Hollow GRP water tank roof support replacements recently completed at a maximum security site in Surrey.
The sites 495,000 litre sectional GRP storage tank had been previously risk assessed by their water treatment service provider.
As part of the assessment’s non-conformities it was highlighted that the storage tanks hollow GRP roof supports were non-compliant with ACOP L8 guidelines.
Why are hollow GRP water tank supports non – compliant?
Hollow GRP (Glass Reinforced Plastic) roof supports can pose a legionella risk due to the potential for stagnant water accumulation within the hollow spaces.
Legionella bacteria thrive in warm water environments, and when water becomes stagnant, it creates an ideal breeding ground for these bacteria to multiply.
Here’s how hollow GRP roof supports can contribute to the legionella risk:
1. Stagnant water: If water becomes trapped or accumulates within the hollow sections of the supports, it can remain stagnant for extended periods. Stagnant water with temperatures between 20 to 45 degrees Celsius (68 to 113 degrees Fahrenheit) provides a favorable environment for the growth of legionella bacteria.
2. Biofilm formation: Stagnant water encourages the formation of biofilms, which are slimy layers consisting of microorganisms and organic matter. Legionella bacteria can thrive within these biofilms, using them as a source of nutrients and protection from disinfection measures.
3. Dispersal of bacteria: If the stagnant water within the hollow GRP supports becomes disturbed or released into the water system, it can introduce legionella bacteria into the water supply of the tank, increasing the risk of infection if the water is inhaled or ingested.
To mitigate the legionella risk, it is important to design water systems with proper maintenance and prevention measures. Regular inspections, cleaning, and disinfection of water tanks, including the roof support structures, can help prevent the accumulation and growth of legionella bacteria.
Our hollow roof supports replacement solution
Echo Square Services were selected to help assist in replacing all non-compliant hollow roof supports within the storage tank.
Our solution proved to be the most cost effective alternative in comparison to carrying out a more regular water tank disinfection regime.
Or completing a full water tank replacement of the non-complaint storage tank which was initially considered.
Due to the size of the storage tank, each support had to be replaced systematically to ensure the water storage tanks structural integrity remained unaffected.
Our team also installed support brackets to each solid GRP tank roof support to help ensure the water tanks tie rods had additional support.
Upon completion of our works the storage tank was cleaned and disinfected prior to placing the system back online.
Should you require help with a similar hollow GRP roof support replacement project please don’t hesitate to contact our team