Section 4 Cast iron

4.1.1 Spheroidal or nodular graphite iron may be accepted for bilge, ballast and cargo oil piping.

4.1.2 Spheroidal or nodular graphite iron castings for pipes, valves and fittings in Class II and Class III piping systems are to be made in a grade having a specified minimum elongation not less than 12 per cent on a gauge length of 5,65 , where S _o is the actual cross-sectional area of the test piece.

4.1.3 Castings for Class II and Class III systems are to comply with the requirements of acceptable national specifications. A manufacturer’s certificate will be accepted and is to be provided for each consignment of material, see also Pt 5, Ch 10, 1.6 Materials and Ch 1, 3.1 General 3.1.3.(c) of the Rules for Materials.

4.1.4 Where the elongation is less than the minimum required byPt 5, Ch 10, 4.1 Spheroidal or nodular graphite cast iron 4.1.2, the material is, in general, to be subject to the same limitations as grey cast iron.

4.2.1 Grey case iron pipes, valves and fittings will, in general, be accepted in Class III piping systems except as stated in Pt 5, Ch 10, 4.2 Grey cast iron 4.2.3.

4.2.2 Grey cast iron valves and fittings may be accepted in Class II steam systems, provided that the design pressure and temperature do not exceed 13 bar and 220°C, respectively.

4.2.3 Grey cast iron is not to be used for the following:

• Pipes for steam systems and pipes, valves and fittings for fire-extinguishing systems.
• Pipes, valves and fittings for boiler blow-down systems.
• Ship-side valves and fittings, see Pt 5, Ch 11, 2.5 Ship-side valves and fittings (other than those on scuppers and sanitary discharges).
• Valves fitted on the collision bulkhead, see Pt 5, Ch 11, 3.5 Fore and after peaks.
• Bilge lines in tanks.
• Pipes and fittings in flammable oil and thermal oil systems where the design pressure exceeds 10 bar or the design operating temperature is greater than 80°C.
• Valves fitted to tanks containing flammable oil under static pressure.
• Piping subject to pressure shock, excessive strains or vibrations.
• Valves chests and fittings for starting air systems, see Pt 5, Ch 2, 8.3 Starting air pipe systems and safety fittings 8.3.3.

4.2.4 Grey iron castings for Class III systems are to be manufactured and tested in accordance with acceptable National Specifications.