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This question comes up every single time anything related to wood construction is talked about. The keyword in mass timber is mass. It's quite hard to set a big
by Tharkun 7y ago
This question comes up every single time anything related to wood construction is talked about. The keyword in mass timber is mass. It's quite hard to set a big mass of wood on fire. It burns slowly and relatively predictably -- meaning you have more time to evacuate. And because of its mass, an outer layer can char, burn out and leave the building standing.
Also sprinklers.
- srfilipek 7y agoThe problem is the glue. When the glue melts (which it does at a much lower temperature than wood burns), the structural integrity is lost. Firefighters do not enter new construction homes in the US because they often use these as floor joists. The time until failure has been greatly reduced compared to older homes. Things may have gotten better in the last few decades, but I'd like to see the data.
- lorenb 7y agoYou’re thinking of I-joists, which are a kind of engineered lumber, not a kind of mass timber. And those do light up like kindling. The glue used in glulams and the like chars at the same rate as the wood, and it’s pretty easy to achieve known fire ratings simply by making the members a little chunkier than they need to be since the char rate is known.
- Tharkun 7y agoThere are various ways of joining large amounts of wood together. CLT uses glue. Brettstapel uses wooden dowels (using two kinds of wood with a different hardness, so the dowels stay in place). I'm sure there are other variants as well.