Rank: Forum user 
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Hello all, I'm back and finally in a job which requires thinking again (by which I mean a job requiring me to bother my peers on here with my innane questions!).
New site has 280employees, relatively new build (1960's with a refit putting in labs and offices 2000's), water system consists of; domestic hot and cold water system, showers, fixed regular and emergency rarely/never used showers for chemical spills in labs, Electromagnetic water softners... Legionella risk assessment carried out on the site by an independent contractor found there to be 6 dead-legs, unused/rarely used outlets incl. emergency showers. Water heaters, Cold Water storage tanks, 3x water supply points, 6xwater heaters, 1xCWST, x40 sinks, x8 showers, x22 TMV, x21 WC, x6 plumbed appliances. I'm being put on the L8 course soon but some input from you in the meantime would be appreciated so I can at least draft a rough testing plan. using BS8580:2010 Water Quality -Risk assessments for legionella control Code of Practice as a basis I'm trying to work out the best testing schedule. I'm experienced with regular 7day bacterial incubation of reverse osmosis Milli-Q filtration systems from a previous quality role and was looking to get a minimum of that put in place here, but I wanted to know if having all CCP's tested on rotation per quarter was sufficient or all CCP's would need to be tested each week. or just one point per quarter etc. Looking at: Temperature as a primary control measure with additional microbiological (bacterial incubation testing to monitor). -Flow, return and stored water temperatures of water heaters and cold water storage tanks - Monthly
-Legionella Sampling from hot water heater - Monthly
-Microbiological (bacterial growth) 7 day incubation testing of water outlets - Weekly (on rotation for each outlet.
-Microbiological (bacterial growth) 7 day incubation testing of water storage tanks - Monthly
-Inspection of water storage vessels - Annual
-Hot and cold water temperatures at outlets - Monthly
-Flush of dead-legs/rarely used pipes and outlets - Weekly
-Dismantle, clean and descale shower heads and hoses - Quarterly
-Taps too? though that is likely to be overkill?
Thanks in advance
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Rank: Super forum user 
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Its a bit difficult to say without having knowledge of the turnover of water, the size of the building and its layout as well as what is going on within the building.
You could consider annual/ biennial tank/ water heater cleans, annual servicing on TMV's and whether their requirement has been fully risk assessed, removal of dead legs or blind ends where practicable.
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Rank: Forum user
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Thank you Jodie, I tried giving a general overview without boring with ALL the details. The dead-legs can't really be engineered out as they are emergency systems e.g. emergency shower and Hydrogen Peroxide bund flooding system, that whilst never, touch wood, used, are still required for their safety function. I'll add the water heater cleans and valve servicing to the consideration though thank you for your input.
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Rank: Super forum user 
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Feels like overkill generally unless you've some specific risk issues I'm missing?
Zero requirement for micro testing of any sort in a domestic hot/cold water setup. I'd normally only recommend when investigating problems or seeking verification of control measures when other measures, like temp, are known to be on the fritz. I'd be clear about what testing for too if you're going to go down that route. TVC tests (normally 2 or 3 day) have no obvious reference value to compare against. It's trend analysis only unless you're up to extremes.
On descaling, don't do your taps unless you need to. But what are your softeners doing if you're getting scaled taps? ;)
Definitely include TMV's - check manufacturer recommendations - often annual service inc. strip down and clean.
No specific mention of sentinel outlet temp testing? Just 'outlets' generally? LRA should have assisted you with identification of those and should be monthly - but certainly don't need to do all of them. Aim to pick them all up over the course of a year or just once a year but only do representative outlets monthly.
Btw, BS8580 is now 2019 version as of last month.
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 1 user thanked Xavier123 for this useful post.
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Rank: Super forum user
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I agree with Xavier123 regarding the microbiological testing- the main controls are water temperature and movement of water with regard to Legionella. Depending on the size of the water heaters and how many outlets they service, you may find dropping water temperatures if you are testing all outlets or if taps are tested shortly after being used- if the sentinels are reaching the right temperature this is a good indication of water flow around the site as well as temperatures being reached within a reasonable time.
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Rank: Super forum user 
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I agree. What return temps are you logging at the water heaters? If your returns are within a couple of degrees of flow that's a good indicator of maintaining temp around the system in the good zone. Log flow (60) and return (55+) once a month, flush your dead legs and little used outlets once a week, record your sentinel temps once a month, and add all the other outlets together, split them over 12 months and record hot/mixed and cold temps for those once a year. Record all your actions and I'm pretty sure that will be sufficient. Do you need the cold water storage tank, they can get pretty hot in summer, especially if they are in a roof space. And yes to TMV servicing, for safe temperature in case of cold supply failure, as well as cleaning out potential legionella bugs.
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Rank: Forum user 
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We have a policy for a RA to be completed every 5yrs unless signifcate change. Under the internal PPM schedule we have monlthly temperature checks along with dead leg run offs
Kind Regards
Marc Owen
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Rank: Forum user
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Have you checked if any previous Legionella issues on site or out of specification trends for hot and cold water temperatures as this will help you evaluate your monitoring going forward.
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