set are conveyed on separate sheets, each sheet giving dimensioned elevation of what is required. They are supplemented by an SC(31) series of details showing SC (31) 301–304 1:5 Sub-component construction details—Sheet 1 SC (31) 305–308 1:5 Sub-component construction details—Sheet 2 constructional details of the components themselves (timber sections, throatings, fixing of glazing beads, etc.). As with the assemblies, where a 500 series was used to keep standard drawings separate from the project numbering sequence, here the 300 series is used for a similar purpose. SC (31) 309–312 1:5 Sub-component construction details—Sheet 3 C (32) 001 1:20 to Internal openings component 1 Components filling internal openings covered by a similar method. The to component is regarded as the doorset, rather than the door. This is in C (32) 015 1:20 Internal openings component 15 line with modern joinery shop practice and avoids the difficulties of some SC (32) 501–504 1:5 Sub-component construction joinery drawing methods where the door and its frame are treated as details—Sheet 1 SC (32) 505–508 1:5 Sub-component construction SC (32) 509–512 1:5 Sub-component construction details—Sheet 2 details—Sheet 3 SC (32) 513–516 1:5 Sub-component construction details—Sheet 4 separately detailed items, giving rise to problems of coordination and of dimensional tolerances. In the present method these problems are placed where they rightly belong, with the manufacturer. The component construction details are in a 500 series, being office standard drawings. This is an area that lends itself profitably to standardisation. The overall size of component is specific to the project, but the frame sections are standard regardless of component size. Schedules Schedule number S (31) 001 Schedule of external openings S (31) 101 Schedule of external ironmongery When the number of components in a category is small, and/or the number of ways in which potentially they may vary is also small, then it S (31) 001 Schedule of external openings may be left to the appropriate location drawing to identify them, and to S (31) 101 Schedule of external ironmongery the appropriate component drawing to illustrate them. Once you start S (31) 001 Schedule of manholes getting half-a-dozen types, however, and each type may vary as regards its head and jamb assembly, ironmongery and architrave, then it becomes a better bet to number the components on the plan and to refer the searcher to a schedule in which can be tabulated all the variables applying to a given component. The three main schedules in this set are of this kind. Each gives a numbered list of manholes and openings and uses this as the starting point from which to refer to drawings covering all the variables affecting the component. The ironmongery schedules are rather different in purpose and in format. They are essentially vocabularies of fittings, made up into sets. The opening schedules call up the set of fittings to be fixed to the relevant door or window. * The examples given are sufficient to illustrate the principle. In practice, other component drawings might cover, for example: copings, pre-cast cladding panels (21), stairs, cat-ladders (24), lintels (31) and (32), balustrades (34), roof lights (37), skirtings (42), litter bins and bollards (70). 131 Working Drawings Handbook 5.8 A useful format for the drawing register. The explanatory notes help site staff as well as the drawing office 132 Working drawing management It may not be released for construction, however, until it described later. However, CAD introduces additional becomes: requirements. CAD drawings are often plotted ‘in house’, with each plot requiring little more effort than a couple of K: Construction drawing. Finally, and where the need for mouse clicks. Very soon you have dozens of prints, each record drawings justifies it, the drawing becomes: superseding the previous in some minor detail and possibly ten minutes apart. It is not practicable to M: As constructed. provide each revision with a unique revision letter. This enables drawings to be issued for information A practice might also be maintaining multiple copies of only, without fear that, for example, the quantity a drawing file on different computers, or in different surveyor will measure from an incomplete drawing or sub-directories on the same computer; some may be that the contractor will build from unauthorised back-up copies in case of hard disk failure; some may information (5.9). represent different stages in the evolution of the design. For internal purposes a practice will need to know more The method is also of value when a drawing is prepared about a drawing plot than just its number and title. as a basis for a manufacturer to prepare his own component drawing. In this case the architect prepares One solution is to have a second ‘For Office Use Only’ his own reference drawing with a status E. This is issued identifying code printed elsewhere on the drawing, to the manufacturer, whose own working drawing is including the time and date the plot is made plus the full issued to site, the architect’s drawing remaining at file name and computer path of the originating CAD file. If status E. placed in the opposite corner of the print and outside the margins of the drawing proper, confusion with the ‘public’ A typical drawing number, containing all the information title panel should be avoided. In this way the version of a referred to above, would be as shown in 5.10. plotted version can always be identified (5.11). (As a bonus, this information can also be written to a simple CAD considerations text file, providing a crude record of drawings plotted.) The addition of status coding is a useful adjunct to the issue of CAD files also, the status reference being added to the layer naming convention reference 5.10 A full drawing number, using the system described. The number within the heavy box is the drawing’s unique identification and is the minimum information required by anyone searching for it. It indicates that the drawing is of a component filling 5.9 Status coding of a drawing indicates only its status an internal opening and that it is number 107 in the at the present time. This stamp freezes the drawing at series. The K at the left indicates that the drawing has the point when it relates to the other contract documents been released for constructional purposes. The issue and is invaluable in managing the contract is Revision B 133 Working Drawings Handbook early on, document it, and ensure that it is used at all times. If you exchange CAD drawing files with other professionals on a project it is essential that everybody uses the same layer naming conventions. Proper naming of layers within the model is important to ensure that each professional can establish ‘ownership’ 5.11 Coding system for internal office use of the layers that they create. The Layer Naming Standard set out in BS 1192 Part 5 makes provision for including an ownership code within each layer name. Depending on the CAD program used it may even be Similarly, an efficient and properly documented layer possible for each professional to lock their layers with naming convention is essential. It is no good drawing password protection, preventing other members of the something on a layer and then forgetting where it is. You design team editing them (intentionally or otherwise) need to establish a naming convention for your practice without their consent. 