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Heat stress measures for outdoor work

Under the Workplace Safety and Health (WSH) Act, employers and occupiers have duties to ensure that workplaces are safe and without risks to the health of every person within the premises and to protect the safety and health of every employee.

A warmer climate puts workers, particularly those performing manual work outdoors, at an increased risk of heat stress.

All workplaces are to assess if the work can be carried out safely, including implementing a heat stress management programme with the following key measures:


  • Workers new to Singapore or returning from prolonged leave of more than a week should gradually increase their daily heat exposure over at least 7 days.
  • Identify workers vulnerable to heat stress and make re-deployment arrangements where required.


  • Rehydrate at least hourly, and drink a recommended intake of 300ml per hour or more depending on the rate of water loss based on work intensity.
  • Provide cool or cold drinking water supply near work areas.


  • Ensure workers get adequate rest under shade to allow for recovery from heat before restarting work. Rest area to be near work area, where feasible.
  • Provide hourly rest breaks of a minimum of 10 minutes for heavy physical work activity when wet bulb globe temperature (WBGT) reaches 32°C or higher. It is recommended to provide longer rest periods as the WBGT increases:

    WBGT value 32 ≤ WBGT (°C) < 33 WBGT (°C) ≥ 33
    Work activity Light physical activity Heavy physical activity Light physical activity Heavy physical activity
    Rest duration
    5 to 10 mins rest
    10 mins rest
    10 mins rest
    15 mins rest
    1. Thresholds are based on outdoor WBGT measurements.
    2. Light physical activities include (but not limited to) light to moderate manual hand, arm, trunk or leg work; pushing and pulling light loads; and normal walking.
    3. Heavy physical activities include (but not limited to) intense arm and trunk work, carrying, shovelling, manual sawing; pushing and pulling heavy loads; and walking at fast pace.
    4. Rest duration to be increased with higher WBGT, heavier physical activity and if shade cannot be provided at work areas.
    5. More rest may be required, depending on workers’ personal health condition.


  • Reduce direct sun exposure at rest areas and work areas as far as possible, such as by setting up tentages.

Other measures

Other measures should also be put in place to ensure that the workers are able to work safely in a high heat stress environment.

Reschedule work

  • Reschedule outdoor physical work to cooler parts of the day where feasible.

Ventilate workplace

  • Cool rest and work areas with fans, air coolers etc.
  • Provide loose-fitting and light-coloured clothing to workers.

Monitor worker

  • Recognise and report early symptoms and signs of heat-related illnesses through close monitoring of worker’s health condition, particularly for vulnerable workers.
  • Consider having a buddy system so that workers can look out for each other for symptoms and signs of heat-related illnesses.

Emergency response

  • Establish emergency response plan and implement reporting procedures.
  • Prepare for emergency response. When a worker exhibits heat stress symptoms, the priority is to quickly reduce the body temperature. This can be achieved by applying ice packs, wet towels or cool water, fanning the affected person, using cooling blankets and cold water immersion. Workplaces should have cold water, ice packs, water spray and cooler boxes on standby for such emergencies.

Monitor wet bulb globe temperature (WBGT)

  • Monitor WBGT every hour during work hours, especially during the hotter periods of the day.


For more information: