Proponents for competing construction products are volleying claims and rebuttals in an increasingly contentious debate about fire risk and safety in taller wood-frame buildings.
Perhaps not surprisingly, the Canadian Wood Council (CWC) and the Cement Association of Canada (CAC) have differing positions on proposals for added flexibility in both the national and Ontario building codes. Neither code currently permits new wood-frame construction exceeding four storeys.
The CAC issued a series of media releases last December directed at the Canadian Commission on Building and Fire Codes review process for the national codes, and has more recently criticized a proposed revision to the Ontario building code to allow wood-frame buildings up to six storeys provided compensating safety measures are in place. An August 19 CAC media release suggests local governments could suffer financially if the Ontario building code is revised.
“Taller wood-frame buildings could compromise the safety of people who might live and work in them, as well as the safety of frontline responders,” CAC president and CEO Michael McSweeney asserted. “Rising emergency services costs are already straining municipal budgets. We cannot afford to take this risk.”
In counterpoint, the CWC emphasizes the mandated life-safety requirements — such as sprinklers and heightened fire ratings for structural materials and components — that are part of the proposed code changes. These are similar to code stipulations in British Columbia where new six-storey wood-frame buildings have been permitted since 2009.
“When competing materials imply that wood is ‘unsafe’, are they advocating for Canadians or their own market share?” an August 21 media release from the CWC states.
“Most of this is fear-mongering, baseless stuff that’s completely over-the-top,” maintains Richard Lyall, president of the Residential Construction Council of Ontario, which has long supported code allowances for taller wood-frame buildings. “When you see a particular group within the industry that has a vested interest in this not happening, and it’s making sensationalistic claims about something that already occurs in other jurisdictions, it’s more than a little annoying.”
Debate among the various product proponents isn’t necessarily unprecedented. Jiri Skopek, managing director, sustainability, with Jones Lang LaSalle, recalls the dynamic in a Green Globes ANSI standard consultation process related to life cycle assessment (LCA) of building materials.
“We had the steel people and the cement people and the wood people. There was much scientific discourse, but they did come to an agreement,” he recounts.
The built environment, itself, demonstrates a largely harmonious melding of the three structural mainstays.
“There should not be a conflict between the various materials because they each have their own qualities. Cement is very good in compressive strength; steel is very good as a tensile material; and wood actually has good qualities in both respects,” Skopek advises. “Good design can combine the qualities of all the materials to reflect structural forces.”
Meanwhile, recently proposed federal regulations to reduce emissions of nitrogen oxides (NOx) and sulphur dioxide (SO2) list the cement industry in the first round of the phased introduction of new performance standards targeting several sectors that produce air pollutants. The proposed regulations, which were posted in the Canada Gazette for public review in early June, would impose emission reduction standards for the kilns used to heat and process limestone, silica, alumina and ferrous oxide to produce the clinker that is the basis of cement.
Fifteen grey cement manufacturing facilities across Canada emitted 28 kilotonnes (kt) of NOx in 2010, representing 3 per cent of total industrial emissions, and 19 kt of SO2, representing 2 per cent of industrial emissions. In the absence of the proposed new controls, the cement industry’s contributing share of NOx emissions is projected to increase by 16 per cent by 2035, while its SO2 output would increase by 23 per cent in the same period.
Conventional production practices also release hundreds of kilograms of carbon dioxide (CO2) for every tonne of cement manufactured. As its chemical formula — CaCO3 — reveals, heating limestone to unbind the lime (CaO) sets CO2 free.
Barbara Carss is the editor-in-chief of Canadian Property Management and Building Strategies & Sustainability.