Above Ground Tanks Frequently Asked Questions

FAQ Index


    What are the requirements for site drawings to accompany AST applications?

    The requirements of the drawings are as follows:

    • Physical location of tank on property
    • Distance from tank(s) to nearest building, property lines, nearest water way (river, stream, lake, etc) if less than 300 feet.
    • Distance between tanks if other tanks are located on the property or more than one tank is being installed. This includes liquefied petroleum gas tanks.
    • Fueling area location if the tanks are used for dispensing.

    If you have Tank drawings they are much appreciated as well.

    What types of aboveground storage tanks (ASTs) are regulated by the Office of the State Fire Marshal (OSFM)?

    ASTs containing flammable or combustible liquids are regulated by OSFM. The OSFM does not exercise jurisdiction over tanks containing liquids that are neither flammable nor combustible (e.g., tanks for water storage, food additives, nonflammable or noncombustible processing chemicals, etc.). Therefore, a product must have an associated flash point or fire point to be regulated in accordance with Part 160 or 180 of the Rules. Some products that may not appear to be volatile to the layperson, do indeed have flash points - such as fresh and waste motor oils, transmission fluids, antifreeze, etc. There are also many products that will not flash when subjected to testing, such as water and many food additives. Tanks containing liquids that do not have an associated flash point are not required to comply with Part 160 or 180 regulations.

    Do I need a permit for the installation of ASTs?

    YYes. The installation of ASTs requires the filing of a permit application with OSFM prior to installation. All storage tanks intended to be used for dispensing fuels are subject to application submittal and subsequent field inspection by OSFM. All bulk liquid storage tanks of greater than 110 gallons capacity are subject to the submittal and field inspection process. 

    Do I need a permit if I am replacing an existing AST with another AST or relocating an existing AST on the same property?

    Yes. Whenever a different tank is being introduced to a site, regardless of whether an AST already existed at the site, a permit application must be filed with OSFM. When a tank is being relocated on the same property, a permit application must also be submitted for approval. This is necessary to ensure that the relocation remains in compliance with applicable separation distances prescribed by codes.

    Is there a fee associated with the installation of an AST?

    No, not at this time. OSFM does not impose a fee for the review of AST permit applications or for the field inspection that is conducted to approve the installation.

    Is there a list available of all registered ASTs in Illinois?

    No. Unlike USTs, there are no requirement for the registration of ASTs. The OSFM does not maintain a database of ASTs installed in Illinois.

    Do Illinois rules address different types of ASTs?

    Yes. Illinois has established separate administrative rules for ASTs intended to be used for dispensing fuel into motor vehicles as opposed to those used for bulk storage purposes. 

    Is the permit application for an aboveground dispensing tank also used for an aboveground bulk storage tank?

    No. Although the permit applications appear similar, they are different and distinct applications for applying to install a bulk tank versus a dispensing tank. If the wrong application is received, it will be returned with a blank copy of the correct permit application.

    Does the Illinois OSFM allow installation in accordance with NFPA #30 or NFPA #30A for flammable or combustible liquid storage tanks?

    No. The OSFM has not adopted NFPA 30 or NFPA 30A for AST installations in Illinois. Although the applicable Illinois Administrative Code sections do reference specific some sections of NFPA 30 the rules do not adopt this NFPA standard in its entirety. AST installations that are designed in accordance with nationally recognized model codes, including NFPA 30, may not comply with Illinois' regulations that are often times more stringent than NFPA 30 and NFPA 30A. 

    What do plan reviewers look for when reviewing an AST permit application?

    Whether the permit application and plan pertains to an aboveground bulk or dispensing tank, plan reviewers examine the permit application for compliance with applicable codes. Primary criteria verified by the reviewers include:

    • Adherence to separation distance requirements to property lines, buildings and other tanks
    • Provisions for electrical grounding of the tank
    • The capacity of the tank(s) is within the maximum allowable limits
    • The number of tanks at the facility is within allowable limits
    • The presence and capacity of normal venting
    • The presence and capacity of emergency venting 
    • The tank(s) to be installed are labeled/listed tanks 
    • The material of tank construction
    • The method of secondary containment for the tanks(s) The presence and method of collision protection
    • The fire rating of adjacent building walls or interior storage rooms (if applicable)
    • Listed and labeled dispensing devices are to be installed (for dispensing tanks) Presence of documentation verifying the condition of used tanks
    • Nearby electrical equipment installations are code compliant

    How many aboveground tanks am I allowed to install at my facility?

