Section 1 General requirements

1.1.1 The requirements of this Chapter apply to the refrigerated cargo installations of refrigerated cargo ships, refrigerated container ships, fish factory ships, fishing vessels, fruit juice carriers, and the reliquefaction/refrigerating plant of liquefied gas carriers and chemical carriers or tankers, where an RMC notation is requested.

1.1.2 Ships with refrigerated cargo installations which are approved, installed and tested in accordance with these requirements will be eligible for the applicable class notation specified in Pt 1, Ch 2 Classification Regulations.

1.1.3 The requirements for the classification of ships for the carriage of liquefied gas are given in Clasifications Register's (hereinafter referred to as 'LR') Rules and Regulations for the Construction and Classification of Ships for the Carriage of Liquefied Gases in Bulk, July 2022 (hereinafter referred to as the Rules for Ships for Liquefied Gases). Where reliquefaction or refrigeration equipment is fitted for cargo temperature and pressure control, the equipment is to comply with the requirements of Pt 6, Ch 3, 2 Design criteria to Pt 6, Ch 3, 11 Acceptance trials, as applicable.

1.1.4 The requirements for the refrigeration equipment and systems necessary for provision stores and air conditioning are specified in Pt 7, Ch 15 Refrigeration Systems and Equipment Serving Provision Stores and Air-Conditioning Installations.

1.2.1 The following plans and particulars, as applicable, and any others which may be specially requested for the refrigerating plant and systems, are to be submitted in triplicate for approval, before construction is commenced:

1. Schematic plans, including full particulars of piping and instrumentations, for:

   • primary and secondary refrigeration systems;
   • air cooler defrosting arrangements;
   • gas reliquefaction systems; and
   • condenser cooling water systems.

2. Detailed dimensioned plans and material specifications for:

   • reciprocating compressor crankshaft and crankcase, where exposed to refrigerant pressure;
   • rotary-type compressor rotors and casing;
   • condensers shell and tube and plate type;
   • evaporators shell and tube and plate type;
   • air coolers;
   • arrangement of air cooling pipe grids and construction method;
   • liquid receivers;
   • oil separators; and
   • any other pressure vessels, see Pt 5, Ch 11, 1.6 Plans 1.6.1.

3. General arrangement of refrigerating machinery compartment in elevation and plan, showing location and arrangement of the plant, ventilation details and location of temperature sensors and vapour detectors.

4. Details of automatic controls, alarms and safety systems, see Pt 6, Ch 3, 1.1 Application.

5. Details of level indicators.

6. Where provision is made for the manufacture and/or storage of inert gas in liquid form, details of the storage vessel insulation arrangements and the reliquefaction equipment and piping system are to be submitted.

7. Capacity calculations for pressure relief valves and/or bursting discs, and discharge pipe pressure drop calculations, see Pt 6, Ch 3, 4.15 Overpressure protection devices 4.15.5 to Pt 6, Ch 3, 4.15 Overpressure protection devices 4.15.21.

8. Programme of tests to be conducted on completion of the installation, see Pt 6, Ch 3, 11 Acceptance trials.

1.2.2 The following plans and particulars, as applicable, and any others which may be specially requested for refrigerated cargo spaces, are to be submitted in triplicate for approval, before work is commenced:

1. Specification of proposed insulation envelope system, including physical, thermal and fire properties.

2. General arrangement of insulated refrigerated spaces in elevation and plan.

   • The plans are to be to a scale adequate for the measurement of the external surfaces and the deck and bulkhead edges.
   • Dimensions and spacing of frames, beams and stiffeners, and details of other steel work intruding into the insulation and within the spaces, are to be shown.
   • Fuel oil and liquid cargo tanks adjacent to or below the refrigerated spaces are to be shown, and whether heating arrangements are provided for such tanks are to be indicated.
   • Ventilating and air-conditioning trunks, and ducts passing through refrigerated spaces are to be shown.
   • The plans are to include a diagram showing the position of the spaces in relation to other parts of the ship if this is not otherwise apparent.

3. Plans showing:

   • the thicknesses and methods of attachment of the insulation and linings on all surfaces including girders, hatch coamings and pillars; and
   • details of prefabricated panels and their fixings, vapour barriers, insulated doors and hatch access, bilge and manhole plugs and their frames.

4. Methods of attachment of air cooling grids (if fitted) are to be indicated.

5. Size and position of refrigerated space pressure equalising devices, where fitted, see Pt 6, Ch 3, 9.2 Insulation systems 9.2.12 and Pt 6, Ch 3, 9.2 Insulation systems 9.2.13.

6. Arrangements of the drainage system, and sounding and air pipes that pass through the refrigerated spaces.

7. Arrangements of air ducts and distribution systems within the refrigerated spaces (including method of cooling spaces within hatch coamings), and air cooler spaces showing location of the coolers and their fans and drive motors.

8. Details of temperature indicating, and recording and sensing equipment, and arrangement of sensors within the refrigerated spaces.

