5.2.4.1 For pipes, the permissible
stress to be considered in the formula for t in 5.2.2.1 is the lower of the following
values:
where:
|
R
m
|
= |
specified minimum tensile strength at room temperature (N/mm2)
|
|
R
e
|
= |
specified minimum yield stress at room temperature (N/mm2).
If the stress-strain curve does not show a defined yield stress, the
0.2% proof stress applies.
|
The values of A and B should be shown
on the International Certificate of Fitness for the Carriage of Liquefied
Gases in Bulk as provided for in 1.5 and
have values of at least A = 2.7 and B =
1.8.
5.2.4.2 The minimum wall
thickness should be in accordance with Recognized Standards.
5.2.4.3 Where necessary for
mechanical strength to prevent damage, collapse, excessive sag or
buckling of pipes due to superimposed loads from supports, ship deflection
or other causes, the wall thickness should be increased over that
required by 5.2.2, or, if this is
impracticable or would cause excessive local stresses, these loads
should be reduced, protected against or eliminated by other design
methods.
5.2.4.4 Flanges, valves and
other fittings should comply with recognized standards, taking into
account the design pressure defined in 5.2.2.
For bellows expansion joints used in vapour service, a lower minimum
design pressure may be accepted.
5.2.4.5 For flanges not complying
with a standard, the dimensions of flanges and related bolts should
be to the satisfaction of the Administration.