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As we usually have an expert in most areas on here....
Small community centre has been closed since lockdown, we're now wondering if we need to do anything to avoid/deal with a risk of Legionnaires Disease whenever we get to reopen.
Essentially only cold water for toilets and an electric water heater for the hot water taps - no heating, air con or showers etc, so I believe the risk should be fairly low. Should we flush the system through with anything though?
Thanks
Legionnaire's disease thrives in badly-maintained open air conditioning systems containing dirty warm water. Your water system contains chlorinated cold water and is closed to the atmosphere. Stop over-thinking it and get on with life.
I'd run the hot taps for about a minute as hot as possible before opening.
How big is the hot water electric heater, is it one with a little storage tank? It probably won’t supply enough hot water for it to be a concern. The hot water temp should be between 50c-60c after the tap has run for a minute, if the heater stores that much which few over the sink heaters do.
To test the cold tap, run it for 2 minutes and check the water temp (it needs to be below 20c after 2 mins).
We're not overthinking it, we're double checking if we might need to overthink it.
I work in a laboratory within a large factory, we are currently isolated from the factory and had access to a single water fountain that is situated on the first floor (that is empty). As part of the normal routine checks site services discovered high levels of legionella and we can no longer use it (they send us down batches of bottled water now).
I was told that normally around 50 people use the water fountain and since lockdown it has been 3 or 4 and they think that is why there is an issue.
Aye, you're not your thinking it, I'd seek some advice from your local authority on procedure, as they should have something in place for reopening schools. we've had similar issues at work as eskay has.
What have you got in there water wise, any dead legs? How many taps? Run them all for a few minutes, if you have a shower remove the head and put the hose in the tray or as low as possible and run for a few mins.
It's fairly likely you'll have some legionella but you've got to get it airborne and respired before you infect anyone
As above there's guidance out there about ongoing management
It’s nearly ten years since I worked in this area and so I would no longer meet the definition of a competent person, not least because the rules in the uk have changed in that time.
That said your system will be relatively low risk. If it’s one of those hot water units mounted on the wall just above the sink then In normal use it would be just about as low risk as anyone ever gets to - but you’ve left it stagnant for 10+ weeks (I presume it wasn’t drained down?) which makes it an ideal breeding ground if there was a legionella bacteria lurking in the system. If it’s an actual how water tank with plumbing to taps (immersion heater like at home) then the design will inherently be higher risk.
Is your system fed direct from the mains or does it go into a cold water tank (somewhere in the loft?). Is the system recent or have there been loads of modifications (dead legs!) over the years as bits have been added removed etc. if it’s direct from mains, a reasonably modern bit of plumbing and the heating was off in the building then I’d probably say a really good flush with fresh water, whack the temp up on the hot water and completely cycle it (fill, heat, empty, repeat) and you’ve done everything you can easily do. If there is a tank you have less chance of the free chlorine in the mains water still being around when it comes out the tap - but at least you can dose it if you need to. (Worth noting Mains levels of free chlorine aren’t necessarily strong enough to kill legionella if you’ve already got colonization).
Those point of use hot water heaters are great in theory from a legionella perspective but I did once deal with an office complex with about 50 of them where nearly a quarter had quite significant amounts of legionella. Thermostats set to not scald, Mixture of high use so never really getting hot and unoccupied units which were sitting stagnant all assisted by a crappy design with rubber components all lead to quite a lot of biofilm. Legionella won’t normally grow by itself - it really needs the biofilm to cause problems. Once you’ve got biofilm quick treatments are often not effective as the won’t penetrate to kill everything and you then leave a load of dead cells as nutrient for those that do survive.
Often overlooked is who are the users of the system - it’s a contributing factor to the risk profile. If it’s used as a day centre for the elderly or for meetings of chronically ill people it’s a different risk profile from a healthy, younger user base. In a reopened world you may also have lower footfall than previously so some taps may never get used, or you may find people are washing hands more and for longer and so the hot water struggles to keep hot enough to kill bacteria...
Is it council owned? They’ll have someone contracted to do the risk assessment for them. I would suggest that common sense of flushing the taps through, making sure the hot gets really hot, and flushing it through, is a good start for a simple building with no showers etc. The council should be concerned generally as with multiple buildings coming back on line it really is a risk and some of the early symptoms are not that different to Covid so could go undetected. I’d imagine a community centre with a simple water system would come quite far down their list compared to schools, sports centres, large offices, etc...
I saw a piece on Alton Towers this week where one guy has been lapping the building daily and running taps and flushing toilets for exactly this reason!
Your water system contains chlorinated cold water and is closed to the atmosphere. Stop over-thinking it and get on with life.
