§ 245.523. Aboveground storage tanks in underground vaults.
The following requirements shall be met when an owner or operator chooses to install an aboveground storage tank in an underground vault:
(1) The vault shall completely enclose the aboveground storage tank. There may be no openings in the vault enclosure except those necessary for access to, inspection of, and filling, emptying and venting of the tank. The walls and floor of the vault must be constructed of reinforced concrete at least 6 inches thick. The top, walls and floor shall be designed to withstand the anticipated loading, including loading from traffic, soil and groundwater.
(2) The vault must be compatible with the stored substance and have a permeability of less than 1 x 10-7 cm/sec for substance stored and be water tight.
(3) An aboveground storage tank must be in its own vault. Adjacent vaults may share a common wall.
(4) There may be no backfill around the aboveground storage tank and there shall be sufficient space between the tank and the vault to allow inspection of the tank and ancillary equipment.
(5) Vaults and aboveground storage tanks must be suitably anchored to withstand uplifting by either water or released substance, including when the tank is empty.
(6) Connections shall be provided to permit venting of each vault to dilute, disperse and remove vapors prior to personnel entering the vault.
(7) A vault must be equipped with a continuous leak detection system capable of detecting vapors and liquids including water. The detection system must activate an alarm that automatically shuts down the dispensing system if vapors or liquids are detected.
(8) A vault must have a means for personnel entry. The entry point must have a warning sign indicating the need for procedures for safe entry into a confined space. An entry point must be secured against unauthorized entry and vandalism.
(9) A suitable means to admit a fire suppression agent shall be provided for each vault.
(10) Aboveground storage tanks and ancillary equipment shall be installed, maintained and inspected in accordance with the requirements for aboveground storage tanks in this subchapter.
(11) Underground piping distribution systems for each aboveground storage tank system used to dispense class I or class II motor fuels for resale must be provided with release detection equivalent to underground piping release detection addressed in § 245.445 (relating to methods of release detection for piping) and monitored as required in paragraph (7) with monitoring records retained for 12 months as required under § 245.516 (relating to recordkeeping requirements).
Source The provisions of this § 245.523 amended November 9, 2007, effective November 10, 2007, 37 Pa.B. 5979; amended December 21, 2018, effective December 22, 2018, 48 Pa.B. 7875. Immediately preceding text appears at serial pages (331102) to (331103).
Cross References This section cited in 25 Pa. Code § 245.513 (relating to preventive maintenance and housekeeping requirements).
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