Section 3 Cargo handling system

3.1.1 A complete system of piping and pumps is to be fitted for dealing with the cargo.

3.1.2 Arrangements for emptying tanks by means of applying pressure above the cargo or by other methods will be specially considered.

3.1.3 Connections should be made for the gas freeing of the cargo tanks, when the cargo has been discharged, and for the ventilation and gas freeing of all compartments adjacent to cargo tanks.

3.1.4 Where gas freeing arrangements are provided, fans are to be installed in the cargo zone. The fans are to be of nonsparking material except for Type N-open. See also Pt 5, Ch 13, 1.8 Non-sparking fans for hazardous areas. Where driving motors are electrical and are situated in the cargo zone, they are to be of the certified safe type, see Pt 6, Ch 2, 13.8 Certified safe type equipment. Otherwise the fan prime mover is to be installed outside the hazardous area in an enclosed space. Where the driving shaft penetrates the bulkhead it is to do so via an approved gastight seal, see also Pt 5, Ch 13, 3.2 Cargo pumps and compressors 3.2.5.

3.1.5 Access hatches and all other openings to cargo tanks, such as ullage and tank cleaning openings are to be located on deck.

3.1.6 Ships carrying toxic products are to be equipped with at least one instrument designed and calibrated for testing for the vapours. For measuring flammable products, see Pt 5, Ch 13, 5.7 Gas measurement.

3.2.1 Pumps for the purpose of filling or emptying the cargo tanks or compressors pumping cargo gas back to shore or to re-liquefy cargo vapour and return it to the cargo tanks are to be used exclusively for this purpose and are to be situated in the cargo zone. They are not to have any connections to compartments outside the range of cargo tanks. This is not applicable for Type N-open tankers with the exemption for tankers carrying corrosive cargoes of class 8.

3.2.2 Means are to be provided for stopping the cargo pumps or compressors from a position outside the cargo zone, as well as at the pumps, or compressors.

3.2.3 Pump suction and discharge pressure gauges are to be provided at the pumps or compressors (except for the suction side of deep well pumps). The pressure gauges are to be readable at the pump control stations at all times.

3.2.4 The pumps or compressors are to be provided with effective relief valves which are to be in close-circuit, i.e. discharging to the suction side of the pumps. Alternative proposals to safeguard against over-pressure on the discharge side of the pump will be specially considered.

3.2.5 Where cargo pumps are driven by shafting which passes through a pump-room bulkhead or deck, gastight glands are to be fitted to the shaft at the pump-room plating. The glands are to be efficiently lubricated from outside the pump-room. The seal parts of the glands are to be of materials that will not initiate sparks. The glands are to be of an approved type and are to be attached to the bulkhead in accordance with Pt 5, Ch 11, 2.5 Ship-side valves and fittings (other than those on scuppers and sanitary discharges). Where a bellows piece is incorporated in the design, it is to be hydraulically tested to 3,4 bar before fitting. Bulkhead penetrations with nitrogen seals with an air back up will be specially considered.

3.2.6 Where cargo pumps are driven by hydraulic motors which are located inside cargo tanks, the design is to be such that contamination of the operating medium with cargo liquid cannot take place under normal operating conditions.

3.2.7 Pumps and compressors situated on deck are to be fitted in a position not less than 6 m away from entrances and openings of accommodation and service spaces outside the cargo zone. This is not applicable to Type N-open tankers with the exemption for tankers carrying corrosive cargoes of class 8.

3.3.1 Cargo pipes are to be situated in the cargo zone and are not to pass through cofferdams or through tanks or compartments which are outside the cargo zone and are to be completely separate from any other piping system. This is not applicable for Type N-open tankers with the exemption for tankers carrying corrosive cargoes of class 8. Cargo pipes are to be clearly marked to distinguish them from other piping systems.

3.3.2 Means are to be provided to enable the contents of the cargo lines and pumps to be drained to a cargo tank or other suitable tank. Where drain tanks are fitted in pumprooms, they are to be of the closed type with air and sounding pipes led to the open deck.

3.3.3 For bunkering vessels where the contents of the cargo lines in way of the connection with the bunkering gig could not be drained as indicated above separate drainage arrangements are to be provided.

3.3.4 Suitable provision for expansion is to be made, where necessary, in the cargo pipe lines as follows;

• Type G tankers are to be provided with bends. Alternatively, expansion bellows of approved type may be fitted, see Pt 5, Ch 10, 9.7 Expansion bellows.
• Type C and N tankers are to be provided with expansion joints of approved type or bends, see Pt 5, Ch 11, 2.7 Provision for expansion 2.7.2 and Table 10.2.5 Application of mechanical joints in Chapter 10.
• Tankers carrying only cargoes listed in Pt 4, Ch 6, 10.1 General 10.1.1 may be provided with mechanical joints of the slip-on type, see Table 10.2.5 Application of mechanical joints in Chapter 10.

