(1). Difference in fire resistance
PU foam: Usually, it is classified as grade B3. By adding flame retardants, it can reach grade B2.
PIR foam: Generally, it is grade B2. Through adjusting the concentration of the polyisocyanurate acid ring and other formulation technologies, it can reach grade B1, and its oxygen index can exceed 35%.
(2). Difference in thermal insulation properties
PU foam: Its thermal conductivity typically ranges from 0.022 to 0.026 W/mK at 25 degrees Celsius.
PIR foam: The thermal conductivity can be as low as 0.018 W/mK at 25 degrees Celsius.
(3). Difference in bulk density
PU foam: To meet satisfactory strength requirements, its bulk density generally reaches 35 – 45 kg/m³.
PIR foam: To achieve satisfactory strength, its bulk density usually reaches 45 – 55 kg/m³.
(4). Difference in temperature range
PU foam: It can work properly below 110 degrees Celsius.
PIR foam: It can withstand temperatures up to 205 degrees Celsius.
(5). Difference in water absorption
PU foam: Its water absorption is generally between 2.5% and 3%.
PIR foam: The water absorption can be up to 0.9%.