134 Working drawing management Portable document format Portable document format (PDF) has long been a de facto standard for the distribution and exchange of electronic documents. It is a computer file format that preserves the be conditioned by his knowledge that further amplifying details are envisaged as part of the complete set. Other people’s drawings fonts, images, graphics and layout of any source When other consultants are circulating CAD files their document, regardless of the application and platform used receipt should be registered and filed under the to create it. Adobe © PDF can be viewed and printed by recipient’s own file storage system. anyone with free Adobe © software which can be sent along with the file, or downloaded from the Internet. The proper recording and storage of incoming drawings however often presents a problem, particularly when their Unlike their originating source files created with CAD or word processing programs, PDF files cannot be edited. They are therefore of no use when a two-way exchange of information is needed. But where it is necessary to provide information in a secure and reliable electronic form that can be viewed or printed by the recipient, yet cannot be modified, they are ideal. From version 6 numbering system bears no relation to the structure of the architect’s set. Should one open up an incoming drawings’ register for each consultant and manufacturer, laboriously entering drawing titles and number and date of receipt? Should one even attempt to give each incoming drawing a fresh number, to bring it into line with internal systems, and to aid storage and subsequent retrieval? onwards, PDF files have supported layers that can be These methods are laborious and irksome, and unless turned on or off by the recipient, giving them more they are carried through 100 per cent efficiently they are flexibility when viewing or printing CAD documents. liable to break down. If only one drawing goes unrecorded because it was needed urgently for reference The major CAD programs have built in ability to create purposes at the workplace before anyone had time to either PDF files, or an equivalent such as AutoCAD’s enter it in the register, the system collapses, and might DWF. as well have never been started. Simple PDF creation programs can be downloaded from It is far better to insist on all consultants preparing and the internet free of charge. circulating their own drawing register in the way previously described. Each office then has a document Circulation against which incoming issues may be checked, and by means of which possible omissions and out-of-date The greater the use that is made of the drawing register revisions may be noted. the more important does it become to exercise proper discipline in its maintenance and circulation. In particular, As for the storage of incoming drawings, they may be it is a useful procedure for the up-dated register (and dealt with in the same way as one’s own prints and those of the other consultants) to be copied to all negatives, and stored in drawers or hung vertically. concerned at regular intervals—e.g. on the first of each Alternatively, they may be folded into A4 size with the month, or as part of the site meeting agenda—so that all drawing number outermost, and stored upright on team members are aware of the up-to-date position. This shelves in numerical order. This is simple and space- is of even greater importance when drawings are being saving, but presupposes that a drawing register is issued in sequence, whether for billing or construction available in which the search for the required drawing purposes. The recipient’s attitude to a given drawing will may be initiated. 135 Working Drawings Handbook Issuing drawings It has already been noted that the drawing register is not a convenient document for recording the issue of drawings to others, neither, although it is sometimes used for this purpose, is the drawing itself. Indeed, one should first start by questioning the need for such a record in the first place. That drawings, both on completion and on subsequent revision, should go to the people who need them, is perhaps self-evident. Yet instances abound of site staff working from out-of-date information, of revision B going to the structural engineer but not the M & E consultant, of the quantity surveyor being unaware of the expensive revised detail agreed on site and hastily confirmed by a sketch to the contractor but not to him. The fundamental question for anyone engaged in preparing working drawings—who am I doing this for?—needs to be asked yet again here. Whoever it is being drawn for needs it, and the commonsense procedure of mentally running through the list of everybody whose understanding of the job is remotely changed by the preparation of the new drawing or revision is a valuable discipline for reducing communication gaps. Send to too many rather than to too few is a good maxim. given drawing, and to some extent throws the onus on them for ensuring that their information is up to date. As to the more mundane question of physically conveying a package of drawings from one office to another, then the larger drawings, unless they are rolled (which is irritating for the recipient) will be folded down to A4 or A3, depending on their volume, and always, of course, with the title panel on the outside (see 4.19 and 4.20). Small drawings, whether of A4 or A3 format, should not be issued loose when they form a set. Their use is sometimes criticised, especially by builders, but a lot of this criticism stems from their misuse in practice rather than from any inherent defect in their size. They are only difficult to coordinate if no logical search pattern holds the set together, and they only get out of sequence or get lost if they are issued unbound. It is important therefore that sets of small drawings should be treated as instruction manuals rather than individual sheets, and should be held together accordingly in simple folders (loose-leaf to facilitate photocopying for issue to suppliers by the contractor). It is anomalous that the motor engineer assembling a car in the protected The keeping of a drawings issue register, however, conditions of a factory or workshop should be given a will not of itself guarantee that the right people get the book of instructions to work from, while the building right drawings. The best we can achieve is to set up operative working on precarious