Section 7 Air and sounding pipes

7.1.1  Air and sounding pipes are to comply with the requirements of Vol 2, Pt 7, Ch 2, 10 Air, overflow and sounding pipes

7.1.2 Striking plates of suitable thickness, or their equivalent, are to be fitted under all sounding pipes.

7.1.3 Air pipes are to be situated clear of areas where damage may occur, such as RAS landing areas and store routes or helicopter decks.

7.2.1 The height of air pipes from the upper surface of decks exposed to the weather, to the point where water may have access below is normally to be not less than:

• 760 mm on exposed decks immediately above the design draught, e.g. quarter decks and well decks.
• 450 mm measured above deck sheathing, where fitted elsewhere.

7.2.2 Lower heights may be approved in cases where these are essential for the working of the ship, provided that the design and arrangements are otherwise satisfactory. In such cases, efficient, permanently attached closing appliances as required by Vol 1, Pt 3, Ch 4, 7.3 Closing appliances 7.3.1 are to be of an approved automatic type.

7.2.3 The height of air pipes may be required to be increased on ships where this is shown to be necessary by the stability and watertight subdivision calculations required by Vol 3, Pt 2, Ch 6, 2.1 Watertight integrity. An increase in height may also be required when air pipes to fuel oil and settling tanks are situated in positions where sea water could be temporarily entrapped, e.g. in recesses in the sides and ends of superstructures or deckhouses, between hatch ends, behind high sections of bulwark, etc.. This may entail an increase in tank scantlings, see also Vol 1, Pt 6, Ch 3 Scantling Determination.

7.2.4 Air pipes are generally to be led to an exposed deck. See also Vol 2, Pt 7, Ch 2, 10.4 Termination of air pipes 10.4.4.

7.2.5 Where air pipes are led through the side of superstructures, the opening is to be at least 2,3 m above the design waterline.

7.2.6 The minimum wall thickness of air pipes in positions indicated in Vol 1, Pt 3, Ch 4, 7.2 Height of air pipes 7.2.1 is to be:

• 6,0 mm for pipes of 80 mm external diameter or smaller.
• 8,5 mm for pipes of 165 mm external diameter or greater.

Intermediate minimum thicknesses are to be determined by linear interpolation.

7.2.7 Air pipe coaming heights may be reduced on ships assigned a service area notation SA4. Coaming heights are to be as high as practicable, with a minimum height of 300 mm.

7.3.1 All openings of air and sounding pipes are to be provided with permanently attached, satisfactory means of closing to prevent the free entry of water (see also Vol 1, Pt 3, Ch 4, 7.2 Height of air pipes 7.2.2 and Vol 2, Pt 7, Ch 2, 10.6 Air pipe closing appliances 10.6.2).

7.3.2 Closing appliances are to be of an approved automatic type where they are below the limit of watertight integrity, see Vol 1, Pt 3, Ch 2, 1.3 Watertight and weathertight integrity. Where the limit of watertight integrity is defined by a bulkhead deck or freeboard deck, the closing appliances are to be of an approved automatic type where, with the ship at its design draught, the openings are immersed at an angle of heel of 40° or, the angle of down flooding if this is less than 40°, which may be agreed on the basis of stability requirements.

7.3.3 Where the closing appliances are not of an automatic type, provision is to be made for relieving the vacuum when the tanks are being pumped out.