PROCURING GLASS FACADES: A SPECIFIER’S GUIDE

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INTRODUCTION

GLASS AND ITS RELATIONSHIP TO INTERNAL PROGRAm

Glass has long been the material of choice to provide our buildings with natural light and visual connection to the outside. Glass has come a long way from its original application, now applied across every project as a practical material for light, views, thermal and acoustic requirements, as well as a solution for specific design intentions, whether that is regarding structure, texture, colour or the like.

However, its purpose extends far beyond its visible qualities to those that affect our other senses. Aside from its function, one primary purpose for any building is to provide shelter and comfort, which is at least in part influenced by the use of glass. The choice of glass for a façade or windows cannot be solely from a lighting perspective, but must also take into account its use in relation to internal program, thermal comfort and energy use, and spatial acoustics. The best practice around designing with windows is to engage with them from the outset of a project, developing answers to each of those considerations as a project progresses.

Clear glass is often used for its superior transparency and ability to transmit natural light. Being linked to “improved productivity, increased job satisfaction, [and] reduced absenteeism,” within office environments, as well as faster recovery times within hospitals, the importance of natural light cannot be underestimated.1,2 Taking advantage of natural light can also reduce a building’s carbon footprint by reducing the reliance on artificial light sources during the day.

Regardless, the use of clear glass needs to be considered wherever too much natural light or the presence of UV rays at all is a problem. These environments include office spaces, where glare might threaten to reduce productivity, or art galleries and museums, whose artefacts can be damaged in unfiltered sunlight. In these instances, clear glass should be reconsidered in favour of glass that has been treated to provide higher UV protection and reduced glare and high contrast lighting risks. For situations in which privacy is of key concern, translucent glass is readily available over its transparent counterpart.

The choice of glass for a façade or windows cannot be solely from a lighting perspective, but must also take into account its use in relation to internal

program, thermal comfort and energy use, and spatial acoustics.

THERmAL COmFORT AND ENERGY USE

SPATIAL ACOUSTICS

ARCHITECTURAL GLASS AND CLADDING

PRODUCT SPOTLIGHT: OKALUX

Windows are often the largest source of heat-loss and heat-gain within buildings, requiring the use of additional mechanical heating and cooling methods to accommodate. As such, glazing needs to be adequately managed in order to optimise thermal comfort and reduce energy use. The thickness and spacing between panes (if applicable) is one consideration when determining the most suitable glass type. These considerations among others are used to determine a system’s U-value and solar heat gain coefficient (SHGC).3 Selecting glass types with a lower U-value, which signify a material’s ability to conduct heat, means that less heat will be lost in winter and less heat gained in summer. Similarly, a lower SHGC is indicative of a window’s ability to resist the transmission of heat from direct sunlight.

Other enhancements such as low emissivity (low E) coatings can also improve U-value and SHGC factors under certain conditions. By account for the qualities of glass, a building’s energy use can be further reduced, removing the dependency on air conditioning for thermal comfort.4

Windows are also typically poor at insulating interior environments from intrusive noise. However, these issues can be solved through the use of treated glass (such as with a laminate), thicker glass, or by providing an additional layer of glazing.

Architectural Glass and Cladding have been providing high quality and high-performance, bespoke architectural glass products for 15 years since their inception. Their ability to work with architects and specifiers through their own engineering services means that the best product for each purpose can be implemented. As such, they have been involved in a number of high-profile projects to date, including the Australian War memorial in the ACT, and the Peter Doherty Institute and 570 Bourke St in melbourne, along with a number of global projects.

Architectural Glass and Cladding’s range, OKALUX, is designed to provide the ultimate level of customisation to any product. The OKALUX range spans from an integrated system of insulated glass with angle selective metal or timber inserts for privacy and solar consideration in OKATECH and OKAWOOD, to functional glass with sun control, OKASOLAR, and daylight diffusion with KAPILUX capillaries all encapsulated within the inter-pane cavity. The OKALUX range has been designed not just to meet the requirements placed upon any glazing system, of natural light exposure, privacy, thermal comfort, energy use and acoustics, but also to become a key design feature in itself.

1 Leslie, R.P. 2003. “Capturing The Daylight Dividend In Buildings: Why And How?”. Building And Environment 38 (2): 381-385. doi:10.1016/s0360-1323(02)00118-x.

2 Burkeman, Oliver. 2013. “Even Short Engagements With Nature Boost Productivity”. Business Insider Australia. https://www.businessinsider.com.au/nature-boosts-productivity-2013-3?r=US&IR=T.

3 Lyons, Peter, and Bernard Hockings. 2013. “Glazing”. Your Home. http://www.yourhome.gov.au/passive-design/glazing.

4 Ibid.

REFERENCES

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