3.3.5 Stainless steel expansion bellows used in piping systems are to be protected against over extension and compression and adjoining pipes are to be suitably supported and anchored. Reference is made to recognised Standards such as EJMA & BS6129 Pt 1 for acceptable methods of support and anchoring.

3.3.6 No cargo piping may be arranged under deck, except inside cargo tanks and pump rooms. This is not applicable for Type N-open tankers with the exemption for tankers carrying corrosive cargoes of class 8.

3.3.7 All cargo pipes and their associated fittings are to be tested after assembly on board by hydraulic pressure as per Pt 5, Ch 10, 8 Hydraulic tests on pipes and fittings. In no case is the hydraulic test pressure to be less than 10 bar.

3.3.8 Type C and N tankers are to be provided with a fixed installed stripping system. See also Pt 5, Ch 13, 1.4 Design 1.4.6.

3.3.9 Loading and discharge lines for Type C tankers, with the exemption of the shore connections, are to be so arranged that no part is situated nearer the side of the ship than B/4.

3.3.10 The loading and discharge lines and vapour collecting lines for Type G tankers, with the exemption of the shore connections but including the safety valves, are to be arranged, together with the relevant segregation devices and valves, between the outside boundary of the dome and B/4.

3.3.11 The above is not applicable to safety discharge pipes. If, however only one dome is present at centre line ship these pipes are to be situated at a minimum distance from the shipside of not less than 2.7 m.

3.3.12 The requirements of Pt 5, Ch 13, 3.3 Cargo piping systems 3.3.13 to Pt 5, Ch 13, 3.3 Cargo piping systems 3.3.18 apply to product and process piping including vapour piping and vent lines of safety valves or similar piping intended for Type G tankers.

3.3.13 All pipelines or components which may be isolated in a liquid full condition should be provided with relief valves.

3.3.14 Consideration will be given to a relaxation of the above requirement for pipe sections with a volume of 50 litres, or less.

3.3.15 Relief valves discharging liquid cargo from the cargo piping system should discharge into the cargo tanks.

3.3.16 The nominal thickness of steel pipes is to be not less than shown in Table 13.3.1 Nominal thickness steel pipes for the appropriate standard pipe size. Stainless steel pipes will receive special consideration.

3.3.17 Flanges, valves and other fittings should comply with recognised Standards, taking into account the maximum applicable gauge pressure. For bellows expansion joints used in vapour service, a lower minimum design pressure may be accepted.

3.3.18 For flanges not complying with a standard, the dimensions of flanges and related bolts will be specially considered.

3.3.19 Ships fitted with a bunker mast in compliance with Pt 4, Ch 6, 10 Bunkermasts shall be provided with a spool piece in the discharge pipe(s) to the hose(s) of the bunker mast. This spool piece is to be removed and blanking flanges are to be fitted if cargoes other than those listed in Pt 4, Ch 6, 10.1 General 10.1.1 are carried. A notice is to be provided, located in a prominent position, clearly indicating when the spool piece is to be removed.

3.4.1 Terminal pipes, valves and other fittings in the cargo loading, discharging and vapour return lines, to which shore installation hoses are connected, are to be steel or approved ductile material from the point of connection up to and including the terminal valves. They are to be of robust construction and strongly supported, see also Pt 5, Ch 13, 1.3 Materials and Pt 5, Ch 13, 1.4 Design.

3.4.2 Shore connections of the cargo loading, discharging and vapour return lines are to be provided with a valve. When not in use, they are to be provided with a blind flange.

3.4.3 For Type G tankers, one remotely operated emergency shutdown valve (quick closing valve) is to be provided in addition to the valve as per Pt 5, Ch 13, 3.4 Terminal fittings at cargo loading stations 3.4.2. Control of this valve is to be from positions fore and aft of the ship, see also Pt 5, Ch 13, 3.7 Remote control valves 3.7.6.

3.4.4 The cargo loading and discharge lines in way of the cargo loading station for Type C and N tankers are to be provided with a connection as per Figure 13.3.1 Connection for the delivery of residual cargoes.

Figure 13.3.1 Connection for the delivery of residual cargoes

3.4.5 Bunker ships or other ships capable of discharging fuel oil, lubricating oil, hydraulic oil, etc. to other ships are to be provided with a quick closing valve of ductile material in the discharge pipe. The valve is to be capable of being closed independent of the remote control, see also Pt 5, Ch 13, 3.7 Remote control valves.

3.4.6 The valve closure time required in the above paragraph is to be such as to avoid surge pressures in the piping system. The valve closure time is to be verifiable and reproducible.

