(6) Engineering and fabrication properties of the materials.
(7) Cost effectiveness of the materials.
e.
Structural adequacy analysis must consider all possible loading of
the system including the following:
(1)
Internal pressures during normal operation.
(2)
Manual force during valve operations.
(3)
Axial and radial pressures during system testing.
(4) External pressures and possible accidental loads during
repairing adjacent piping.
(5)
External pressures and spacing of rigid supports of pipes and
tubes.
f.
Fatigue due to vibration of components can cause fracture in the
piping system. Sway braces or vibration dampeners to control the movement of
piping caused by vibration, as specified in ANSI B 31.1 Code for Power
Piping, Paragraph 121.2.5 (Reference 2), should be considered.
g.
Maintainability and provision for thorough cleaning must be planned
and shown on the piping design drawings. During conventional commercial
construction this problem is usually ignored or left to the best effort of
the pipe contractor's draftsman when he makes the pipe "shop drawings" and to
the knowledge and skill of the plumber when he is doing the on-site
fabrication of the system. This procedure should be avoided.
Piping runs must be planned in neat orderly groups with in-line valves,
filters, pressure gauges, and regulators located so that they may be
serviced, maintained, repaired, and removed, if necessary, without the need
to dismantle large sections of the system. Also pipe runs should not
interfere with other systems.
Since hyperbaric piping must be frequently cleaned or checked for
cleanliness, the installed pipe should have planned high points with gas
bleeds for venting and low points with draining provision built in. It
should be possible to dismantle the entire piping system in large sections
without damaging hardware. This is particularly true of pipes which carry
high percentages of oxygen.
h.
Special consideration must be given to:
(1)
Routing of each pipe run and selection and location of each
pipe support.
(2) Selection and location of each fitting and valve. Within
practical consideration, working components of the system must be located so
that operators do not have to climb on the hardware, use ladders, or stand on
stools to operate the complex.
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