533-1_Potable Water Tank Disinfection.pdf

AMC-533-1

AUGUST 1991

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA)

ATLANTIC MARINE CENTER

STANDARD SPECIFICATION AMC-533-1

POTABLE WATER TANK DISINFECTION

1. SCOPE. This specification contains the general requirements for disinfecting potable water tanks on NOAA ships.

2. REFERENCES.

None

3. REQUIREMENTS.

3.1 General Requirements.

3.1.1 When introducing chlorine treatment solution to a

potable water tank, ensure that the solution is diluted and is introduced only through a sounding tube or threaded connection.

Immediately after adding the treatment solution, add a rinse consisting of at least five gallons of potable water through the same sounding tube or threaded connection.

3.1.2 Isolate the tank(s) from the rest of the potable

water service system and thoroughly rinse and drain the tank interiors.

3.2 Disinfect Procedure.

3.2.1 Fill the potable water tank with potable water until

it overflows, exercising care not to pressurize the tank. As it fills, introduce sufficient chlorine solution to provide at least 100 parts-per-million (ppm) Free Available Chlorine (FAC) content in the completely filled tank.

3.2.2 Monitor the FAC content hourly for at least four

hours. If the FAC content drops below 50 ppm at any time, add additional chlorine solution to the tank to bring the FAC content back up to 100 ppm and begin the four-hour period anew. Continue until the FAC content remains at or above 50 ppm for a four-hour period.

3.2.3 If more than one tank is to be disinfected, repeat

the above procedure for the other tank. At the contractor's discretion, the same water used to disinfect the first tank may be used, as long as the initial FAC content in the second tank is increased to 100 ppm at the start of the four-hour test period.

AMC-533-1

AUGUST 1991

3.2.4 Drain the tank(s) and refill with potable water.

Repeat the above tests, except that an initial FAC content of

1.0 ppm or greater shall be provided, the monitoring period shall be 30 minutes, and the minimum allowable FAC content shall be

0.2 ppm.

3.2.5 After successfully completing the 30-minute test

period, drain and refill the tank(s) with potable water until the total FAC content falls to 1.0 ppm or less.

END OF SPECIFICATION