Section 20 Refrigerated cargo installations

20.1.1 The Surveyors are to examine the machinery under working conditions as soon as practicable after a ship's arrival at a port of discharge before the cargo is unloaded. An examination of the refrigerated cargo installation log book (or other records) is to be made and any breakdowns or malfunctions of the plant during the previous twelve months are to be noted and reported to the Committee.

20.1.2 A General Examination of the refrigerating plant is to be carried out, and satisfactory operation of safety devices, controls and thermometry is to be verified. Insulated cargo spaces are to be inspected, and the condition of insulation, lining, scuppers, hatches, coolers, air ducting and air refreshing arrangements are to be checked. The Surveyors may request opening out of suspected items, or recommend repair or renewal of defective items, as a result of inspection.

20.1.3 A General Examination is to be made of electrical motors driving refrigerant compressors, pumps and fans, together with their controlgear and cables. Random tests for insulation resistance are to be made on the cables, switchgear, motors, etc. and this resistance is to be not less than 1 MΩ between individual conductors and between those conductors and earth. The installation may be subdivided for the purpose of this test, and the Surveyor may at his discretion accept the results of tests carried out by a competent member of staff or contractor.

20.1.4 A survey book or other permanent record is to be kept on board the ship to show the date of examination of the various parts. This is to be available to the Surveyor at all times, and is to be signed by the Surveyor on the occasion of each survey.

20.2.1 At the first Special Survey, the examinations outlined below are to be carried out. Where there is a programme of replacement instead of maintenance on board, alternative survey arrangements will be considered. Each case will be given individual consideration.

20.2.2 Detailed internal examination of each reciprocating compressor, opened up for inspection of cylinders, pistons, connection rods, valves, seats, glands, relief devices, filters, lubrication and crankshaft.

20.2.3 For screw-type compressors, the period before opening up may be extended to six years or 25 000 running hours, whichever is the earlier. Examination should be made of rotors, clearances, gearing, etc.

20.2.4 Refrigerant condenser cooling water pumps, including standby pump(s) which may be used on other services, are to be opened up and their working parts exposed.

20.2.5 Primary and secondary refrigerant pumps are to be opened up and their working parts exposed.

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

20.2.7 In the case of pressure vessels covered by insulation, any evidence of dampness or deterioration of the insulation which could lead to external corrosion of the vessels or their connections is to be investigated.

20.2.8 Sufficient insulation is to be stripped from insulated pressure vessels to allow the condition of the vessels and their connections to be ascertained. Care is to be taken that in replacement of the insulation, the vapour sealing of the outer covering is made good.

20.2.9 Sufficient insulation is to be stripped from pipes carrying the refrigerant at various points of the system both outside and inside the insulated chambers to permit the condition of the pipes to be ascertained. Sections of piping exposed are to include locations where lengths of piping have been connected by screwed couplings or butt welding. Care is to be taken that when ungalvanized portions of the piping in way of joints have been exposed, they are to be suitably coated and taped, after pressure testing, to prevent corrosion. On replacement of the insulation, the vapour sealing of the outer covering is to be made good.

20.2.10 A General Examination is to be made of all pressure relief valves and/or safety discs throughout the refrigerating plant to ensure that they are in good order and covered by current certification. However, no attempt is to be made to test primary refrigerant pressure relief on board ship. Relief valves are to be removed, overhauled and recalibrated every five years or in accordance with the manufacturer's recommendations, whichever is sooner.

20.2.11 Sea connections to refrigerant condenser cooling water pumps are to be opened up on the occasion of the hull and/or main machinery Special Survey.

20.2.12 The electric motors driving refrigerant compressors, pumps and fans, together with their controlgear and cables, are to have their insulation resistance tested and this is to be not less than 1 MΩ between individual conductors and between those conductors and earth. The installation may be subdivided to any desired extent by opening switches, removing fuses or disconnecting appliances for the purpose of this test.

20.2.13 All automatic controls, alarms and safety systems are to be tested and correct operation confirmed.

20.2.14 Sufficient air ducting and insulation lining is to be stripped from the cargo spaces or chamber's overhead and vertical surfaces to allow the condition of the insulation, insulation linings, grounds, supports, hangers and fixtures which support the insulation, grids, meat rails, etc. to be ascertained. Care is to be taken that on replacement, the ducts and linings are sealed against air blowing into the insulation, or against moisture ingress from refrigerated cell or space atmosphere.

20.2.15 Sufficient tank top insulation is to be stripped to allow the condition of the grounds and inner insulation lining to be ascertained.

20.2.16 Due consideration is to be given to the type of insulation used in the cargo spaces and chambers when determining the amount of insulation lining to be removed. Where organic foam insulants have been used, including panel systems or foamed in situ, or other insulants in slab form, the removal of panels or linings is to be at the Surveyor's discretion.

