Polyurethane (PU) foam fillers - also known as ‘fire foam’ - are common in construction, but if you use them without properly understanding them they can end up costing you money, creating worse fire risks and potentially ruin your hard-earned reputation.
Fire foams are usually tinted pink to distinguish them from other non-fire rated foams, but they’re all different and have varying functions and properties - make sure you're using the right one.
Normally expelled from pressurised cans as a sticky liquid, which quickly expands to around 40 times its original volume to form rigid foam, PU foam is designed to fill small linear gaps or service penetrations. Without clear manufacturer's guidance, they shouldn’t be used to fill large voids or openings as the foam’s fire-stopping properties may only be effective and tested in narrow voids or gaps. (See cover image and right for incorrect usage).
Key points to remember:
Is your foam properly tested?
PU foam products must have their fire performance determined by testing to standards BS 476 Part 20/22 and BS EN 1366-4 for linear gaps and BS EN 1366-3 for service penetration seals. Visit the Association for Specialist Fire Protection website for more information on fire safety and protection in construction.