At which point does a substance sustain combustion?

• A. Flash Point
• B. Fire Point
• C. Melting Point
• D. Boiling Point

Answer: (B)

The fire point is the temperature at which a substance can sustain combustion. At this temperature, the vapors produced by the substance mix with the air in sufficient quantities to ignite and continue burning. This characteristic distinguishes the fire point from the flash point, which is the lowest temperature at which enough vapor can form to ignite in the presence of an ignition source but may not continue to burn once the source is removed.

Understanding the difference between these points is crucial in hazardous materials management, as knowing the fire point helps responders assess the conditions under which a material will consistently burn. The melting and boiling points, while important physical properties, do not directly indicate combustion sustainability.