24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
is not required every 3 years provided the vessel (or vessel bank) successfully passes a gas analysis
with oil mist plus particulate matter concentration equal to or less than 5 milligrams per cubic meter and
dew point equal to or colder than -40C (-40F); and an ultrasonic thickness measurement check in
accordance with Paragraph 5-4.2. The maximum acceptable interval between visual inspections is 12
At intervals indicated in Naval Ship's Technical Manual S9086-SY-STM-010, Chapter 551,
vessels will be required to be tested according to "551-1.14.1". The flask(s) requiring re-certification is
to be tested by Ultrasonic (UT) testing or Acoustic Emission (AE) testing. Hydrostatic testing is being
eliminated because it does not provide data on flask wall cracking which has been determined to be the
primary failure mode."
Activities may elect to prepare and inspect MILSPEC vessels using NAVSEASYSCOM boiler
inspectors according to Naval Ship's Technical Manual S9086-SY-STM-010, Chapter 551, Compressed
Air Plants and Systems. However, if either a NAVSEASYSCOM or NAVFAC boiler inspectors are used
they will be required to perform internal and external inspections as explained above every 3 years (as
opposed to the 6-20 year re-certification intervals allowed in Naval Ship's Technical Manual S9086-SY-
STM-010, Chapter 551). A pressure vessel that is neither MILSPEC nor ASME code may only be
certified when design drawings and engineering calculations from the manufacturer are available to the
inspector to positively determine whether the vessel is safe to operate. The inspector may ask for proof
of the manufacturer's quality control procedures and tests prior to issuing a certificate of safety.
For hyperbaric facility support pressure vessels, the test pressure is to be in accordance with
the nationally accepted standard to which the pressure vessel was constructed. For example, ASME
BPVC Section VIII 1 or 2.
We recommend inspectors familiarize themselves with current versions of Compressed Gas
Association (CGA) G-6.1-2002, Standard for Insulated Carbon Dioxide Systems at Consumer Sites, and
CGA G-6.7-1996, Safe Handing of Liquid Carbon Dioxide Containers That Have Lost Pressure.
Inspection must include testing of relief valves by an ASME Repair Facility Holding a "VR"
stamp or replacement with new ASME stamped valves. Also required is calibration of all pressure and
temperature gages. Note: The external inspection should be limited to the visible portions of the
system, including the vessel and appurtenances such as pressure relief devices, the piping system, and
hose lines. Initial inspections may require adding an isolation valve between the vessel and relief valve.
The mandatory isolation valve requirements are listed in the ASME Boiler and Pressure Vessel Code,
Section VIII, Division I, Appendix M, Paragraph M-5.
The minimum required rate of safety valve discharge for aboveground LPG tanks is to be in
accordance with the following table: