Section 2 Piping systems for bilge, ballast, fuel oil, etc.

2.1.1 The pumping arrangements in the machinery space and at the forward end of the ship are to comply with the requirements for general cargo ships, in so far as they are applicable, and with the special requirements detailed in this Section.

2.1.2 Bilge, ballast and fuel oil lines, etc. which are connected to pumps, tanks or compartments at the ends of the ship, are not to pass through cargo tanks or have any connections to cargo tanks.

2.1.3 The fuel oil bunkering system is to be entirely separate from the cargo handling system.

2.1.4 Where non-permanent connections are required in piping systems between non-hazardous and hazardous spaces, two means of isolation are to be provided. One of these means is to provide positive separation by means of a removable spool piece or flexible hose, and blank flanges are to be fitted. The other is to be a non-return valve, or similar, in accordance with an acceptable national or international Standard that is appropriate for the design conditions of the piping system. The non-return valve and removable piece are to be located within the existing hazardous spaces. A notice is also to be provided located in a prominent position adjacent to the means of isolation, clearly indicating that the spool piece or flexible hose is to be removed, and blanking flanges are to be fitted, when the piping is not in use. The removable spool piece is to be clearly identified (labelled/painted in a distinctive colour) and stowed close to its working position.

2.2.1 Provision is to be made for the bilge drainage of under deck cargo pump-rooms by pump or bilge ejector suctions. The pump-room bilges of small tankers may be drained by means of a hand pump having a 50 mm bore suction. Pump-room suctions are not to enter machinery spaces. In case of emergency the pump-room is to be drained by a bilge unit situated outside the pump-room and independent of all other installations in the cargo zone.

2.2.2 For all tankers, a bilge alarm is to be fitted in under deck pump-rooms which will activate a visual and audible alarm in the wheelhouse to warn that the liquid in the pump room bilge has reached a predetermined level.

2.2.3 Bilge or ballast pumps serving spaces within the cargo zone other than cargo tanks are to be placed in that zone and their piping systems are to be separate from any other piping system. For exemptions, see Pt 5, Ch 13, 2.2 Drainage and/or ballasting of spaces within the cargo zone 2.2.10.

2.2.4 For all tankers, arrangements are to be made to fill the cofferdams by means of a pump. The filling is to be carried out within 30 minutes. Provision is to be made to prevent the cofferdams being subjected to a pressure which is in excess of that for which the cofferdams have been constructed.

2.2.5 For ships required to comply with the ADN Regulations and provided with an A-60 bulkhead insulation as per Pt 5, Ch 13, 1.6 Cargo pump-room 1.6.2, filling of the cofferdam may be waived.

2.2.6 For cofferdams arranged as service space the requirements of Pt 5, Ch 13, 2.2 Drainage and/or ballasting of spaces within the cargo zone 2.2.4 may be waived.

2.2.7 Cofferdams may be drained by a pump situated in the cargo zone. Alternatively, they may be drained by bilge ejectors.

2.2.8 Cofferdams are not to have any direct connections to the cargo tanks or cargo lines.

2.2.9 Cofferdam pipe systems are to be independent from any other pipe system of the ship.

2.2.10 Bilge or ballast pumps serving spaces within the cargo zone other than cargo tanks may be placed outside that zone only under the following conditions:

• All Types of tankers; for wing tanks and double bottom tanks not having a common boundary with the cargo tanks.
• Type G tankers; for cofferdams and hold spaces containing cargo tanks if ballasting will be carried out through a flexible connection with the fire main. Upon completion of the ballast operation, the fire main must be disconnected from the relevant spaces. The cofferdams and hold spaces are to be drained by bilge ejectors.
• Type N & C tankers; for cofferdams, wing tanks, double bottom tanks and hold spaces containing cargo tanks if ballasting will be carried out through a flexible connection with the fire main. Upon completion of the ballast operation, the fire main must be disconnected from the relevant spaces. The cofferdams and hold spaces are to be drained by bilge ejectors.

As an alternative to a flexible connection, a fixed connection with a spectacle flange could be accepted. Upon completion of the ballast operation the fire main must be separated from the relevant spaces by fitting the spectacle flange in the ‘closed’ position.

2.2.11 The shipside connection for ballast pumps placed in the cargo zone is to be situated within that zone but outside the cargo tanks.

2.2.12 Where bilge and ballast pumps are driven by shafting which passes through a pump room bulkhead or deck, gastight glands of an approved type are to be fitted as per Pt 5, Ch 13, 3.2 Cargo pumps and compressors 3.2.5. See also Table 13.1.1 Alarms and safety arrangements.

2.2.13 Bilge systems for hold spaces containing independent cargo tanks are to comply with Pt 5, Ch 13, 2.2 Drainage and/or ballasting of spaces within the cargo zone 2.2.14 .

2.2.14 The diameter d_b of the bilge line suction pipe is to be not less than required by the following formula, to the nearest 5 mm, but in no case is the diameter of any suction to be less than 50 mm:

2.2.15 Calculation of the minimum required bilge capacity is to be in compliance with Pt 5, Ch 11, 6.3 Capacity of pumps.

2.2.16 If the volume of the cargo tank exceeds 75 per cent of the total volume of the hold space the bilge capacity may be reduced by 50 per cent.

2.2.17 The minimum required bilge capacity is to be not less than 12.5 m³/h.

2.3.1 Cofferdams are to be provided with not less than two air pipes each in order to obtain a reasonable circulation of air. One of the air pipes is to be led near the bottom of the cofferdam. Sounding pipes on the cofferdam are to be led to the open deck. The air pipes, except for Type N-open Tankers, are to be fitted with a wire gauze diaphragm at their outlets, of an approved type and capable to resist a deflagration.

2.3.2 Double bottom tanks and wing tanks in the cargo area intended for ballast purposes are to be provided with an air pipe as per Pt 5, Ch 11, 10 Air and sounding pipes. Sounding pipes on the cofferdam are to be led to the open deck.

2.3.3 Hold spaces containing independent cargo tanks are to provided with not less that two air pipes. The diameter and position of the air pipes are to be such that each place in the hold will be sufficiently ventilated.

2.3.4 Alternatively the above hold spaces are to be inerted or filled with dry air if air pipes are not provided.

2.3.5 The following tanks and voids in the cargo area are to be ventilated by a suitable appliance:

1. Double bottom tanks not intended for ballast purposes.

2. Wing tanks not intended for ballast purposes.

3. Cofferdams other than mentioned in Pt 5, Ch 13, 2.3 Air and sounding pipes 2.3.1.

4. Hold spaces containing independent cargo tanks for Type C and N tankers.

2.4.1 Where double bottom tanks are fitted below cargo tanks and for wing tanks, the requirements of Pt 5, Ch 13, 2.2 Drainage and/or ballasting of spaces within the cargo zone 2.2.7 are applicable. For air and sounding pipes see Pt 5, Ch 13, 2.3 Air and sounding pipes 2.3.2.

2.4.2 Double bottom tanks below cargo tanks and wing tanks may be used for ballast purposes only.

2.4.3 For ships having hold spaces containing cargo tanks, double bottom tanks may be used as fuel oil tanks provided:

• the height of the double bottom tank is not less than 0,60 m.
• fuel oil pipes and openings of these tanks are not fitted or terminating in the hold spaces.
• air pipes are led to the open deck with a height of not less than 0,60 m above deck.
• air pipes are fitted with a wire gauge as per Pt 5, Ch 11, 10.6 Gauze diaphragms.