Working in Extreme Hot Weather: A Practical Guide for Facilities, Warehousing and Construction Sites

Extreme hot weather is becoming an increasingly common challenge for UK employers. While the UK has historically had a temperate climate, successive heatwaves have highlighted the need for proper planning when temperatures soar. Facilities management, warehousing, and construction sites each present unique risks — but all share a common duty under the Management of Health and Safety at Work Regulations 1999 to assess and control heat-related hazards.

Understanding the Risks

Heat stress occurs when the body cannot regulate its temperature effectively. Early symptoms include headaches, dizziness, excessive sweating, muscle cramps, and reduced concentration. Left unaddressed, it can progress to heat exhaustion and potentially fatal heatstroke. Workers in physically demanding roles, those wearing PPE, and those working in poorly ventilated indoor environments are at the greatest risk.

Construction Sites

Outdoor construction work exposes employees to direct sunlight, radiant heat from surfaces, and the physical exertion of manual labour. Consider the following measures:

• Reschedule high-effort tasks to cooler parts of the day (early morning or late afternoon)
• Set up shaded rest areas close to the work zone
• Encourage frequent hydration — at least 250ml of water every 20–30 minutes
• Rotate workers on physically demanding tasks to limit individual exposure
• Review PPE requirements: where safe to do so, remove non-essential layers and use breathable materials
• Brief all workers on heat stress symptoms during daily pre-start talks

Warehousing

Warehouses can become dangerously hot due to poor ventilation, metal roofing, and heat generated by machinery. Internal temperatures can exceed outdoor readings significantly. Recommended controls include:

• Maximise natural ventilation by opening loading doors and roof vents during cooler hours
• Install or deploy industrial fans and air circulation systems
• Position hydration stations at regular intervals throughout the warehouse
• Monitor indoor temperatures and implement a threshold for mandatory rest breaks (e.g., when indoor temps exceed 30°C)
• Consider reflective coatings on metal roofs to reduce radiant heat gain

Facilities Management

Facilities teams — including cleaners, maintenance engineers, and security staff — may work in varied environments, from plant rooms to rooftop plant areas. Heat exposure can be less obvious but equally dangerous:

• Assess heat exposure in plant rooms, boiler houses, and mechanical voids as part of your risk assessments
• Provide portable cooling or ventilation for confined or enclosed work areas
• Ensure lone workers in hot environments have regular check-in protocols
• Adjust work schedules during heatwaves to avoid peak temperature windows
• Train facilities staff to recognise heat stress in themselves and colleagues

Legal and Regulatory Framework

There is no specific maximum workplace temperature defined in UK law, but the Workplace (Health, Safety and Welfare) Regulations 1992 require that temperatures in indoor workplaces are "reasonable." The HSE recommends a minimum of 16°C (13°C for physical work) but does not set a maximum — instead, employers must assess risk and take appropriate action based on the circumstances.

The Management of Health and Safety at Work Regulations 1999 require employers to conduct suitable and sufficient risk assessments, which must account for environmental conditions including extreme heat. Failure to do so can result in enforcement action, civil claims, and serious harm to workers.

Practical Action Plan

Conclusion

Extreme hot weather is no longer a rare event — it's a foreseeable risk that demands proactive management. By updating risk assessments, implementing practical controls, and educating your workforce, you can protect your team and stay compliant with your legal obligations. If you need support reviewing your heat stress risk assessments or updating your safety documentation, Maintain Safety Consulting Ltd can help.