Reg. 555 d
Seatings for Mountings
Attachment of Standpipes
The following constructions as to stand-pipes attached
to shells and end plates shall be permissible:
||When the internal diameter
of the standpipe does not exceed 1 inch, the standpipe
may be screwed into the plate with a nut on the
||Where the internal diameter
of the standpipe exceeds one inch but does not exceed
2 inches, it may be screwed in and seal-welded.
||Where the diameter of
the standpipe exceeds 2 inches, it may be welded
to the end plate.
The foregoing provisions as to the standpipe attachment
shall be regulated by the following conditions:-
||When standpipes are screwed,
the screwing shall be of standard pipe thread.
||Standpipes shall be attached
by one of the methods shown in Figures XII/84,
XII/93 or by any other method approved
by the Inspecting Authority.
||Where the standpipes
are fabricated by fusion-welding they shall be stress
relieved by heat-treatment before attachment to
the boiler unless the whole boiler is subject to
heat-treatment on completion.
||Where the bore of the
standpipe does not exceed 5 inches or the diameter
of the opening in the shell does not exceed 5 inches
plus twice the thickness of the plate to which it
is attached, the standpipe may be welded to the
plate without subsequent heat-treatment of the weld
so made. If these limits are exceeded the whole
plate to which the standpipe is attached shall be
stress relieved by heat-treatment on completion