REGULARS- TALKING TIMBER
The T3 building in the US. Image: Ema Peter
But rest assured, all the existing buildings, such as the built 14-storey tall timber Treet building in Norway, for instance, or 18-storey Brock Commons in Vancouver, would not have been built without careful, thoughtful scrutiny.
There are many ways to protect the wood. They include gypsum wall board and the natural charring ability of the wood itself.
For instance, there’ s really rigorous research going on right now about how to measure that char layer. What that means is that when a heavy timber member burns, it burns in a very slow way from the outside in and tends to char over and protect the inner structural layers from being burned further. There are scientific ways to design so that in the rare case of fire or event when a system might fail and that member starts to burn, there could be a protection borne out by the natural wood properties to achieve standard two-hour fire rating.
If the testing bears that out, it will add a lot of momentum to the code process.
PGB: Will the tests next year dictate how the timber market and timber construction industry move forward in relation to commercial structures? Jones: Once these tests results are in place, that will be the trigger. Once the codes committee – and I should stress that I don’ t speak for the committee, I’ m only one member of 18 – performs the tests and, assuming they’ re performed at an acceptable level, once we have data that is very trustworthy and carefully thought out, the code committee will act quickly to assemble model code language. Once that goes ahead, it will go into a broader voting process sometime in early 2018.
Once the language is assembled, even in draft form, it can be used by authorities and cities at their discretion. They’ ll know it has been carefully scrutinised by an interdisciplinary body.
Everybody is waiting for that sweet spot to move quickly ahead for construction of taller timber buildings. The industry is aware that for multi-family buildings up to six storeys it makes sense to use light wood frame construction. But between seven and 14 storeys, it is usually too cost-prohibitive to use concrete or steel, and light frame wood is not allowed. So, once that height is allowed for mass timber buildings, I see the industry moving very fast to adopt mass timber construction.
It’ s really exciting to imagine growing your own high-rise from a handful of seeds. It’ s the only material that is renewable.
Source: Proud Green Building
52 APRIL / MAY 2017 //