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Home > Plans Review Division > Above Ground Storage Tank Requirements

Above Ground Storage Tanks for Flammable or Combustible Liquids Safety Requirements

When a tank is to be removed from service, all residue must be removed by a licensed hazardous waste hauler, and the tank must be made vapor-free! (NFPA 30-2003, 4.6.4.1*)

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A permit is required for the installation. The permit must be obtained before any construction is started. (Title 25, M. R. S. A. §2482) Contact the State Fire Marshal's Office for more information on permit requirements. Applications are available online on the Applications Page. Plans to be submitted with the permit application for a facility with a total aggregate capacity greater than 1320 gallons must be certified by a professional engineer.

All tanks, piping, valves, and associated equipment must be listed for the use for which they are intended, and must be used according to their listing. (NFPA 30-2003, Ch 4)

Example: a tank listed for combustible liquids use CAN NOT be used as an aboveground tank for flammable liquids.

A tank or piping listed for underground use CAN NOT be used aboveground! (NFPA 30- 2003, 4.2.1.1)

(Listing is a certification from a recognized testing agency. The tank or equipment must show the listing on a label. (NFPA 30-2003, 3.2.5*))

The intended use of the facility will determine the code requirements that are applied. If the facility is intended to provide fuel for automobiles or boats to the public, NFPA 30-A-2003 Code for Motor Fuel Dispensing Facilities and Repair Garages will apply. If the facility is intended to provide fuel for your own equipment or vehicles, or if the facility is for bulk storage, NFPA 30-2003 Standards for Flammable and Combustible Liquids will be used. A facility permitted as a private fueling facility under NFPA 30 would have to be upgraded to meet the standards of NFPA 30-A before it could be used as a public fueling facility.

Flammable Liquids, also called Class I Liquids present a greater hazard than Combustible Liquids that may be Class II or Class III liquids. Some requirements may be less strict if the facility is for Combustible Liquids only. These terms are used frequently in the codes.

Examples of Flammable Liquids are gasoline and acetone. Examples of Class II Combustible Liquids are diesel fuel and kerosene. Examples of Class III flammable liquids are motor oil and hydraulic fluid.

(Contact the State Fire Marshal's Office for information regarding permits and requirements for public fueling facilities. (Title 25, M. R. S. A. §2482))

Tanks for motor fuel at public fueling facilities must be placed according to Table 4.3.2.4 State of Maine Minimum Separation Requirements for Aboveground Tanks. Tanks may be no less than:

  • 50 feet from the nearest important building
  • 50 feet from the nearest fuel dispensing device
  • 100 feet from the nearest property line that may be built upon
  • 50 feet from the nearest side of a public way.
  • There must be no less than 3 feet, and there may need to be more space between tanks.

(see above referenced table for special requirements)

An individual tank at a public fueling facility may be no more than 12,000 gallons. The total aggregate capacity of the facility may be no more than 48,000 gallons. (NFPA 30-A-2003, 4.3.2.3)

Tanks at private motor fuel facilities, bulk storage facilities, and for special equipment must be placed according to Table 4.3.2.1.1(b) State of Maine Reference Table…. Tanks of up to 30,000 gallons may be no less than:

  • 25 feet from the nearest property line that may be built upon
  • 25 feet from the nearest important building
  • 25 feet from the nearest side of a public way
  • 50 feet from dispensing device if tank is greater than 6000 gallons. No minimum from dispensing device if tank is 6000 gallons or less.

Secondary Containment must be provided for every tank. (NFPA 30-2003, 4.3.2.3). Secondary Containment may be a liquid tight dike with a capacity of 110% of the largest tank in the dike (NFPA 30-2003, 4.3.2.3.2). A "Secondary Containment" commonly called a "double wall" tank not more than 12,000 gallons nominal capacity (NFPA 30-2003, 4.3.2.3.3) meets this requirement.

Supports for tanks shall be of concrete (protect against corrosion), masonry, or protected steel (NFPA 30-2003, 4.3.2.1). Steel Support structures shall be protected by materials having a fire resistance rating of not less than 2 hours unless the support is a saddle no more than 12 inches high at the lowest point. (NFPA 30-2003, 4.3.1.3*)

Every tank must have a normal vent to prevent over-pressure or vacuum from damaging the tank when it is being filled or product is being withdrawn. (NFPA 30-2003, 4.2.5.1) The vent for a tank for Class I liquids must be normally closed (NFPA 30-2003, 4.2.5.1.6), and it must terminate no less than 12 feet above ground level. (NFPA 30-2003, 5.7.1.1)

Every tank, the interstitial space of a secondary containment tank, and each chamber of a multiple chamber tank must have emergency relief venting to prevent rupture of the tank or chamber if it is exposed to fire. (NFPA 30-2003, 4.2.5.2.1)

All piping must be liquid tight. Any piping that is leaking or seeping must be removed from service immediately until it is repaired. (NFPA 30-2003, 5.2.2)

Fill pipes that enter the top of a tank shall terminate within 6 inches of the bottom of the tank. They shall be installed to minimize vibration. (NFPA 30-2003, 4.3.2.5.4*)

Aboveground piping must be substantially supported and protected against physical damage (NFPA 30-2003, 5.5.1). Underground piping must be installed in compliance with Department of Environmental Protection regulations.

There are special requirements if the tank is in an area subject to flooding. (NFPA 30-2003, 4.3.2.6)

All tanks located where they are subject to vehicular impact must have collision protection. (NFPA 30-2003, 4.3.2.7)

All electrical wiring and equipment must be of the type specified by and installed in accordance with NFPA 70, National Electrical Code (NEC) (NFPA 30-2003, 8.2.1)

There are many extra requirements and other codes for a "Storage Tank Building." (NFPA 30-2003, 4.3.4) Discuss plans for any structure in the diked area or near tanks with the State Fire Marshal's Office.

Any structure at or over a tank (including cat walks) must be built of non-combustible materials (NFPA 30-2003, 4.3.2.3.4.5)

An emergency action plan to respond to fires or other emergencies (leaks), consistent with available equipment and personnel, shall be established (NFPA 30-2003, 4.5.6.1). Planning for effective fire control measures shall be coordinated with local emergency response agencies. (NFPA 30-2003, 4.5.6.3)

All tanks must have a method to prevent overfilling (NFPA 30-2003, 4.6.1.5). A mechanism that blocks the normal vent or emergency vent CANNOT be used. (NFPA 30-2003, 4.6.5.3)

Secondary containment tanks require an audible alarm that will sound at 90% of capacity, and will stop the flow of product at 95% of the tank capacity. (NFPA 30-2003, 4.3.2.3.3 (5))

Each tank shall be marked to show the product stored in the tank (example: gasoline) and the hazard (example: Flammable) (Diesel, Combustible; Kerosene, Combustible) (NFPA 30-2003, 4.6.2.1). The area surrounding the tanks shall be marked with "No Smoking" signs (NFPA 30-2003, 4.5.3.1)

Underground piping must comply with Maine Department of Environmental Protection regulations. (Title 38 M.R. S. A. §3)

Facilities with an aggregate capacity of greater than 1320 gallons must comply with the Federal Environmental Protection Agency Spill Prevention Control & Countermeasures Plan requirements. (40 CFR 112)