    For dispensing ASTs, the aggregate total gallons of fuel stored at one facility to 12,000 gallons regardless of the number of containers. For bulk tanks, the number of tanks is not limited, but what usually limits the number of tanks on a property are the tank-to-tank and tank-to-property line separation distance requirements, which increase as the volume of the storage tank increases.

    Is there a limit on the size/capacity of aboveground tanks?

     For dispensing ASTs, the aggregate total gallons of fuel stored at one facility to 12,000 gallons regardless of the number of containers. For bulk tanks, the number of tanks is not limited, but what usually limits the number of tanks on a property are the tank-to-tank and tank-to-property line separation distance requirements, which increase as the volume of the storage tank increases.

    Are all aboveground tanks required to be equipped with secondary containment?

    The OSFM currently requires all flammable and combustible liquid storage tanks other than Class IIIB liquid storage tanks to be provided with secondary containment regardless of the capacity of the tank.

    What are the allowable means of secondary containment recognized by the OSFM?

    The OSFM currently accepts the following as methods of secondary containment for regulated ASTs: concrete dikes, earthen dikes, steel catch pans, double-walled tanks, concrete encased tanks, vaulted tanks, sealed room enclosures with raised door sills and remote impounding.

    Are cinder blocks an acceptable method of secondary containment?

    No, not by themselves. Cinder blocks are porous, and flammable or combustible liquids will leach through the material. If cinder blocks are used as a method of secondary containment, a lining material or sealant must be applied.

    What is the required capacity of secondary containment dikes or pans?

    The secondary containment area must be able to contain the capacity of at least the largest tank contained within the secondary containment area. It is not required that the secondary containment area be able to hold the total capacity of all tanks contained within a dike.

    Are steel or concrete secondary containment installations allowed to be equipped with a drainpipe?

    Yes. The OSFM will allow this as a method of removing rainwater from the secondary containment area of small dikes or steel pans. However, three conditions apply:

    • The piping must be equipped with a lockable valve that is kept locked in the closed position and only under the control of responsible personnel at the facility.
    • The opening created when the pipe passes through the secondary containment wall must be sealed with appropriate material that will resist the passage of product to the outside of the containment area.
    • Only one such penetration is allowed per secondary containment area.

    Are there any relaxation of the rules for Class III-B liquids storage tanks?

    Yes. See this link.

    Addendum A for Class IIIB liquids.

    In some cases, the rules differ if the stored liquid is a Class III-B Combustible Liquid. How is it determined if a liquid is a flammable or combustible liquid, and how is the class of a liquid determined?

    Liquids are classified as flammable, combustible, or not regulated by the OSFM, based upon their flash point. Liquids that do not exhibit a flash point when tested are not regulated by the OSFM under Parts 160 or 180. Liquids that do exhibit a flash point, no matter how high, are regulated and classified as follows:

    ClassificationFlash Point (° F)
    Flammable LiquidLess than 100

    Combustible Liquid
    Flash Point (° F)
    Class IIAt or above 100 and below 140
    Class III-AAt or above 140 and below 200
    Class III-BAbove 200

    How does the OSFM classify Waste Oil collected at public collection sites.

    See this link 

    Addendum A for Class IIIB liquids

    Part 160 rules require that concrete dikes have footings located below the frost line. Is this required on all concrete dikes?

    No. The OSFM has not been requiring such deep-poured footings on concrete dikes that surround relatively small installations. 

    What are the U.L. standards applicable to ASTs?

    The applicable standards are:

    • UL 142 Aboveground Steel Storage Tanks for Flammable and Combustible Liquids
    • UL 2080 Fire Resistant Aboveground Tanks for Flammable and Combustible Liquids
    • UL 2085 Protected Aboveground Tanks for Flammable and Combustible Liquids
    • UL 2244 Tank Systems
    • UL 2245 Vaulted Tanks
    • UL 2258-Nonmetallic Tanks for Oil Burner Fuels (permitted under limited conditions)

    What is the difference between U.L. Standard 2080 and 2085?

    UL 2080: "Fire Resistant Aboveground Tanks for Flammable and Combustible Liquids": this standard requires ASTs to withstand a two-hour fire test during which a single point temperature may reach 1000 ° F but the average tank temperature may not exceed 800 ° F.

