24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
Special Combination Units. Test special combination units so that each
pressure chamber (vessel) receives the required hydrostatic test without pressure in the
Hydrostatic Tests with Fluids Other than Water. Test procedures for
fluids other than water must be approved by the NAVFACENGCOM Boiler Inspection
Tightness Test Pressure. Perform the tightness test pressure at above
the normal operating pressure, but not exceeding the lowest safety valve set pressure.
Safety valves may be blocked or gagged for this test.
Direct connection of the boiler to the water system is prohibited, where an
approved back-flow prevention device is not installed, to prevent
Provide a power-driven or hand pump for application of the test pressure if
the boiler feed pump will not deliver the test pressure. The test pump will
be provided by the activity or its utilities contractor and operated and
inspected to ensure that it is in proper working condition prior to
connecting it to the boiler or the vessel.
Possible Deformation. If any indications of probable permanent
deformation are observed, cease the test until the weak parts have been properly
strengthened. If necessary repairs are not practicable, apply a new test, progressing up
to 20 psi less than the pressure at which the preceding test ceased. If the test is
successful, make the new maximum allowable working pressure two-thirds of the test
pressure, and reset or replace the safety valves in accordance with the new maximum
allowable working pressure.
. For all boilers, UPVs and heat exchangers, pressure
should not drop more than 10 percent within 15 minutes. If the pressure drop exceeds
10 percent, repair leaks and repeat the test. If the pressure drop is within 10 percent
and inspection does not reveal leaks in the pressure parts, assume that the leaks are
through the isolation valves, manholes, and handholes.
Inspection Under Pressure. Inspect all joints and connections for leaks
or other defects while the vessel is under pressure. The pressure held during this
inspection need not necessarily be equal to the hydrostatic test pressure, but will not be
less than two-thirds of the hydrostatic pressure. Where the test pressure exceeds the
MAWP of the item, the test pressure must be reduced to the MAWP for close
examination by the inspector.
Permanent Deformation. Where permanent deformation of the unfired
pressure vessel shell or heads, or of the boiler shell or drum has occurred, whether as a