Window Glazing

Windows are often pointed to as the weakest elements in building facades, given their low thermal resistance. Consequently, they are
a main focus during building retrofits, when their substitution is often considered an expensive but necessary choice. This article
describes a new high-performance glazing coating, which can be used for the in situ retrofit of existing windows. The easy
application of this new liquid-applied coating on the internal side of the glazing makes it possible to reduce the solar heat gain
coefficient of an existing window substantially and quickly, without interrupting the building occupancy. Experimental
characterizations of light transmittance and thermal characteristics are presented in this article. Although the new coating allowed a
reduction in the visible transmittance (VT) of only 0.1 compared to nontreated insulating glass units (IGUs), it proved to reduce
significantly the solar heat gain coefficient (SHGC) of the investigated IGUs to values below 0.45. This article also reports the results
of aging studies aiming at assessing the risks of long-term performance reductions of this new liquid-applied coating. Finally, the
results of energy simulations investigating the energy-efficiency improvements when this coating is applied to different kinds of
windows in Canada are reported.

Acoustic transmission describes the transfer of sound through materials. The insulation provided by building facades against airborne sound transmission has significant impact on the acoustic comfort of their indoor environments. External noise (unwanted sound) from roads, railways, aircraft, industry, and machinery must be excluded to ensure the indoor acoustic environment meets the required standard for its intended use. This performance requirement is typically specified by a ‘noise rating’ (NR) or similar acoustic criteria. The Building Regulations of England and Wales require a minimum standard for building envelopes, while most modern buildings require compliance with higher standards to satisfy various design ratings.

A key weak point in any building façade against airborne acoustic transmission are their window elements, particularly glazing. The purpose of the following experiment is to examine and report on the acoustic transmission qualities of different glazing types. The experiment has been designed and implemented in compliance with British and International Standards BS EN ISO 140-3 and 140-5.

The need to reduce energy consumption in buildings leads to the development of new facade systems that can be energy efficient; thus, contributing significantly to heat transfer between outdoor and
indoor spaces. Here, the versatility and flexibility of the modules are key attributes. For this purpose, this study focused on the thermal performance of Trombe walls and glazings and the glazing daylighting
performance of a modular fac¸ade system in four different Portuguese cities. Computational simulations for the thermal performance of different arrangements of the modules were accomplished with the DesignBuilder software, while the glazing daylighting performance was studied by means of Ecotect and Desktop Radiance software, and compared with the transmittance curves of glazings. Occupancy profile and internal gains were fixed according to the Portuguese reality for both studies. The main characteristics considered in this research were the use of two double glazings, four different
Portuguese climates and one or two Trombe walls in the facade. According to results, the use of Trombe walls and double self-cleaning glazing in the fac¸ade showed an important reduction in the energy consumption as well as better daylighting performance.

Purpose Application of nanotechnology in construction sector brings innovation to building materials like self-cleaning and antifog. These features make it possible to shorten the maintenance and repair periods of building materials, and thereby reduce maintenance costs. The development of environmentally friendly building materials become very important to reduce air pollution and adverse effects. The competitiveness of companies in the construction sector is based on technological developments. Now, it is possible to reduce costs and respond to various customer demands owing to new technologies. Nanotechnology affects many sectors as a technology that contributes significantly to the development of the properties of materials, and it has also found its place in the construction sector. The purpose of this study is to examine the use of nanomaterials used in the construction sector in the context of glass and curtain wall systems. Also, the aims of this paper are to reveal the advantages of nanomaterials by examining the differences between the traditional and the nanotechnology applications used in glass and curtain wall systems, to remark nanomaterial applications in construction sector, and finally to expand awareness in this regard.

This paper describes a conservative analytical approach for quantification of glazing hazard in terms of number of casualties among building occupiers from flying glass fragments produced by shattered windows due to external explosive blast. Three main stages are discussed in the proposed analytical approach: modelling nonlinear transient–dynamic response of monolithic windows subjected to conventional explosions, conservative estimation of glass fragment trajectories influenced by additional aerodynamic forces due to vented blast pressures and estimation of casualties. Four injury severity levels are considered, ranging from minor cuts and bruises to multiple serious injuries with significant blood loss. The total kinetic energy of fragments at impact on occupiers is estimated and used to predict the severity level of injuries, with calculation based on available injury data from archive events. Comparison studies presented in this paper highlight the lack of robustness of existing methods towards quantification of glazing hazard due to explosive blasts. The proposed analytical method will be of direct importance to both engineers and practitioners involved with planning glazing retrofits for existing buildings and identifying cost-effective combinations of protection measures for new buildings.

In this investigation, TiO2 and Ag based single and multilayer-films were deposited on microscope glass slides with varying individual layer thicknesses by radio-frequency reactive magnetron sputtering. Prior to multilayer development, single layers of Ag and TiO2 were deposited and characterized. All the films were prepared at an elevated pressure of 3 Pa at room temperature. It was found that single layer of TiO2 showed anatase polycrystalline structure. It also exhibited high visible transmittance of above 80% and higher refractive index of 2.31 at a wavelength of 550 nm. The indirect optical band gap of the TiO2 films was estimated as 3.39 eV. The Ag single layer films were found to be crystalline with a very high reflectance for IR (Infra-red) light. Finally, the multi-layers have been deposited and characterized by X-ray diffraction, UV-visible-NIR spectro-photometry, scanning electron microscopy and Auger electron spectroscopy.

www.arpnjournals.com/jeas/research_papers/rp_2010/jeas_0910_381.pdf

In this investigation, TiO2 and Ag based single and multilayer-films were deposited on microscope glass slides with varying individual layer thicknesses by radio-frequency reactive magnetron sputtering. Prior to multilayer development, single layers of Ag and TiO2 were deposited and characterized. All the films were prepared at an elevated pressure of 3 Pa at room temperature. It was found that single layer of TiO2 showed anatase polycrystalline structure. It also exhibited high visible transmittance of above 80% and higher refractive index of 2.31 at a wavelength of 550 nm. The indirect optical band gap of the TiO2 films was estimated as 3.39 eV. The Ag single layer films were found to be crystalline with a very high reflectance for IR (Infra-red) light. Finally, the multi-layers have been deposited and characterized by X-ray diffraction, UV-visible-NIR spectro-photometry, scanning electron microscopy and Auger electron spectroscopy.

www.arpnjournals.com/jeas/research_papers/rp_2010/jeas_0910_381.pdf

For typical high-rise residential building in Hong Kong, we evaluated the impact of using switchable glazing on energy use for space cooling. By using software EnergyPlus, it was found that application of switchable glazing would lead to a reduction in annual cooling electricity consumption ...

Windows have a major influence on indoor comfort and are critical factors in terms of the energy consumption of buildings. Accordingly, the design and performance of window glazing and frames are key elements in the implementation of thermal regulations and contribute to the success of energy renovation policies. However, despite their multifaceted-role, there is a lack of holistic studies that bring together the environmental issues resulting from the production, use and disposal of windows. The aim of this article is to review these multiple aspects holistically and to provide a better understanding of the role that windows can play in reducing the environmental impact of buildings.

As such, this paper analyses twenty-three environmental studies of windows, frames and glazing, including recent Environmental Product Declarations. It is the first study to address environmental issues related to windows from a holistic perspective considering both quantitative and qualitative studies. Through this approach, this paper outlines the methodological issues associated with the environmental analysis of windows, particularly regarding the definition of the functional unit and the quantification of impact during the use phase. Additionally, this review provides new insights into the life cycle of windows, frames and glazing by comparing the results of research carried out since 2000. The paper also defines important questions pertaining to the understudied area of the end-of-life of windows and their recyclability and reusability.

Finally, this paper takes advantage of the complementarity of the reviewed studies to discuss three propositions that would support the development of an improved framework that would be suitable for the life cycle assessment of individual building elements such as windows, where energy efficiency depends both on the behaviour of occupants as well as on the rest of the energy systems of a building.

The use of vacuum glazed windows is increasing due to their application in modern building design. Among various types of vacuum glazed windows reported in literature, thermal transmittance of single glass sheet (conventional window) i.e 6 W/m2k is reduced by 66 and 77% using air filled double glazed and air filled triple glazed windows respectively. Using low emittance coatings thermal transmittance of double glazed windows is reduced by 53%, however it offsets the visibility by reducing light transmittance by 5%. Stresses due to temperature/pressure gradients if not eliminated may lead to reduction in service life of vacuum glazed windows. Vacuum created between the glass sheets is used to reduce conductive heat transfer. Degradation in the vacuum is caused by number of factors such as, permeation of gaseous molecules through glass sheets, leakage through sealing, thermal/optical desorption and photo-fragmentation of organic species have been critically reviewed and future trends are outlined.

The growth of Western urban landscapes in the aftermath of World War II brought new standards of com-fort and convenience; one of the emblematic products of this modernization was glazing. Openings became larger, enhancing transparency and bringing abundant light; however, they also led to considerable heat loss. It became imperative that glazing play a part in insulating buildings. This article traces the history of glaz-ing insulation across the second half of the 20th century. Focusing on case studies of residences in France and Belgium and industry archival material, this article analyses the wide variety of glazing products that were developed between 1950 and 1990. Although all of them significantly improved thermal comfort, each conditioned the relationship between indoor and outdoor climates in a different way. In response to increas-ing demands for energy efficiency, sealed insulated glazing ultimately became ubiquitous, bringing about a profound transformation of our relationship with our environment.

