HSE - Legionnaires' disease - Hot and cold water systems

Dead/blind end – a redundant length of pipe, closed at one end, through which water cannot flow.

Dead leg – a pipe leading to an outlet through which water flows but the outlet is unused/rarely used.

Sentinel outlets – the nearest and furthest/last outlets from hot and cold water cylinders and tanks.

Thermostatic Mixer Valves (TMVs) – these blend hot and cold water to reduce the temperature where a scald risk is present.

Health and Safety
Executive