Heat Stress Prevention

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Overview

Heat stress is a serious, escalating risk that needs a structured programme.

Control depends on WBGT, work/rest ratios, acclimatization and early recognition.

The heat illness continuum

Heat rash — prickly skin irritation from blocked sweat ducts.
Heat cramps — muscle spasms from salt and fluid loss.
Heat exhaustion — heavy sweating, weakness, nausea, dizziness.
Heat stroke — confusion or collapse; a medical emergency.

Step-by-step procedure

Assess task, workload and environment; forecast heat exposure.
Measure WBGT at the work front and set the work/rest regime.
Acclimatize new or returning workers over about one to two weeks.
Hydrate every 15–20 minutes, with electrolytes as needed.
Set up shaded rest areas; schedule heavy work in cooler hours.
Operate a buddy system to watch for early symptoms.
If symptoms appear, stop work, move to shade and start cooling.
For suspected heat stroke, cool aggressively and call EMS at once.

Key controls

WBGT-based work/rest regimes scaled to the workload.
Cooling PPE and light, breathable clothing.
Hydration stations and shaded rest areas near the work front.

Roles & responsibilities

Role	Responsibility
HSE	Sets WBGT thresholds and work/rest tables; trains crews.
Supervisor	Applies the regime, enforces breaks, adjusts schedules.
Workers / Buddy	Hydrate, take breaks, watch each other, report symptoms.

Common mistakes to avoid

Putting unacclimatized workers straight onto heavy work.
Relying on thirst instead of scheduled drinking.
Mistaking heat stroke for exhaustion and delaying EMS.

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 heat, light and noise B.E. 2559 (2016).

Frequently asked questions

What is Heat Stress Prevention?

Heat stress occurs when the body cannot lose heat fast enough, and it is a serious risk for crews working outdoors or near hot equipment in Thailand's climate. Left unmanaged it progresses from mild discomfort to heat stroke, which is a life-threatening medical emergency. A structured programme combines environmental monitoring, work/rest scheduling, hydration and trained observation.

Who is responsible?

HSE: Sets WBGT thresholds and work/rest tables, monitors conditions and trains crews.; Supervisor: Applies the regime on site, enforces breaks and adjusts schedules to the heat.; Workers / Buddy: Hydrate, take breaks, watch each other and report symptoms early.

What are the most common mistakes to avoid?

Putting unacclimatized new workers straight onto heavy work in full sun. Relying on thirst instead of scheduled, regular drinking. Treating heat stroke as exhaustion and delaying aggressive cooling and EMS.

References — ACGIH WBGT TLV; Thai OSH Act B.E. 2554 and heat/light/noise regulation B.E. 2559.