| (D) Any preexisting background contamination in the
excavation zone shall not interfere with the capability of the vapor
monitoring equipment to detect releases from the UST system.
(E) The vapor monitoring equipment shall be designed
to detect vapors from either the stored regulated substance, a component
or components of the stored substance, or a tracer substance placed
in the UST system, and shall be capable of detecting any significant
increase in vapor concentration above preexisting background levels.
(F) Prior to installation of any vapor monitoring equipment,
the site of the UST system (within the excavation zone) shall be assessed
by qualified personnel to:
(i) ensure that the requirements in subparagraphs (A)
- (D) of this paragraph have been met; and
(ii) determine the appropriate number and positioning
of any monitoring wells and/or observation wells, so that releases
into the excavation zone from any part of the UST system can be detected
within 30 days.
(G) All monitoring wells and observation wells shall
be designed and installed in accordance with the requirements of §334.46(g)
of this title.
(6) Groundwater monitoring. Equipment or procedures
designed to test or monitor for the presence of regulated substances
floating on, or dissolved in, the groundwater in the excavation zone
may be used, subject to the following limitations and requirements.
(A) The stored regulated substance shall be immiscible
in water and shall have a specific gravity of less than one.
(B) The natural groundwater level shall never be more
than 20 feet (vertically) from the ground surface, and the hydraulic
conductivity of the soils or backfill between all parts of the UST
system and the monitoring points shall not be less than 0.01 centimeters
per second (i.e., the soils or backfill shall consist of gravels,
coarse to medium sands, or other similarly permeable material).
(C) Any automatic monitoring devices that are employed
shall be capable of detecting the presence of at least 1/8 inch of
free product on top of the groundwater in the monitoring well or observation
well. Any manual monitoring method shall be capable of detecting a
visible sheen or other accumulation of regulated substances in, or
on, the groundwater in the monitoring well or observation well.
(D) Any preexisting background contamination in the
monitored zone shall not interfere with the capability of the groundwater
monitoring equipment or methodology to detect releases from the UST
system, and the groundwater monitoring equipment or methodology shall
be capable of detecting any significant increase above preexisting
background levels in the amount of regulated substance floating on,
or dissolved in, the groundwater.
(E) Prior to installation of any groundwater monitoring
equipment, the site of the UST system (within and immediately below
the excavation zone) shall be assessed by qualified personnel to:
(i) ensure compliance with the requirements of subparagraphs
(A) and (B) of this paragraph; and
(ii) determine the appropriate number and positioning
of any monitoring wells and/or observation wells, so that releases
from any part of the UST system can be detected within 30 days.
(F) All monitoring wells and observation wells shall
be designed, installed, and maintained in accordance with the requirements
in §334.46(g) of this title.
(7) Interstitial monitoring for double-wall or jacketed
UST systems. Equipment designed to test or monitor for the presence
of regulated substance vapors or liquids in the interstitial space
between the inner (primary) and outer (secondary) walls of a double-wall
or jacketed UST system may be used, subject to the following conditions
and requirements.
(A) Any double-wall UST system using this method of
release detection shall be designed, constructed, and installed in
accordance with the applicable technical and installation requirements
in §334.45(d) and §334.46(f) of this title.
(B) The sampling, testing, or monitoring method shall
be capable of detecting any release of stored regulated substances
from any portion of the primary tank or piping within 30 days of the
release.
(C) The sampling, testing, or monitoring method shall
be capable of detecting a breach or failure in the primary wall and
the entrance of groundwater or any other water into the interstitial
space due to a breach in the secondary wall of the double-wall or
jacketed tank or piping system within 30 days of such breach or failure
(whether or not a stored regulated substance has been released into
the environment).
(8) Monitoring of UST systems with secondary containment
barriers. Equipment designed to test or monitor for the presence of
regulated substances (liquids or vapors) in the excavation zone between
the UST system and an impermeable secondary containment barrier immediately
around the UST system may be used, subject to the following conditions
and requirements.
(A) Any secondary containment barrier or liner system
at a UST system using this method of release detection shall be designed,
constructed, and installed in accordance with the applicable technical
and installation requirements in §334.45(d) and §334.46(f)
of this title.
(B) The sampling, testing, or monitoring method shall
be capable of detecting any release of stored regulated substance
from any portion of the UST system into the excavation zone between
the UST system and the secondary containment barrier within 30 days
of the release.
(C) The sampling, testing, or monitoring method shall
be designed and installed in a manner that will ensure that groundwater,
soil moisture, and rainfall will not render the method inoperative
where a release could remain undetected for more than 30 days.
(D) Prior to installation of any secondary containment
release monitoring equipment, the site of the UST system shall be
assessed by qualified personnel to:
(i) ensure that the secondary containment barrier will
be positioned above the groundwater level and outside the designated
25-year floodplain, unless the barrier and the monitoring equipment
are designed for use under such conditions; and
(ii) determine the appropriate number and positioning
of any observation wells.
(E) All observation wells shall be designed and installed
in accordance with the requirements in §334.46(g) of this title.
(9) SIR in combination with inventory control.
(A) A combination of SIR and inventory control may
be used as a release detection method for UST system tanks and piping,
subject to the following requirements.
(i) Inventory control procedures must be in compliance
with paragraph (1)(B) of this subsection.
(ii) The SIR methodology as utilized by its provider
or vendor, or by its vendor-authorized franchisee or licensee or representative
must:
(I) analyze inventory control records in a manner which
can detect a release of 0.2 gallons per hour from any part of the
UST system; and
(II) use a threshold that does not exceed one-half
the minimum detectable leak rate.
(iii) The UST system owner and/or operator must take
appropriate steps to assure that they receive an analysis report from
the entity which actually performs the SIR analysis for the 30-day
period (either the SIR provider/vendor or the provider/vendor-authorized
franchisee or licensee or representative) in no more than 15 calendar
days following the last day of the 30-day period for which the analysis
is performed. This analysis report must, at minimum:
(I) state the name of the SIR provider/vendor and the
name and version of the SIR methodology which was utilized for the
analysis as they are listed in the independent third-party evaluation
of that methodology;
(II) state the name of the company and the individual
(or the name of the individual if no company affiliation) who performed
the analysis, if it was performed by a provider/vendor-authorized
franchisee or licensee or representative;
(III) state the name and address of the facility at
which analysis is performed and provide a description of each UST
system for which analysis has been performed;
(IV) state the date that the analysis was conducted;
(V) quantitatively state in gallons per hour for each
UST system being monitored: the leak threshold for the 30-day period
analyzed, and the minimum detectable leak rate for the 30-day period
analyzed, and the indicated leak rate for the 30-day period; and
(VI) qualitatively state one of the following for each
UST system being monitored: "pass," "fail," or "inconclusive."
(iv) Any UST system analysis report result other than "pass"
must be reported to the agency by the UST system owner or operator
as a suspected release in accordance with §334.72 of this title
(relating to Reporting of Suspected Releases).
Cont'd... |
