| (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).
(v) Any UST system analysis report result of "inconclusive"
which has not been investigated and quantified as a "pass"
(in the form of a replacement UST system analysis report meeting the
requirements of clause (iii) of this subparagraph) must be reported
to the agency as a suspected release within 72 hours of the time of
receipt of the inconclusive analysis report result by the UST system
owner or operator.
(B) At least once per calendar quarter, the SIR provider/vendor
must select at random, at least one of the individual UST system analyses
performed by each of its authorized franchisees or licensees or representatives
during that period and audit that analysis to assure that provider/vendor
standards are being maintained with regard to the acceptability of
inventory control record data, the acceptability of analysis procedures,
and the accuracy of analysis results. The written result of that audit
must be provided to the authorized franchisee or licensee or representative
and to the owner and/or operator of the audited UST system(s) by the
SIR provider/vendor during that calendar quarter. In addition, within
30 days following each calendar quarter, the SIR provider/vendor must
provide to the agency a list containing the name and address of each
of its authorized franchisees or licensees or representatives which
specifies for each one, the name and address of each facility at which
one or more UST system audits were performed during the previous calendar
quarter.
(10) Alternative release detection method. Any other
release detection method, or combination of methods, may be used if
such method has been reviewed and determined by the agency to be capable
of detecting a release from any portion of the UST system in a manner
that is no less protective of human health and safety and the environment
than the methods described in paragraphs (2) - (9) of this subsection,
in accordance with the provisions of §334.43 of this title (relating
to Variances and Alternative Procedures).
(e) Release detection records.
(1) Owners and operators shall maintain the release
detection records required in this subsection in accordance with the
requirements in §334.10(b) of this title (relating to Reporting
and Recordkeeping).
(2) Owners and operators shall maintain records adequate
to demonstrate compliance with the release detection requirements
in this section, and in accordance with the following minimum requirements.
(A) All appropriate installation records related to
the release detection system, as listed in §334.46(i) of this
title, shall be maintained for as long as the release detection system
is used.
(B) All written performance claims pertaining to any
release detection system used, and documentation of the manner in
which such claims have been justified, verified, or tested by the
equipment manufacturer, methodology provider/vendor, or independent
third-party evaluator shall be maintained for as long as the release
detection system is used.
(C) Records of the results of all manual and/or automatic
methods of sampling, testing, or monitoring for releases (including
tank tightness tests) shall be maintained for at least five years
after the sampling, testing, or monitoring is conducted.
(D) Records and calculations related to inventory control
reconciliation shall be maintained for at least five years from the
date of reconciliation.
(E) Written documentation of all service, calibration,
maintenance, and repair of release detection equipment permanently
located on-site shall be maintained for at least five years after
the work is completed. Any schedules of required calibration and maintenance
provided by the release detection equipment manufacturer shall be
retained for as long as the release detection system is used.
(F) Records of site assessments required under subsection
(d)(5) and (6) of this section (concerning vapor monitoring and groundwater
monitoring) must be maintained for as long as the methods are used.
Records of site assessments must be signed by a professional engineer
or professional geologist, or equivalent licensed professional with
experience in environmental engineering, hydrogeology, or another
relevant technical discipline acceptable to the agency.
|
| Source Note: The provisions of this §334.50 adopted to be effective September 29, 1989, 14 TexReg 4714; amended to be effective June 25, 1990, 15 TexReg 3424; amended to be effective November 23, 2000, 25 TexReg 11442; amended to be effective April 2, 2002, 27 TexReg 2522; amended to be effective November 18, 2004, 29 TexReg 10532; amended to be effective October 30, 2008, 33 TexReg 8790; amended to be effective March 17, 2011, 36 TexReg 1675; amended to be effective May 31, 2018, 43 TexReg 3390 |
