Heat or humidity? Talking tools-down rules in Queensland


How hot is too hot on the construction site?

When is it too hot to work? And should humidity be just as much of a factor as temperature?

A contentious issue in the industry

Tools-down rules are up for heated discussion in the Sunshine State, as they often are at this time of the year as we move into the warmer months. Warm weather can be extremely dangerous for workers in the construction industry, given how exposed they are to the elements and extreme direct sunlight when weather conditions become more intense in summer. 

Some experts have controversially recommended that tradespeople should be allowed to stop working when the humidity level reaches 70 per cent — even if the actual temperature is only in the high 20s.

There are policies currently in place in 2023 across Victoria and South Australia that require that all work stops on union-affiliated job sites when the temperature reaches 35 degrees Celsius.

Logically, you might expect Queensland, with one of the warmest climates in the country, to have a similar system. However, their current rules only require more breaks — not a day off — for tradespeople when temperatures hit above 35 degrees Celsius.

The ABC has reported that construction workers in Queensland were calling on their state branch of the Construction, Forestry, Mining and Energy Union (CFMEU) to establish a stop-work rule starting at 35 degrees Celsius.

Humidity is a key factor in working capabilities

But the debate then changed course thanks to heat stress expert Dr Liz Hanna. Dr Hanna is recommending that humidity be the main factor in any tools-down policy in Queensland. 

As she explained to the ABC, the body’s rate of cooling is much slower in humid conditions.

“We need to have guidelines in Queensland that reflect the level of intensity of the heat and reflect climatic variables, such as humidity.”

Following a survey of more than 500 people who work outdoors, and a study measuring both on-site temperatures and signs of heat stress in workers, Dr Hanna is recommending that all work be cancelled at humidity levels of 70 per cent and above in Queensland — regardless of the temperature. 

This week, she strongly urged unions to push for this rule on behalf of their members, so tradespeople aren’t being forced to work in dangerous conditions. 

“If you book a builder to build your house, there will inevitably be a clause in there for rain delays.”

“We need to do the same for heat and humidity… if the unions aren’t looking after these people, I’m not quite sure who will.”

Interested in learning more about heat restrictions on the work site?

You can read more about the signs of heat stress, along with Dr Hanna’s recommendations for Queensland tradies, on the ABC’s website


This article has been updated and republished on 27 December 2022.