Code of Maine Rules › 06 - DEPARTMENT OF ENVIRONMENTAL PROTECTION › 096 - DEPARTMENT OF ENVIRONMENTAL PROTECTION - GENERAL › Chapter 695 - RULES FOR UNDERGROUND HAZARDOUS SUBSTANCE STORAGE FACILITIES › Appendix 096-695-B - Installation Requirements Applicable to New and Replacement Tanks

Current through 2024-29, July 17, 2024
1. Cathodically protected steel tanks must be
				set on a firm base and surrounded on all sides with at least 12 inches of
				noncorrosive inert material, such as clean sand, pea stone, or gravel, well
				tamped in place. The tanks shall be placed in the hole with care, making sure
				not to scrape the protective coating off coated tanks, or damage attached
				cathodic protection components. Cathodic protection systems require electrical
				wiring which is connected to the tank and shall be accessible for voltage
				readings at the ground surface as well as a location along the centerline of
				the tank to place a reference electrode in contact with the soil. If soil is to
				be covered by asphalt, concrete, or other materials then a test station must be
				installed over the center of the tank to provide access to the soil for
				cathodic protection monitoring.
NOTE: To facilitate future precision testing in the event
				  that a leak is indicated, the owner or operator may install access to tank
				  openings for vapor pocket removal, and a monitoring well to determine the
				  location of the water table.
2. Cathodically protected steel underground
				tanks shall be covered with a minimum of 2 feet of sand, pea stone or gravel or
				shall be covered with not less than 1 foot of sand on top of which shall be
				placed a slab of reinforced concrete not less than 4 inches thick. This fill
				shall be free of debris, boulders. large rocks or other materials, which may
				cause abrasions to the protective coating of the tank. When tanks are, or are
				likely to be, subjected to traffic, they shall be protected from damage from
				vehicles passing over them by at least 3 feet of backfill or, 18 inches of
				well-tamped backfill plus 6 inches of reinforced concrete of 8 inches or
				asphalt paving. When asphalt or reinforced concrete paving is used as part of
				the protection, it shall extend at least I foot horizontally beyond the
				perimeter of the tank in all directions.
3. All underground hazardous substance
				storage tanks shall be installed in accordance with the manufacturer's
				instructions. The minimum depth of cover shall be as specified in paragraph 2
				above.
4. New underground tanks
				shall be pneumatically tested for tightness in conformance with the
				requirements of Appendix C before being covered or placed in use. Alternative
				testing methods may be used if approved by the Department.
NOTE: Air pressure testing shall not be conducted after a
				  hazardous substance has been placed in the tank unless approved in writing by
				  the Department. Air pressure testing after certain hazardous substances have
				  been in contact with the tank may result in explosion of the tank.
5. All temporary supports must be
				removed prior to final backfilling.
6. All electrical wiring shall be performed
				in accordance with the current State of Maine electrical code.
7. Anchoring of tanks shall be required where
				tanks will be installed in areas where groundwater will be in contact with the
				tank. When anchoring tanks equipped with cathodic protection the hold downs
				must be electrically isolated from the tank. Anchoring of all tanks shall be
				performed in accordance with the tank manufacturer's specifications.
NOTE: Tank installation instructions may require specific
				  aggregate sized peastone or gravel. Instructions may also specify mechanical
				  compaction or layered placement of bedding and backfill. Always consult the
				  installation instructions provided by the manufacturer, prior to
				  installation.