Section 2 Construction and installation

2.1.1 Pipes, valves and fittings are to be made of steel, ductile cast iron, copper, copper alloy, or other approved ductile material suitable for the intended purpose.

2.1.2 Where applicable, the materials are to comply with the requirements of Vol 2, Pt 7, Ch 1, 4 Materials.

2.1.3 Materials sensitive to heat, such as aluminium, plastics, or elastomers, are not to be used for Ship Type piping systems where leakage or failure caused by fire could result in fire spread, flooding or loss of the system. They may be permitted, where necessary, for signature or shock purposes, in which cases they are to have suitable fire certification.

2.1.4 The selection of materials in piping systems is to recognise the following details:

1. Fluids properties, pressures and temperatures.

2. Location and configuration.

3. Compatibility of materials.

4. Fluid flow rates and static conditions.

5. Minimising corrosion and erosion through life of system.

6. System survey and maintenance requirements.

See Vol 2, Pt 7, Ch 1, 17 Guidance notes on metal pipes for water service for guidance notes on metal pipes for water services.

2.2.1 The minimum nominal wall thickness of steel, copper and copper alloy pipes is to be in accordance with Vol 2, Pt 7, Ch 1 Piping Design Requirements. Where refrigerant tubes are in tube bundles, special consideration will be given to the minimum thickness requirements recognising the inherent strength of tube bundles and the benefits of increased heat transfer properties of thin wall tubes.

2.2.2 Special consideration will be given to the wall thickness of pipes made of materials other than steel, copper and copper alloy.

2.3.1 Air receivers and gas pressurised hydraulic accumulators are to be in accordance with Vol 2, Pt 8, Ch 2 Other Pressure Vessels or a recognised Code, where applicable. Materials used in the construction are to be manufactured and tested in accordance with the Rules for the Manufacture, Testing and Certification of Materials (hereinafter referred to as the Rules for Materials).

2.3.2 Valves, flexible hose lengths, expansion pieces and pumps are to comply with the relevant requirements of Vol 2, Pt 7, Ch 1, 12 Valves to Vol 2, Pt 7, Ch 1, 15 Pumps. Equipment used in Ship Type piping systems is to be suitable for its intended purpose, and accordingly, wherever practicable, be selected from the Lists of LR Type Approved Products published by LR.

2.3.3 Pipes in piping systems are to be permanent pipes made with approved pipe connections to enable ready removal of valves, pumps, fittings and equipment. The pipes are to be efficiently secured in position to prevent chafing or lateral movement. The selection of pipe connections in refrigeration systems is to minimise the possibility of refrigerant leaks and the use of flared fittings in such systems is to be avoided.

2.3.4 Suitable means for expansion are to be made, where necessary, in each range of pipes.

2.3.5 Efficient protection is to be provided for all pipes situated where these are liable to mechanical damage.

2.3.6 All moving parts are to be provided with guards to minimise danger to personnel.

2.3.7 Piping systems that may contain low temperature refrigerant are to be thermally insulated to an extent that will minimise condensation of moisture. Chilled water pipes are to be provided with insulation for system efficiency.

2.4.1 Valves are to be fitted in places where they are at all times readily accessible.

2.4.2 All valves that are provided with remote control arrangements are to be arranged for local manual operation, independent of the remote operating mechanism. The local manual means of operation is to be readily accessible.

2.4.3 Relief valves are to be adjusted and bursting discs so selected that they relieve at a pressure not greater than the design pressure of the system. When satisfactorily adjusted, relief valves are to be protected against tampering or interference by wire with a lead seal or similar arrangement.

2.4.4 The related discharge capacity of pressure relief valves is to be determined in accordance with a recognised Standard or Code.