By Kat Harrold
Photo ~ Green Roof Technology
In 1988 fire research testing on green roofs was begun by the Research and Material Testing laboratory of Baden-Wurttemberg in Stuttgart Germany. Initial testing began with the evaluation of bituminous waterproofing layers. It was discovered that the bituminous waterproofing when burned produced 50 kWh/m2. Alternatively when this burn test was done on an extensive green roof with dry grasses only 3 kWh/m2 were produced.
Tests were then done to see if it was possible to establish a fire that would spread across an extensive green roof and or start a glowing/burning of the growing media. After several tests the conclusion was made that it was nearly impossible to create a fire on an extensive green roof that would spread across the roof or ignite the growing media. Conversely it was discovered that a bare regular bituminous waterproofing membrane was 15-20 times more likely to catch fire than an extensive green roof with grasses and perennials. It is for these reasons that many Germany insurance companies offer a 10-20% discount on fire insurance when a building has a built in place green roof.