Critical Radiant Flux is used to classify

Critical radiant flux is used to classifyinterior floor finishes. Critical radiant flux is a measure of the minimum radiant heat energy required to sustain flame propagation on a floor material or covering. It is determined by exposing a specimen to a radiant heat gradient and observing the distance from the ignition point to the flame-out point.The shorter the distance, the higher the critical radiant flux and the better the fire performance of the floor material or covering1.Critical radiant flux is used to classify floor materials and coverings according to their fire hazard and resistance, and to specify the minimum requirements for different occupancies and applications2.For example, the International Building Code (IBC) requires that interior floor finishes and coverings in exit access corridors and exit enclosures have a critical radiant flux of not less than 0.45 W/cm2, while those in other spaces have a critical radiant flux of not less than 0.22 W/cm23.Critical radiant flux is also used to evaluate the fire safety of floor materials and coverings in transportation vehicles, such as aircraft, trains, and buses4.