Section 11 Steam pipes

11.1 Frequency of surveys

11.1.1 Saturated steam pipes, and superheated steam pipes where the temperature of the steam at the superheater outlet is not over 450^°C, are to be surveyed 10 years from the date of build (or installation) and thereafter at five-yearly intervals.

11.1.2 Superheated steam pipes where the temperature of the steam at the superheater outlet is over 450^°C are to be surveyed five years from the date of build (or installation) and thereafter at five-yearly intervals.

11.1.3 At 10 years from the date of build (or installation) and thereafter at five-yearly intervals, all copper or copper alloy steam pipes over 76 mm external diameter supplying steam for essential services at sea are to be hydraulically tested to twice the working pressure.

11.2 Scope of surveys

11.2.1 At each survey, a selected number of main steam pipes, also of auxiliary steam pipes, which:

are over 76 mm external diameter;
supply steam for essential services at sea; and
have bolted joints,

are to be removed for internal examination and are to be hydraulically tested to 1,5 times the working pressure. If these selected pipes are found satisfactory in all respects, the remainder need not be tested. So far as is practicable, the pipes are to be selected for examination and hydraulic test in rotation so that in the course of surveys all sections of the pipeline will be tested.

11.2.2 Where main and/or auxiliary steam pipes of the category described in 11.2.1(a) and (b) have welded joints between the lengths of pipe and/or between pipes and valves, the lagging in way of the welds is to be removed, and the welds examined and, if considered necessary by the Surveyor, crack-detected. Pipe ranges having welded joints are to be hydraulically tested to 1,5 times the working pressure. Where lengths having ordinary bolted joints are fitted in such pipe ranges and can be readily disconnected, they are to be removed for internal examination and hydraulically tested to 1,5 times the working pressure.

11.2.3 Where, on cylindrical boilers having smoke tube superheaters, the saturated steam pipes adjoining the saturated steam headers are situated partly in the boiler smoke boxes, all such pipes adjoining and cross-connecting these headers in the smoke boxes are, at the surveys required by 11.1, to be included in the pipes selected for examination and testing, as defined in 11.2.1. Where the saturated steam pipes inside the smoke boxes consist of steel castings of substantial construction, these requirements need only be applied to a sample casting. Where steel castings are not fitted, the Surveyor is to be satisfied of the condition of the ends of the saturated steam pipes in the smoke boxes at each Boiler Survey and, if the Surveyor considers it necessary, a sample pipe is to be removed for examination.

11.2.4 At the surveys specified inPt 1, Ch 3, 11.1 Frequency of surveys, any of the copper or copper alloy pipes, such as those having expansion or other bends, which may be subject to bending and/or vibration, also closing lengths adjacent to steam driven machinery, are to be annealed before being tested.

11.2.5 Where it is inconvenient for the Owner to fulfil all the requirements of a Steam Pipe Survey at its due date, the Classification Committee will be prepared to consider postponement of the survey, either wholly or in part.