scaffolding and battling disciplines which, if they cannot prevent errors and against wind and rain should traditionally be expected to omissions, can at least assist their detection in work from loose sheets of paper flapping round him. due time. It is appropriate that such bound manuals should Two such disciplines may be mentioned. First, the use of contain the drawing register, and some form of guide to a drawings issue slip when any drawing leaves the the drawing method. office—even though accompanied by a covering letter— provides an easily leafed-through file record in the One approach with CAD is to publish all drawings in issuing drawing office (5.12). Second, the routine issue electronic format on a secure ‘members only’ website. All at regular intervals to all members of the team— the team can see the latest revisions and can call for contractors, sub-contractors and consultants alike—of their own copy if needed. This puts the onus on the drawing register. This at least enables the recipient recipients to request drawings rather than on the to check that they are working to the latest revision of a architect to issue them. 136 Working drawing management drawing method becomes universally employed and recognised throughout the building industry—and despite the increasing emphasis being laid on the Coordinated Project Information documents previously referred to we are still a long way from that—it is incumbent on the producing office to give clear directions as to how its drawings may best be used. Instruction must take two forms if it is to be effective. There must be a verbal explanation of the method, when the building team is shown the search pattern for information. The initial site meeting is a useful venue for this. There must also be a written guide for subsequent reference, and this will be a useful document to bind into the office manual. Newcomers to the office need to know how the office method works. An office manual which embodies the drawing and coding methods advocated in this handbook could be prepared for use by other members of the office, other consultants and contractors alike. It might be set out as shown below. A Guide to these Drawings The drawings in this project have been 5.12 Drawing issues form accompanying all drawings issued provides a convenient file record of such issues arranged in the following manner: 1.0) All information in the drawing set is divided into five basic categories Drawings guide of drawing. These are (relating for example to windows): It is no use preparing your drawings on a well structured and carefully thought out basis if you are the only one who knows about it. Until such time as a standard ● General arrangement drawing (coded G) showing where anything 137 Working Drawings Handbook is—e.g. where a particular window is located in the ● (3-) building. (This includes general arrangement plans (i.e. everything filling openings in walls, floors and and elevations, locating all major building elements— roofs; suspended ceilings and balustrades). walls, doors, windows, etc.—and indicating where (4-) Finishes. more detailed information may be found. (5-) Services. Component drawing (coded C) showing what it is— (6-) Installations. e.g. what the window looks like, how big it is, etc. (7-) Fixtures (This includes the size and appearance of all components—windows, doors, shutters, fitments, (i.e. sanitary fittings, cupboards, shelving, etc). (8-) cupboards, etc.). ● Secondary elements Assembly drawing (coded A) showing how it is Loose equipment (i.e. fire extinguishers, unfixed furniture, etc.). (—) The project in general incorporated in the building—e.g. how the window (i.e. information of a general nature which cannot relates to the sill and to the wall in which it is built. readily be allocated to any of the preceding (Demonstrating the manner in which the various elements). building elements and components fit together. ● Storey sections through external walls are an obvious 3.0) All of these codes will not necessarily be used on instance.) any one project. A list of the elements into which the Sub-component drawing (coded SC) showing the present set is divided is given at the end of this guide. detailed construction of each component—e.g. the The element will always be recognisable from the section of the window frame. (A timber window, for drawing number box however. For example: example, would be treated as a component— coded C—whereas sections of its frame, glazing, ● G(2-)003 is a general arrangement drawing, and deals beads, etc. would be the subject of an SC drawing.) with the positioning and referencing of primary Schedule (coded S), providing an index to the elements. It is the third drawing in that series. retrieval of information from other sources, and tabulating items—e.g. windows, doors, manholes, ● C(3-)012 is a component drawing, and is of a secondary etc.—located on other drawings throughout the element component, such as a door or a roof building. light. It is the twelfth drawing in that series. Information drawing (coded IN) giving supplementary information which is relevant, but not part of the 4.0) building—e.g. survey drawings, bore hole (C3-) indicates that the drawing deals with a secondary analyses, etc. element component. (C32) however indicates that it is a One further sub-division is built into the system. secondary component in an internal wall, and (C37) that 2.0) Each category is then divided into broad sections it is a secondary element in a roof. A complete table or elements, each of which deals with a different (known as CI/SfB Table I) is given below. Once again all subject. The codes for these are given in brackets these sub-divisions will not necessarily appear in this following the drawing category, as follows: drawing set. Furthermore you may well find a general arrangement drawing coded GA(3-) covering all (1-) Substructure. secondary elements but containing in it references to (2-) Primary elements component drawings (C31), (C32), C(37), etc. This is so (i.e. walls, floors, roofs, stairs, frames). 