Section 8 Pumps on bilge service
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Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Special Service Craft, July 2022 - Part 15 Piping Systems and Pressure Plant - Chapter 2 Ship Piping Systems - Section 8 Pumps on bilge service

Section 8 Pumps on bilge service

Parent topic: Chapter 2 Ship Piping Systems

8.1 Number of pumps

8.1.1 For craft fitted with a bilge main, at least two power bilge pumping units are to be provided. One of these units may be worked from the main engines and the other is to be independently driven.

8.1.2 For multi-hull craft, the power bilge pumping units in Pt 15, Ch 2, 8.1 Number of pumps 8.1.1 are to take suction from the bilge main in each hull. Where the bilge system in each hull is entirely separate, at least two power bilge pumping units are to be provided in each hull.

8.1.3 Each unit may consist of one or more pumps connected to the main bilge line, provided that their combined capacity is not less than that required by Pt 15, Ch 2, 8.3 Capacity of pumps 8.3.2.

8.1.4 A bilge ejector in combination with a high pressure sea-water pump may be accepted as a substitute for an independent bilge pump as required by Pt 15, Ch 2, 8.1 Number of pumps 8.1.1.

8.1.5 For craft fitted with fixed submersible bilge pumps, one pump is to be provided for each watertight compartment.

8.2 General service pumps

8.2.1 The bilge pumping units or pumps required by Pt 15, Ch 2, 8.1 Number of pumps may also be used for ballast, fire or general service duties of an intermittent nature, but not for pumping fuel or other flammable liquids. These pumps are to be immediately available for bilge duty when required.

8.3 Capacity of pumps

8.3.1 Each bilge pumping unit is to be connected to the bilge main and is to be capable of giving a speed of water through the Rule size of bilge main of not less than 2 m/s.

8.3.2 To achieve the flow velocity required by Pt 15, Ch 2, 8.3 Capacity of pumps 8.3.1, the capacity Q of each bilge pumping unit or bilge pump is to be not less than that required by the following formula:

where
d m = is as defined in Pt 15, Ch 2, 7.1 Bilge main 7.1.1.
Q = Rule minimum capacity, in m3/hour

8.3.3 Where one bilge pumping unit is of slightly less than Rule capacity, the deficiency may be made good by an excess capacity of the other unit. In general, the deficiency is to be limited to 30 per cent.

8.3.4 Where fixed submersible bilge pumps are fitted, the total capacity Q t of the pumps (in each hull for multi-hull craft) is to be not less than that required by the following formula:

where
d m = is as defined in Pt 15, Ch 2, 7.1 Bilge main 7.1.1.
Q t = Rule minimum total capacity, in m3/hour

8.3.5 The capacity Q n of each submersible bilge pump is to be not less than that required by the following formula:

where
N = number of fixed submersible pumps (in each hull for multi-hull craft)
Q t = is as defined in Pt 15, Ch 2, 8.3 Capacity of pumps 8.3.4
Q n = Rule minimum submersible pump capacity, in m3/hour
Q n = is in no case to be less than 8 m3/hour.

8.4 Self-priming pumps

8.4.1 All power pumps which are essential for bilge services are to be of the self-priming type, unless an approved central priming system is provided for these pumps.

8.5 Pump connections

8.5.1 The connections at the bilge pumps are to be such that one unit may continue in operation when the other unit is being opened up for overhaul.

8.5.2 Pumps required for essential services are not to be connected to a common suction or discharge chest or pipe unless the arrangements are such that the working of any pumps so connected is unaffected by the other pumps being in operation at the same time.

8.6 Direct bilge suctions

8.6.1 The direct bilge suction in the machinery space required by Pt 15, Ch 2, 5.1 General 5.1.2 and referred to in Pt 15, Ch 2, 5.1 General 5.1.3 is to be led to an independent power pump, and the arrangements are to be such that the direct suction can be used independently of the main bilge line suctions.

8.6.2 The machinery space direct bilge suction is not to be of a diameter less than that required for the machinery space branch bilge suction and arranged as detailed in Pt 15, Ch 2, 8.6 Direct bilge suctions 8.6.1.

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