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As most installers will already be aware, Legionella is a naturally occurring bacteria widespread in ponds, rivers and other natural water systems. When this bacterium enters water systems in the built environment, conditions such as water temperature and ineffective disinfection levels, can encourage rapid growth. Common sources of Legionella bacteria in buildings include cooling towers, taps, showers, air conditioning units and hot water tanks

Legionnaires’ disease is a potentially fatal lung infection caused by inhaling droplets of water containing Legionella bacteria. If the infection is not contained or treated early on, it can cause confusion, coma, heart failure and ultimately death. According to the World Health Organization (WHO), the death rate for Legionnaires’ disease in untreated immuno-suppressed patients could be as high as 40-80%. Moreover, Legionnaires’ disease has been seen to cause health related quality of life impacts to the large majority people who have recovered from it. These include fatigue, neurologic and neuromuscular symptoms, and post-traumatic stress disorder.

What many installers may not realize, however, is that the Legionella risk is rising. In the USA, the incidence of Legionellosis has surged by approximately 1000% over the past two decades. Though the reasons for this dramatic global rise have been declared a ‘scientific mystery,’ it’s clear that factors such as climate change, warming temperatures and increasingly complex water systems have all contributed to the rapidly increasing count.

As a result, it is more important than ever for installers to stay informed about the latest solutions that can help public buildings optimize infection control. Installers play a vital role as custodians of public safety. However, there is an additional, critical consideration: research shows the large majority of today’s plumbing and heating installers are aged 45 or older. Moreover, the workforce is predominantly male. Given that individuals over 50 face a higher risk of Legionella, and males are statistically more vulnerable, installers working on unmanaged water systems may be exposing themselves to significant health risks.

Preventative practices

Of course, the established approach to preventing Legionella growth appears fairly simple: hot water should be stored above 140°F and circulated so that it remains at least 124°F, while cold water storage and distribution should be below 68°F. Infrequently used outlets should be flushed out regularly and showerheads de-scaled and cleaned.

Thermostatic Mixing Valves (TMVs) play a key role in this by allowing water to be stored and distributed at temperatures high enough to kill Legionella bacteria, while reducing it to a safe temperature for use by mixing it with cold water. However, while TMVs are essential for minimizing the risk of scalding, they can inadvertently increase the risk of Legionella growth. This is because the blended water downstream of a TMV can create an environment conducive to the bacteria's multiplication. Ensuring safe TMV use depends on implementing a robust maintenance program, including regular flushing to prevent water stagnation - a known factor for promoting Legionella. Despite this, the consensus is that TMV maintenance, inspections and servicing are not necessarily always as thorough as they need to be.

Installers working on unmanaged water systems may be exposing themselves to significant health risks with Legionella. Image courtesy of Hydrosense, click to enlarge.

Testing times

With this, it may be easy to ascertain why Legionella cases can, and do still, continue to happen across all sectors, as demonstrated by regular headlines surrounding Legionnaires’ outbreaks.

The good news in this is that there is scope to address this, and help raise the bar on safety through a more robust and routine Legionella testing regime.

For the uninitiated, most duty holders will tend to rely on the lab-culture method - whereby water samples are collected from water systems on site and sent to an accredited laboratory which will identify the presence or absence of Legionella – for Legionella testing. However, this approach is timely, cumbersome and has limitations.

Foremost, most lab culture tests take 7-10 days to return results. Yet, Legionella can double in a day. This large time lag means increased exposure and risk for installers and the premises they serve. Water samples can also get damaged in the transportation process, potentially killing the Legionella inside and increasing the risk of a false negative result. Lab culture testing is also unable to detect Viable but Non-Culturable (VBNC) Legionella – which, though dormant, can still be incredibly dangerous due to their ability to resuscitate and reinfect a water system – also being able to directly infect human cells even in their dormant state.

To address these limitations, the latest generation of rapid testing kits enable the detection of Legionella in just 25 minutes, and are incredibly accurate at quickly detecting the potentially fatal Legionella pneumophila. Not only does using this method during installation help reduce risk and minimize potential exposure, but it also offers additional information during necessary reviews of risk assessment, and provides peace of mind for the customer.

What can installers do?

Inherently, plumbing and heating installers may not have been the obvious first port of call when it comes to Legionella testing. However, given the scope of their work in the commercial field and being so close to the front line, there is an obvious opportunity for this to change.

By being proactive about Legionella control and providing on-site testing as part of an installation or maintenance package, installers have an opportunity to help to reduce liability risks for the commercial clients they serve. As awareness around growing Legionella rates grows, this will further secure an installer’s reputation as a trusted professional dedicated to helping to protect the public, creating a competitive edge and helping attract more business especially from industries with heightened health and safety priorities.

Lightening the Legionella load

There’s no doubt that building managers, owners and other duty holders tasked with keeping on top of ever-mounting legislation, efficiency and decarbonization targets and the like, would appreciate any additional support in tackling the developing Legionella risk.

By incorporating rapid Legionella testing, installers have an opportunity to create a competitive edge, boost revenue, help to optimize occupant safety and, in turn, provide peace of mind for their client.

For further information please visit the Hydrosense website.