Section 1 General

1.1.1 The requirements of this Chapter apply to the welding of pressure vessels and pressure pipes. The allocation of Class is determined from the design criteria referenced in Pt 5, Ch 8 Fired Boilers, Pt 5, Ch 9 Pressure Vessels other than Boilers and Pt 5, Ch 10 Piping Design Requirements.

1.1.2 Fusion welded pressure vessels will be accepted only if manufactured by firms equipped and competent to undertake the quality of welding required for the Class of vessel proposed. For independent tanks intended for Type G tankers or pressure vessels containing LNG for propulsion purposes, the Manufacturer’s works are to be assessed and approved see Pt 5, Ch 14, 2.1 General requirements 2.1.3.

1.1.3 For pressure vessels which only have circumferential seams, see Pt 5, Ch 9, 1.5 Classification of fusion welded pressure vessels 1.5.5.

1.1.4 Requirements for fusion welding of pressure vessels and piping of other recognised Codes or standards, giving an equivalent level of quality, can be accepted.

1.2.1 In the first instance, and before work is commenced, the Surveyors are to be satisfied that the required quality of welding is attainable with the proposed welding plant, equipment and procedures reference is made to the Materials and Qualification Procedures for Ships, Book A, Procedure 0-4.

1.2.2 All welding is to be in accordance with the requirements specified in Ch 13 Requirements for Welded Construction of the Rules for the Manufacture, Testing and Certification of Materials (hereinafter referred to as the Rules for Materials).

1.3.1 Pressure vessels are to be constructed and examined in accordance with the requirements specified in Ch 13 Requirements for Welded Construction of the Rules for Materials, unless more stringent requirements are specified.