Purpose Application of nanotechnology in construction sector brings innovation to building materials like self-cleaning and antifog. These features make it possible to shorten the maintenance and repair periods of building materials, and thereby reduce maintenance costs. The development of environmentally friendly building materials become very important to reduce air pollution and adverse effects. The competitiveness of companies in the construction sector is based on technological developments. Now, it is possible to reduce costs and respond to various customer demands owing to new technologies. Nanotechnology affects many sectors as a technology that contributes significantly to the development of the properties of materials, and it has also found its place in the construction sector. The purpose of this study is to examine the use of nanomaterials used in the construction sector in the context of glass and curtain wall systems. Also, the aims of this paper are to reveal the advantages of nanomaterials by examining the differences between the traditional and the nanotechnology applications used in glass and curtain wall systems, to remark nanomaterial applications in construction sector, and finally to expand awareness in this regard.

Polymer electrolytes containing poly(ethylene imine) (PEI) and lithium bis(trifluoromethylsulfonyl) imide (LiTFSI) can serve as model electrolytes for electrochromic devices. Such electrolytes were characterized by differential scanning calorimetry, conductivity, and viscosity measurements.

Solar gain and thermal energy transfer through windows is studied for three different sites in Jordan using the TRNSYS computer program. Solar and thermal energy is calculated using the monthly average daily data for the above-mentioned three regions. Calculation of ...

This paper aims to verify the impact of glazing façade system on the thermal performance of residential environments, applying the revision of the Brazilian Standard 15575/2021. The object of study adopted was a living room of a high-cost multifamily building located in Londrina, Paraná, where it was evaluated both by the simplified procedure and by the computer simulation procedure, present in the revision of the performance standard. As a result, it was obtained that the long permanence room (APP) does not meet the minimum performance due to the new simplified procedure, in the criterion of surface area of transparent elements, exceeding the limit established. As for the new computer simulation procedure, the APP in its real model did not reach the minimum level, due to the failure to meet the maximum annual operating temperature criterion. The criterion of the percentage of hours within the operating temperature range was met, however, with a value of 44.5%, demonstrating that the environment is highly dependent on an artificial air conditioning system to thermal comfort. The study pointed out that the use of glass façades negatively impacted the thermal performance of the residential environment, for the local climate, with insufficient strategies to compensate for its application. The revision of the Brazilian Standard 15575, on the other hand, presented completer and more rigorous analyzes, with indicators that provide assistance in the elaboration of solutions.

Traditional windows cannot adapt to external and internal environmental conditions. Smart windows are the next generation of windows, which can change their thermal and optical properties to control indoor environmental conditions. Electrochromic (EC) windows can control solar energy and provide visual comfort. These windows can be used with other tools such as various glazing types, building integrated photovoltaic (BIPV) and building energy management system (BEMS). This paper aims to evaluate the effect of EC windows, various glazing types, BIPVs and BEMS on energy consumption of high-rise office buildings. A model was created and several inputs were entered into the model. Then, annual simulations evaluated the effect of EC windows and other parameters on energy consumption of the building in four climate conditions of Iran. First, the effect of EC windows and various glazing types on energy consumption of the building were identified separately. Afterward, 12 different scenarios were defined to evaluate the effect of using both EC windows and optimal glazing type on energy consumption of the building. Then, BIPVs were combined with EC windows and photovoltachromic (PVC) windows were modeled using inputs of EC windows and BIPVs. In the end, BEMS was combined with PVC windows and had a positive effect on energy consumption of the building in all climate conditions. Finally, simulation results indicated that energy consumption of the building reduced up to 35.57% using EC windows and other tools. The difference between simulation and actual results is predicted to be at least 1.60% and maximum 6.22%.

Résumé:
Durant les décennies d’après-guerre, le vitrage isolant fait son apparition dans l’architecture belge et française. Parvenant à résoudre une équation a priori insoluble, il apporte transparence et isolation devenant ainsi un produit emblématique de la modernisation des bâtiments. Dès lors, l’industrie verrière n’aura de cesse d’améliorer les performances des vitrages, répondant ainsi à l’impératif d’efficacité énergétique et aux exigences croissantes des usagers en termes de confort. Mais ce développement entraîne aussi la marginalisation des pratiques de réparation et accélère l’obsolescence des fenêtres existantes dont la biographie s’achève bien souvent en décharge.
Cet article retrace la trajectoire du vitrage isolant en France et en Belgique depuis sa commercialisation en 1947 jusqu’à la mise en place des réglementations thermiques en 1974. Y sont analysées les conditions de l’avènement de la non-réparabilité des fenêtres, mais aussi celles du maintien de techniques proposant des alternatives à leur mise au rebut.

Abstract:
In the post-war period, insulating glass appeared in Belgian and French architecture, meeting a double, a priori contradictory, requirement. Indeed, it provides transparency and insulation and thus quickly became an emblematic product in the modernisation of buildings. Since then, the glass industry has continuously improved the performance of glazing, meeting energy efficiency imperatives as well as increasing comfort standards. However, this development has also led to the marginalisation of repair practices and has accelerated the obsolescence of existing windows, which usually end up in landfills.
This article follows the trajectory of insulating glass in France and Belgium from its first commercialisation in the 1940s to the introduction of thermal regulations in 1974. It analyses how window repair has become almost impossible and discusses techniques that offer an alternative to landfill.