Lol!! There's an entire industry almost devoted to preventing the growth of legionella in closed, chlorinated potable water systems. If I took that attitude in my job (consultant services engineer) I'd probably be sacked and jailed...
OP, we're seeing a lot of issues now with heat gains in ceiling voids, so any potable water sat in pipework within a ceiling could realistically gain enough heat to become potentially dangerous (e.g. warm enough that Legionella will start to multiply). However this is modern buildings with good insulation and low leakage construction. A draughty old council building probably never sees the sort of temperatures in ceiling voids which could cause issues (e.g. over 20C).
I'd be tempted to follow the advice above, e.g. flushing all taps through. If you want to be very unscientific I'd be tempted to say run all the taps until you can feel the fresh cold water come through (you can usually feel this by hand) or get a temperature probe.
I don't know what the official guidance is for flushing but it probably won't be far different.
As others have said take it seriously. If you have a cold water storage tank you should drain and clean it.
Otherwise, clean all outlets, run water through the system until you are sure that fresh water has gone through the pipes and all sitting water has been flushed out.
You must run water through every pipe/ outlet.
Generally if water is sitting for more then a few days in a pipe you should ensure that fresh water flows through it before using it (and clean the outlet).
The symptoms for legionnaires are similar to Covid!
Our building is having the water system chlorine-treated this weekend to start to prepare for it reopening (labs in Scotland, so able to open once we reach phase2, which it is hoped will be announced following Thursday's review)...Legionnaires is a very real risk
Ok , so you want to sleep at night ,
Just Google “Aquacert”
They charge a few quid , send you a couple of plastic bottles and a padded envelope .
A courier turns up takes the bottles and they get tested .
You then have a certificate which will
Pass the book should something go wrong.
How else would you be sure 😀
Our shower at work got Legionnaires, was out of commission for months as a result.
Legionnaire’s disease thrives in badly-maintained open air conditioning systems containing dirty warm water. Your water system contains chlorinated cold water and is closed to the atmosphere. Stop over-thinking it and get on with life.
This is why the Internet is so dangerous! Thankfully for every bad response you usually get 10 good ones on here.
I believe the person with responsibility can be held responsible for any harm and be prosecuted. I seem to remember a chief exec of a council being found guilty years ago.
We have someone whose job it is to run all the taps and showers and sign off a checklist in our building, he does it once a month.
Good luck
Another +1 for take it seriously. I've dabbled (not an expert) in water systems on rail vehicles, there are various procedures and equipment in place to mitigate against legionella.
I believe the person with responsibility can be held responsible for any harm and be prosecuted. I seem to remember a chief exec of a council being found guilty years ago.
Our boss always gets very worried looking if there's a Legionnaire's outbreak reported in the press, always a mad scramble to check if it was one of our projects! Up front our job is relatively easy thankfully, don't envy the people managing the systems, always worried there's some grotty dead leg hiding away somewhere with mouldering insulation falling off...
Not sure on what an 'Open air conditioning unit is' , But Legionnaires and air conditioning seems to send everyone into a blind panic and blame A/C for respiratory diseases and infections. Its all tosh...........
In years gone by, there used to be wet cooling systems , which were cooling towers. Usually found at larger places , such as hospitals ( ironically) breweries and larger factories needing cooling for process equipment. These cooling systems would need to be maintained and utilising dip slides to check on levels of bactericides used to keep the level of certain bugs low to be safe. Legionnaires was an issue many years ago, from people not doing this and skimping on treatments. Most cooling towers are now obsolete and now changed to a dry system, which is basically radiators ( condensers) and fans to dissipate the heat. No water means no legionaires.
As for a/c systems and smells in the car and at work/ home. This is caused by stagnant condensate water and particles of dust ( mostly skin !) that rots in the unit , from mainly lack of use or filter cleanliness. You wont get anything unpleasant from this other than the smell.
Heading onto the water front. I think most people have commented on this now, but you are more likely to get legionnaires from standing water in pipes and cold water storage tanks at work than from any other source. So, you do need to do something and not throw caution to the wind and hope.
Make sure all taps are scale free as the bugs feed off it. That includes your showers at home !! If you go away for 2 weeks ( that seems to be the guideline) , then disinfect the shower before you switch it on.
It is very important to worry about this as infections and stomach upsets and worse can be around us , especially now with offices not 'moving water' while they have been closed up.
Yes, i work in air conditioning and maintain buildings for my job 🙂
Since CV19 and the lack of HSE training jobs I picked up some PT work at a student halls
My Monday every week consists of double flushing toilets, running HW taps for 2 min CW taps for 2 mins and shower for 2 mins, currently there are 127 rooms to do........😒 more will have to be done once the exodus starts proper.
Once a month HW flow and return temps taken from plant room and temps from the CW storage tanks to ensure they are above/below the required temps.