The Thermal Environment

New, Simple Heat Stress Management System

• By Ross Di Corleto
• 24/03/2025
• No Comments

Managing heat stress at work can be tricky. It’s important to keep things simple but also make sure the process really reflects the risk. Heat stress depends on many factors, not just air temperature. Even adding humidity isn’t always enough to show the true danger.

A new system has been developed and is already being used at several sites in Australia. It’s called the Heat Strain Charts Model. This method is simple and easy to use. It works well for both technical and non-technical people. It’s made for frontline workers so they can use it without special training or fancy tools.

Whilst it is easy to use and looks simplistic, this system is based on solid science. It follows the international standard ISO 7933 Predicted Heat Strain to develop the colour charts. It also uses Trigger Action Response Plans (TARPs). These are common in mining but can be used in other industries too. The TARPs are created with input from workers, supervisors, managers, and health & safety staff. This way, everyone is involved—not just the specialists.

How to use the tool:

1. Find the air temperature and humidity. You can get this from a site weather station or meteorology websites or by using a simple handheld device at the work site.
2. Look at the type of work being done. For example:
   • Easy work, like an inspection or walking around = Low
   • Moderate work, like using hand tools for maintenance = Medium
   • Hard work, like digging or trenching by hand = High
3. Check the heat strain chart. Find the colour that matches your workload and temperature/humidity conditions.
4. Follow the response guide. Look up the actions linked to the colour you found on the chart for your role.

There’s also a flowchart below that shows these steps clearly.

People using this system have given positive feedback. It’s simple, practical, and helpful. Work is ongoing to continue to improve it.

Want to know more? Below is a PDF of a conference paper based on the first implemntation of the model with a bit more detail.