We helped sustainable designer Joost Bakker, test an environmentally friendly building option for bushfire-prone areas.

Update 1/3/12 – Justin Leonard, the CSIRO scientist involved with the burn, has answered some questions in the comments section.

In the fight between straw and fire, what do you think would come out on top? Yesterday our fire scientists found out when they tried to burn down a house made of straw.

They took an eco-friendly house with ModakBoard cladding, a steel frame and walls insulated with straw and exposed it to a worst case bushfire scenario. Did it survive? Results say, yes it did.


 

The house, created by sustainable designer Joost Bakker, may provide an environmentally friendly building option for bushfire-prone areas.

The affectionately named “straw house” was blasted with a range of real life bushfire conditions, from a radiation build up phase to full flame immersion and then a radiation decay phase.

So how did it fair? The external temperature reached a scorching 1000oC while inside the house was a cool 35oC. There was minimal damage to the straw house’s cladding and while the steel frame heated up  to 100–110oC it remained structurally sound and intact. Attached to the house was a about 70–odd sensors that measured what was happening inside and outside the building, so there are plenty more results to be analysed. For now, we know that when exposed to extreme bushfire conditions the little house that could, stood.

Big thanks go out to the New South Wales Rural Fire Service. They let us use the Eurobodalla Rural Fire Service Training Facility near Mogo – the only facility in Australia with a bushfire flame front simulator (pretty much  a giant barbeque) that can test entire buildings under realistic bushfire conditions. Plus they were the only guys who could have put out the fire if the house did go up in flames.

0 comments

  1. What is Modek board made from?

    1. It is magnesium oxide board, I think the brand involved is called ‘ Modak’

  2. @David King
    I couldn’t find it called a strawbale house anywhere in the article. Although I agree that it didn’t look much like a straw house from the pictures.

    I’d like to see the same test done an an actual straw bale house (as opposed to a straw house with Modek board cladding) to see how that would fare.

    1. The label on the video is ‘Strawbale House- Fire Test’.
      My basic query here is what is this test trying to establish. Is it that straw is a viable insulation material in domestic construction?
      if so shouldn’t it be tested in a more typical type of house construction – one with windows and the usual gaps ( no matter how well sealed) which allow embers into the building frame and thus onto the wall insulation?

      1. Thanks David,
        I will pass on your comments to the scientist involved and get a response.
        Cheers,
        Huw.

      2. Hi David,
        Yes agree the name is not a perfect fit, the name was coined before we did the experiment.
        The test was a whole of house experiment, with a very novel house design approach, no one really knew whether the cladding would protect the straw effectively.

        The wall cavities are ventilated through holes which are covered with metal mesh that prevents ember entry. There are no vents between the wall cavity and the inside space. The cladding is two layers of Modak board which are layered so there are no overlapping joins, the joins are also sealed with a fire rated sealant. So even with this bushfire exposure the enveloped did not develop any gaps that would allow ember entry into the wall cavity. The preliminary results seem to indicate that you could use a wide variety of construction approaches behind this calling system.

        The house design uses a door that also doubles as windows, we only tested one in this house, while a large house would obviously have many of them. We carefully measure the heat and smoke entry through the door system so that you can estimate the exposure to people in houses with many more windows/doors.

  3. Perhaps it should be called a ‘Modek board clad house with no windows’? It certainly shouldn’t be called a strawbale house.

  4. Has somebody told The Three Little Pigs?

  5. Nice burn!

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