What should be done to openings in buildings before using thermal fog?

What should be done to openings in buildings before using thermal fog?

• A. Open all doors to vent fumes.
• B. Install new seals on windows.
• C. Extinguish all flames and pilot lights.
• D. Turn on HVAC system.

Answer: (C)

Ignition sources must be removed before using thermal fogging because the solvent used is highly flammable. Extinguishing all flames and pilot lights eliminates the risk of vapors igniting from a spark or flame, which is the most important safety step. Opening doors to vent fumes could let fog escape and expose others, turning on HVAC would circulate flammable vapors, and installing new seals on windows isn’t the immediate safety action needed.

Ignition sources must be removed before using thermal fogging because the solvent used is highly flammable. Extinguishing all flames and pilot lights eliminates the risk of vapors igniting from a spark or flame, which is the most important safety step. Opening doors to vent fumes could let fog escape and expose others, turning on HVAC would circulate flammable vapors, and installing new seals on windows isn’t the immediate safety action needed.