UFC 4-390-01
23 July 2003
Penetrations with gasketed sealing areas should have corrosion
protection provisions for these areas.
Alternative design methods may be approved by the SCA on a case-
by-case basis.
B.6.1 Piping Penetrations. Pipe penetrations to the pressure
envelope should be located and arranged so that, in the event of
flooding, loss of atmosphere or similar emergency, a maximum
amount of atmosphere will become entrapped in the unmanned
pressure test facility. Emergency shutoff capability should be
provided to protect the internal breathing atmosphere from
exhaust, full flooding, or contamination.
B.6.2 Electrical Penetrations. The bodies of electrical
penetrators and connectors that may be exposed to water or spray
should be made of corrosion-resistant material. Electrical
penetrations to the pressure envelope should be gas-/watertight,
even when the connecting cables have been damaged. Pin-type
connections or cable entrances into compensated enclosures are
the preferred methods and should be used on all new design
pressure vessels. Terminal tube entrances are acceptable on
existing pressure vessels when evidence of compatibility of the
cable jacket and insulation with the compensating medium is
provided.
B.6.3 View Ports. The applicant should show that view port
design is adequate for the system pressure and temperature range,
environmental conditions and expected number of pressure cycles.
The materials used must have adequate fatigue strength for the
stress levels incurred over the expected life of the vessel.
Resistance to the stresses applied continuously over long periods
of time, as well as cyclic stresses, must be properly considered.
Full specification must be made of the materials used; their
composition; thermal, chemical, or physical treatment(s)
required; dimensions and tolerances; and renewal or replacement
criteria. Where necessary, view ports must be protected against
accidental impact or other mechanical abuse. Although the use of
various materials for view ports is not restricted, acrylic view
ports have a demonstrated high level of success and are
recommended above all other types when design parameters permit
the use of acrylic. View port penetrators should be designed
such that the view port seals against an integrally machined
sealing surface when pressure is applied (i.e., the retaining
ring should not be part of the primary sealing boundary when
pressure is applied). Acrylic materials, view port designs and
view port penetrators should conform to ASME/ANSI PVHO-1, Safety
Standards for Pressure Vessels for Human Occupancy unless prior
approval is obtained from the SCA.
In-service (i.e., used) view port defect criteria should be based
on view port material, dimensions, and loading conditions, and
must be determined separately for each view port design. SCA
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