    UL 2085: "Protected Aboveground Tanks for Flammable and Combustible Liquid": this standard covers tanks with insulated secondary containment and requires tanks to withstand a four-hour fire test of 2000 ° F during which no single point temperature may exceed 400 ° F.

    What conditions permit the use of UL 2258 tanks?

    • UL 2258 tanks can only be used for the storage of IIIB liquids
    • UL 2258 tanks are limited to 60-660 gallons in size
    • If UL 2258 tanks are used for DIY collection of waste oils, the OSFM policy related to classification of waste oils applies.

    If an AST is protected or fire resistant can it be placed closer than normally required to buildings, property lines and other tanks?

    Yes. If a tank is listed as fire resistant (as indicated by compliance with U.L. Standard 2080 or an equivalent) or protected (as indicated by compliance with U.L. Standard 2085 or an equivalent), it may be placed directly adjacent to a building, a property line, or other tank. However, for dispensing tanks, any vehicle being fueled from the tank must still maintain a 30-foot separation distance to all buildings, property lines and other tanks. (Therefore, the dispensing hose must be of sufficient length in order to allow the vehicle being fueled to be placed 30 feet from any buildings, property lines or tanks).

    The rules require a noncombustible base for ASTs. Does this mean that a concrete pad must be poured below all tanks?

    No. Paved or gravel surfaces will suffice. Furthermore, skid type tanks may be placed virtually on any surface if the ground is solid and relatively level. Regardless of the material of the base, the area must be kept free from vegetation and other combustible material.

    Must all wiring within 30 feet of an aboveground fuel-dispensing tank be in conduit?

    Yes. Not only wiring that supplies the dispensing unit, but also all wiring within 30 feet.

    Part 160 rules require a 5 ft minimum separation distance between tanks regardless of capacity. How strictly is this enforced and are there exceptions?

    The OSFM does not require the 5-foot separation distance for Class IIIB tanks. OSFM permits tank separation to be reduced to 3 ft based on NFPA 30 requirements.

    Part 180 tank separations. 

    The tank separation distances for dispensing tanks must comply with the requirements of Part 160.

    Are tanks allowed to be multi-compartmented?

    Yes. Tanks can be subdivided as long as the total number of tanks, and total capacity limitations are followed. An aboveground tank that contains multiple compartments is considered a singular aboveground when applying the rules that restrict the number of aboveground tanks allowed per facility. For example, the rules now establish the aggregate amount of fuel that can be stored on any one site up to a maximum of 12,000 gallons total. Single or subdivided tanks are allowed as long as the aggregate quantity of liquid on site does not exceed 12,000 gallons.

    Can Fiberglass Reinforced Plastic (FRP) piping be used on ASTs?

    No, not if the FRP piping is located aboveground. FRP has a low melting temperature that makes it susceptible to failure when exposed to fire or high heat. Furthermore, FRP is subject to deterioration by some flammable and combustible liquids.

    Can a listed UST be installed as an AST?

    No, at least not unless the UST has also been evaluated and listed by U.L. as an aboveground liquid storage tank. While several manufacturers produce both USTs and ASTs, the OSFM is not aware of any singular tank that is listed for installation as either an UST or AST. USTs are designed to have backfill serve as an essential part of the structural support for the tank, especially the tank ends. Therefore, when an UST is installed aboveground, without the assistance of backfill to offer structural support, it is subject to failure. In addition, USTs are not designed with emergency venting because they are not subjected to fire/high heat conditions.

    Can a tank truck or railroad tank car be used as an AST?

    No, tank trucks and cars are not designed for permanent storage. Pipe and appurtenance openings are not always compatible with permanent storage tank needs. Furthermore, tank trucks and tank cars do not meet the UL listing requirements for ASTs. Illinois regulations prohibit off-loading directly from a tank car to a tank truck or other vehicle.

    What are the types of emergency venting devices?

    Methods of emergency venting include: pop-up devices, flip-up devices, loose-bolt manhole covers, weak roof-to-shell seams, and weak top design in vaulted tanks. It should also be remembered that on some smaller capacity tanks, the capacity/size of normal vent openings may be sufficient to service both normal and emergency vent purposes.

    Can regular (normal) venting serve as emergency venting if it is large enough?

