2.1.1 The design and construction of expansion pieces intended for installation in piping
systems is to be in accordance with an acceptable standard or design code
appropriate to the piping system. Where suitable standards are not available,
details of materials and construction are to be submitted for consideration.
2.1.2 The design of expansion pieces is to take account of pressure, temperature, fluid
compatibility, loads to accommodate axial and lateral movements and fatigue life due
to vibration.
2.1.3 Prototype pressure tests are to be carried out on each new type of expansion piece,
and in no case is the burst pressure to be less than four times the design
pressure.
2.1.5 Expansion pieces are only to be used in permanent piping system installations to
accommodate axial and lateral movements. They are not to be used to compensate for
piping misalignment unless specifically designed for the purpose.
2.1.6 Expansion pieces are to be used within their specified pressure, temperature and
movement conditions for all normal operating conditions. The design and operating
ratings of expansion pieces are not to be less than that of the piping system in
which the expansion piece is installed.
2.1.7 Expansion pieces used in compressed air, boiler feed water and steam piping systems
are to be of steel or other approved material.
2.1.8 Expansion pieces incorporating oil resistant rubber or other suitable synthetic
material may be used in cooling water lines in machinery spaces. Where fitted in sea
water lines, they are to be provided with guards which effectively enclose, but do
not interfere with, the action of the expansion pieces and will reduce to a minimum
practicable, any flow of water into the machinery spaces in the event of failure of
the flexible elements. Proposals to use such fittings in water lines in other
services will be specially considered when plans of the piping systems are submitted
for approval.
2.1.9 Expansion pieces are to be installed in accordance with the manufacturer's
instructions and are to be protected against over extension and over compression.
The adjoining pipes are to be suitably aligned, supported and anchored. Where
necessary, expansion pieces of bellows are to be protected against mechanical
damage.
2.1.10 All moving parts are to be provided with guards to minimise danger to personnel.