138 that component drawings relating to windows, internal Working drawing management doors and roof lights, respectively, may be grouped together for easy reference. Changing roles Changing the roles of the profession and the industry may well be desirable, but it is a long-term process As noted above, the complete CI/SfB Table 1 should be and not the function of this book. The best must be included. (If, of course, the Uniclass coding system is made of the present situation. It is therefore incumbent being used then a complete copy of Uniclass Table G on the architect to acknowledge his management should be provided, and the individual element function as coordinator of the professional team, and references should be to that system.) he must accept responsibility for ensuring that the structural engineer is aware of M & E requirements, Other consultants’ drawings Little has been said so far about the drawings of other consultants and it may be appropriate to comment here on the problems of liaison and coordination of drawings and that M & E are equally aware of structural constraints. In an imperfect world nobody else is going to do this. Elemental drawings produced outside the architect’s immediate control. Part of the difficulty arises from the fact that neither the Another consideration must be that if we are dealing, as structural engineer nor his M & E counterpart really proposed, with a largely elementalised set of drawings as produces production drawings in the strict sense of the an aid to communication between designer and operative, term as it has been used here, i.e. as a definitive then it ought to be made possible for a carpenter to build instruction to the builder. Each produces traditionally his formwork from the engineer’s drawings alone, without what is in effect a design drawing, relying on others to the need to refer to drawings prepared by others for provide supplementary information for construction information which may be vital to him. purposes. For example, the structural engineer constantly relies on the architect’s drawings to convey Requirement of a formal meeting such fundamental information as chases in upstand It is beneficial for drawings which are to be prepared by beams for asphalt, throatings in soffits and the required others to be agreed at a formal meeting, which can be finish for exposed in situ concrete. The M & E consultant minuted. Clearly the architect is in a better position if he is more often than not unable to provide information on, has firm proposals and methods worked out to put to for example, holding down bolts because the position of the meeting than if he throws the meeting open these is dependent upon a plant manufacturer who may to suggestions from all sides. not have been selected at the time he considered his drawing effort complete. So ‘See architect’s detail’ Design team meeting appears on the structural drawing (if we are lucky) and Such a meeting should cover the following points: ‘See manufacturer’s shop drawing for setting out of pockets’ is frequently the best that can be achieved by 1 Introductions. Individuals in each organisation must M & E. Neither is very satisfactory, yet the difficulties in be named as the link men through whom information effecting an improvement are substantial, for both spring is to be channelled. They should be of sufficient from a historical and artificial fragmentation of the standing to be able to act and make decisions building process: in the first instance a fragmentation of responsibly and with authority and, if possible, they professional disciplines; in the second an unnatural should be of comparable standing within their own alienation of the designer and the constructor. organisations. It is unhelpful to the project for a 139 Working Drawings Handbook young project architect to be out-gunned by the sine qua non that all professional offices involved in senior partner of the engineering consultants. the project will be using it. With this exception it is 2 Procedures. The means by which all team members not essential for all consultants to follow the are to be kept informed must be established. There is structuring and coding disciples that the architect no necessity for the architect to insist on acting as a imposes on himself. Nevertheless, it is highly post office, nor need he insist on being party to desirable that they should be persuaded to do so. In day-to-day discussions between other consultants, practice it should not be very onerous. All disciplines but it is vital that he be kept informed of the outcome have their equivalent of the general arrangement of such discussions and that all drawing exchanges drawing, and all use schedules. These are worth are copied to him. bringing into the structuring method, even though the 3 Programme. An example of a programme for the structural engineer may still adopt his traditional design team has been given in 5.6. Table it, but do practice of inserting larger scale sections on his not insist unreasonably on its detailed initial general arrangement drawings. If CI/SfB is in use acceptance by other team members against their then blanket codes of (16) Foundations and (28) better judgement. It must at all costs be realistic. But Frame for structural drawings and of (5-) Services once it has been accepted, it must be taken and (6-) Installations for services engineers’ drawings seriously. Tongue-in-cheek agreement with one eye provide a simple expedient for bringing all disciplines on an escape route when the inevitable problems within a common retrieval framework without occur can be a costly business for everyone. launching others on to waters, the depth of which the 4 Format. Thought should have been given at the design stage of the project to the question of suitable architect may not yet have plumbed fully. It is important that layer naming for CAD should be production drawing scales and sizes, so the architect agreed in advance by all the professional team. should be well prepared to table his proposals for the 6 Definition of responsibilities. Many defects, both of format. Consistency between all drawing producing omission and of overlapping information, may be offices is important. Apart from the demonstrable avoided if the responsibilities of each team member advantages of enabling the architect’s basic can be defined precisely at the outset of the project. drawings to be used by other consultants and the Apart from the more straightforward contractual reduction of storage and retrieval problems on site, responsibilities which it is assumed will have been the indefinable authority generated by a well- covered in the respective letters of appointment but organised set of drawings and the impression given which it will be sensible to confirm at this inaugural of a team well in control of affairs all help in meeting (matters such as, for example, who tackles promoting confidence in the team among both lifts, cold water supply, drainage, roads and outsiders and its own members. footpaths; who details and checks pre-cast concrete Note that the desirability of maintaining a consistent components, etc.)