Straw bale fire testing

A few posts ago, we saw that straw bale construction holds up well to earthquakes. What about fire?

Turkey is dry enough in summer that you can get fires in the pine forests up in the hills, so you never know. And a lot of people’s first reaction to the idea of a straw bale wall is that it would surely be a bit flammable. Are we in danger of losing our hotel bungalows to a fire that comes sweeping down from the mountains?

Loose straw obviously burns very easily, and so cleaning up on the job site is important. Straw in a bale doesn’t burn as well as you would think, because it’s hard to get oxygen in there. And once you get 40mm of clay plaster on them, straw bale walls turn out to be surprisingly fire-resistant.

Here are a couple of videos. The first one is from Australia and shows a really dramatic simulated bushfire with temperatures of over 1000 °C pitted against a pre-fab straw bale wall. Temperatures on the other side of the wall stay at a comfortable 35 °C. The second video shows more of a backyard test but it gives a good impression of how the thick coating of plaster helps stop the bale from burning.