Lightning strikes on construction sites pose a serious risk to workers, particularly those working at height, operating cranes, or in open areas with no shelter. The UK experiences thousands of lightning strikes each year, and construction sites with tall structures and metal equipment are attractive targets. This talk explains how to assess the risk, when to stop work, and the safety procedures everyone must follow during thunderstorms.
Key Hazards
Direct lightning strike on workers at height or in exposed open areas
Side flash from lightning striking a crane, scaffold, or metal structure
Ground current travelling through wet soil injuring workers standing nearby
Equipment damage and fire from lightning striking fuel stores or electrical systems
Control Measures
Monitor weather forecasts before and during each shift and plan for thunderstorm warnings.
Stop all outdoor work and evacuate to a substantial building or enclosed vehicle when thunder is heard.
Cease all crane, MEWP, and scaffold operations immediately when thunderstorms are forecast nearby.
Stay away from tall isolated structures, metal fences, scaffolding, and steel reinforcement during storms.
Do not shelter under trees, in temporary site cabins with no lightning protection, or in open-sided structures.
Wait at least 30 minutes after the last thunder before resuming outdoor work activities.
Ensure lightning protection systems are installed on site buildings where required by the risk assessment.
Lower crane booms and jibs to their lowest safe position when thunderstorms are expected.
Brief operatives on the lightning safety procedure at the start of each shift during storm season.
Emergency / Rescue
If someone is struck by lightning, call 999 immediately. It is safe to touch the casualty — they carry no residual charge. Begin CPR if they are unresponsive and not breathing. Move to safe shelter while awaiting the ambulance.
Remember
Stop all outdoor work and evacuate to a substantial building when thunder is heard
Cease crane, MEWP, and scaffold operations immediately when thunderstorms are nearby
Stay away from tall structures, metal fences, scaffolding, and reinforcement during storms
Wait at least 30 minutes after the last thunder before resuming any outdoor work
It is safe to touch a lightning strike casualty — begin CPR immediately if they are unresponsive
Applicable Legislation: Health and Safety at Work etc. Act 1974 · Management of Health and Safety at Work Regulations 1999 · CDM Regulations 2015 · BS EN 62305 (Lightning Protection)