At what temperature does combustion usually start?

The ignition temperature, or the temperature at which combustion usually starts, is often around 300°F, depending on the material involved. At this temperature, materials reach a point where they can emit enough vapor to ignite when exposed to an open flame or spark.

Different substances may have varying ignition temperatures, but for many common combustible materials, this is a typical threshold. For instance, wood, paper, and many oils will start to smoke and can ignite at approximately this temperature. Understanding the ignition temperature is crucial for fire safety inspection practices because knowing the combustion point helps inspectors assess fire hazards in different environments.

While lower temperatures are mentioned in the other choices, they do not typically reach the necessary vaporization required for efficient combustion across many materials. Hence, 300°F serves as a general guideline for the onset of combustion for a range of common materials in fire safety contexts.