To demonstrate mass timber’s fire resistance, engineers put the wood elements in gas-fired chambers and monitor their integrity. Other tests set fire to mock-ups of mass timber buildings and record the results.

These tests have gradually convinced regulators and customers that mass timber can resist burning long enough to be fire safe. That’s partly because a layer of char tends to form early on the outside of the timber, insulating the interior from much of the fire’s heat.

I live in a country where single family homes are built with wood. Everyone seems to trust their life to that. I don’t know why it would be different in an apartment.