Section 2 Construction and installation

2.1.1 Except where otherwise stated in this Chapter, pipes, valves and fittings are to be made of steel, cast iron, copper, copper alloy, or other approved material suitable for the intended service.

2.1.2 Where applicable, the materials are to comply with the relevant requirements of Vol 2, Pt 7, Ch 1 Piping Design Requirements.

2.1.3 Materials sensitive to heat, such as aluminium or plastics, are not to be used in systems essential to the safe operation of the ship, or for containing combustible liquids or sea-water where leakage or failure could result in fire or in the flooding of watertight compartments. See Vol 2, Pt 7, Ch 1 Piping Design Requirements for plastic pipes.

2.2.1 The minimum nominal wall thickness of steel, copper and copper alloy pipes is to be in accordance with Vol 2, Pt 7, Ch 1 Piping Design Requirements.

2.2.2 Special consideration will be given to the wall thickness of pipes made of materials other than steel, copper and copper alloy.

2.3.1 Valves and cocks are to be fitted in places where they are at all times readily accessible, unless otherwise specifically mentioned in the Rules. Valves in ballast systems may be fitted inside tanks, subject to Vol 2, Pt 7, Ch 2, 2.3 Valves - Installation and control 2.3.2.

2.3.2 All valves which are provided with remote control arrangements are to be arranged for local manual operation, independent of the remote operating mechanism. For shipside valves and valves on the collision bulkhead, the means for local manual operation are to be permanently attached. For submerged valves in ballast systems, as permitted by Vol 2, Pt 7, Ch 2, 2.3 Valves - Installation and control 2.3.1, local manual operation may be by extended spindle, a portable hand pump or similar energy device. Where manual operation is by hand pump or stored energy device, the control lines to each submerged valve are to incorporate quick coupling connections, as close to the valve actuator as practicable, to allow easy connection of the hand pump or stored energy device. No fewer than two hand pumps or stored energy devices are to be available for each space where valves can be locally and remotely operated.

2.3.3 In case of valves which are required by the Rules to be provided with remote control, opening and/or closing of the valves by local manual means is not to render the remote control system inoperable.

2.4.1 Valve chests, cocks, pipes or other fittings attached direct to the plating of tanks, and to bulkheads, flats or tunnels which are required to be of watertight construction, are to be secured by means of studs screwed through the plating or by tap bolts, and not by bolts passing through clearance holes. Alternatively, the studs or the bulkhead piece may be welded to the plating.

2.4.2 For requirements relating to valves on the collision bulkhead, see Vol 2, Pt 7, Ch 2, 3.3 Fore and after peaks 3.3.3.

2.5.1 All sea inlet and overboard discharge pipes are to be fitted with valves or cocks secured direct to the shell plating, or to the plating of fabricated steel water boxes attached to the shell plating. These fittings are to be secured by bolts tapped into the plating and fitted with countersunk heads, or by studs screwed into heavy steel pads fitted to the plating. The stud holes are not to penetrate the plating.

2.5.2 Valves for ship-side applications are to be installed such that the section of piping immediately inboard of the valve can be removed without affecting the watertight integrity of the hull.

2.5.3 Distance pieces of short, rigid construction, and made of approved material, may be fitted between the valves and shell plating. Distance pieces of steel may be welded to the shell plating. Details of the welded connections and of fabricated steel water boxes are to be submitted.

2.5.4 Gratings are to be fitted at all openings in the ship’s side for sea inlet valves and inlet water boxes. The net area through the gratings is to be not less than twice that of the valves connected to the sea inlets, and provision is to be made for clearing the gratings by use of low pressure steam or compressed air, see Vol 2, Pt 7, Ch 2, 2.5 Ship-side valves and fittings (other than those on scuppers and sanitary discharges) 2.5.5.

2.5.5 All suction and discharge valves and cocks secured direct to the shell plating of the ship are to be fitted with spigots passing through the plating, but the spigots on the valves or cocks may be omitted if these fittings are attached to pads or distance pieces which themselves form spigots in way of the shell plating. Blow-down valves or cocks are also to be fitted with a protection ring through which the spigot is to pass, the ring being on the outside of the shell plating. Where alternative forms of attachment are proposed, details are to be submitted for consideration.

2.5.6 Blow-down valves or cocks on the ship’s side are to be fitted in accessible positions above the level of the working platform, and are to be provided with indicators showing whether they are open or shut. Cock handles are not to be capable of being removed unless the cocks are shut, and, if valves are fitted, the hand wheels are to be suitably retained on the spindle.

2.5.7 Sea inlet and overboard discharge valves and cocks are in all cases to be fitted in easily accessible positions and, so far as practicable, are to be readily visible. Indicators are to be provided local to the valves and cocks, showing whether they are open or shut. Provision is to be made for preventing any discharge of water into rescue boats. The valve spindles are to extend above the lower platform, and the hand wheels of the main cooling water sea inlet and emergency drainage suction valves are to be situated not less than 460 mm above this platform.

2.5.8 Ship-side valves and fittings, if made of steel or other approved material with low corrosion resistance, are to be suitably protected against wastage.

2.5.9 The scantlings of valves and valve stools fitted with steam or compressed air clearing connections are to be suitable for the maximum pressure to which the valves and stools may be subjected.

2.5.10 Valves, cocks and distance pieces, intended for installation on the ship’s side below the waterline, are to be tested by hydraulic pressure to not less than 5 bar.

2.5.11 For sea connections for ships having notation for ice navigation, see Vol 3, Pt 1, Ch 1 Ice Navigation - First-Year Ice Conditions.

2.6.1 Bilge, dewatering, ballast and cooling water suction and discharge pipes are to be permanent pipes made in readily removable lengths with flanged joints are to be efficiently secured in position to prevent chafing or lateral movement. For joints in fuel oil piping systems, see Vol 2, Pt 7, Ch 3, 4.5 Pipes conveying heated oil and Vol 2, Pt 7, Ch 3, 4.6 Low pressure pipes.

2.6.2 Where lack of space prevents the use of normal circular flanges, details of the alternative methods of joining the pipes are to be submitted.

2.6.3 Long or heavy lengths of pipes are to be supported by bearers so that no undue load is carried by the flanged connections of the pumps or fittings to which they are attached.

2.7.1 Suitable provision for expansion is to be made, where necessary, in each range of pipes, see Vol 2, Pt 7, Ch 1, 14 Expansion pieces.

2.8.1 All pipes situated where they are liable to mechanical damage are to be efficiently protected.

2.8.2 So far as practicable, pipelines, including exhaust pipes from engines, are not to be led in the vicinity of switchboards or other electrical appliances in positions where the drip or escape of liquid, gas or steam from joints or fittings could cause damage to the electrical installation. Where it is not practicable to comply with these requirements, drip trays or shields are to be provided as found necessary. Short sounding pipes to tanks are not to terminate near electrical appliances, see Vol 2, Pt 7, Ch 2, 10.4 Termination of air pipes 10.4.2.

2.9.1 After installation on board, all steam, hydraulic, compressed air and other piping systems within the Mobility and Ship Type category, together with associated fittings which are under internal pressure, are to be subjected to a running test at the intended maximum working pressure.

2.10.1 For guidance on metal pipes for water services, see Vol 2, Pt 7, Ch 1, 17 Guidance notes on metal pipes for water service