New Mexico Administrative Code
Title 20 - ENVIRONMENTAL PROTECTION
Chapter 5 - PETROLEUM STORAGE TANKS
Part 109 - NEW AND UPGRADED ABOVE GROUND STORAGE TANK SYSTEMS: DESIGN, CONSTRUCTION, AND INSTALLATION
Section 20.5.109.912 - VAULTS

Universal Citation: 20 NM Admin Code 20.5.109.912

Current through Register Vol. 35, No. 6, March 26, 2024

A. Owners and operators shall provide project drawings for and install new AST systems which include vaults in accordance with the following requirements:

(1) A vault must completely enclose each tank, with no openings in the vault enclosure except those necessary for access to, inspection of, and filling, emptying, and venting of the tank. Each tank shall be enclosed in its own vault, although adjacent vaults may share a common wall. However, for good cause shown, the department, in its sole discretion, may grant a variance from the one-tank-one-vault requirement, for existing tanks only, if owners and operators demonstrate that the variance will provide equivalent protection of health, safety and welfare and the environment.

(2) Every vault shall be liquid tight or sealed with no backfill around the tank. If a vault is constructed of concrete, owners and operators shall ensure it meets the requirements of Subsection B of 20.5.109.904 NMAC.

(3) There shall be adequate space between the tank and the vault for inspection of the tanks and its appurtenances.

(4) Above-grade vaults shall be resistant to damage from the impact of a motor vehicle, or suitable collision barriers shall be installed.

(5) A vault shall include connections to permit venting of each vault to dilute, disperse, and remove any vapors prior to personnel entering the vault.

(6) A vault shall be equipped with a detection system capable of detecting liquids, including water, and capable of activating an audible alarm.

(7) A vault shall include a means for recovering liquid from the vault.
(a) If a pump is used to meet this requirement, it shall not be permanently installed in the vault.

(b) Electric-powered portable pumps shall meet the requirements of the current edition of an industry standard or code of practice developed by a nationally recognized association or independent testing laboratory approved in advance by the department.

(c) National Fire Protection Association Standard 70, "National Electrical Code" shall be used to comply with the requirements of this paragraph.

B. Vault construction. Owners and operators shall design and construct:

(1) the walls and floor of a vault of reinforced concrete at least six inches thick;

(2) the top of an above-grade vault of noncombustible material, and shall design and construct the top:
(a) to be weaker than the walls of the vault, to ensure that the thrust of any explosion occurring inside the vault is directed upward before significantly high pressure can develop within the vault; and

(b) to safely relieve or contain the force of any explosion occurring inside the vault.

(3) the top and floor of the vault and the tank foundation to withstand the anticipated loading, including loading from vehicular traffic, where applicable; and

(4) the walls and floor of any vault installed below grade in compliance with good engineering practice to withstand anticipated soil and hydrostatic loading.

C. All tanks, piping and other associated equipment in the interior of a vault shall meet the requirements of the current edition of an industry standard or code of practice developed by a nationally recognized association or independent testing laboratory approved in advance by the department. One of the following shall be used to comply with this requirement:

(1) National Fire Protection Association Standard 70, "National Electrical Code"; or

(2) Underwriters Laboratories 2245, "Standard for Below-Grade Vaults for Flammable Liquid Storage Tanks".

D. Venting of vaults.

(1) Vent pipes that are provided for normal tank venting shall extend at least 12 feet above ground level.

(2) Emergency vents shall be vapor tight and may be permitted to discharge inside the vault.

(3) Owners and operators shall not use long-bolt manhole covers for this purpose.

(4) Owners and operators shall ensure that all vault vents meet the requirements of the current edition of an industry standard or code of practice developed by a nationally recognized association or independent testing laboratory approved in advance by the department. The following shall be used to comply with this requirement: National Fire Protection Association Standard 91, "Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids".

E. Vault entry.

(1) A vault shall include a method of personnel entry.

(2) Owners and operators shall post a warning sign indicating procedures for safe entry at each entry point.

(3) Owners and operators shall secure each entry point against unauthorized entry and vandalism.

(4) Owners and operators shall provide each vault with a suitable means for admission of a fire suppression agent.

Disclaimer: These regulations may not be the most recent version. New Mexico may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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