    Yes. Part 160 rules reference NFPA 30 for determining the size/capacity of emergency venting. NFPA 30 allows all vent openings present on the storage tank (normal and emergency) to be credited when determining the available venting capacity for the tank. The required capacity of emergency venting is dependent upon the size of the storage tank. Larger tanks require more emergency venting capacity. 

    Must emergency vents for indoor tanks terminate outside of buildings?

    Yes. Part 160.90 of the bulk AST rules requires that emergency venting must be installed in accordance with NFPA 30. NFPA 30 in turn, requires that both normal and emergency venting terminate outside of a building, except when serving tanks that contain Class III-B liquids. 

    What is special about kerosene storage tanks?

    Kerosene tanks are addressed separately from other combustible liquid storage tanks within Section 180.20 d-f of the rules. Although kerosene is indeed a combustible liquid, it has long been treated differently in the OSFM rules. This section of the rules allow for the indoor storage and dispensing of kerosene in tanks of up to 60 gallons in capacity. Furthermore, outdoor aboveground kerosene storage tanks are allowed to be installed even at self-service retail gas stations, only eight feet from roadways. (Dispensing from an aboveground kerosene tank is not allowed to be by self- service but rather must be performed by an attendant at a self-service station.)

    What is special about airport dispensing tanks?

    Airport dispensing storage tanks are specifically addressed in Section 180.22. Unlike regular dispensing sites, airports are allowed to install two tanks of up to 10,000 gallons capacity each, for a total storage capacity of up to 20,000 gallons. However, with this increased capacity allowance comes several restrictions: 

    • The tanks must be fire-insulated, U.L. 2085 listed tanks
    • The tanks may only be used to dispense fuel into aircraft, not vehicles
    • The tanks must be equipped with overfill and spill prevention equipment
    • The installation of such tanks requires the approval of not only the OSFM, but also the Illinois Department of Transportation's Division of Aeronautics. The OSFM offers a special application for such airport tanks.

    What is special about marina dispensing tanks?

    Marina facility tanks that will be used to fuel boats and watercraft are further regulated beyond regular vehicular dispensing tanks because of their close proximity to waterways and the potential for high water/flotation problems. Marina dispensing tanks are required to be provided with double-walled piping with flexible fittings. Furthermore, emergency and manual shutoff means are required. Dispensing areas must be provided with spill containment means. Dispensing at marinas must be supervised by an attendant, meaning self-service is prohibited. The application must indicate that the tank will be provided with a method of anchoring to prevent tank flotation in the event of flooding.

    Are rainshields allowed on aboveground tanks?

    Yes, but rainshields cannot prevent methods of secondary containment from being effective and they cannot be constructed of combustible materials.

    What is the API?

    American Petroleum Institute. This is an organization made up of petroleum processors and equipment manufacturers. Similar to the National Fire Protection Association, the API develops and publishes standards relating to their industry. API 650 is referenced by Part 160 as the standard for the installation of field-erected ASTs.

    What is the STI?

    Steel Tank Institute. This is a trade organization made up of steel tank manufacturers. STI-P3 underground tank. This tank was one of the first to offer corrosion protection for underground installation. The S.T.I. organization developed the criteria for the manufacturer of the tank. The STI has developed standards for aboveground flammable liquid storage tanks.

    What have been the predominant sources of fires/accidents associated with aboveground flammable or combustible liquid storage tanks?

    There are two general reasons. Inadequately sized, or absence of, emergency venting and unattended delivery of product causing overfilling/spillage

    Can combustible/flammable liquids be stored inside a building?

    Yes. While the Part 160 rules do not adequately address the subject, the OSFM does allow indoor storage of flammable and combustible liquid storage tanks. Until rules can be modified to address the issue, the OSFM governs such installations by policy as well as the requirements found in the 2012 edition NFPA 30 (as referenced by OSFM's adoption of NFPA 101-2015) for storage in containers 110 gallons or less. Indoor storage tanks that are greater than 110 gallons must be separated from the remaining areas of the occupancy by 2-hour fire-rated construction or a fire resistant or protected AST must be used. Tanks must also be filled from, and vented to, the exterior of the building. Also, OSFM policy now allows relaxation of the rules specifically for Class IIIB combustible liquid storage tanks. (See link in FAQ above for link a list of relaxed requirements related to Class IIIB liquids.)

    If I am only installing a temporary (AST) must I submit an application to the OSFM?

