A pyrophoric chemical will ignite spontaneously in air at or below what temperature in °F?

A pyrophoric chemical will ignite spontaneously in air at or below what temperature in °F?

• A. 90
• B. 100
• C. 120
• D. 150

Answer: (B)

Pyrophoric materials ignite in air without an ignition source because they react vigorously with oxygen at relatively low temperatures, often at room temperature. The question asks for the air temperature threshold at or below which spontaneous ignition occurs. In typical safety training, that threshold is about 100°F, so at or below roughly 100°F, these substances can ignite spontaneously. Higher temperatures like 120°F or 150°F are above that threshold and aren’t the standard figure used for this concept, and a value such as 90°F would be below the commonly cited cutoff. That’s why 100°F is the best answer.

Pyrophoric materials ignite in air without an ignition source because they react vigorously with oxygen at relatively low temperatures, often at room temperature. The question asks for the air temperature threshold at or below which spontaneous ignition occurs. In typical safety training, that threshold is about 100°F, so at or below roughly 100°F, these substances can ignite spontaneously. Higher temperatures like 120°F or 150°F are above that threshold and aren’t the standard figure used for this concept, and a value such as 90°F would be below the commonly cited cutoff. That’s why 100°F is the best answer.