UFC 4-390-01
23 July 2003
accordance with approved system PMS.
B.8.2.1.9 Special Considerations for Oxygen Systems. The
applicant should give special consideration and analysis to the
use of oxygen in the specific unmanned pressure test facility
design. Oxygen leaks are extreme fire hazards. Every attempt
should be made to design oxygen-piping systems to eliminate the
possibility of leaks. Use of seamless stainless steel
piping/tubing is permitted in oxygen systems. Wherever possible,
high-pressure portions of the oxygen system should be welded,
vice using mechanical fittings. Quick-opening valves should not
be used in high-pressure oxygen systems.
For further guidance on designing oxygen systems refer to ASTM
G88, Standard Guide for Designing Systems for Oxygen Service;
NFPA 53M, Manual on Fire Hazards in Oxygen Enriched Atmosphere
and CGA G-4, Oxygen. Deviation from any of the above criteria
requires technical justification and approval from the SCA.
B.8.2.1.10 Special Considerations for Hydrogen Systems. The
applicant should give special consideration to the use of
hydrogen in a UPTF. Dialog with the SCA early in the planning
and design process is strongly recommended. The primary emphasis
of the design is to prevent a flammable mixture of hydrogen and
air or oxygen from forming. This can be broken down into two
areas;
1.
hydrogen gas leaking from the vessel, component or piping
2. flammable mixtures of hydrogen, oxygen or air within the
piping system or vessel.
In the design of hydrogen piping systems special consideration
should be given to the choice of piping joints, type of
components and location of ancillary equipment. Special safety
features and operating procedures should be considered to prevent
the inadvertent forming of a flammable mix within piping or the
pressure vessel.
Consideration should be given to monitoring equipment to alert
operators of hydrogen gas leaks or hydrogen flames that may be
undetectable to the naked eye.
The following additional references should be considered when
designing a UPTF utilizing hydrogen as a pressurization media:
a)
Flame Arresters in Piping Systems. API Publication
2028, Second Edition, American Petroleum Institute, December
1991.
b)
Hydrogen as a Diving Gas. UHMS Publication number
69(WS-HYD), Undersea and Hyperbaric Medical Society, February
1987.
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