Civil Engineering Reference
In-Depth Information
Figure 13.2
Copper pipe covered with black foam in a PVC pipe
Fire is a major concern during construction
Whilst a completed straw bale house has a high level of fire resistance, the risk of fire
during construction is significantly higher than when building a brick veneer house.
Straw in itself is extremely flammable. In fact, I believe it is just as flammable as paper
and paper is the very thing that most people use to light a fire.
We all acknowledge that paper is flammable, and that the finer the paper the greater
the flammability. Take a page from the phone book for example. This would ignite very
easily and would be totally consumed in a very short time. However, if you were to try to
burn a complete phone book it would be difficult. The outside would first burn a little
and then char. The only way to get it to burn properly would be to continue prodding it
to let the flames grasp at a few pages at a time. Actually it is not that you are letting the
flames get to the pages, but rather you are allowing the oxygen to get to the pages. The
reason the phone book will not readily burn is because there is a lack of oxygen between
the pages, and oxygen is a necessary component for fire. Tightly packed bales of straw are
to fire just as a phone book is to fire. The material is extremely flammable, but the
presentation of straw in the form of a bale starves the fire of the necessary oxygen.
Bales of straw do not self-combust like hay
There have been more fires of straw bale homes than any of us would like. To my
knowledge there has never been a fire from self-combustion. This is an issue for hay bales
that are baled green - another story in itself. I do not know of any fire in a straw bale
house that has not been caused by man.
A fire extinguisher could save the day
We could speak of the house that was burnt to the ground when a spark from an angle
grinder set an unrendered straw bale wall on fire. Or the fire that started in loose straw on
the ground and got into the building before it could be stopped. As a CFA member
(Country Fire Authority) explained to me, it doesn't take much to stop a fire on the face
of straw bales if you get to it in the first few seconds. Once it is feeding on the loose straw
ends protruding from the bales on the whole face of a wall it is a totally different thing. A
9-litre fire extinguisher is a fast answer to an immediate risk. At around $200 it is a small
price to pay for at least some peace of mind. I insist that all tradespeople working with
equipment that produces sparks or has flames, such as welding equipment, keep the fire
