Beware of PU Foam Fillers – Advice by the LABC

Below is an interesting article by the LABC, warning of the dangers of PU Foam.  In addition to their advice, please remember that dual-sided Big Wipes Heavy-Duty cleaning wipes are absolutely ideal for removing PU Foam from your hands, tools and surfaces. This video will show you how.

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.

Key points to remember:

Try not to use them at all. Take care to cut and install fire protection so that it fits exactly. Use proper collars and seals if compartments need to be penetrated

PU foams are combustible and generally will only offer fire-stopping properties when used in narrow voids or gaps

Fire foams are usually tinted pink to distinguish them from other foam products but they’re not all the same – read the instructions

Most are only suitable where the gaps to be filled are 10-30mm wide, such as bed and side joints to lintels, frames and small penetrations in blockwork walls or concrete floors

The use of foams in timber structures is not likely to achieve satisfactory fire-resistant results

Some fire-resistant foams are specifically designed and tested to fill larger gaps. Closely follow the conditions of use stated in the certification if installing a fire-rated foam product

Check what independent third-party tests have been carried out to show any PU foam’s suitability before use

There are life safety implications – use the foam correctly and in the right situations to achieve conformity with the Building Regulations.

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.