Benefits of polyurethane spray foam insulation:
Fire Resistance
Insulation materials made of rigid
polyurethane foam (PUR/PIR) have a high level of thermal resistance
and good dimensional stability properties. Depending on the density
and facings, rigid polyurethane foam (PUR/PIR) insulation materials
for building applications can be used long-term over a temperature
range of – 30°C to +90°C. Rigid polyurethane foam (PUR/PIR)
insulation materials can withstand temperatures of up to 250°C ( 482
°F ) for short periods with no adverse effects.
Rigid polyurethane foam (PUR/PIR) is a thermosetting plastic and
does not melt under the effects of fire.
Link to a study of the fire resistance of closed cell polyurethane foam.