Figure 2. The evolution of a fire caused by spontaneous heating

SPONTANEOUS HEATING/IGNITION

Spontaneous Heating and Pyrophoricity

DOE-HDBK-1081-94

OF HYDROCARBONS AND ORGANICS

Dry Coal

Smaller particles

Air and

(fines) are likely

Moisture

to heat

spontaneously

Figure 1a. Dormant pile of dry coal

Figure 1b. Addition of moisture and

containing small particles.

oxygen causes spontaneous heating.

Inadequate heat transfer from the pile

causes the temperature of the coal to

increase until. . . .

Ignition and flame occur.

Conduction

Figure 1c. Conduction, convection, and

Figure 1d. Coal reaches its ignition

radiation heat transfer mechanisms.

temperature resulting in a fire.

Figure 2. The evolution of a fire caused by spontaneous heating.

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Pyrophoricity