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Enhanced Measures to Reduce Heat Stress for Outdoor Workers





               Rising temperatures in Singapore will place workers, especially outdoor workers, at an increased risk of heat stress. Unlike the general population, outdoor workers have less discretion over their work activities, and may be more exposed to heat stress. The Ministry of Manpower (MOM), in consultation with the Ministry of Health (MOH)’s Heat Stress Expert Panel, has introduced an enhanced set of measures to reduce the risks of heat stress for outdoor workers. These measures will take immediate effect.


2            A combination of measures focusing on the four aspects of acclimatise, drink, rest, and shade, will provide protection to outdoor workers across various industries (see Annex). New workers must be given time to gradually adjust to outdoor work and all outdoor workers must hydrate at least hourly, and take regular rest breaks under shaded areas to dissipate accumulated body heat.


3        Employers are required to monitor the Wet Bulb Globe Temperature[1] (WBGT) for every hour of outdoor work performed, especially during the hotter periods of the day.  Construction sites with a contract sum of S$5 million or more, shipyards and the process industry, will be required to have a WBGT meter [2] on-site for localised measurements as these workplaces are likely to have prolonged outdoor activities. Other workplaces can use NEA’s myENV app to monitor WBGT readings.


4        When WBGT (oC) is 32 or higher, a minimum rest break of 10 minutes hourly under shade has to be provided to workers carrying out heavy physical activities. For workers with pre-existing health conditions, the rest duration should be longer or as advised by their doctors.


5         Workplaces are also encouraged to effect a buddy system for early recognition of heat injury symptoms and implement prompt interventions when any worker shows signs of excessive heat exposure.


6        Employers will be required to implement these measures to reduce heat stress risks for outdoor workers and MOM will conduct inspections at workplaces to ensure that these measures are adequately implemented. More information on the enhanced measures can be found at

Annex – 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) reaches32°C or higher. It is recommended to provide longer rest periods as the WBGT increases:

WBGT value

32 ≤ WBGT (oC) < 33

WBGT (oC) ≥ 33

Work Activity

Light physical activity

Heavy physical activity

Light physical activity

Heavy physical activity

Frequency, 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 (below) should also be put in place to ensure that the workers are able to work safely in a high heat stress environment.  


Other Measures

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 WBGT

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


For more information on the general heat stress management programme, refer to the WSH Guidelines on Managing Heat Stress in the Workplace published by the WSH Council.

[1] The WBGT is an internationally recognised measurement that reflects the main environmental factors contributing to heat stress.  Besides air temperature, WBGT is also affected by humidity, wind speed, and solar radiation.


[2] The requirement of WBGT meter on-site for localised measurement is effective from 1 Jan 2024.