UFC 4-390-01
23 July 2003
retested with the appropriate documentation being added
to the REC package.
Block (10)If required, make a sketch to show the joint
configuration clearly marking the joint numbers.
Block (11)The test technician should sign stating the test was
completed as documented.
C.1.2.7 System Tightness Test. A system tightness test is
performed when the scope of work exceeds the complexity at which
a joint tightness test can be performed. When a system is
applying for initial certification or has undergone an extensive
overhaul a system tightness test should be run. This test is
used to identify long-term leakage of an entire system. The
system is gradually pressurized to 100% of maximum operating
pressure. Data is then taken to measure the change in pressure,
corrected for temperature, over an extended period of time.
System tightness tests, unless otherwise specified by the SCA,
should be at least 6 hours in duration. The test pressure
tolerance used to perform this test should be within + or - 3%
(but not greater than 100 psig) of the specified test pressure.
Pressurize the entire system to its maximum
Step 1
operational pressure with the appropriate pressurization
medium.
Step 2
Ensure accurate temperature monitoring throughout
the system being tested.
Step 3
Allow approximately two (2) hours for the
temperature to stabilize and repressurize if necessary.
Step 4
Log the test pressure and temperature hourly.
Monitor the tightness of the installed using A and B
below.
a)
For gas filled systems, apply leak detecting soap
solution to all joints (mechanical, welded, brazed, etc.,)
within the test boundaries. Solution should be applied at
least hourly. For liquid filled systems, look for physical
evidence of leaks.
b)
Verify installation of a calibrated pressure gage for
monitoring pressure within the system undergoing test.
Observation of the test pressure is required to ensure that
the test pressure is maintained throughout the test duration
and that no piping leakage goes undetected due to piping
porosity that may not be detected by the leak detecting
solution. For systems with small volumes, acceptable
tightness of the system based on the pressure drop method
may be indeterminate. Therefore, step A should be an
integral part of all tightness tests.
C.1.2.7.1
Acceptance Criteria.
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