Essex Heating Services comes across a lot of situations during its day to day activities where FE and Cold Water Storage tanks have become contaminated due to non-compliance with BY-LAW 30.
The tank must have a cover and various screen/filters to prevent the ingress of dirt/dust/insects and various small animals and birds. The Water inlet must be at the opposite side of the tank from the Water Outlet to avoid water stagnation. Specifications apply to the diameter of the various pipes and their height in relation to the bottom and top of the tank and in relation to each other. The main thrust of BYLAW 30 is to make sure that any domestic stored water remains free of contaminants but especially potable water that is water that is used for drinking.
The water storage tanks that we have come across can be up to 10cm deep in sludge and sediment, this having accumulated over time. The surface of the water can have a thin film of biomass material that can feed various bacterial organisms such as Legionnaires disease. Most householders don’t even realize that they are serious risk.
The most effective solution is to have your water storage tanks inspected to see if there is any build up of sediment or sludge and that they comply with BYLAW 30 and then to have the tanks cleaned and disinfected with Chlorine. If the Tanks do not comply it really is in your best interest to have them fitted with a BYLAW 30 Kit. Where this is not possible the Tank will need to be replaced with one that does.
It should be noted that Hot and Cold Systems should be cleaned and chlorinated at least annually.
We have found that one of the most effective products on the market is “STEROX”, by Fernox. There are other products on the market but we have found that this product is cost effective for the customer and easy and straight forward to check after the process that the chlorine has been reduced to a safe level.
- Advise the householder/occupant that the water should not be used or consumed during the chlorination process. Let them know that you will give them the all clear.
- Make sure that the pipework has sufficient drain off points to completely drain the system – take note of any low points or dead legs.
- If necessary fit additional drain off point and Gate/Lever Valves.
- Depending if you are treating both the Hot Water and Cold Water Systems, you will need to lock off the cold water supply and turn off the boiler.
- Completely drain the Cold and Hot Water systems – including the Hot Water Cylinder, lavatory cisterns etc.
- Clean the water storage tanks – removing all sediment, sludge and debris
- Isolate the feeds to the Cold Water Tank and fill with cold water and add 2 Sterox Tablets for every 225lts (50 gallons) of water. This will give more that the required dosage of 50mg/L. Make sure that the tablets have fully dissolved.
- Turn off the supply to the Cold Water Tank and open the Gate/Lever Valves to the system. Make sure that you have locked off all the drain off points first. Do not allow the Cold Tank to fully empty. If it gets too low – close the Gate/Lever Valve to the system, top the water up and add some more chlorination tablets as necessary. Let the tablet’s dissolve and re-open the Gate/Lever Valve to the system.
- The whole system should now be chlorinated to the required dosage – you can check this at a number of outlets with the test kit provided.
- Make sure that the Cold Water Tank is just above its normal level and add one more tablet. The system must then stand for one hour. You will need to check the level of chlorination during this period to make sure that it stays in excess of 50mg/L. If it drops the system should be re-chlorinated.
- You can now flush the system. This is best done by completely draining the system and then flushing through a couple of times. Check the level of chlorination with the kit provided. It should be no higher than the incoming water mains.
- Keep a record of the date of chlorination and initial and final chlorine concentration levels and the time. Advise the householder/occupants that it is safe to use the water.
Essex Heating Services can carry out this work for you and supply all the chemicals necessary to do an effective job. In the fist instance give us a call to arrange a time to come round and do an inspection. This can be done at the same time that you have your boiler serviced.