Hot Work & Fire Prevention

Overview

Hot work supplies the heat — the job is to remove the fuel and be ready to extinguish.

Step-by-step procedure

Obtain a hot-work permit; consider cold-work alternatives.
Gas-test for flammable vapour before and during work.
Remove/shield combustibles; cover drains and openings.
Station a dedicated fire watch with an extinguisher.
Do the work only within the permitted area/time.
Keep the fire watch ≥ 30 minutes after work.

Key controls

Gas-free certificate near hydrocarbon equipment.
Fire blankets and spark screens.
Cylinders secured upright with flashback arrestors.

Roles & responsibilities

Role	Responsibility
Permit issuer	Confirms gas tests and controls before approving.
Welder / operator	Works within the permit; stops on gas alarm.
Fire watch	Watches for fire; stays after work.

Common mistakes to avoid

Leaving immediately — fires start during cool-down.
Sparks falling through grating onto combustibles below.
Skipping continuous gas testing.

Legal requirements (Thailand)

Occupational Safety, Health and Environment Act B.E. 2554 (2011) — the governing workplace-safety law in Thailand.
Ministerial Regulation on OSH for fire prevention and protection B.E. 2555 (2012).
Ministerial Regulation on OSH for work in confined spaces B.E. 2562 (2019).

Frequently asked questions

What is Hot Work & Fire Prevention?

Hot work introduces an ignition source into the plant. The fire triangle needs fuel, oxygen and heat — hot work supplies the heat, so the job is to remove or control the fuel (flammable gas, vapour, dust, combustibles) and to be ready to extinguish any ignition immediately.

Who is responsible?

Permit issuer: Confirms gas tests and combustible controls before approving.; Welder / operator: Works within the permit; stops if a gas alarm sounds.; Fire watch: Watches for sparks/fire, ready to extinguish, stays after work.

What are the most common mistakes to avoid?

Leaving immediately after work — most hot-work fires start during the cool-down period. Sparks falling through grating or drains onto combustibles below. Skipping continuous gas testing in changing conditions.

References — Company hot-work procedure; fire-prevention practice; Thai OSH Act B.E. 2554.