—these are grey areas where format applies equally to computer-aided drawings. some early agreement will be of benefit. The With the possible exception of drawings transmitted allocation to the structural drawing office of the electronically—model exchange, for example— responsibility for indicating accurately detailed communication between offices will be by means of profiles has already been referred to. Reinforced drawings in the form of hard copies on paper. concrete staircases provide another area where it is 5 Coding of drawings. If the model exchange method for producing CAD information is in operation, it is a 140 unnecessary and confusing for the architect to prepare elaborately detailed sections for the benefit Working drawing management of a contractor who is going to build from the structural engineer’s drawings anyway. An early agreement should be reached to limit the architect’s role to providing design profiles within which the structural engineer may work, and against which the structural details may be subsequently checked. Drawing office programming The design team programme will have identified the time available for production of the working drawings, and the first shot at the drawing register will have revealed the magnitude of the task. The reconciliation of one with the other, and of both with the financial resources available, is one of the essential arts of architectural management and as such demands more space than can be devoted to it in this handbook. Certain points may usefully be made however. Size of drawing office team The right size and structure of the team is all-important, and in many ways it is a case of the smaller the better. Any increase over a team of one starts to invoke the law of diminishing returns and as the numbers increase so do the problems of control and communications. On the 5.13 This histogram, taken from the records of an other hand, the diversity of work demanded by most actual project, shows the difficulties of coordinating building projects coupled with the constant and multi-disciplinary efforts. The peaking of resources remorseless pressures of the overall programme mean during the production drawing stage is clearly shown that too small a team lacks the necessary flexibility of response. When the office is working with CAD it is probable that for more than one drawing position will be linked to the In practical terms, the size of the team will be the size of printer/plotter, which may well be inoperative for long the tasks in man-weeks divided by the number of weeks periods. Unless the team is very small and its members available, and if the latter is unreasonably low then the are in constant touch with one another it is essential to team becomes unwieldy and difficult to coordinate. In have some form of unified control so that the any case, the size of the team is bound to fluctuate printer/plotter is not operated from two drawing positions throughout the working drawing period, with a small but simultaneously (or that everyone has a small high-powered element at stage E, rising to a peak soon printer/plotter for check plots). after commencement of stage F, and tailing off towards the end of that stage as the main flow of information to Backing up is also essential. Data are the most valuable the quantity surveyor is completed 5.13. thing you own; guard them well. With manual drawings 141 Working Drawings Handbook your data are stored as negatives and prints and carbon general arrangement plans and of other consultants’ copies of letters in filing cabinets. If they were destroyed work. After that the priorities will probably be dictated by fire it would be possible to recover most of the lost by the needs of the quantity surveyor. An elemental information by getting copies back from the client, format makes it easier to group the issue of drawings colleagues, contractor, and so on. Possibly you had into separate packages—e.g. internal joinery, finishes, backed-up to microfiche, and kept copies away from etc., but this is only helpful if the packages are the office. genuinely complete. Few quantity surveyors will object to receiving information piecemeal, but an early issue With CAD everything is kept on disk. All your data are of the openings schedule with half the details it refers concentrated in one place, the hard disk. This is very to still incomplete, only leads to an abortive start being efficient, but it does allow the possibility of losing made on the measurement. On the other hand, the fact everything at once. No technology is perfect and can that drawings of the basic structure may be issued and and will fail eventually, often without warning. Full and measured without having to wait for the finishes to be frequent back-up procedures are essential. Back-ups added to the same sheet does allow a bigger overlap should be kept away from the office, in a fire-proof of the production drawings and billing programmes. safe, or preferably both. All back-up media have a limited life. Drawings should be allocated to team members in the form of a simple bar chart. By this means, everyone can Production drawing programme see his personal short-term and long-term targets (5.14). The production drawings, if properly structured so that a predetermined amount of information is conveyed in Introducing new methods them, should be the simplest aspect of the architect’s When Working Drawings Handbook first appeared in work to quantify in terms of time taken. Having 1982 the concept of structured drawings was alien to established the list of drawings, it is better for two of the many drawing offices. Their number has now diminished, more experienced people to make independent but the following notes are intended for offices which assessments of the time that should be taken over each have still not taken the plunge. drawing and to compare notes afterwards. Factors of personal optimism or pessimism may thus be The introduction of structured drawings into an office discounted, and a more realistic time allocation made. which hitherto has managed without them requires But experience is everything, and an inquest after the some thought. There must be many offices which, whilst programme has been completed, with feedback of agreeing in principle that their work could be improved the actual time taken over each drawing as against the by rationalisation of their working drawing methods, are time budgeted for, is essential if future programmes reluctant to take the first step on what might prove to be are to be timed more accurately. a seductively attractive slippery slope. Priorities As with dieting and exercise, the two important things In framing the stage F programme certain priorities will are to start today rather than tomorrow and not to be emerge. Clearly, the establishment of the basic set of put off by the prophecies of failure which will be made general arrangement plans is fundamental, for they will by those around you. In this latter respect, one common form the basis for elementalisation of subsequent fallacy may be dispelled at the outset. You will be told 142 Working drawing management 5.14 A drawing office programme allocates individual team members appropriate work loads. The elemental approach means that DC, for example, can follow the (3-) element right through, dealing with it in its general arrangement, component and assembly aspects confidently that architects are individualists and will fight ● tooth and nail against any suggestion of rationalised arrangement, assembly, component, sub-component, drawing, standardised detailing or mathematically oriented coding systems. This you will find to be untrue, Rationalise new projects into the general schedule format. ● Select one such project for the experimental architects being as fundamentally lazy and anxious for application of CI/SfB (or Uniclass) coding and let it a trouble-free existence as anyone else. Experience run through its production phase before attempting a indicates that given a common-sense system which is general application of the method. You will thus have fundamentally easy to use, people will use it. built up some office case law to assist in answering the query ‘How do we code for this situation?’ which The sequence to take However, take one step at a time. There are several will arise on subsequent projects. ● Now that you have each project producing degrees of rationalisation and they should be introduced component and assembly information in a common in sequence: format and within the context of a coding system offering ease of retrieval, you are in a position, if you ● Standardise drawing size and format for all new so wish, to introduce standard solutions to various projects entering production drawing stage. aspects of your detailing. 143 Working Drawings Handbook What does it cost? As to the cost of introducing (and indeed of operating) new drawing methods one is on less certain ground. Certainly all the available feedback suggests that it is unusual for a practice to revert to unstructured working drawings once it has started producing structured sets, which seems to indicate that at least the structured set is not so overwhelmingly expensive to produce as to render it uneconomic in practice. Short of carrying out parallel drawing exercises using two methods and comparing the cost there is no real way of being sure. What is clear, however, is that the more comprehensive nature of the information likely to be produced within a structured format, its greater potential for coordination, and the greater ease of information retrieval which details which could (and in retrospect clearly should) have been provided during the working drawings stage. Consider also the predictable reaction of the poor unfortunate who is dragged back a year later from the multi-million pounds fantasy on which he is happily engaged in order to sort out the door detail he had unfortunately omitted from the working drawing set which had been his previous task. It must always be cheaper to produce information at the right time. On the other hand, any change in working method must have some cost implication, as the change to metric dimensioning demonstrated. As with metrication, this cost should be looked upon as an investment for the future. And the future? it offers to the contractor, will all combine to reduce A whole new world of technology lies ahead of us. But it time-consuming queries once the work is on site. An is difficult to visualise a bricklayer laying bricks other honest analysis of office time spent on so-called ‘site than by using a paper drawing to instruct him where to operations’ is perhaps a salutary exercise for any lay them. The role of the architect and of the practice. Bearing in mind that the plan of work defines architectural drawing office appear to be secure for the stage K as consisting of ‘Administration of the building foreseeable future. contract up to and including practical completion. Provision to the contractor of further information as and The more important consideration is: how will CAD itself when reasonably required’, consider how much time in develop? practice is spent in the drawing office in amending existing drawings and in providing new ones to illustrate 144 The twenty-first century looks like being an exciting one. APPENDIX Building elements and external features The degree of detail used in representing any element 1 Doors is dependent on the scale at which it is shown. The examples given below give an indication of what may be considered appropriate for various scales. Scale 1 : 200 Windows Scale 1 : 200 Scale 1 : 100 Scale 1 : 100 Scale 1 : 50 Scale 1 : 50 and over and over 145 Working Drawings Handbook Manholes Scale 1 : 100 and under Scale 1 : 50 and over Staircases Scale 1 : 50 and over 146 Scale 1 : 100 and under Appendix 1 External features Trees: 1 existing 2 to be removed 3 new Contours (existing) Contours (proposed) Hedge (existing) Grading (the arrows point to the lowest Hedge (proposed) level) Grass Woodland (existing) Fence Features in fence: 1 gate Woodland (proposed) 2 stile 147 APPENDIX Conventions for doors and windows Doors Double leaf, each Single leaf, single action leaf single opposite action Single leaf, double Sliding door, hung in action recess Double leaf, single action Sliding door, face hung Double leaf, Folding door, edge double action hung 148 2 Appendix 2 Folding door, centre hung Horizontal sliding sash Revolving door Windows Vertical pivot (opening edge should be stated) Horizontal pivot (bottom edge opens out unless Side hung casement (L.H.) otherwise stated) Top hung casement (opening out unless otherwise stated) Vertical sliding sash Bottom hung hopper (opening in unless Convention assumes all windows are viewed from the otherwise stated) outside 149 APPENDIX Symbols indicating materials Blockwork Brickwork Hardcore Precast concrete Blockwork (commonly Earth used alternative) Concrete Stone 150 3 Appendix 3 Marble Metal (at large scale) Rubble stonework Metal (at small scale) Slate Plaster (or cement screed) Some abbreviations in common use Insulation Unwrot timber section Wrot timber section Wrot timber section on two faces alum. aluminium asb. asbestos bit. bitumen (or bituminous) bk. brick bkwk. brickwork C.I. cast iron conc. concrete cp. chromium plated h/wd. hardwood PVA. polyvinyl acetate PVC. polyvinyl chloride PCC. pre-cast concrete rfmt. reinforcement SAA. satin anodised aluminium SS. stainless steel s/wd. softwood t&g tongued and grooved UPVC. unplasticised polyvinyl chloride W.I. wrought iron 151 APPENDIX Electrical, telecommunications and fire protection symbols 4 Extracts from British Standards Nos BS 1192 Certain symbols are differently represented in different (1984–2000); BS 3939 (1986–1991) and BS 1635 Standards. Furthermore, other symbols have acquired a (1990) are reproduced here with the permission of BSI use in practice but do not appear in any laid down under license number 2004DH0029. British Standards Standard. In such cases the most common usage has can be obtained from BSI Customer Services, 389 been given. Chiswick High Road, London W4 4AL, Tel ⫹44 (0)20 8996 9001, email: cservices@bsi-global.com Reference should be made to the British Standards listed above for more comprehensive lists of symbols. The symbols for use in these fields are covered in a number of publications, primarily: BS 1192: 1984–2000 Construction drawing practice Main control or intake (Pts I and II) BS3939: 1986–1991 Graphical symbols for electrical Distribution board power, telecommunications and electrics diagrams BS 1635: 1990 Graphical symbols and abbreviations for fire protection drawings Earth The symbols shown represent a small selection of those Consumer’s earthing terminal available. They have been restricted to those which the architect is most likely to encounter when dealing with the type of small-scale work in which an electrical consultant has not been appointed. 