For non-circulating systems: take temperatures at sentinel points (nearest outlet, furthest outlet, and long branches to outlets) to confirm they are at a minimum of 50 °C within one minute (55 °C in healthcare premises)
For circulating systems: take temperatures at return legs of principal loops (sentinel points) to confirm they are at a minimum of 50 °C (55 °C in healthcare premises). Temperature measurements may be taken on the surface of metallic pipework.
For circulating systems: take temperatures at return legs of subordinate loops, temperature measurements can be taken on the surface of pipes, but where this is not practicable, the temperature of water from the last outlet on each loop may be measured and this should be greater than 50 °C within one minute of running (55 °C in healthcare premises). If the temperature rise is slow, it should be confirmed that the outlet is on a long leg and not that the flow and return has failed in that local area. This should be undertaken quarterly (ideally on a rolling monthly rota)