Facts on Flammability

Slide 27 of 37

The way in which the fire develops also contributes greatly to the degree of the hazard.

If the ignition source does not continue burning, then presumably no hazard will develop. However, if the test material becomes involved, a number of other considerations apply.

Fire growth rate is based on the involvement of the test material. The fire spread behavior and the fire growth are vital to the time at which a room becomes untenable.

FPF when burning usually produces a hot flame with melting but relatively slow lateral speed. Slow spread is important because it impacts the involvement of adjacent materials. But burning with melting can very quickly produce burn-through with flaming dripping, which can involve flooring materials. The behavior of fabrics whether burning with charring or melting also plays an important role in determining flame spread.

The rate of heat release is determined by rate of material consumption and the chemical composition of the material. The hazard potential is largely impacted by the rate at which heat evolves. Unless rapidly ventilated, heat can accumulate on the ceiling and reflect back increasing the sample’s burning rate.