152 Single pole one way switch Appendix 4 Similar, but the number indicates the number of switches at one point Two pole one way switch Key operated switch Socket outlet Cord operated single pole one way switch Switched socket outlet Two way switch Double socket outlet Dimmer switch Lighting point—ceiling mounted Period limiting switch Emergency lighting point Time switch Lighting point—wall mounted Thermostat Lighting point with integral switch Push button Single fluorescent lamp Luminous push button Three fluorescent lamps 153 Working Drawings Handbook Outdoor lighting standard Outdoor lighting bollard Telephone point (internal only) Public telephone point Automatic telephone Illuminated sign exchange equipment Illuminated emergency sign Automatic telex exchange equipment Electric bell Manual switchboard Clock (or slave clock) Master clock Fire protection Hydrant point Telecommunications Telecommunications Wall valve—wet socket outlet. State use—e.g. TV (for television) R (for radio), etc. Wall valve—dry Aerial Telephone point (to exchange lines) 154 Hose reel Appendix 4 Fire extinguishers. Indicate type, e.g. SA Soda Acid W Water F Foam Alarm call point CO2 Carbon dioxide, etc. Visual warning device Sprinkler Smoke detector Heat detector Audible warning device Indicator panel 155 APPENDIX Non-active lines and symbols 5 Coordinating dimension Leader lines, indicating where notes or descriptions apply Other dimensions generally. The method, although recommended in most BSI literature, tends to be replaced in practice by the oblique slashes shown below. Centre lines or grid lines. Most commonly used method for general dimensioning. Drawn in thin line to distinguish them from service runs. Neat, legible and rapid (See Appendix 1) Controlling line Dotted line indicates important lines hidden in the particular plan or section view taken. (Also, on demolition drawings, work to be removed) Running dimensions. Use should be restricted to surveys Break line Small dimensions are best indicated thus Modular dimension 156 Section line. The arrows point in the direction of view and the line joining them indicates the plane of the section Appendix 5 Spot level—existing HT high tension Htg. heating H/V heating and ventilation (or H & V) Spot level—proposed Level shown on section or elevation—existing Level shown on section or elevation—proposed Some abbreviations in common use ID internal diameter inc. including (inclusive) int. internal (interior) IV invert LT low tension max. maximum mfr. manufacturer min. minimum misc. miscellaneous NBS National Building Specification nom. nominal NTS not to scale o/a overall OD outside diameter O/H overhead AD above datum opp. opposite app. approximately partn. partition BM bench mark PC pre-cast BSCP British Standard Code of Practice pr. pair BSS British Standard Specification prefab. pre-fabricated c/c cL centre to centre pt. point (or part, depending on context) centre line rect. rectangular (rectilinear) diam. diameter reinf. reinforced dim. dimension rad. radius exc. excavate (excavation) req. required exg. existing ret. return (returned) Eq. equal sch. schedule extn. extension spec. specification FFL finished floor level susp. suspended fin. finish (finished) sq. square FS full size std. standard fluor. fluorescent vert. vertical HD heavy duty wt. weight 157 APPENDIX Glossary of CAD terms Architectural CAD packages or programs 6 and Draughting’ are terms that refer to the process of creating drawings or designing with the aid of (Based on AutoCAD terminology. Other programs may computers. use different terms.) Database An organised collection of data that can be These are CAD programs with capabilities beyond the interpreted and operated upon by a computer. A drawing drawing of simple lines, arcs and text. They have file is effectively a database of drawn information that is additional capabilities specific to the architectural and manipulated by a CAD program. CAD users also refer to building industries and usually allow a 3D model of the ‘External Databases’. These refer to data files other than building to be created from intelligent ‘objects’ rather the drawing file. than simple entities. Dimension entities Attribute A special type of text entity, included within a Dimensions that are calculated by the program based on the entities to which they block definition that can be used to hold information are attached. Most CAD users use ‘associative’ about that block. Attribute information can be defined, dimensions that update automatically when the set and read by the CAD program, making automated entity that the dimension relates to is modified. links to separate databases possible. Non-associative dimensions require the CAD user to type in the dimension text manually and their use can Blocks A set of entities defined so that they act as if be dangerous. they were a single entity. For example, a WC is drawn with a few lines and an arc and saved to disk as a separate Drawing (1) drawing. It is then ‘inserted’ into plans as many times as is understood sense, printed or plotted on to paper, and needed. Generally blocks are inserted full size (1:1). created from the CAD file. CAD and CADD ‘Computer-Aided Draughting’, Drawing (2) ‘Computer-Aided Design’, and ‘Computer-Aided Design A computer file containing the ‘model’ information 158 A drawing in the conventionally Sometimes called the ‘Model File’. Appendix 6 describing all or part of a building, plus definitions of Layers any number of paper plots that might be created from programs. A way of grouping entities together so that it. This was not always so. Early versions of CAD their visibility can be controlled as a named set. The programs could only create small files, containing just CAD version of ‘Overlay Draughting’. May be known as ‘levels’ in some CAD one plotted drawing. When CAD terminology was being coined, it wasn’t important to distinguish Model, CAD model The set of entities, objects and between the paper plot and the computer file used to other data that describe the project in full in 2D or 3D. generate it. The name stuck, hence the current This is the data set from which the paper drawings are confusion. created. Dyeline machine A machine used for preparing paper Objects prints from large drawings. Now largely superseded by create their drawings from ‘intelligent objects’ rather than large format photocopiers. Many CAD users now create entities. CAD files will be created from doors, walls and multiple ‘originals’ rather than one original from which windows rather than lines, arcs and circles. A ‘door’ copies are made. object knows it is a door