Current through Register Vol. 35, No. 6, March 26, 2024
A. Owners and operators of underground
storage tanks may use interstitial monitoring between the UST and a secondary
barrier immediately around and underneath the tank, but only if the system is
designed, constructed and installed to detect a leak from any portion of the
storage tank system that routinely contains any regulated substance and also
meets one of the following requirements:
(1)
For double-walled UST systems, the sampling or testing method can detect a
release through the inner wall in any portion of the tank that routinely
contains a regulated substance, and the sampling or testing method complies
with the requirements of the current edition of an industry code or standard
approved in advance by the department; Steel Tank Institute
Standard F841, "Standard for Dual Wall Underground Storage
Tanks" may be used to meet this requirement.
(2) For UST systems with a secondary barrier
within the excavation zone, the sampling or testing method used can detect a
release between the UST system and the secondary barrier; the monitoring system
shall meet all of the following requirements:
(a) The secondary barrier around or beneath
the UST system consists of artificially constructed material that is
sufficiently thick and impermeable (at least one X 10(-6)) centimeters per
second for the regulated substance stored) to direct a release to the
monitoring point and permit its detection.
(b) The barrier is compatible with the
regulated substance stored so that a release from the UST system will not cause
a deterioration of the barrier allowing a release to pass through
undetected.
(c) For cathodically
protected USTs, the secondary barrier shall be installed so that it does not
interfere with the proper operation of the cathodic protection
system.
(d) The groundwater, soil
moisture, or rainfall will not render the testing or sampling method used
inoperative so that a release could go undetected for more than thirty
days.
(e) The site is assessed to
ensure that the secondary barrier is always above the groundwater and not in a
25-year flood plain, unless the barrier and monitoring designs are for use
under such conditions.
(f)
Monitoring wells are clearly marked and secured to avoid unauthorized access
and tampering, or
(3) For
USTs with an internally fitted liner, an automated device can detect a release
between the inner wall of the UST and the liner, and the liner is compatible
with the regulated substance stored.
B. For all interstitially monitored USTs,
owners and operators shall have all sensors tested by a qualified tester at
least annually to ensure proper operation and functionality, including for
alarm operability and communication with controller or monitoring equipment,
and sensors shall be verified as set to the proper height, placement, and
location in accordance with Subsection A of 20.5.108.800 NMAC and 20.5.107
NMAC. At a minimum, these tests shall follow either:
(1) liquid sensor functionality testing
procedures described in Petroleum Equipment Institute
Publication RP 1200,
"Recommended Practices for the
Testing
and Verification of Spill, Overfill,
Leak Detection and
Secondary
Containment
Equipment at UST Facilities";
or
(2) the equipment manufacturer's
published testing procedures.
C. Owners and operators shall ensure the
requirements in 20.5.108.800 NMAC are met prior to implementing interstitial
monitoring.
D. Owners and operators
shall maintain and provide the department reports relating to the requirements
of this section in accordance with 20.5.108.815 NMAC and 20.5.108.816
NMAC.
