COLD WATER STORAGE TANK DISINFECTION BUNDLE
DISINFECTION OF COLD WATER STORAGE TANKS (CWST) AND DOMESTIC DOWN SERVICES
Chlorine can be pulled through a calorifer to disinfect hot water down services although this isn’t usually required as the pacification of the heat should be enough. If doing so ensure the calorifer is flushed through afterwards so no chlorine sits in the system.
This bundle includes everything needed to perform a thorough disinfection of a cold water storage tank.
- Wash down internal walls and base with a 10% FEEDCHLOR solution. Depending on the nature of deposits present, brushes, sponges, or scouring pads maybe used to aid removal of staining and accumulation of scale.
- Use a Wet Vac to clean the base of tank such that all traces if sediment are removed.
- Exit tank and add sufficient FEEDCHLOR to ensure that when the tank is refilled at least 65ppm of chlorine is introduced i.e. at least 0.65 litre of FEEDCHLOR per 1000 litre of tank capacity, this should be measured by the chlorine test strips.
- If you need to disinfect the down services you should draw chemical through any water heaters to the outlets in the building checking with the test strips that you are reaching at least 50ppm at the outlets. This product contains enough strips to test the down services of 100 outlets.
- When the pre-determined contact period has elapsed (minimum 1 hour) it will be necessary to neutralise the free chlorine in the tank with DECHLOR.
- Add the necessary quantity of DECHLOR to the tank. In the case of large tanks it maybe necessary to mix the tank contents with a submersible pump.
(Extract from feedwater tank cleaning procedure)
DECHLOR DOSAGE RATE
The DECHLOR should be added at the rate of 11ml per ppm of Chlorine per m3 of water.
Example To remove 40 ppm of free residual chlorine in a 20m3 tank requires:-
11(ml) x 40(ppm) x 20(m3)
= 8,800 ml or:
= 8.8 litres of DECHLOR
N.B. It is important not to over dechlorinate since this will absorb any free chlorine residual in the incoming main.
Please read HSG 274 Part 2 guidance on cleaning and disinfecting water storage tanks and down services, guidance is found on pages 43, 44.
Dechlor – a de-chlorinating product.
Feedchlor – Strong stabilised chlorine solution
Chlorine Test Strips (100 included)
High Range Chlorine test Kit 0-250mg/l (Supplied Separately if required – 30 tests)
High Range Chlorine test Kit 0-50mg/l (Supplied Separately if required – 30 tests)
Low Range Chlorine test Kit 0-5mg/l (Supplied Separately if required – 30 tests)