The important article on safety concerning the growing menace of legionnaires’ disease (H&V News 23 march) is accompanied by numerous discussions on increasing efficiency of many renewable technologies by reducing water temperatures.
Both give advice which work in contradiction and therefore dangerously against safety.
In the case of modern heating technology, everything points to the value of lower domestic and commercial water temperatures in heating systems.
Larger heat emitters are recommended so condensing boilers and heat pumps can operate more efficiently. Legislation limits bath and shower temperatures to quite low limits.
Green recycling by councils create piles of green waste ready for processing which will become warm, as compost heaps, and create ideal havens for the legionella bacteria.
Above all the very sensible idea of collecting “grey” water for toilet flushing and washing could be a risk if the stored water, full of germs from roof collection, warms up before use.
So our current environmentally friendly technology seems to conflict with us “ensuring that adequate steps are taken to control the circumstances in which the legionella bacterium is likely to thrive”.
The way forward does seem to rest with the scientific and medical professions to develop more potent biocides and speed up diagnosis in patients and general monitoring.
Peter Field, consultant