What does combustibility describe?

• A. Whether a material will burn and how quickly it will burn
• B. The amount of heat required to ignite a material
• C. The vapor pressure of the material at ignition
• D. The color of the flame produced

Answer: (A)

Combustibility describes how readily a material will burn and how quickly it will burn. It captures both the tendency to ignite under typical conditions and the rate of the flame’s spread, which is key for assessing fire risk and choosing appropriate suppression methods. This is different from the heat needed to ignite (ignition energy or flash point) and from vapor pressure (how much vapor forms to feed a flame). The color of the flame, by the way, doesn’t indicate combustibility.