Each method of leak detection for piping used to meet the
requirements of § 280.41 must be conducted in accordance with the
following:
(a)
Automatic line
leak detectors. Methods which alert the operator to the presence of a
leak by restricting or shutting off the flow of regulated substances through
piping or triggering an audible or visual alarm may be used only if they detect
leaks of 3 gallons per hour at 10 pounds per square inch line pressure within 1
hour. Testing must be performed in accordance with the following requirements:
(1) Frequency.
(i) Automatic line leak detectors installed
on or after October 1, 2008, must be tested in accordance with the requirements
of this rule at startup to verify proper operation and at least once every 12
months thereafter.
(ii) Automatic
line leak detectors installed before October I, 2008, must be tested in
accordance with the requirements of this rule by no later than October 1, 2009,
and at least once every 12 months thereafter.
(2) Criteria. All testing of automatic line
leak detectors must be conducted in accordance with the manufacturer's
specifications and any applicable code of practice listed in § 280.13 and
(i) Involve the simulation of a leak in the
piping at the dispenser that is at the highest elevation above the submersible
pump. If there is no change in elevation, the test must be conducted at the
dispenser that is the furthest away from the submersible pump;
(ii) Be conducted with the leak detector
installed in the system as it normally would be during operation;
(iii)Verify that the leak detector is capable
of detecting a leak equivalent to 3 gallons per hour at 10 pounds per square
inch line pressure within 1 hour; and
(iv) Be conducted finitely and the test
results reported quantitatively.
(3) Records. A written record documenting the
testing of automatic line leak detectors must be maintained (in accordance with
§ 280.35) to demonstrate compliance with this section. These records must
provide the results of the last two (2) tests required in this
section.
(b)
Line
tightness testing. A periodic test of piping may be conducted only if
it can detect a 0.1 gallon per hour leak rate at one and one-half times the
operating pressure and the test is conducted in accordance with manufacturer
specifications or other recommended code of practice.
(c) Interstitial monitoring. Monitoring of
the space between the inner (primary) and the outer (secondary) pipe walls may
be used, but only if the system is designed, constructed and installed to meet
the following requirements:
(1) The sampling
or testing method can detect a leak from any portion of the pipe that routinely
contains product;
(2) The sampling
or testing method can detect ingress of water or other external fluids into the
interstice;
(3) Records must be
maintained that show the interstice has been checked at least every 30 days for
evidence of a leak or ingress of external fluids;
(i) If the interstice is monitored
continuously, records must document that the electronic device monitoring the
interstice is in communication with the control console at least
monthly;
(ii) If the interstice is
monitored continuously, records must document the alarm history and provide the
appropriate reporting (if applicable) and reconciliation of each
alarm;
(iii)Any electronic device
that monitors the interstice must be tested at least once every 12 months for
proper function. The functionality test must be in accordance with the
manufacturer's specifications and any applicable industry code or recommended
practice listed in § 280.13. The functionality test must simulate a leak;
and
(4) Any regulated
substance that enters the interstice must be removed within 24 hours of
discovery or another time frame determined by the MDEQ to be
reasonable.
(d)
Applicable tank methods. Any of the methods in §
280.43(e), (0 or (h) may be used if they are designed to detect a leak from any
portion of the underground piping that routinely contains regulated
substances.
