Combustion of wood equipping package shock absorbers: after regulatory fire test

Abstract

According to IAEA regulation, type B packages are designed to withstand a fire test following the mechanical tests, simulating accident conditions during transport. The wood of the shock absorber located near the damage zones produced by these tests may ignite and the conditions of air accessibility inside the absorber could mean that wood smouldering persists during the cooling period. IRSN has conducted an experimental study in which a real scale shock absorber specimen has been exposed to a large scale heptane pool fire test. A dedicated facility makes it possible to simulate the thermal power of the package contents and to measure in real time the heat transfer at the rear surface of the absorber. After a pool fire of 35 min duration, wood combustion continued for four days. Significant values were measured on the contact surface between lid and shock absorber for heat flux (up to 8 kW m⁻²) and temperatures (reaching 460°C). The impact of wood smouldering induced heat fluxes on typical lid gaskets has also been evaluated.

Keywords:

• Wood combustion
• Shock absorber
• Smouldering
• Fire test
• Damage
• Gasket
• Air inlet
• Safety