Appendix B to Part 180 - Acceptable Internal Self-closing Stop Valve Leakage Tests for Cargo Tanks Transporting Liquefied Compressed Gases
49:184.108.40.206.220.127.116.11.10 : Appendix B
Appendix B to Part 180 - Acceptable Internal Self-closing Stop
Valve Leakage Tests for Cargo Tanks Transporting Liquefied
For internal self-closing stop valve leakage testing, leakage is
defined as any leakage through the internal self-closing valve or
to the atmosphere that is detectable when the valve is in the
closed position. On some valves this will require the closure of
the pressure by-pass port.
(a) Meter Creep Test.
1. An operator of a cargo tank equipped with a calibrated meter
may check the internal self-closing stop valve for leakage through
the valve seat using the meter as a flow measurement indicator. The
test is initiated by starting the delivery process or returning
product to the cargo tank through the delivery system. This may be
performed at an idle. After the flow is established, the operator
closes the internal self-closing stop valve and monitors the meter
flow. The meter flow must stop within 30 seconds with no meter
creep within 5 seconds after the meter stops.
2. On pump-actuated pressure differential internal self-closing
stop valves, the valve must be closed with the remote actuator to
assure that it is functioning. On other types of internal
self-closing stop valves, the valve(s) may be closed using either
the normal valve control or the discharge control system (e.g.,
3. Rejection criteria: Any detectable meter creep within the
first five seconds after initial meter stoppage.
(b) Internal Self-Closing Stop Valve Test.
An operator of a cargo tank that is not equipped with a meter
may check the internal self-closing stop valve(s) for leakage as
1. The internal self-closing stop valve must be in the closed
2. All of the material in the downstream piping must be
evacuated, and the piping must be returned to atmospheric
temperature and pressure.
3. The outlet must be monitored for 30 seconds for detectable
4. Rejection criteria. Any detectable leakage is considered
[64 FR 28052, May 24, 1999]