As Jan Růžička announced on the ESBG in Bouzov already, a specimen of a loadbearing strawbale wall, a 3m square 58cm thick was subjected to a standard fire test in June 2011. The inner (heated) side has been earth-plastered (5cm), the outer side had a lime plaster (3cm). Bales had 77kg/m³ originally and 93 kg/m³ when fixed in the specimen. During the test, the load on the specimen had been 12kN/m (so, like 360kg on the whole specimen). The wall had endured for 144min, the test had been stopped due to the vertical deformation exceeding the allowed limit – this happened shortly after a large part of the earth plaster fell down.
Another pair of specimens were tested as well, one of them using strawbales as insulation (41cm thick) in a wooden construction and earth plastered. This test had to be finished after 69min due to a failure of the other specimen; the strawbale-filled one remained almost intact – so it had been declared compliant with requirements for at least 60min.
The outcome has been achieved with the financial support of the Program Efekt of the Ministry of Industry and Trade of the Czech Republic within Project 1221420507: Selected Properties of Natural Based and Other Materials, Structural Components and Buildings.
Project leader: Jan Růžička, Faculty of Civil Engineering, CTU in Prague, Department of Building Structures.
Project partners for the preparation of the first specimen: ABatelier (abrotanek at pasivnidomy.cz) and Hliněné omítky Picas (navratil at rigi.cz).
Author: Jenik Hollan