3.4.7 Shore connections shall be located not less than 6,0 m from entrances to, or openings of, the accommodation and service spaces outside the cargo area. This requirement is not applicable to ships of Type N-open with the exemption when corrosive liquids of Class 8 will be carried.

3.4.8 The distance required by Pt 5, Ch 13, 3.4 Terminal fittings at cargo loading stations 3.4.7 may be reduced to 3,0 m subject to the requirements of Pt 4, Ch 4, 3.3 Protection against the ingress of gases within accommodations and entrances 3.3.3.

3.5.1 Piping systems which serve tanks containing incompatible cargoes are to be isolated from each other by means of removable pipe lengths and blank flanges. Isolating shut-off valves, single or double, or spectacle flanges are not acceptable as equivalent arrangements.

3.5.2 Blind Flange Valves of an approved type are acceptable as an equivalent means of segregation in cargo systems.

3.5.3 Spectacle Flanges could be accepted in vapour return systems except for tankers carrying toxic cargoes Class 6.1.

3.5.4 Cargoes, residues of cargoes or mixtures containing cargoes which react in a hazardous manner with other cargoes, residues or mixtures should:

1. be segregated from such other cargoes by means of a cofferdam void space, cargo pump room, pump-room, empty tank or tank containing a mutually compatible cargo;

2. have separate pumping and piping systems which should not pass through other cargo tanks containing such cargoes, unless encased in a tunnel; and

3. have separate tank venting systems.

3.6.1 Where cargo tanks are provided with direct filling connections, the loading pipes are to be led to as low a level as practicable inside the tank.

3.6.2 Where cargo suction and/or filling lines are led through cargo tanks, the connection to each tank is to be provided with a valve secured to the bulkhead and situated inside the tank it serves, and capable of being operated from the deck. Cargo compatibility is to be assured in the event of pipe failure, (see Pt 5, Ch 13, 3.5 Cargo segregation 3.5.4.(b)). Where a pump can be used for more than one cargo tank, shut-off valves are to be provided in the pump-room. For Type N tankers this valve is to be fitted not less than 0,60 m above the bottom.

3.6.3 Cargo lines on Type G tankers are not to be used for ballast purposes.

3.6.4 For Type C and N tankers, the piping system is to be so arranged that water for cleaning out the cargo tanks or for ballasting the ship, is to be taken from a suction pipe situated inside the cargo zone but outside the cargo tanks. At the junction with the cargo filling pipes a screw-down non-return valve is to be fitted.

3.6.5 On Type C or N tankers, pumps for tank wash systems, including their co

• The discharge side of the system is arranged such, that suction through this pipeline is not possible.
• A spring loaded non-return valve, is to be fitted in the discharge pipe when entering the cargo zone.

3.6.6 The connections on the tank domes for Type G tankers with two cargo tanks situated side by side are to be arranged at the dome part facing the centre line of the ship only. Connections positioned at the centre line dome parallel to the centre line of the ship are acceptable accordingly. The valves are to be fitted as close as practicable to the dome.

3.6.7 All liquid and vapour connections on Type G tankers at each cargo tank dome, except safety relief valves and liquid level gauging devices are to be equipped with a manually operated stop valve and a remotely controlled emergency shutdown valve. These valves are to be located as close to the tank as practicable. Where the pipe size does not exceed 50 mm in diameter, excess flow valves may be used in lieu of the emergency shutdown valve.

3.7.1 Valves which are provided with remote control are, in general, to be arranged for local manual operation independent of the remote operating mechanism, see also Pt 5, Ch 11, 2.3 Valves - Installation and control 2.3.2.

3.7.2 Where the valves and their actuators are located inside the cargo tanks, hydraulic (not pneumatic) means for operating the valve actuators are to be provided.

3.7.3 Emergency means are to be provided for operating the valve actuators in the event of damage to the main hydraulic circuits on deck. This could be achieved by ensuring that the supply lines to the actuators are led vertically inside the tanks from deck, and that connections, with the necessary isolating valves, are provided on deck for coupling to a portable pump carried on board.

3.7.4 All actuators are to be of a type which will prevent the valves from opening inadvertently in the event of the loss of pressure in the operating medium. Indication is to be provided at the remote control station showing whether the valve is open or shut.

3.7.5 Materials of construction of the actuators and piping inside the cargo tanks are to be suitable for use with the intended cargoes. See Pt 5, Ch 13, 1.3 Materials.

3.7.6 The control system for all required emergency shutdown valves is to be so arranged that all such valves may be operated by single controls situated in at least two remote locations on the ship. One of these locations is to be from a position from which all the cargo tanks can be controlled or from the cargo control room.

3.8.1 On Type C tankers, flanges in cargo lines and glands on cargo tanks or lines are to be fitted with adequate arrangements to prevent any accidental spray of cargo.

