Where should re-circulating direct gas-fired industrial air heaters NOT be used?

Re-circulating direct gas-fired industrial air heaters should not be used in buildings containing flammable solids or gases because the operation of these heaters involves combustion, which generates heat and exhaust gases. This presents a significant fire hazard in environments where flammable materials are present. The nature of how these heaters circulate air can potentially distribute any flammable vapors or particles, increasing the risk of ignition.

Using these heaters in such environments violates safety protocols and standards designed to prevent fire and explosion risks. Proper consideration of the materials and conditions in the vicinity of gas-fired equipment is crucial for safe operations, which is why it is explicitly advised against using them where flammable substances are present. This attention to safety is vital in ensuring a secure working environment.