Heat stress TARP template
A heat stress trigger action response plan (TARP) sets out what changes on site as the heat builds: work-rest cycles, water, shade, who checks on whom and how often, and when only essential work goes ahead. This template uses WBGT bands. Print it or save it as a PDF, and fill it in with your own levels.
WBGT in brief
The wet bulb globe temperature (WBGT) combines air temperature, humidity, sun and wind into one number for heat stress at work, and many workplace heat stress procedures use it to set work-rest cycles. On site it is measured with a WBGT meter.
A forecast can only estimate it. Lumen Sites uses the Bureau of Meteorology’s simplified method in daylight, which assumes moderate sun and light wind, so a forecast WBGT is for planning the day, not a measurement: it cannot see radiant heat from plant and rock, enclosed spaces, workload or clothing. To try the formula on any reading, use the WBGT calculator.
Rules and guidance
Australian work health and safety laws don’t set a maximum working temperature, but heat has to be managed like any other risk. Some industries have more specific rules. In New South Wales, the Resources Regulator’s heat stress control plan (May 2024) states: “NSW Work Health and Safety (Mines & Petroleum Sites) Regulation 2022 requires underground mines to implement control measures to manage heat stress in places in the mine where people travel and work where the wet bulb globe temperature (WBGT) exceeds 27° C.” Check the requirements for your state, your industry and the type of work.
How to use it
- Set your WBGT bands. Lumen Sites starts with a caution level of 28 °C and a stop level of 32 °C. Many procedures use more bands, with longer rest breaks in each higher band and only essential work above the top one.
- Fill in the controls for each band.
- Decide who measures WBGT on site, where and how often, and who checks the forecast at pre-start.
- Work through the plan with the people who will use it and their health and safety representatives, then brief every crew.
- Review it before each summer and after any case of heat illness.
Site details
| Site name | |
|---|---|
| Work covered (for example pit crews, the plant, maintenance) | |
| WBGT measured with (meter and location) | |
| Who measures it, and how often | |
| Who checks the forecast at pre-start | |
| Prepared by | |
| Approved by | |
| Date | |
| Next review |
WBGT bands and controls
Write your levels into the column headings. Add a column for each extra band your procedure uses.
| Control | Below caution: under ____ °C | Caution: ____ to ____ °C | Stop: ____ °C and above |
|---|---|---|---|
| Work-rest cycle (minutes of work and of rest each hour) | |||
| Water and electrolytes | |||
| Shade, rest areas and cooling | |||
| Clothing and protective equipment | |||
| New starters and returning workers (acclimatisation) | |||
| Checks on workers (who, how often, buddy system) | |||
| Work that goes ahead | |||
| How people are told |
Who is most at risk
- People who aren’t used to the heat. The body adapts to working in heat over about one to two weeks, and the adaptation fades after a week or more away. New starters, and fly-in fly-out crews arriving from a cooler city at the start of a swing, are most at risk in their first hot days.
- Heavy work in heavy gear. Muscles make heat, and coveralls, respirators and other protective equipment trap it.
- Hot spots the forecast can’t see. Radiant heat from plant, rock faces and enclosed spaces, and cabs whose air conditioning has failed.
Heat illness response
| First aiders on each shift | |
|---|---|
| How to call for help on site (radio channel, phone) | |
| Directions to give 000 (site access, coordinates) | |
| Cooling equipment and where it is kept | |
| Nearest medical help and travel time | |
| Who reports and investigates |
Treat confusion or collapse in the heat as a medical emergency: call 000 and start cooling the person while help is on the way.
Planning with the forecast
- Check the hourly WBGT forecast at pre-start, and brief crews on the hours that will reach your caution and stop levels.
- Move heavy work into the cooler hours and plan early starts.
- Schedule rest and water breaks ahead of the hottest part of the day.
- When the forecast reaches caution, measure on site and follow the band you measure.
More on forecasting heat stress for a site in heat stress forecasts (WBGT).
Sign-off
| Role | Name | Signature | Date |
|---|---|---|---|
| Prepared by | |||
| Consulted (workers and health and safety representatives) | |||
| Approved by |
This template is a starting point. Adapt it to your site with your own risk assessment, in consultation with your workers, and check it against the requirements of your regulator and your emergency procedures. It is not legal, medical or safety advice.
Related: Lightning TARP template · WBGT calculator · Pilbara weather for site work