Which PU foam is best for passive protection against fire risk?
Polyurethane (PU) foam is a material resistant to mould and mildew, odourless, and chemically neutral. It is also resistant to the most common building materials and biochemically inert. It exhibits high resistance to solvents used in construction, such as those found in paints, adhesives, bituminous pastes, wood preservatives and sealants.
It remains stable even when exposed to exhaust gases or aggressive industrial atmospheres. It has good dimensional stability in a temperature range from -50ºC to + 110ºC, with peaks at 250ºC.
These characteristics, combined with the intrinsic insulating qualities of the foam, make it a product particularly suited to the building sector, due to its stability and long lifespan.
However, not all PU foams have the same properties of resistance or reaction in the event of a fire. The level of protection provided to your personnel and your structure can therefore be strongly impacted by an unsuitable choice of PU foam.
What the regulations say
Like any filling product, PU foams are subject to strict regulations, which define their use and application.
The decree of 22 March 2004 published in the “Journal Official” of 1 April 2004 implements the fire resistance classification system for construction products defined at European level. Thus, classes R, E and I replace the designations Fire-Resistant (SF), Flame Arrestor (PF) and fire damper (CF) as soon as the corresponding European test standard is available.
| Criteria (Functions to be performed) | Former classification (1999 decree) | Former classification (2004 decree) |
| Mechanical strength | Fire-resistant SF | R |
| Hot gas sealing | Fire-resistant SF | (R) + E —> E |
| Mechanical strength | Fire rating CF | (R) + E —> E |
