Section 10 Air and sounding pipes

10.1.1 Reference to cargo oil in this Section is to be taken to mean cargo oil which has a flash point of 55°C or above (closed cup test).

10.2.1 Air and sounding pipes are to be made of steel or other approved material. For use of plastic pipes of approved type, see Pt 5, Ch 10, 5 Plastic pipes.

10.3.1 Nameplates are to be affixed to the upper ends of all air and sounding pipes.

10.4.1 Air pipes are to be fitted to all tanks and other compartments (except the void space mentioned in Pt 5, Ch 11, 3.1 General 3.1.4). which are not fitted with alternative ventilation arrangements.

10.4.2 The air pipes are to be fitted at the opposite end of the tank to that which the filling pipes are placed and/or at the highest part of the tank. Where the tank top is of unusual or irregular profile, special consideration will be given to the number and position of the air pipes.

10.4.3 Air pipes are to be arranged to be self-draining under normal conditions of trim.

10.4.4 Air pipes passing through cargo holds are to be of substantial thickness and well protected against mechanical damage.

10.5.1 Air pipes to double bottom tanks, deep tanks extending to the shell plating, or tanks which can be run up from the waterway are to be led to above the deck. Air pipes to fuel oil and cargo oil tanks, cofferdams and all tanks which can be pumped up are to be led to the open as follows;

1. For height of air pipes above deck for fuel oil tanks on ships carrying dangerous goods or tankers, see Pt 4, Ch 1, 12.5 Arrangements 12.5.3 and/or Pt 4, Ch 4, 3.4 Miscellaneous 3.4.1.

2. For height of air pipes above deck, in general, see Pt 3, Ch 11, 10 Air and sounding pipes.

10.5.2 Air pipes from storage tanks containing lubricating or hydraulic oil may terminate in the machinery space, provided that the open ends are so situated that issuing oil cannot come into contact with electrical equipment or heated surfaces.

10.5.3 The open ends of air pipes to fuel oil and cargo oil tanks are to be situated where no danger will be incurred from issuing oil or vapour when the tank is being filled.

10.5.4 The location and arrangement of air pipes for fuel oil service, settling and lubricating oil tanks are to be such that in the event of a broken vent pipe, this does not directly lead to the risk of ingress of outboard water or rainwater.

10.6.1 The open ends of air pipes to fuel oil and cargo oil tanks are to be furnished with a wire gauze diaphragm of incorrodible material which can be readily removed for cleaning or renewal.

10.6.2 Where wire gauze diaphragms are fitted at air pipe openings, the area of the opening through the gauze is to be not less than the cross-sectional area required for the pipe, see Pt 5, Ch 11, 10.8 Size of air pipes.

10.7.1 Air pipe closing devices are to be of a type acceptable to Clasifications Register. If of an automatic opening type they are to be tested in accordance with a National or International Standard recognised by LR.

10.7.2 Wood plugs and other devices which can be secured closed are not to be fitted at the outlets.

10.7.3 For closing requirements, see also Pt 3, Ch 11, 10.3 Closing appliances.

10.8.1 For every tank which can be filled by the ship’s pumps, the total cross-sectional area of the air pipes and the design of the air pipe closing devices is to be such that when the tank is overflowing at the maximum pumping capacity available for the tank, it will not be subjected to a pressure greater than that for which it is designed.

10.8.2 In all cases, whether a tank is filled by ship’s pumps or other means, the total cross-sectional area of the air pipes is to be not less than 25 per cent greater than the effective area of the respective filling pipe.

10.8.3 Air pipes are to be not less than 40 mm bore. In the case of small gravity filled tanks smaller bore pipes may be accepted but in no case is the bore to be less than 25 mm.

10.9.1 Where overflow sight glasses are provided, they are to be in a vertically dropping line and designed such that the oil does not impinge on the glass. The glass is to be of heat resisting quality, adequately protected from mechanical damage and well lit.

10.10.1 Provision is to be made for sounding all tanks and the bilges of those compartments which are not at all times readily accessible (except the void spaces mentioned in Pt 5, Ch 11, 3.1 General 3.1.4). The soundings are to be taken as near the suction pipes as practicable.

