CSLB C-33 Painting & DecoratingSafetyMedium
A painting crew is applying a highly flammable solvent-based sealant inside a newly constructed, unventilated room. What is the most effective method to dilute the concentration of flammable vapors and prevent a fire or explosion?
- ASpraying water mist into the air to absorb vapors
- BHeating the room to promote faster evaporation
- COpening a single window in the room
- DUsing explosion-proof exhaust fans to create continuous airflow
Show answer & explanationAnswer & explanation
Correct answer: D. Using explosion-proof exhaust fans to create continuous airflow
In an unventilated room with flammable vapors, active mechanical ventilation using explosion-proof exhaust fans is crucial. This creates continuous airflow, diluting the vapor concentration below the Lower Explosive Limit (LEL) and expelling them from the space, significantly reducing the risk of fire or explosion.
Why the other options are wrong
- A. Spraying water mist is ineffective for absorbing flammable organic solvent vapors and could create other hazards.
- B. Heating the room would increase the evaporation rate and vapor concentration, significantly increasing the fire/explosion risk.
- C. A single window provides insufficient ventilation for highly flammable vapors in an unventilated room.
Flammable Vapor Dilution
The process of reducing the concentration of flammable vapors in the air to below their Lower Explosive Limit (LEL) to prevent combustion.
- Achieved primarily through ventilation.
- Critical in confined or unventilated spaces.
- Prevents fire and explosion hazards.
Memory trick: Ventilate the air, or risk a fiery scare.