3.8.2 On Type N tankers, flanges in cargo lines and glands on cargo tanks or lines are to be fitted with adequate arrangements to prevent any accidental spray of cargo when it is intended to carry corrosive cargoes.

3.9.1 Liquid and vapour hoses, used for cargo transfer should be compatible with the cargo and suitable for the cargo temperature.

3.9.2 Details of such hoses are to be submitted together with a type test certificate issued by a recognised Authority.

3.9.3 Hoses subject to tank pressure or the discharge pressure of the pumps should be designed for a bursting pressure of not less than 5 times the maximum pressure the hose will be subjected to during cargo transfer.

3.9.4 Each new type of cargo hose, complete with end fittings should be prototype-tested to a pressure not less than 5 times its specified maximum working pressure. The hose temperature during this prototype test should be the highest and/or lowest service temperature for which the hose is intended.

3.9.5 Hoses used for prototype testing should not be used for cargo service.

3.9.6 Thereafter, before being placed in service, each new length of cargo hose should be hydrostatically tested at ambient temperature to a pressure not less than 1,5 times its specified maximum working pressure but not more then two-fifths of its bursting pressure.

3.9.7 The hose should be stencilled or otherwise marked with the date of testing, its specified maximum working pressure and, if used in other than ambient temperature services, its maximum and minimum service temperature as applicable.

3.9.8 The specified maximum working pressure should be not less than 10 bar gauge.

3.9.9 For Type G tankers, Pt 5, Ch 13, 3.9 Ship's cargo hoses 3.9.10 to Pt 5, Ch 13, 3.9 Ship's cargo hoses 3.9.13 will also be applicable.

3.9.10 Each new type of cargo hose, complete with end fittings, should be prototype-tested at a normal ambient temperature with 200 pressure cycles from zero to at least twice the specified maximum working pressure.

3.9.11 After this cycle test pressure has been carried out, the prototype test should demonstrate a bursting pressure as per Pt 5, Ch 13, 3.9 Ship's cargo hoses 3.9.3 and Pt 5, Ch 13, 3.9 Ship's cargo hoses 3.9.4.

3.9.12 It is assumed that the hoses referred to are ship-toshore or ship-to-ship hoses which are traditionally considered to be outside the scope of classification. The design, construction and testing of such hoses are to be for the relevant National or Port Authority to approve.

3.9.13 Materials having a melting point below 925°C should not be used for piping outside the cargo tanks except for short lengths of pipe attached to the cargo tanks, in which case fire-resisting insulation should be provided. This temperature limitation indicates that any hoses for use in cargo systems on board ship are to be of metallic construction having a melting point higher than 925°C.

3.9.14 For general requirements on rubber hoses, see Pt 5, Ch 10, 7 Flexible hoses.

3.10.1 Type C and N tankers are to be provided with at least one slop cargo tank and, so far as applicable, with drums for slops which cannot be pumped.

3.10.2 Slop tanks and drums, intended for slobs, are to be located in the cargo zone only.

3.10.3 IBCs (Intermediate Bulk Containers) or portable tanks may be used instead of a fixed residual cargo tank based on special consideration.

3.10.4 Slop tanks For Type N closed tankers and Type C tankers are to be provided with:

• A high velocity valve in compliance with Pt 5, Ch 13, 5.1 General 5.1.2 as far as applicable.
• A vacuum valve in compliance with Pt 5, Ch 13, 5.1 General 5.1.2 as far as applicable.
• A vacuum valve in compliance with Pt 5, Ch 13, 5.2 Pressure/vacuum and venting systems for various tanker types 5.2.3.(e) when explosion protection is required as per the ADN Table C, Column 17.
• A high velocity vent valve in compliance with Pt 5, Ch 13, 5.2 Pressure/vacuum and venting systems for various tanker types 5.2.3.(c) when explosion protection is required as per the ADN Table C, Column 17.
• A sounding device of approved type.
• Connections with valves intended for pipes and hoses.

3.10.5 Slop tanks For Type N-with wire gauze tankers are to be provided with:

• A flame arresting pressure equilibrium device.
• A sounding opening.
• Connections with valves intended for pipes and hoses.

3.10.6 Slop tanks for Type N open tankers are to be provided with:

• A pressure equilibrium device.
• A sounding opening.
• Connections with valves intended for pipes and hoses.

3.10.7 IBCs or tank containers for collecting slobs are to be provided with:

• A connection for venting gases in a safe manner during filling operations.
• A sounding arrangement of approved type.
• Connections with valves intended for pipes and hose

3.10.8 Slop tanks, IBCs and tank containers are not to be connected to the vapour return system of the cargo tanks except in case the slob tanks or containers are filled.

3.10.9 Slop tanks shall not be connected to a common pipe system when incompatible cargoes will be carried simultaneously, see Pt 5, Ch 13, 3.5 Cargo segregation.