5 ms·
I'm bit worried with this getting too popular, because of fire safety. Fire safety of a material is about two things: Fire load(kJ) and fire-resistance(hours).
by vlehto 11y ago
I'm bit worried with this getting too popular, because of fire safety. Fire safety of a material is about two things:
Fire load(kJ) and fire-resistance(hours). Wood increases fire load, but it has surprisingly good fire-resistance. Better than steel. The elevated fire load is usually compensated by sprinklers, and so far wooden skyscrapers have been safer than concrete ones because of this. Currently fire-resistance is lot more important, because that pretty much dictates loss of life in regular fire.
But imagine city where you don't have just few wooden skyscrapers, but like 90% of the buildings are wood. Then earthquake hits. Now the sprinklers don't work anymore, and the fire can spread from building to building. Whole cities burning was relatively common before 20th century, partially because they we're mostly built from wood.
>"So wood structures make sense in seismic-heavy regions, especially in the Pacific Northwest, where a 9.0 magnitude earthquake is expected to hit in the next 50 years."
>"Ideally there comes a day when people can choose between mass timber, steel and concrete. We don’t see mass timber replacing those, it just becomes another option when certain parameters and goals apply to a project."
I hope these cancel each others out. And there will be regular buildings in between to act as firewall of sort.
- kawera 11y agoInteresting but considering how cities exist today, specially large cities that are basically concrete/steel jungles, I guess it would take decades for wooden buildings to reach, say, a 20-25% share.
- kibwen 11y agoAn earthquake that shuts off water to a whole city seems just as liable to render uninhabitable all those concrete buildings (assuming they don't outright collapse). Wooden structures seem more likely than concrete to survive the initial quake, even if they're less likely to survive the resultant fires, so it may be a wash in the end.
- vlehto 11y agoHistorically the fires have been often even more hazardous than the quakes. https://en.wikipedia.org/wiki/1906_San_Francisco_earthquake#Fires https://en.wikipedia.org/wiki/1906_San_Francisco_earthquake#... Something like 30% wood might be the best. But it creates interesting problem, who gets to live in a wooden building? Who gets to build one?
- kansface 11y agoMany of those fires were set intentionally for insurance claims. Many other fires were caused by dynamite, gun powder, or artillery used to create fire breaks.
- kibwen 11y agoI trust that the vast majority of the destruction in the aftermath of the earthquake was caused by fire, but what I'm curious about is the death toll of the fires themselves, which I don't see in the article. The reason that it matters is because an earthquake can easily cause structural damage to a building that leaves it standing but renders it uninhabitable, forcing you to demolish it anyway. Even structures that are specifically built to withstand earthquakes aren't necessarily safe to occupy after the quake. From this (simplistic) perspective, wood is no worse than concrete because either way you'll be forced to rebuild the vast majority of the city after the big one hits.
- vlehto 11y agoYou have good points. My only counter point is that rescuing people from ruble is easier if there are not much fires around.
- sliverstorm 11y agoThe cynic in me suggests if cities still burned down every few decades, we'd have a chance to fix entrenched mistakes in the planning/zoning/etc.