The tests at the HSE‘s Buxton laboratory compared ignition of heavy-weight timber pallets with medium load, closed top recycled polyethylene pallets. Both were loaded with empty steel drums.
The time taken for fire to spread upwards to the pallet above the ignited pallet was around 18mins for plastic and nearly 50mins for timber.
Researchers found that the plastic produced copious black smoke and was easily ignited by a match, whereas the timber required a more energetic ignition source.
Flames on the timber pallets were seldom greater than 1m high, while those on the plastic reached a maximum height of 6-7m.
The HSE concluded that a serious fire could develop in a stock of incombustible but potentially dispersable toxic materials stored on plastic pallets. It recommends that large numbers of plastic pallets in stores containing such materials, such as heavy metal compounds, should be controlled and if possible “eliminated”.
It also recommends that further work be done on other types of plastic pallets to determine how widespread the problem is.