    Not necessarily. The OSFM defines temporary for an AST installation as six months or less. ASTs that will be in place for less than six months are not required to file an application for installation with the OSFM, and the installation is not typically inspected by the agency. However, tank owners are cautioned that the absence of an application submittal or field inspection does not alleviate the need for owners to comply with applicable regulations.

    Are fuel dispensing tanks for farm use addressed any differently by the applicable AST rules?

    Yes. The Part 180 rules do address aboveground fuel dispensing storage tanks at farms differently than those located at other vehicle fleet locations. The rules allow for up to four aboveground fuel storage tanks for dispensing purposes to be located at a farm or agricultural facility (as opposed to the two aboveground fuel dispensing storage tanks allowed at other facilities). Furthermore, the rules for farm sites recognize relaxed standards that allow for gravity dispensing of fuel.

    Are other testing laboratories or listing organizations than Underwriters Laboratories recognized by the OSFM?

    Yes. There are other third party testing and product listing organizations that are recognized by the OSFM. For example, ASTs listed in accordance with the standards of Southwest Research Institute are acceptable as are tanks constructed in accordance with the standards of the Steel Tank Institute. Although ASTs manufactured in accordance with Underwriter's Laboratories standards are acceptable, it is not the intent of the agency to exclude the testing work conducted by other legitimate independent testing organizations.

    Can a previously used AST be installed?

    Yes. The applicable rules do not mandate that a new AST be installed. However, a used AST is subject to compliance with all of the rules and criteria applicable to a new AST (i.e., listed by a recognized testing agency, properly vented, provided with secondary containment, etc.). Furthermore, the OSFM requires that the tank owner or installer provide evidence that a used tank has been re-inspected or retested prior to installation.

    What if I have a previously existing AST that is not labeled or was not constructed to any recognized standard for flammable or combustible liquid storage tanks?

    It is the policy of the Office of the Illinois State Fire Marshal to allow the use of such tank only if one of the following two criteria are met:

    • The tank is recertified by a recognized listing organization; or
    • Documentation is submitted to the OSFM under the signature of an Illinois professional registered engineer (P.E.) with expertise and experience in the evaluation of storage tanks and/or tank construction materials, indicating that the design and construction integrity meets or exceeds a recognized listing standard for aboveground atmospheric storage tanks, and indicating in accordance with what standard the tank was evaluated. Furthermore, if tanks are relined, the documentation must indicate that the relining material is compatible with the contents to be stored in the tank.

    What is NFPA #58 and how does it apply to tank installation in Illinois?

    National Fire Protection Association Standard #58 is titled The LP Gas Code. The 2011 edition of the NFPA #58 standard has been adopted by the OSFM as the applicable rules for liquefied petroleum gas handling, use and storage. NFPA Standard #58 is adopted into 41 Illinois Administrative Code 200. This is the standard that is applied to LP-Gas tank installation in Illinois.

    If the OSFM approves an AST installation is an owner still obligated to comply with local regulations?

    Local regulators are allowed to apply zoning ordinances and requirements to AST installations. The OSFM often encounters installations that are approvable under the rules applied by the state, but not compliant with local regulations. Tank owners and installers are cautioned to ensure that their installation complies with all applicable rules - both state and local - before setting an AST.

    What is a vaulted AST?

    A vaulted tank is the term that was originally used to describe any tank that was surrounded in concrete and/or offered fire resistance beyond that of a bare steel tank. However, with advancements in the design and manufacturing of AST's in recent years, the term vaulted has taken on a different meaning. The industry now reserves the term vaulted for a tank that is installed in a below-grade concrete enclosure. Such tanks are classified as aboveground tanks by nationally recognized codes, and by the OSFM, despite the fact that they are actually installed below-grade. The enclosure containing the tanks, being the equivalent of a large concrete bathtub without a drain, allows visual inspection of the tanks, and does not allow leaking product to contact the surrounding earth. These vaults are not backfilled. (Backfilling the vault will essentially classify the installation as an underground tank site). There are strict rules within NFPA standards for such vaulted installations. The rules include provisions for forced ventilation of the vaulted enclosure, separation of the tanks within the vault,  and construction standards for vault tops. Although the NFPA rules on vaulted tanks have not been formally adopted in Illinois Administrative Code, the OSFM uses the NFPA rules as policy.  Vaulted tanks are listed by UL 2245.