Fire protection of straw-insulated panels

18. February 2020 Sustainable Construction

It may seem like a house insulated with straw poses a significant fire hazard. Yes, loose straw is indeed highly flammable. 

Yet, EcoCocon straw wall panels provide excellent fire resistance that is comparable to or even higher than other construction materials.

There are 4 main reasons why EcoCocon is safe from fire: 

  1. The straw in the panels is packed so tightly (110kg/m³) that there is no oxygen in the wall that could fuel the flames. 
  2. The high content of silica, a natural fire retardant, and the lack of oxygen turn the surface into a layer of non-combustible carbon. 
  3. The clay plaster coating completes the fire-resistant seal. 
  4. The thermal insulation property of straw additionally protects the material inside from reaching high temperatures and self-igniting.

Testing the fire resistance

We put the panels through an official test in 2018. The testing wall consisted of modules up to 2.9 m high and 1.2 m wide. They were covered by a waterproof membrane with wood fibre boards on the outside and clay plaster from the interior side. An axial force of 70 kN/m was applied vertically to simulate the roof/ceiling load. 

The internal clay covered surface was then exposed to fire with a temperature of up to 1050°C (1922°F). We were aiming to pass the 30-minute mark that is the standard requirement. 

The result: EcoCocon wall showed no signs of damage whatsoever even after a full two hours of the fire test! The other side only reached an average temperature of 32.1°C (89.78°F). 

Now there is no doubt that a straw panel/clay surface composite can provide excellent fire protection that surpasses building regulation requirements. We were awarded the RE 120 (120 minutes) fire resistance classification, making EcoCocon panels a safe yet sustainable construction material. 

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