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 in Pt 1, Ch 3, 11.1 Frequency of surveys 11.1.3, 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.