Section 8 Ships for liquefied gases under pressure and/or partially refrigerated

8.1.1 The requirements of Pt 1, Ch 3, 2 Annual Survey – Hull requirements are to be complied with as applicable.

8.1.2 The requirements of Pt 1, Ch 3, 10.1 Annual Surveys for machinery are to be complied with as applicable.

8.1.3 The Annual Survey requirements of Pt 1, Ch 3, 12.2 Annual and Intermediate Surveys for electrical equipment are to be complied with as applicable.

8.2.1 Cargo liquid level indicating devices are to be generally examined. The low level, high level and overfill alarms are to be examined and tested to ascertain that they are in working order. Consideration will be given to the acceptance of simulated tests provided that they are carried out at the cargo temperature and/or pressure.

8.2.2 Where applicable, gas leakage systems are to be examined and tested to ascertain that they are in working order and calibrated using sample gas.

8.2.3 Where applicable, the correct functioning of the cargo containment system temperature indicating equipment, together with any associated alarms, is to be verified.

8.2.4 Where applicable, the ventilation system for the spaces surrounding the cargo tanks and in working spaces is to be examined and checked for satisfactory operation.

8.2.5 Where applicable, inert gas systems for the environmental control of cargo tanks and/or spaces surrounding the cargo tanks are to be generally examined.

8.2.6 Where applicable, control devices for the cargo containment system and cargo handling equipment, together with any associated shut-down and/or interlock, are to be checked under simulated working conditions, and if required, recalibrated.

8.2.7 The arrangements for manually operated emergency shut-down are to be checked to ascertain they are in working order.

8.2.8 Cargo pipelines, valves and fittings are to be generally examined, with special reference to expansion bellows, supports and vapour seals on insulated pipes.

8.2.9 Portable and/or fixed drip trays, or insulation for deck protection in the event of cargo leakage are to be examined for their condition.

8.3.1 Where refrigerating equipment for cargo temperature and pressure control is fitted the following are to be examined so far as practicable:

1. The machinery under working conditions.

2. Shells of all pressure vessels in the system including primary refrigerant gas and liquid pipes, cargo vapour and liquid condensate pipes and condenser cooling arrangements. Insulation need not be removed, but any deterioration or evidence of dampness is to be investigated.

8.4.1 For requirements of Special Survey for electrical equipment, see Pt 1, Ch 3, 12 Electrical equipment

8.4.2 All cargo tanks are to be examined internally and externally so far as practicable, particular attention being paid to the plating in way of supports and of chocking and securing arrangements and pipe connections.

8.4.3 Where cargo tanks are insulated and the insulation accessible, the insulation should be examined externally and sections removed for examination of the tank if considered necessary by the Surveyor.

8.4.4 The Surveyor may require to gauge, by ultrasonic thickness measurement or other approved means, the thickness of the material in any portion of the cargo tank structure where sign of wastage is evident, wastage is normally found or where there is doubt as to the condition of the structure in way of insulation. Any parts of the cargo tank structure which are found defective or materially reduced in scantlings are to be made good by materials of approved scantlings and quality.

8.4.5 Cargo tank internal pipes and fittings are to be examined, and all valves and cocks in direct communication with the interiors of tanks are to be opened out for inspection and connection pipes are to be examined internally, so far as practicable.

8.4.6 Pressure relief valves and vacuum relief valves are to be opened out for inspection and are to be adjusted afterwards. Valves may be removed from tanks, cargo gas and liquid pipelines for this purpose.

8.4.7 All cargo pumps, cargo booster pumps and cargo vapour pumps, where applicable, are to be opened out for examination.

8.4.8 Where considered necessary by the Surveyor, insulated cargo gas and liquid pipelines are to have sections of insulation removed to ascertain the condition of the pipes.

8.4.9 Where equipment for the production of inert gas is fitted, it is to be examined and tested to show it to be operating satisfactorily within the gas specification limits. Pipelines, valves, etc. for the distribution of the inert gas are to be generally examined. Pressure vessels for the storage of inert gas are to be examined internally together with their fastenings. Pressure relief valves are to be demonstrated to be in good working order. Liquid nitrogen storage vessels are to be examined as far as practicable and all control equipment, alarms and safety devices are to be verified as operational.

8.5.1 Each reciprocating compressor is to be opened out. Cylinder bores, pistons, piston rods, connecting rods, valves and seats, glands, relief devices, suction filters and lubricating arrangements are to be examined. Crankshafts are to be examined but crankcase glands and the lower half of main bearings need not be exposed if the Surveyor is satisfied with the alignment and wear.

8.5.2 Where other than reciprocating type compressors are fitted, or where there is a program of replacement instead of surveys on board, alternative survey arrangements will be considered. Each case will be given individual consideration.

8.5.3 The water end covers of condensers are to be removed for examination of the tubes, tubeplates and covers.

8.5.4 Refrigerant condenser cooling water pumps, including standby pump(s) which may be used on other services, are to be opened out for examination.

8.5.5 Where a pressure vessel is insulated, sufficient insulation is to be removed, especially in way of connections and supports, to enable the vessel’s condition to be ascertained.

8.5.6 Insulated pipes are to have sufficient insulation removed to enable their condition to be ascertained. Vapour seals are to be specially examined for condition.

8.5.7 The Surveyor is to satisfy himself that all pressure relief valves and/or safety discs throughout the system are in good order. No attempt, however, is to be made to test primary refrigerant pressure relief valves on board ship.

8.6.1 The requirements of Pt 1, Ch 3, 8.1 Annual Surveys are to be complied with so far as applicable.

8.6.2 All pressure vessels of inert gas installations are to be examined internally and externally and tested.

8.6.3 Cargo tanks are to be pressure tested to a pressure of 1,25 times the working pressure.

8.7.1 In addition to the requirements of Pt 1, Ch 3, 8.4 Special Surveys – General requirements 8.4.4, thickness measurement of cargo tank plating is to be carried out at each Special Survey by ultrasonic thickness measurement or other approved means, to determine the amount of any general diminution. The gauging is to be carried out in at least two places of the bottom, forward and aft tank plating, side and top plating. The remainder of the plating is to be gauged as deemed necessary by the Surveyor, taking into account the results of gauging already carried out.