1.2.3 Single copies of the following plans and particulars are to be submitted:

• LR Data Sheet for refrigerated cargo installations (LR Form 3905).
• Specification of proposed refrigerating system and auxiliary equipment, including the refrigerating capacities of the compressors, condensers, evaporators and air coolers.
• Heat load calculations at all design operating conditions justifying the refrigerating capacity which is to be installed.

1.3.1 Steel plating used in ship construction is to be of an appropriate grade corresponding to the proposed temperature notation, see Pt 3, Ch 2, 2.2 Refrigerated spaces.

1.3.2 Materials used in the construction of the refrigerating equipment and associated systems are to be generally manufactured and tested in accordance with the requirements of the Rules for the Manufacture, Testing and Certification of Materials, July 2022 (hereinafter referred to as the Rules for Materials).

1.3.3 Where it is proposed to use materials other than those specified in the Rules for Materials, details of the chemical compositions, heat treatment and mechanical properties are to be submitted for approval. In such cases the values of the mechanical properties used for deriving the allowable stress are to be subject to agreement with LR.

1.3.4 All materials used in refrigerating equipment and systems are to be suitable for use with the selected refrigerants. This includes joints, sealing materials and lubricants. For example, the following materials and refrigerants are not to be combined:

• Copper with ammonia.
• Magnesium with fluorinated hydrocarbons.
• Zinc with ammonia or fluorinated hydrocarbons.

1.3.5 For ammonia systems, the condensers/evaporators are to be manufactured in titanium or a suitable grade of stainless steel.

1.4.1 All major items of equipment are to be surveyed at the manufacturer's works. The workmanship is to be to the Surveyor's satisfaction and the Surveyor is to be satisfied that the components are suitable for the intended purpose and duty. Examples of such units are:

• Crankshafts, crankcases, rotor shafts and casings for all compressors.
• Condensers.
• Evaporators (secondary refrigerant coolers).
• Air coolers.
• Pressure vessels (e.g. liquid receivers, surge drums, suction separators, intercoolers, oil separators).
• Cooling water pumps for condensers.
• Valves and other components intended for installation in pressure piping systems having a maximum working pressure greater than 0,7 MPa.
• Thermal insulating panels (factory made).

1.5.1 Where it is proposed to use components (e.g. compressors, condensers, oil separators) which have valid LR Type Approval or General Approval Certificates, the types and model numbers of the components are to be stated. Plans of components that have been so approved need not be re-submitted.

1.6.1 The class notation assigned will state the minimum temperature or a temperature range approved by the Committee for the installation with the maximum sea temperature stated, e.g. `Clasifications RMC to maintain temperature(s) of minus 29°C to plus 14°C with sea temperature plus 32°C maximum'.

1.6.2 For refrigerated installations aboard container ships with approved refrigerating plant and arrangements to supply refrigerated air through ducting to insulated containers, the class notation assigned will additionally specify the maximum number and characteristics of the containers for which the plant is approved, e.g. `to supply refrigerated air at temperatures of minus 25°C to plus 14°C to 800 certified insulated containers with an average thermal transmittance per container of 27 W/K with sea temperature plus 32°C maximum'.

1.6.3 For reliquefaction or refrigerating plants aboard liquefied gas carriers, the notation assigned will state the minimum cargo temperature for which the installation is approved, unless otherwise qualified, see LR III.3 Class notation (refrigerated installations) of the Rules for Ships for Liquefied Gases.

1.6.4 On application from an Owner, consideration will be given by the Committee to an alternative temperature notation being assigned to that appearing in the Register Book.

1.7.1 Where the proposed construction of the refrigerating plant or refrigerated spaces or chambers is novel in design or involves the use of unusual material, special tests may be required, and a suitable class notation may be assigned when the Committee considers this necessary.

1.8.1 A heat balance test will be required as prescribed in Pt 6, Ch 3, 11 Acceptance trials on a classed installation, or one being considered for reclassification, when extensive repairs or alterations have been carried out, or when the Surveyors consider that an amended temperature condition should be assigned.

1.9.1 Where it is intended to install a CA system on a vessel intended for classification, the requirements of Pt 7, Ch 1 Controlled Atmosphere Systems are to be complied with.

1.9.2 Where a CA notation is requested by an Owner, it is a prerequisite that the refrigeration installation be assigned an RMC notation.

1.10.1 It is recommended that adequate spares, together with the tools necessary for maintenance, or repair, be carried. The spares are to be determined by the Owner according to the design and intended service. The maintenance of the spares is the responsibility of the Owner.

1.10.2 For systems complying with Pt 6, Ch 3, 2.5 Design pressures 2.5.6 sufficient carbon dioxide is to be carried on board to allow the refrigeration system to be fully recharged. In addition, adequate reserve supplies of refrigerant are to be carried for maintenance purposes. The replacement refrigerant is to be stored in containers complying with Pt 6, Ch 3, 3.3 Gas storage compartments 3.3.5.