(1) Each cargo
tank must be tested for leaks in
accordance with paragraph (c) of
this section. The leakage test must
include testing product piping with
all valves and accessories in place
and operative, except that any
venting devices set to discharge at
less than the leakage test pressure
must be removed or rendered
inoperative during the test. All
internal or external self-closing
stop valves must be tested for leak
tightness. Each cargo tank of a
multi-cargo tank motor vehicle must
be tested with adjacent cargo tanks
empty and at atmospheric pressure.
Test pressure must be maintained for
at least 5 minutes. Cargo tanks in
liquefied compressed gas service
must be externally inspected for
leaks during the leakage test.
Suitable safeguards must be provided
to protect personnel should a
failure occur. Cargo tanks may be
leakage tested with hazardous
materials contained in the cargo
tank during the test. Leakage test
pressure must be no less than 80% of
MAWP marked on the specification
plate except as follows:
(i) A cargo
tank with an MAWP of 690 kPa (100
psig) or more may be leakage tested
at its maximum normal operating
pressure provided it is in dedicated
service or services; or
(ii) An MC
330 or MC 331 cargo tank in
dedicated liquified petroleum gas
service may be leakage tested at not
less than 414 kPa (60 psig).
(iii) An
operator of a specification MC 330
or MC 331 cargo tank, and a
nonspecification cargo tank
authorized under §173.315(k) of this
subchapter, equipped with a meter
may check leak tightness of the
internal self-closing stop valve by
conducting a meter creep test. (See
appendix B to this part.)
(iv) An MC
330 or MC 331 cargo tank in
dedicated service for anhydrous
ammonia may be leakage tested at not
less than 414 kPa (60 psig).
(v) A
non-specification cargo tank
required by §173.8(d) of this
subchapter to be leakage tested,
must be leakage tested at not less
than 16.6 kPa (2.4 psig), or as
specified in paragraph (h)(2) of
this section.
(2) Cargo
tanks used to transport petroleum
distillate fuels that are equipped
with vapor collection equipment may
be leak tested in accordance with
the Environmental Protection
Agency's “Method 27—Determination of
Vapor Tightness of Gasoline Delivery
Tank Using Pressure-Vacuum Test,” as
set forth in Appendix A to 40 CFR
part 60. Test methods and procedures
and maximum allowable pressure and
vacuum changes are in 40 CFR
63.425(e)(1). The hydrostatic test
alternative, using liquid in
Environmental Protection Agency's
“Method 27—Determination of Vapor
Tightness of Gasoline Delivery Tank
Using Pressure-Vacuum Test,” may not
be used to satisfy the leak testing
requirements of this paragraph. The
test must be conducted using air.
(3) A cargo
tank that fails to retain leakage
test pressure may not be returned to
service as a specification cargo
tank, except under conditions
specified in §180.411(d).
(4) After
July 1, 2000, Registered Inspectors
of specification MC 330 and MC 331
cargo tanks, and nonspecification
cargo tanks authorized under
§173.315(k) of this subchapter must
visually inspect the delivery hose
assembly and piping system while the
assembly is under leakage test
pressure utilizing the rejection
criteria listed in §180.416(g).
Delivery hose assemblies not
permanently attached to the cargo
tank motor vehicle may be inspected
separately from the cargo tank motor
vehicle. In addition to a written
record of the inspection prepared in
accordance with §180.417(b), the
Registered Inspector conducting the
test must note the hose
identification number, the date of
the test, and the condition of the
hose assembly and piping system
tested.
(5) The
inspector must record the results of
the leakage test as specified in
§180.417(b).
