C.M.R. 06, 096, ch. 691, app 096-691-B
1. Volumetric tank tightness testing for single-walled tanks
A. For all tanks without overfill and spill prevention equipment installed in accordance with section 5(B)(3) or 6(B)(3) and properly operating, all tests must be conducted by overfilling the tank at least to grade level. For tanks with operating overfill and spill prevention equipment meeting the requirements of this Chapter, tests may be conducted if the tank is at least 60 percent full, provided the test is in accordance with manufacturer protocols and with any limitations determined by independent testing in accordance with EPA approved protocols, or other protocols approved by a nationally recognized independent testing organization, including but not limited to the ASTM and the National Work Group on Leak Detection Evaluations.
B. All tests must take into consideration all variables which may affect the determination of a leak rate, including, but not limited to, temperature, pressure, external water table elevation, vapor pockets and tank end deformation.
C. External water table elevation must be verified via a tank back fill ground water observation well at the time of testing for each tank location. The observation well is to be installed in accordance with paragraph 6(C) of this appendix.
D. All tests must be performed in strict conformity to all of the testing equipment manufacturer's operating procedures, and the following standard protocols:
(1) Tests must not be conducted during a fluctuating ground water table;
(2) Height-to-volume conversion factors must be measured rather than calculated;
(3) The test must be conducted under nearly constant hydrostatic pressure; and
(4) If the tank is less than 95 percentfull during the volumetric test then the ullage space must also be tested using an appropriate tank tightness test method.
2. Non-volumetric tightness testing for single walled tanks
A. Non-volumetric and all other tank tightness tests must be performed in strict conformity to the manufacturer's protocols as used in the method's independent performance testing.
B. The ground water elevation must be measured at the time of testing via a ground water observation well installed in accordance with paragraph 6(C) of this appendix. If ground water is encountered in the observation well, a sample is to be taken and visually inspected for the presence of free product.
3. Tightness testing for single-walled piping
A. All pressurized product piping tests must be performed at 150 percent operating pressure, or if performed at a lower pressure, it must be able to obtain a leak rate equivalent or smaller than that determined by the piping test method's independent performance testing in accordance with EPA approved protocols.
B. All tests must be performed in strict conformity to all of the testing equipment manufacturer's standard operating procedures. In addition, the test must be run a minimum of one hour.
C. Tightness testing requirements for single-walled safe suction piping are considered to be met when a Maine Certified Underground Oil Storage Tank Installer or Inspector confirms in writing that each suction line is properly sloped back to the tank, and there is only one check valve in each line installed as close as practical to the pump.
4. Tightness testing of tanks and piping with secondary containment
For double walled tanks and piping, the integrity of both the inner and outer walls will be tested by testing the interstitial space rather than the primary containment. Tanks and piping with secondary containment shall be tested in accordance with sections 4 and 5 of the PEI Recommended Practice for Testing and Verification of Spill, Overfill, Leak Detection and Secondary Containment Equipment at UST Facilities, PEI 1200 or in accordance with protocols reviewed and approved by the Commissioner prior to use.
5. Tightness testing of containment sumps
Containment sumps will be tested by an alternative procedure approved by the Commissioner, or in accordance with testing procedures outlined in section 6 of the Petroleum Equipment Institute, Recommended Practices for Testing and Verification of Spill, Overfill, Leak Detection and Secondary Containment Equipment at UST Facilities, PEI 1200, or the manufacturer's instructions.
6. Other requirements
A. Testing technicians shall be certified by the manufacturer of the testing equipment.
B. The additional requirements of this paragraph apply to the testing of single-walled tanks used to store ethanol blended gasoline.
(1) Tightness tests must be conducted with 10 or less inches of product in the tank using a test method approved for use with such product levels; and
(2) The tank must be tested manually for water and phase-separated gasoline.
C. Ground water elevation observation well installation. The observation well to determine the elevation of ground water is to be installed in the sand, gravel or pea stone backfill of the tank excavation to a depth of one (1) to two (2) feet below the tank bottom in accordance with EPI Recommended Practice 100. The observation well is to be a minimum of 1 inch in diameter and may be installed using direct push technology. The well is to be constructed of factory screened PVC pipe. Well screening is to start 5 feet above the ground water table and extend to the bottom of the well. Wells are to be installed flush with the ground surface and in a raised, limited access road box. The annulus around the well must be sealed with bentonite or a similar sealing material from 2 feet above the screen upward to the bottom of the road box. Permeables and must be placed around the road box so that water can drain from the road box. A Maine Certified Underground Tank Installer must be present during the installation of the well to minimize the risk to the structural integrity of the facility.
D. Tank and piping tightness tests involving the removal and reinstallation of existing facility components, including but not limited to, leak detection or overfill prevention equipment, drop tubes, or vent valves, must have an Underground Oil Storage Tank Installer or Inspector present to supervise such facility equipment removals and repairs. The installer or inspector must be certified by BUSTI and by the manufacturer of the equipment being repaired, when such manufacturer certification is available. Tank testing involving excavation above, around or within 10 feet to tanks or piping also requires a Maine Certified Tank Installer to be present to supervise such excavation in accordance with section 5(D)(19) of this Chapter.
E. All test results must include the following information in order to be accepted by the Commissioner:
(1) Facility name, address, registration and tank number, and the product stored;
(2) Depth to ground water and whether free product was found in the ground water observation well;
(3) Whether the facility components tested passed or failed, and the measured leak rate;
(4) The method's threshold for declaring a leak; and
(5) Certification that the test method has been performed according to the manufacturer's protocols used in the third party evaluation, or a protocol for double-walled tanks approved by the Commissioner, and that ground water elevation was measured and taken into account in determining if a leak was present.
F. Written test results must be submitted to the Commissioner by the facility owner and the tester when conducted to verify evidence of a possible leak. Routine annual precision tests conducted to meet the requirements of section 5(C)(2)(a) or 5(F) of this Chapter need only to be submitted by the facility owner.
C.M.R. 06, 096, ch. 691, app 096-691-B