Legionella Awareness on Construction Sites - Construction Toolbox Talk

Legionella bacteria thrive in warm, stagnant water systems and can cause Legionnaires' disease, a potentially fatal form of pneumonia. On construction sites, risks arise from welfare facility water systems, cooling towers, and temporary pipework that has not been properly flushed or maintained. Outbreaks can affect both workers and the neighbouring community. This talk explains the legionella risks on construction sites and how to control them.

Key Hazards

Legionnaires' disease from inhaling contaminated water droplets

Bacterial growth in stagnant temporary water systems and tanks

Contaminated welfare facility showers producing infected aerosols

Cooling tower drift spreading legionella bacteria to neighbouring areas

Control Measures

Flush all temporary water systems weekly and after any period of non-use exceeding seven days.
Maintain hot water above 60°C at the calorifier and cold water below 20°C in storage tanks.
Clean and disinfect welfare facility showerheads and taps on a regular schedule.
Ensure water storage tanks are covered, insulated, and protected from heat sources.
Appoint a responsible person to manage legionella risk on site as required by ACOP L8.
Keep written records of all flushing, temperature checks, and disinfection activities.
Avoid creating spray or aerosol from stagnant water sources during construction activities.
Commission newly installed water systems with a full chlorination and flushing procedure.
Report any flu-like symptoms or suspected cases to occupational health immediately.

Remember

Flush all temporary water systems weekly and after any period of non-use over seven days
Hot water must be stored above 60°C and cold water below 20°C to prevent bacterial growth
Clean welfare facility showerheads and taps regularly to prevent biofilm buildup
A responsible person must be appointed to manage legionella risk on every site
Report any flu-like illness to occupational health promptly for investigation

Applicable Legislation: COSHH 2002 · ACOP L8 (Legionnaires' Disease) · HSG274 (Parts 1-3) · Health and Safety at Work etc. Act 1974

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