10.10.2 Where fitted, sounding pipes are to be as straight as practicable, and if curved to suit the structure of the ship, the curvature must be sufficiently easy to permit the ready passage of the sounding rod or chain.

10.10.3 Sounding devices of approved type may be used in lieu of sounding pipes for sounding tanks. These devices are to be tested, after fitting on board, to the satisfaction of the Surveyor.

10.10.4 Where gauge glasses are used for indicating the level of liquid in tanks containing lubricating oil, fuel oil or other flammable liquid, the glasses are to be of the flat type of heatresisting quality, adequately protected from mechanical damage, and fitted with self-closing valves at the lower ends and at the top ends if these are connected to the tanks below the maximum liquid level.

10.11.1 Except as permitted by Pt 5, Ch 11, 10.12 Short sounding pipes sounding pipes are to be led to positions above the bulkhead deck which are at all times accessible, and in the case of fuel oil tanks, cargo oil tanks, lubricating oil tanks and tanks containing flammable oils, the sounding pipes are to be led to safe positions on the open deck.

10.11.2 For closing requirements, see also Pt 3, Ch 11, 10 Air and sounding pipes.

10.12.1 In machinery spaces where it is not practicable to extend the sounding pipes as mentioned in Pt 5, Ch 11, 10.11 Termination of sounding pipes, short sounding pipes extending to well lighted readily accessible positions above the platform may be fitted to double bottom tanks. Any proposal to terminate in the machinery space, sounding pipes to tanks, other than double bottom tanks, will be the subject of special consideration.

10.12.2 Short sounding pipes to fuel oil, (flash point not less than 55°C), lubricating oil tanks and other flammable oil tanks (flash point not less than 55ºC) are to be fitted with cocks having parallel plugs with permanently attached handles, loaded such that, on being released, they automatically close the cocks. In addition, a small diameter self-closing test cock is to be fitted below the cock mentioned above, in order to ensure that the sounding pipe is not under a pressure of oil before opening-up the sounding cock. Provision is to be made to ensure that discharge of oil through this test cock does not present an ignition hazard. An additional small diameter self-closing test cock is not required for lubricating oil tanks.

10.12.3 As a further precaution against fire, such sounding pipes are to be located in positions as far removed as possible from any heated surface or electrical equipment and, where necessary, effective shielding is to be provided in way of such surfaces and/or equipment.

10.12.4 In passenger ships, short sounding pipes are permissible only for sounding cofferdams and double bottom tanks situated in a machinery space, and are in all cases to be fitted with self-closing cocks as described in Pt 5, Ch 11, 10.12 Short sounding pipes 10.12.1.

10.13.1 In passenger ships, elbow sounding pipes are not permitted.

10.13.2 Elbow sounding pipes are not to be used for deep tanks unless the elbows and pipes are situated within closed cofferdams or within tanks containing similar liquids. They may, however, be fitted to other tanks and may be used for sounding bilges, provided that it is not practicable to lead them directly to the tanks or compartments, and subject to any sub-division and damage stability requirements that may apply.

10.13.3 The elbows are to be of heavy construction and adequately supported.

10.14.1 Striking plates of adequate thickness and size are to be fitted under open ended sounding pipes.

10.14.2 Where slotted sounding pipes having closed ends are employed, the closing plugs are to be of substantial construction.

10.15.1 Sounding pipes are to be not less than 32 mm bore.

10.16.1 For ventilating and gauging equipment for cargo tanks in oil and chemical tankers, see Pt 5, Ch 13, 4 Cargo tanks for Type G tankersand Pt 5, Ch 13, 5 Cargo tank venting arrangements.

For control engineering equipment, see Pt 6, Ch 1 Control Engineering Systems.

For requirements relating to scuppers and sanitary discharges, see Pt 3, Ch 11 Closing Arrangements to Openings in Shell and Deck, Ventilators, Air Pipes, Sounding Pipes and Discharges.