Preventing Legionella Growth In Your Water Tank Systems

  • Hot and cold water outlets
  • Hot and cold water storage and recirculation systems
  • Atomisers
  • Wet air conditioning plant
  • Whirlpools or hydrotherapy baths
  • Risk Assessments Depending on the nature of the water system you have there are various different control measures you can implement, but common to all systems is the need to carry out a suitable legionella risk assessment. This should include:
    • A list of all systems and equipment involving water on site
    • Current standards of cleanliness
    • Sampling currently undertaken from all relevant outlets
    • pH measurements
    • Temperature measurements
    • Identifying sources of risk in the systems
    • List the control measures currently in place
    • Document the procedures and best practice
    Control Measures Other control measures that should be considered include:
    • Hot water tanks should be maintained and distributed at a temperature of 60?C or above
    • Cold water tanks should be maintained and distributed at a temperature of 20?C or below
    • A competent person or third party contractor should routinely check, inspect or clean the system, including taking samples for analysis
    • Distribution temperatures should be checked regularly
    • Legionella grows rapidly in stagnant water so systems should be designed to remove dead legs and dead ends where water can sit for long periods. It helps to flush your system out completely on a regular basis, but it also helps to minimise pipe lengths and make them as direct as possible
    • Insulate pipes to maintain water at the temperature desired
    • Some water systems are used as a re-circulating cooling tower, in order to cool machinery and equipment in operation. In this system cold water is fed in but warmer water returns to the tank. To prevent Legionella growth, biocides are dosed into the system to maintain the pH where it needs to be. This is required to be routinely monitored and the system maintained, again, often by a qualified third party contractor. A separate risk assessment is recommended for this process also
    • Legionella bacteria grows where scale or sediment accumulates in a water tank, so regular cleaning is required to prevent or remove this.
    Water Hygiene Services can advise on the potential for Legionella growth in your water systems and we can consult with you on the best methods of controlling any risks in the future. This can only be done by understanding your individual system and system needs, and we can tailor our advice to ensure you are presented with a custom-made solution. Click here to contact us today.]]>