20.2.17 Under normal circumstances, the condition of the cargo space and chamber insulation, grounds, etc. can be ascertained when the Special Survey of the ship's steel structure is being held.

20.2.18 Arrangements made for defrosting air coolers, and for draining condensate from trays below coolers, are to be examined to ascertain that they are in working order. Trace heating elements around drain pipes should be specially examined.

20.2.19 Any air refreshing arrangements are to be examined.

20.3.1 A subsequent Special Survey is to be held approximately five years from the date of the previous Special Survey. Where a Continuous Survey procedure has been agreed, the interval between consecutive examinations of each item should not exceed five years.

20.3.2 In addition to the requirements for the first Special Survey as detailed in Pt 1, Ch 3, 20.2 Special Surveys and Pt 1, Ch 3, 20.3 Subsequent Special Survey 20.3.3 are to be complied with.

20.3.3 `Shell-and-tube' condensers and evaporators (secondary refrigerant coolers) in which the primary refrigerant is in the shell, are to have the shell pneumatically tested with the refrigerant, or air, or a mixture of inert gas and refrigerant (with the end covers removed) at pressures as stated in Pt 6, Ch 3, 2.5 Design pressures 2.5.5.

20.3.4 Shell-and-tube evaporators (secondary refrigerant coolers) in which the secondary refrigerant is in the shell are to have the shell hydraulically tested (with the end covers removed) to 1,5 times the design pressure, but in no case less than 0,29 MPa. After refitting the end covers, the primary refrigerant side is to be pneumatically tested as stated in Pt 1, Ch 3, 20.3 Subsequent Special Survey 20.3.3, and an examination made as far as practicable for gas leakage in the shell with the secondary refrigerant connection removed.

20.3.5 Heat exchangers used for cooling refrigerant liquid by the suction return gas to a compressor are not subject to internal corrosion, and would normally require to be specially examined internally only if leakage is suspected between high and low pressure sides. This type of heat exchanger, together with others using brine or water, are to be examined and tested at the discretion of the Surveyor according to the design of such equipment.

20.4.1 When a Loading Port Certificate is required by the Owner or his representative, a survey as detailed in Pt 1, Ch 3, 20.4 Loading Port Surveys 20.4.2 to Pt 1, Ch 3, 20.4 Loading Port Surveys 20.4.7 is to be carried out at the loading port. The certificate is not in respect of the cargo to be loaded or the manner in which it is to be stowed.

20.4.2 The refrigerating installation is to be examined under working conditions, and the temperatures in the cargo chambers are to be noted.

20.4.3 A General Examination of the generating plant supplying electric power to the refrigerated cargo installation is to be carried out to confirm that it complies with Pt 6, Ch 3, 6.1 General.

20.4.4 The refrigerated cargo spaces and chambers are to be examined in an empty state to ascertain that they are clean and free from odour which may adversely affect the cargo to be loaded, that the air cooler coils and cooling grids and their connections are free from leakage, that cargo battens, where fixed to the vertical surfaces, are in good order, that cargo gratings or dunnage battens (see Pt 6, Ch 3 Refrigerated Cargo Installations) are available as necessary for the floors or decks, and that no damage has been sustained to the insulation or its lining prior to the loading of the refrigerated cargo. Any indications of defective insulation not considered to warrant immediate attention are to be noted and specially reported.

20.4.5 All scuppers and bilge suctions draining insulated spaces are to be examined to ensure that they are in good working order, and that any liquid seals are primed.

20.4.6 If the ship loads at more than one port, one survey only at the first loading port will be required, provided that it includes the examination of all spaces or chambers which are to be used for refrigerated cargo during the voyage, and that general cargo is not subsequently carried in any of the spaces or chambers prior to loading the refrigerated cargo.

20.4.7 In the case of ships engaged on voyages of less than two months' duration, a Loading Port Certificate will be considered as valid for two months, provided that the cargoes carried are of such a nature as not to damage the insulation or appliances in the insulated chambers, nor to affect, by taint or mould, the refrigerated cargoes loaded during that period. For longer voyages, the certificate is valid for only one cargo from the loading port(s) to the discharge port(s).

20.4.8 If there is no LR Surveyor available at the loading port(s), or if none is obtainable from a port within a reasonable distance, the Committee will accept the report of a survey held at the loading port by two competent engineers of the ship.

20.5.1 In the case of refrigerating installations being constructed under Special Survey on ships not intended to be classed with LR, the installation is to comply with the applicable requirements of Pt 6, Ch 3 Refrigerated Cargo Installations.

20.5.2 The generator engines and electrical equipment, which supply power to the refrigerating installations are to be constructed in accordance with the requirements of the Classification Society concerned and the installation is also to comply with the requirements of Pt 6, Ch 3, 6.1 General 6.1.2. Such plant is to be examined generally and under working conditions by the Surveyors.