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The spectrally selective coatings are one such type that should only be used with care if the optimum light: heat gain is to be achieved. “[Double and triple silver coatings] are not always suitable for use in the UAE,” warns Lipscombe, “but they can be enormously useful. For example, if an architect is designing a building and [using external architectural screens in front of the windows] they are doing this to increase solar control and stop heat gain, but in doing so have created setback windows and now need to get more light inside. So, these spectrally selective products are great for this type of application,” explains Lipscombe.
“Spectrally selective coatings are making a foothold in the region, but when you add more light, you also add more glare, so there has to be a balancing act when using these as sickness can be provoked due to solar glare,” adds Lipscombe.
But with a price difference of at least US $10-15/m² between the triple and double silver coatings, the current economic downturn is playing a part in the choice of technology uptake. “The market [for triple-silver] is there, but most firms switched back to using double-silver [after the recession started] as the triple-silver products have to come from the US so are more expensive,” reports Lelievre.
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Photovoltaic films and cells that have a greatly enhanced effectiveness are also under development. “These products are much more effective [than existing ones],” states Lipscombe. “Solar power has been around for a long time but it’s now much more efficient and cost-effective,” he adds. Developments underway mean that such products are likely to become even more effective in future.
Market trends
In a visual comparison of a new building to one that was constructed say, 15 to 20 years ago there are some obvious differences. In terms of glass facades, the older buildings generally have a reflective glass exterior, while the more recent structures tend to have clear glass.
“The trend in glass now is for extremely high light transmission,” explains Lelievre. “Around four to five years ago the reflective box disappeared [from drawing boards] and for the last two years most projects we are working on are neutral buildings with clear glass,” he reports.
One of the main reasons for this change is the development of more advanced coatings. “Ten years ago reflective glass was the only way to reduce light transmittance. That ratio is switching with nanotechnology,” explains Lelievre. “The only difficulty associated with high light transmission in [the Middle East] is glare control; when the sun hits, it is too bright [for occupants],” Lelievre states.
Architects are combating this issue by adding architectural features for shading so the transparency and high light transmission glass can be used without detrimental effect on the indoor environment. “This [technique] started 20 years ago, but it has taken a while because the coatings were not up to par yet to keep the heat down and protect properly,”
explains Lelievre.
Meeting the local environmental conditions is one of the primary factors that must be considered when selecting the glass coating for a project.
“Every area of the world has its own peculiarities; here we are fighting a sun that has 850W/m² of power and around 700lux in terms of light, which is a very white light, so you wouldn’t use the same coatings here as you would in say Paris or Berlin, where there is a more yellow light” explains Lipscombe. And although the same fundamental issues of heat and light gain exist worldwide, how they must be tackled depends on local conditions.
“[In the Middle East] we mix and match coatings to make them more effective [for the local conditions]. Some of the coatings used here are specifically designed to tackle the problems of high heat gain and glare,” adds Lipscombe.
“There are two main coatings in demand in the UAE but the main one will always remain reflective, high msvd coatings. The next is multi-functional low-e (low-emissivity) coatings; these are good for residences where you don’t want the building to look like a mirror,” he predicts.
Meeting standards
When considering the choice of glass coating and the use of glass in general there are certain local regulations that must be considered. Among these is Dubai Municipality’s Decree 66: 2003, which is aimed at minimising solar thermal heat gains and lists the acceptable amount of heat gain through windows.
Further regulations are expected to be introduced in the future as the region strives for high levels of sustainable building. “The Emirates Green Building Council and Federal National Council are actively working on guidelines and regulations for the correct use of solar control glass to ensure the sustainability of buildings,” reports Lipscombe, “This is an ongoing process.”
The increasing use of the US Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system, is also making a difference to the amount and type of glazing used in the region. “LEED encourages high light transmission,” explains Lelievre. The aim here is to reduce the amount of artificial lighting needed in a building, which is pushing towards more transparent glazing and the use of specialist coatings if thermal gains are to be minimised.
“The trend for extremely high light transmission [and the use of transparent glass] has been increasing for the last two years and I expect this trend to continue,” predicts Lelievre. And the good news for those seeking such products for their projects is that with advances in technology the relative cost is falling. “The cost of glass and coatings relative to the early developments is on a real downward trend,” reports Lipscombe.
Company moves
With the use of glass for building facades set to remain popular in the region, the glass manufacturers and suppliers have been taking steps to ensure that they can meet future demand.
In April, Dubai Investments (DI) subsidiary Emirates Float Glass launched commercial operations at a $200 million manufacturing facility in Abu Dhabi. Here premium float glass products will be produced for the architectural markets throughout the GCC countries.
“This marks a significant milestone in our efforts to boost indigenous production of float glass in the UAE and position the country as a major manufacturing hub for glass products,” commented Emirates Float Glass chair Khalid Kalban, md and CEO of Dubai Investments.
Emirates Glass, meanwhile, has begun commissioning of its new AED100 million glass coating line, with production at the facility scheduled to go online in August 2009. Once operational, the coating line will increase the firm’s current production capacity by threefold up to 3.7 million square metres of coated glass per annum.
The new production facility upgrade is part of an overall expansion programme worth AED175 million that will see the firm relocate its entire operations to the Dubai Investments Park. Further news from the firm is expected in the coming months: “We will be introducing a new range of products that challenge the market norms in the near future,” reports Lipscombe.
“One product that we’ll be pushing hard is the post-temperable low-e range. This is a development of an existing range - with the new coater it will be easier to get much finer and more precise stacking of coating layers. The range will be aimed at the GCC market,” reveals Lipscombe.
“Our expansion programme comes on the back of a thriving glass marketplace,” explains Emirates Glass gm Ziad Yazbeck. Surely a positive sign indeed for all involved in the glass sector and for those relying on the product as their facade material, with more advances in coatings materials surely set to follow in the future.
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