TANK CLEANING WORK - BY NEMCO UTILITIES (WWW.NEMCO-UTILITIES.CO.UK)
TANK CLEANING WORKAs with any other organism, Legionella bacteria require a sourceof food / nutrients to grow efficiently and divide to sufficientnumbers to colonise a water system. This can be provided in anumber of ways; scale, rust, sludge, silt and even other organicmatter such as amoebae. Indeed, recent evidence hassuggested that the presence of other bacteria, common incomplex water systems at outlets, can both hinder of facilitatethe growth and proliferation of Legionella bacteria. That aside,tank cleaning and disinfection of water systems forms a criticalpart of managing the risk of water systems and general hygiene. For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
TANK CLEANING WORKOne common misconception is that stored water systems shouldbe cleaned and chlorinated on an annual basis. In a largenumber of cases this infact not required and can prove to becostly, time consuming and disruptive to the site and personnelinvolved. With reference to ACOP L8 (Approved Code ofPractice for Legionnaire’s Disease) water systems should becleaned ‘when routine inspection shows it to be necessary’ andin addition to this, where there is reason to suspect there hasbeen some form of contamination or intrusive work has beencompleted on the plumbing system. These recommendationsfor tank cleaning would usually come from routine 6 monthlytank inspections. For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
TANK CLEANING WORKSo, where does the thought of annual tank cleaning comefrom? This is actually a suggestion made by the DWI (DrinkingWater Inspectorate) that does not form part of the Legionellaguidance and only relates to where water is stored forconsumption i.e. is of potable quality. In general, and suggestedin the Water Regs, it is not advised thatstored water is used drinking purposes, where possible this shouldtaken directly from a mains supplied outlet. However, storedwater can be consumed if; For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
TANK CLEANING WORK1. The cistern meets all the Water Regulations (including the old By law 30) e.g. insect screen fitted, sealed lid, insulation and screened cistern breather.2. Is sampled at least on a six monthly basis for bacteria, usually TVC, e-coli & coliforms3. Is drained, cleaned and chlorinated to BS6700 standards on an annual basis For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
TANK CLEANING WORKTaking the average water system, where kitchen and drinkingwater outlets are taken directly from the mains, and tankedwater is used simply for toilet flushing, hand washing andshowering then tank cleaning may only be required every 3-5years dependent on turnover, silt content etc. The above isbecoming more and more important for large new builds whereall site water is provided by means of a break tank and thenpassed through a booster set. For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
TANK CLEANING WORKThere may of course be other mitigating circumstances orspecific risk assessment recommendations that require a greaterfrequency of tank cleaning e.g. history of positive samples /biofilm in old pipework, but annual tank cleaning shouldcertainly not be the default position in the absence of any ofthe above.One other issue not addressed above is that where sitepersonnel are known to consume water from non-potableoutlets where a fresh mains supply is available – in this instance adecision would need to be made by the Duty Holder. One wayto mitigate this risk is the provision of suitable signage above theoutlets which can save considerable money in the long run. For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
NEMCO UTILITIES LIMITEDAddress Email:Nemco Utilities Ltd • email@example.com Kempson Way • firstname.lastname@example.orgHillside Business Park • accounts@nemco-Bury St Edmunds utilities.co.ukSuffolkIP32 7EA Website: http://www.nemco- utilities.co.uk/Telephone: 01284 724503Fax No.: 01284 724826 For more information on tank cleaning and water system disinfection, please visit our website www.nemco-utilities.co.uk
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