Tank Diving Services
Underwater Inspection and Refurbishment

Storage tanks and suction tanks shall be suitable for sprinkler use and shall be fitted with rigid roofs that are made of material other than timber.

1. The following types of storage tank and suction tank will normally be deemed suitable for sprinkler use:

• a) concrete tanks designed and constructed in accordance with the requirements of SABS 0100-1 and SABS 0100-2 and that have rigid roofs of concrete, metal or plastic reinforced with glass fibre;
• b) approved propriety storage or suction tanks, including their roofs;
• c) pressed steel hot-dip zinc-coated (galvanized) tanks (the galvanizing in compliance with the requirements of SABS 763), that comply with SABS 0329, and that are painted, if necessary; and
• d) welded steel tanks painted with a suitable protective coating.

2. Painting should proceed as follows:

• a) The internal surfaces of the tank to be painted should be sand-blasted or grit-blasted in accordance with 4.3 of SABS 064:1979 to a cleaning degree Sa 3 (white metal cleaned) in accordance with 4.3.5.2 of SABS 064:1979. The profile limits should be as given in 4.3.5.3 of SABS 064:1979, i.e. 50 μm
• b) Immediately after cleaning, a protective coating comprising at least one coat of an anti-corrosive primer of dry film thickness 25 μm (for example epoxy zinc-rich primer that complies with SABS 926) should be applied.
• c) After 24 hours, one of the following or an equivalent protective coating or coatings should be applied to give a protective coating of total dry film thickness at least 225 μm:
  • 1) epoxy tar paint that complies with the requirements for type 2 paint of SABS 801; or
  • 2) vinyl resin-based coating; or
  • 3) chlorinated rubber resin-based coating, or
  • 4) polyurethane resin-based coating.
• d) Paint should be allowed to dry for one week before the tank is filled with water.
• e) Where alternative protection is used, the lining should be applied and maintained in accordance with the recommendations of the product manufacturer.

3. See 7.3.1 for information on suction tanks and 7.3.1.2 for the classification of suction tanks.

7.3.1.2 Types of suction tank or suction pit

7.3.1.2.1 A suction tank or suction pit shall be classified as either

a) type A, when a town mains is fed from it and when it is designed to be suitable for sprinkler use without emptying, cleaning, maintenance or repair for a period of at least 15 years; or

b) type B, when a town mains is fed from it and when it is designed to be suitable for sprinkler use without emptying, cleaning, maintenance or repair for a period of less than 15 years, but not less than 3 years.

Type B suction tanks or suction pits shall be subject to three-yearly emptying, cleaning or painting, or regalvanizing (see 5.1.2.3).