Flushing Infrequently Used Outlets

Duty holders are responsible for preventing and controlling the risk of exposure to Legionella bacteria, which can lead to the potentially fatal Legionnaires’ disease. 

 

HSG274 Part 2 tells us: 2.4 Within hot and cold water systems, the risk areas that support the growth of microorganisms, including legionella, are controllable with good design, operation, maintenance and water system management and include where optimum temperatures for microbial growth and stagnation occur, eg dead legs, capped pipes (dead ends), infrequently used outlets. 

 

 

Removing an infrequently used outlet is desirable but if this is not possible, implementing a good flushing regime will help to reduce the risks. Infrequently used outlets could be anything from an outside tap that is rarely used to an emergency eye wash station. It could also be a shower room used only for storage or an accessible WC that is only required occasionally. 

 

Weekly flushing is a good way of minimising bacterial issues and will effectively kick-start a closed water system that's been redundant for a while. Turn on each tap and water outlet and leave them to run for at least five minutes. The running water passing through its infrastructure will disturb and disrupt the presence of biofilms. Be careful not to splash any water as the risk of legionella in these outlets is a lot higher. 

 

Don't forget water temperatures, as these are equally as important when carrying out your flushing routine.  

Any showers in the building should be turned up as hot as the settings allow and should reach a temperature no lower than 50 degrees Celsius after 1 minute's flow; conversely cold water should attain a maximum of 20 degrees Celsius (or below) after 2 minutes running.