Centuries ago, builders discovered that a tightly sealed one-inch air gap between two layers of a wall provided thermal insulation against the elements. While we know today that the air gap only offers a maximum insulating value of R-1, strides in materials research over the past century have hiked insulating values to R-6 per inch typically achieved by filling the gap with closed cell foam insulation.
Those strides seem like baby steps these days when compared to the latest insulation product: vacuum insulated panels. Otherwise known as VIPs, they offer a jaw-dropping insulating value of up to R-60 per inch or more.
Panels are made with open porous core material encased and vacuumed in a gas barrier with sealed edges. A gas barrier/facer foil provides an airtight and vapor-tight enclosure for the core material. A desiccant (drying agent) is added inside the core material to adsorb residual atmospheric gases or water vapour in the VIP enclosure, explains Phalguni Mukhopadhyaya, senior research officer, National Research Council of Canada (NRC).
“Normally the core material is an open porous fibre, powder, or mix of both,” adds Mukhopadhyaya, who has been researching VIPs for about eight years.
More information on VIPs will be presented at the NRC-hosted 10th Vacuum Insulation Symposium to be held in Ottawa at the NRC Research facilities from Sept. 15 to 16, 2011. International experts will present findings focusing on advances in applications that are expected to speed up the development of VIPs for marketing in the North American construction industry. Usually held in Europe, it is the first time the symposium is hosted in Canada.
With the latest edition of the National Energy Code of Canada for Buildings set to launch this fall, the timing for VIPs couldn’t be better. The new code stipulates an improvement of 25 percent energy efficiency over the levels set in 1997 when the last edition was published. That is an easily achievable number with VIPs, says Mukhopadhyaya.
“The construction industry is driven by rules and regulations. I think the new energy code will give the necessary impetus for this insulation to be adapted into the construction market.”
But first VIPs have some tests to pass. The NRC is two years into a three-year research agenda on a building in which vacuum insulation panels are installed. The building is located at the NRC’s research facilities in Ottawa. Researchers are examining alternative materials as a way of reducing the cost of VIPs. A recent study reveals that fibre-powder composites, made with traditional fibre insulation materials and volcanic powders, show promise as core materials. Furthermore, the use of bio-fibres in construction of VIPs also has potential, says Mukhopadhyaya.
VIPs are also being evaluated at the 4,700-square-foot Harmony House, Burnaby, a CMHC Equilibrium Sustainable Housing Demonstration Initiative. There will be a presentation on the initiative at the Ottawa symposium.
One of the key hurdles for VIPs is price. They are “very expensive” but the NRC and research teams in other countries (China, France, and Japan, for example) are working on technology to reduce the cost and make it practical for the North American residential and commercial construction market, Mukhopadhyaya says.
One of the unknowns about VIPs is long-term performance in construction because vacuum insulation has been used primarily for refrigeration, rarely for buildings.
Germany and Switzerland are the European leaders in its development and application for the building industry.
Mukhopadhyaya says while there are no Canadian manufacturers of VIPs yet, at least one Asian manufacturer is selling the product in Canada. But VIPs won’t be widely used in building construction in Canada until they have Canadian Construction Materials Centre (CCMC) certification.
When it does hit the market, vacuum insulation won’t be difficult to install, says Mukhopadhyaya. Typically, panels will be rectangular or square shaped, usually less than a metre square, and lightweight because of their low density. Panels, which will be prefabricated according to construction requirements, can either be glued or taped between two foam boards. Precautions must be taken during installation not to perforate the surface which will break the vacuum seal.
Although there are some uncertainties when it comes to the future applications of vacuum insulated panels, one thing we can be sure of is that this product will be making more headlines in future construction news.
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