Legionnaires’ disease is a type of pneumonia that is potentially fatal. Legionella, the bacterium causing it, is commonly found in water, normally multiplying in temperatures of 20 to 45 degrees Celsius and becoming dormant in temperatures below 20 degrees. It does not survive in temperatures above 60 degrees.

The disease is contracted by inhaling airborne legionella-contaminated water droplets usually coming from sources such as hot and cold water outlets, whirlpools or hydrotherapy baths, atomisers, and wet air conditioning plants. Anybody can develop Legionnaire’s disease, but the most at risk are the elderly, cancer patients, diabetics, those inflicted with chronic respiratory or kidney disease as well as the smokers and the alcoholics. Since the ill and those with a weakened immune system are more susceptible to it, health and social care facilities are mandated to regularly carry out a full risk assessment of their water systems.

Regarding the Approved Code of Practice (ACoP) for Legionella referred to as the L8, the HSE has revised it with an update of an additional three-section guidance document called the HSG 274. In it, guidelines regarding the control of Legionella in water systems are detailed, including separate segments for control in evaporative cooling systems, an interim guidance for control in hot and cold water systems, and control in other risk systems.

The guidance is for dutyholders – those in control of premises such as employers and administrators, and anybody else tasked to bear health and safety responsibilities for others. HSG 274 specifically includes care homes among the high-risk healthcare premises. Holding a population with increased susceptibility, these facilities are certainly included among those required to conduct regular monitoring for its water systems.

Sampling from water systems should be done in accordance with BS 7592:2008 Sampling for legionella organisms in water and related materials. There are specific instructions for this, taking into account the complexity of the system. Some variations are also present, including the target control parameters set for the different facilities. For instance, the required temperature for hot water systems in healthcare premises should be 55 degrees Celsius — higher than the usual 50 degrees for other places.

ACoP L8 has been in force for more than a decade, but due to the continued outbreaks of Legionnaires’ disease, revisions were introduced in the form of the HSG 274. While the law has not essentially changed, it does offer a more detailed guidance for dutyholders and responsible individuals. With the update, they can better follow the law and prevent incidents of infection.

+Duncan Hollis