and interacts appropriately with Some dedicated architectural CAD programs a ‘wall’ object. Move the door, say, and the adjacent light DXF As in filename.dxf. A common file format used for switch moves with it. Flip the door and the light switch the transfer of files from one CAD system to another. All moves to the other side without intervention by the major CAD systems can convert between their own designer. native file format and DXF. Pin registration (overlay draughting) A manual DWG As in filename.dwg. AutoCAD’s file format. drawing method that enjoyed popularity in a few offices Because AutoCAD is so widely used, many other CAD before the advent of CAD. Each type of information was programs can read and write direct to AutoCAD format, drawn on a different sheet of acetate, say walls on though often with inconsistent results. one sheet, doors on a second and light fittings on a third. Sheets were aligned by dropping the appropriate DGN As in filename.dgn. Microstation’s file format. Microstation is another widely used CAD program. sheets over pins fixed in the drawing board. Once the individual sheets were finished different paper drawings could be created by photographing the combined Entities Arcs, lines, circles, text, faces and so on, held image. in the drawing file, together with information about their size, position and orientation. In dedicated architectural Printing and plotting design programs, walls, windows, and so on might also and plotting is less important than it once was. In the be defined as ‘entities’. early days of CAD, the only machines capable of The distinction between printing producing large format architectural drawings accurately Internet A communications network linking computers, to scale were pen and drum plotters. Printers, on the that allows people to share information. Now used other hand, were slow, low resolution devices, printing extensively to obtain information from manufacturers, to mostly to A4 size. order goods, as a means of communication by email, and for transfer of CAD and other computer files Today, large format pen plotters have largely been between professionals. abandoned as expensive and as too troublesome to 159 Working Drawings Handbook maintain. They have been replaced by reliable, large method. The terms are becoming interchangeable in format inkjet ‘plotters’ which use the same technology as common usage. A4 inkjet printers. Symbols A set of symbols designed so that they act Daisy-wheel and dot-matrix printers have now as if they were a single entity in the same way a block is been replaced with high resolution laser and inkjet defined. For example, the symbol for a light fitting. Like printers, equally capable of producing text blocks, they are then ‘inserted’ into plans as many times documents, colour photographs, 3D photo-realistic as is needed. Generally, symbols can be inserted at any images and drawings. The terms ‘printing’ and scale, to make them bigger or smaller on the plotted ‘plotting’ now refer as much to size as to printing drawing. 160 Index Activity drawings, 86 Assembly drawings, 65 check lists, 69 role in information package, 68 coding of, 71, 77 principles, 71 scale, 71 Bills of Quantities, 7, 17 operational bills, 87 British Standards Institution, 102, 152 BSI on tolerance and fit, 102 Building information, 10 primary structuring, 11 secondary structuring, 15 assembly drawings, 65 component drawings, 61 sub-component drawings, 65 schedules, 78 pictorial views, 79 specification, 81 Building Research Establishment, 2 paper on ‘tolerance and fit’, 102 paper on ‘working drawings in use’, 2 CAD see Computer aided draughting CI/SfB system, 32 Coding of drawings, 23 by building element, 19 by building information type, 11 by levels, 45 by Uniclass Table G, 24 by CI/SfB, 32 Computer aided draughting, 88, 158 elements of system, 88 drawing overlay method, 89 model exchange method, 89 BSI layer naming convention, 134 portable document format, 135 glossary of terms, 158 major advantages, 89 line thickness, 91 Common arrangement of work sections, 17 Component drawings, 61 format, 63, 54 principles, 61 examples, 64, 65 use of CAD, 63 manufactured components, 61 contractor fabricated components, 61 use in office library, 63 Construction Project Information Committee (CPI), 7 CPI documents, 7, 24, 32 Consultants’ drawings, 136, 139 registration and storage, 136 Conventions, 95 handing – doors and windows, 96, 148 building elements, 145 electrical symbols, 98, 152 fire protection symbols, 154 building materials, 150 telecommunications symbols, 154 Conversions, alterations and re-habilitation, 82 Data sheets see Room data sheets Demolitions, 83 earth movement, 58 in alterations, 84 Design drawings, 114 final set – Stage D, 114 use of CAD, 88 Design team, 139 architect as leader, 139 formal meetings, 139 liaison with other members, 139 programme of work for, 121 Dimensioning, 99 co-ordinating dimensions, 100 co-ordinating planes, 100 definitions, 103 grids, 105 controlling dimensions, 104 setting out, 103 Draughting – manual, 90 materials, 90 sheet size, 92 line thickness, 91 format, 94 non-active lines, 98 templates, 98 Drawing annotation (lettering), 108 by CAD, 108 manually, 110 Drawing Guide, 137 Drawing Management, 113 register, 125 storage of incoming drawings, 135 drawing office programming, 141, 143 production drawing programme, 142 Drawing register, 125 example, 132 maintenance and circulation, 135 for general arrangement drawings, 127 for assembly, component, sub-component drawings and schedules, 130 Electrical symbols, 98 Elevations, 52 general arrangement elevations, 52 sectional elevations, 53 Extensions, 82 Finishes, 38 ceiling finishes, 41 finishing schedules, 38 examples, 41, 42 General arrangement drawings, 12, 35, 127 floor plans, 35, 37 basic plan, 37 roof plans, 45 site plans, 57 elemental floor plans, 37 primary structuring, 37, 46 secondary structuring, 50 format, 51 elevations, 52 sections, 53 strip sections, 56 Grids see dimensioning Information drawings, 15 Introducing new methods, 142 Issuing information, 136 Layer naming conventions, 89, 134 Location drawings see general arrangement drawings 161 Index Operational bills of quantities, 87 Pictorial views, 79 Planning the set, 124 Plan of work see RIBA plan of work Programme of work see design team Responsibilities, definition of, 140 RIBA plan of work, 6, 113 management handbook, 3 Roof plans, 45 162 Room data sheets, 117 as finishes schedule, 43 as source document, 117 Schedules: role in information package, 14 finishes, 38 by elevation, 53, 54 component, 80, 82, 83 vocabulary, 81 Site plans, 57 Specification: relationship with drawings, 81 outline specification, 119 Standard details, library, 119 Stage F, 113 pre-requisites for, 114 examples, 122, 123 Status coding, 129, 133 Sub-component drawings, 14, 65, 130 role in information package, 65 examples, 66, 67, 69 Title panel, 195 example, 109 Trade literature, 119 Uniclass Table G, 24