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Are Fire Sprinklers a Legionella Risk?

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While it’s not necessarily the first thing you think about when the topic turns to legionella risk, that’s not to say that the otherwise innocuous-looking fire sprinklers found in and around your office, factory or a host of public buildings don’t pose a threat to our health and general wellbeing, should the right conditions prevail. And that’s for the inescapable reason that your typical sprinkler system is designed and manufactured to tackle a blaze; and as such is linked to the building’s closed system water storage supplies, which in turn could be accommodating various waterborne nasties. Chief amongst which might be legionella bacteria.

A series of ifs and buts, maybe; yet not something which takes a great leap of faith to imagine panning out given the very nature of the beast. Consider this. Water will infiltrate a fire sprinkler system obviously, as that’s the whole premise when it comes to the first line of defence in tackling fires in a raft of property scenarios. So should there be any traces of legionella residing in the internal water supply at the juncture which a fire sprinkler is called into action, then  there is always a chance of proliferation beyond the constructs of the installation. Which of course, could result in human exposure.

In terms of just how the governing body, the HSE view the threat posed by legionella in fire sprinkler systems, and the answer is in a measured way. Of the 3 primary risk groups associated with bacteria in workplace environments, this particular assemblage falls into risk category 3; with 1 being recognised as the highest in this instance. And is grouped in with other systems and equipment which might frequent water for the purposes of cooling and misting and which typically are responsible for generating aerosols when the water is released for various purposes and a number of differing outlets which bring water into close contact with individuals.

How Big Are We Talking Then, With Reference to Legionella Risks for Fire Sprinkler?

As mentioned above, they are included within category 3, officially; which is the lowest group. That said, complacency shouldn’t be allowed to creep into the equation because of this downgraded threat, as nevertheless legionella remains a clear and present danger. And for the following reasons, predominantly.

While water temperatures associated with fire sprinkler systems are historically low (therein meaning on paper at least, that the growth and repopulation of legionella bacteria is relatively nominal when looked at as a threat to human health as such), that’s not to say that the overall risk is diminished. And that’s because the connecting pipework could well be at the optimum temperatures for legionella to take hold. Aside from the temperature concern, there also the not inconsequential matter of stagnant water. Water in fire sprinkler systems can remain standing for sizeable passages of time, which along with poor maintenance can bring about problems if unmonitored. But then to counter this perceived threat to a certain degree, is the knowledge that water droplets (vapour) produced by sprinkler systems are fairly large. Which subsequently means that aerosols aren’t necessarily a by-product; and it’s that means of distribution that when inhaled can, potentially, lead to the onset of Legionnaires’ disease in more susceptible members of the public.

<Want to learn more about the water-borne pathogens that can inhabit domestic  water systems? Check out our infographic>

So How Would You Describe the Main Ways In Which The Public Could Become Vulnerable to Legionnaires’?

In essence, one of the three scenarios addressed below (and whereby legionella bacteria is present in the fire sprinkler system) would have to come into play to realistically set off alarm bells.

Multiplication – Although legionella can be in evidence – albeit in very small doses – in many bodies of stored water, they have to multiply significantly for them to have meaningful and far-reaching implications. The bottom line is whether or not the conditions in the sprinkler system are sufficiently advantageous to the expansion of the bacteria, stagnant water can be a breeding ground and something to be mindful of. Substandard maintenance, especially of the non-routine variety, will also play into the hands of legionella.

Aerosol Threat – As we touched on earlier, despite the larger water droplets dissuading aerosols sprays from occurring, that’s not to rule out the threat in its entirety. For example, faulty plumbing, accidents during cleaning or maintenance of the pumps/system and/or the operational vagaries of the sprinkler system itself could prove to be dangerous in the event.  Plus there’s always the outside chance that large droplets breaking up or evaporating could lead to smaller droplets taking shape; which might harbour more vapour-like qualities, and which then suddenly, and dramatically increase the risk.

At Risk Demographic – The main reason why legionella risk is perceived to be low when discussing fire sprinkler systems is largely due to one aspect; whenever a fire sprinkler system becomes operational (as a fire breaks out in a building) then as a matter of course the property is immediately evacuated. And then only suitably protected people – firefighters that is – enter the building to tackle the blaze. Yet you can’t rule out that anyone carrying out sprinkler system maintenance, testing or cleaning might not find themselves susceptible should the legionella bacteria be already making its presence felt.

So, How Do You Guard Against It?

Simply by ensuring that your existing legionella risk assessment plan and on-going practices take the risk of fire sprinkler systems into account at the time a protocol and subsequent procedures are drawn up. Which equates to proactively managing the threat any dormant from the outset. With direct regards to the sprinkler maintenance then a few key points need being made aware of, and routine tabs on thereafter. These being preparing a written scheme which not only identifies any legionella risks, but also extends to ideally prevent, observe and manage said risks. What’s more, a competent person should be appointed (or a specialist third part water treatment company) to oversee things once the initial risk assessment has been rolled out. It will be their responsibility to also log detailed records of their findings from day one, so there is plenty of points of reference.

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