Working outdoors in hot weather on construction sites puts workers at risk of heat exhaustion, heat stroke, severe sunburn, and dehydration. These conditions can develop rapidly and heat stroke is a medical emergency that can be fatal. UK summer temperatures increasingly exceed 30°C, and the combination of physical labour, heavy PPE, and direct sun exposure significantly increases the risk. Planning work around the hottest hours, providing shade and water, and recognising the early warning signs are essential.
Key Hazards
Heat stroke causing collapse, confusion, seizures, and potential death
Heat exhaustion from dehydration, excessive sweating, and prolonged exertion
Severe sunburn and long-term skin cancer risk from UV radiation exposure
Impaired concentration and judgement leading to accidents and poor decisions
Control Measures
Provide unlimited access to cool drinking water at locations close to all work areas.
Schedule physically demanding tasks for the cooler hours early morning and late afternoon.
Provide shaded rest areas for breaks away from direct sunlight and radiated heat.
Allow workers to take additional rest breaks during periods of extreme heat.
Encourage workers to wear sunscreen with SPF 30 or higher and reapply regularly.
Monitor workers for signs of heat illness including confusion, dizziness, and excessive sweating.
Ensure lightweight, breathable clothing is worn where PPE requirements allow flexibility.
Brief workers on the symptoms of heat exhaustion and heat stroke at the start of every hot day.
Consider rescheduling non-urgent outdoor work when temperatures exceed safe working thresholds.
Emergency / Rescue
If someone shows signs of heat stroke — hot dry skin, confusion, or collapse — call 999 immediately. Move them to a cool shaded area, remove outer clothing, and cool them with water. Do not give fluids if they are unconscious.
Remember
Heat stroke is a medical emergency that can kill — recognise the symptoms and act immediately.
Drink water regularly throughout the day and do not wait until you feel thirsty to start drinking.
Schedule heavy physical work for the cooler early morning and late afternoon hours wherever possible.
Sunburn increases your long-term risk of skin cancer — wear sunscreen and cover exposed skin.
If you feel dizzy, nauseous, or confused in hot weather, stop work and move to shade immediately.
Look out for your colleagues because heat illness can impair judgement and they may not recognise it.
Applicable Legislation: Management of Health and Safety at Work Regulations 1999 · Workplace (Health, Safety and Welfare) Regulations 1992 · Health and Safety at Work etc. Act 1974