Wood is a wonderful building material; it is renewable and sequesters carbon dioxide for the life of the building. There is a lot of it around these days as the Mountain Pine Beetle works its way through the forest. Traditionally it has not been used for big commercial projects; conventional wood is flammable and spans were limited.
Cross-laminated timber, or CLT, changes all that; wood is glued together into strong panels of almost any size, and is fire resistant as it is designed to char, which acts as a fireproofing. It can replace concrete and steel in apartment buildings, offices and now, airports.
The Office of McFarlane + Biggar Architects and Designers have used CLT in the new airport at the oil sands boomtown of Fort McMurray, Alberta. It's a big airport (170,000 square feet) for such a small town, as a lot of the workers fly home to the Maritimes at the end of their shifts.
The CLT is made at Structurlam's new plant in Penticton, British Columbia; about 50% of the wood in it is beetle-kill pine, although the stuff people will see in the airport is what's called J-Grade, without the distinctive tint of beetle-kill wood. The architect explains that "J stands for Japan, and it is specified as blue-stain free."
The amount of pine in SPF varies depending on the geography, with the highest concentration around Prince George, BC. The percentage of the pine killed by mountain pine beetle varies as well and generally decreases toward the east. Wood harvested from west of Quesnel, BC, for example, will have a very high concentration of blue-stained pine in the SPF mix. If the lumber comes from east of the Canadian Rockies, there will be much less.
The CLT Panels are sitting on Glulam beams, an older technology patented in Germany in 1872. Almost all of the wood is from certified forests, although not much is our favorite, FSC [Forest Stewardship Council]. Architect Steve McFarlane explains:
Ninety-three percent of the timberland in BC and Alberta is Crown land, and almost all of it is certified sustainably managed. Most is certified under SFI [Sustainable Forestry Initiative] or CSA [Canadian Standards Association]. Only a very small amount is FSC certified, as FSC rules change depending on geographic location. Also, the rules regarding harvesting of old growth and first-nations approvals for forests make it difficult to get BC and Alberta lands FSC certified.
It's not just the wood that's green, either;
In addition to incorporating mass-wood technologies, the project includes several other sustainable strategies to reduce its carbon footprint. This includes extensive natural daylighting strategies, passive ventilation, extensive heat recovery, and inherent flexibility in the design to accommodate continually changing airline and security requirements.
The mountain pine beetle will probably kill 80% of British Columbia's pine forests, and according to CST Innovations,
This wood is only usable for 5-15 years from the time it dies, and after that becomes unusable, even for wood chips or pulp. It becomes an even greater carbon source in our forests as it rots and possibly burns in uncontrollable forest fires. By 2020, rather than absorbing CO2, our forests are expected to emit as much carbon dioxide as 5 years of all transportation in Canada.
Making it into Cross Laminated timber sequesters all that carbon dioxide for the life of the building. Building the Fort McMurray Airport out of it might just offset five seconds of the oil sands production down the road, but it's a start.
Thanks for the tip from The Office of McFarlane Biggar