Wearables and Heat Stress Monitoring in Kitchens

Fitting wearables into a real kitchen plan

There is no maximum workplace temperature in UK law. The Workplace (Health, Safety and Welfare) Regulations 1992 only require a "reasonable" indoor temperature, with a suggested minimum of 16°C, or 13°C for strenuous work, and no ceiling at all. That silence at the top end is exactly why kitchens need to manage heat actively - the duty is to control a foreseeable risk under general health and safety law, and you cannot control what you do not measure. It is worth noting the pressure here is building: a debate in the Lords in June 2025 pressed the case for a maximum working temperature, and the HSE has signalled a review of the associated Approved Code of Practice, so the direction of travel is toward more scrutiny, not less.

The sensible way to start is with the environment, because it is cheaper, less intrusive and gives you the baseline everything else hangs off. A WBGT meter placed near the hottest processes - the grill, the fryer bank, the pass - tells you whether the conditions themselves are pushing people toward strain. ISO 7243 is a screening tool: if the WBGT sits below the reference limit for the work rate, conditions are broadly acceptable; if it climbs above, unacceptable heat strain becomes likely and you need to act. For heavy kitchen work those reference values are lower than people expect, which is often the moment a manager realises the pass has been running hot for years.

Where screening flags a problem, or where the work is unusually demanding, personal wearables earn their place. A wrist or arm band that tracks heart rate and skin temperature, estimates core temperature and raises an alert when a threshold is crossed turns an abstract WBGT figure into something specific about your actual staff - who is coping, who is not, and when. This matters because people vary enormously. Age, fitness, medication, hydration and simple acclimatisation all shift how a body handles the same air, and a wearable is the only thing that sees the individual rather than the average. For the deeper detail on the physiology, our guide to how heat stress affects the body at work is a useful companion, because understanding what the numbers represent is what stops a device becoming an ignored beep.

Wearables are not a licence to run the kitchen hotter, though, and this is the trap to avoid. Monitoring is the last line, not the first. The hierarchy still starts with removing heat at source - well-designed and properly cleaned extraction canopies, adequate make-up air, and equipment that is not fighting a greased-up system. When your canopy, ductwork and fans are clean and pulling the design airflow, the ambient heat load on the line drops before anyone straps a sensor on. A monitoring programme layered on top of poor ventilation simply documents a problem you could have engineered out. Practical controls that pair well with monitoring include rotating people off the hottest stations, protected and genuine breaks in a cooler space, easy access to cool water, and adjusting expectations during summer peaks or heatwaves.

For a formal picture, ISO 7933's Predicted Heat Strain method takes the same environmental inputs plus metabolic rate and clothing to model strain analytically, which is worth commissioning if you have a persistent problem or a health surveillance concern. But for most kitchens the everyday value is simpler - a WBGT reading you trust, a handful of wearables on the people working hardest, clear alert thresholds, and a manager who knows what to do when one sounds. If you want the practical, non-technical version of recognising and heading off trouble on the floor, our piece on spotting and preventing heat stress in commercial kitchens walks through the warning signs and the low-cost fixes that make the biggest difference.