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FAQ's

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

Answer: 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.


Question: Do I need a permit for the installation of ASTs?

Answer: Yes. The installation of regulated tanks (flammable or combustible liquid storage tanks or LP-Gas tanks) 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. For LP-Gas tanks, singular tanks of greater than 2,000 gallons capacity, or multiple tanks at the same facility with an aggregate capacity of greater than 4,000 gallons, or any size tank that will be used for dispensing LP-Gas into smaller cylinders or vehicles, are subject to the OSFM permit application and field inspection process.


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

Answer: 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 (to ensure that the relocation remains in compliance with applicable separation distances prescribed by codes).


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

Answer: No, not at this time. Unlike the Underground Storage Tank (UST) Program, OSFM does not impose a fee for the review of AST permit applications or the field inspection that is conducted upon installation.


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

Answer: No. It must be realized that only new installations (or relocations) of ASTs are required to complete a permit application. At this time, there is not a requirement for all existing ASTs to be registered with OSFM. Therefore, no comprehensive list of ASTs in the state is available.


Question: What is the approximate turn-around time for AST Installation Permits?

Answer: Typically, AST permit applications are reviewed and corresponding documentation of findings are returned to the applicant within one week to 10 days of application receipt by the agency.


Question: Do Illinois rules address different types of ASTs?

Answer: 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. Furthermore, tanks containing liquefied petroleum gas (i.e., propane, butane, etc.) are addressed by yet another separate section of the Illinois Administrative Code.


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

Answer: 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. Likewise, there is a separate and distinct permit application for the installation of a LP-Gas tank.


Question: Does the Illinois OSFM allow installation in accordance with the National Fire Protection Association (NFPA) Standard #30 for flammable or combustible liquid storage tanks?

Answer: No. The OSFM has not adopted NFPA Standard #30 for AST installations in Illinois. Although the applicable Illinois Administrative Code sections do reference specific sections of NFPA #30 (e.g., for certain definitions and venting requirements) the rules do not adopt the 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' code. (A common mistake made by designers and installers is to space ASTs too close to each other or too close to adjacent property lines and buildings because NFPA #30 has less stringent distance separation requirements that the code adopted and enforced by the OSFM).


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

Answer: Whether the permit application and plan pertains to an aboveground bulk or dispensing tank, or a LP-Gas 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)
  • Either fencing or other forms of tamper protection are present (for LP-Gas tanks) 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


Question: How are liquefied petroleum gas tanks classified for application procedures and rule enforcement in Illinois?

Answer: LP-Gas tanks are addressed separately from either fuel dispensing or bulk storage flammable and combustible liquid storage tanks. Liquefied Petroleum Gas (LPG), meaning that the product is stored as a liquid under pressure in the tank, but at normal pressures and temperatures, the product is a gas. Therefore, different rules apply (Title 41 IL Adm. Code Part 200). In addition, there is a separate permit application for the installation of a LP-Gas tank.


Question: If a LP-Gas tank is installed underground or mounded in earth who has jurisdiction over the tank and what rules/applications apply?

Answer: LP-Gas tanks, whether installed above or below ground, are still considered LP-Gas tanks by the OSFM and NOT an Underground Storage Tanks. Therefore, underground LP-Gas tanks, although required to undergo the OSFM's application and field inspection process upon installation or relocation, and being subject to Ill. Adm. Code 200 rule requirements, are not required to be registered or pay annual fees under the OSFM's UST regulatory program. (NFPA Standard #58 does contain special rules when a LP-Gas tank is installed underground or under a mound of earth).


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

Answer: The answer to this question depends upon the purpose for which the tank will be used. The rules allow a maximum of two aboveground flammable or combustible liquid storage tanks per facility if fuel is going to be dispensed into vehicles from the tanks. (The rules also allow that if the installation is a farm, four aboveground storage tanks may be installed). For bulk storage tanks (those that will not have product dispensed directly into the fuel tank of a vehicle from the tank) there is no limit on the number of ASTs that may be installed, however tank-to-tank and tank-to-property line separation distance requirements, which increase as the volume of the storage tank increases, may limit the number of tanks that can fit on a site.


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

Answer: Similar to the answer to the question above, this depends upon the purpose of which the tank will be used. The rules limit the capacity of a tank intended for dispensing fuel into vehicles to 2,500 gallons. (Because only two aboveground dispensing tanks area allowed, this limits the total fuel capacity at the facility to 5,000 gallons). Even though farm sites are allowed to have up to four aboveground dispensing storage tanks, they are also limited to a maximum of 2,500 gallons capacity each, and no one product can constitute more than 5,000 gallons of the total storage at the site. For dispensing storage tanks located at airport facilities and used only to fuel aircraft, the capacity is allowed to increase to 10,000 gallons per tank. Similarly, at mining and coal-fired electrical generation facilities, ASTs that are used to store specifically diesel fuel for off-road equipment are allowed to have capacities of up to 12,000 gallons. For bulk storage tanks (not used to dispense fuel directly into the fuel tanks of vehicles) there is no limit on the size or capacity of an AST, however, the rules prescribe tank-to-tank and tank-to-property line separation distance requirements, which increase as the volume of the storage tank increases.


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

Answer: 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.


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

Answer: 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 doorsills and remote impounding.


Question: Are cinder blocks an acceptable method of secondary containment?

Answer: 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.


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

Answer: 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).


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

Answer: 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.


Question: Are there any relaxation of the rules for Class IIIB liquids storage tanks?

Answer: Yes. In consideration of the absence of fire history related to the storage of Class IIIB liquids along with an examination of the nationally-recognized standard for the storage of flammable and combustible liquids - National Fire Protection Association (NFPA) Standard #30 the OSFM now, by policy, modifies the applicable rules for the regulation of Class IIIB combustible liquids in aboveground storage tanks. Aboveground storage tanks for Class IIIB combustible liquids are now granted the following exceptions to the requirements set forth in Title 41 Illinois Administrative Code Part 160 "Storage, Transportation, Sale and Use of Gasoline and Volatile Oils: Rule and Regulations Relating to General Storage":

  • Aboveground Class IIIB liquids are not required to be equipped with secondary containment. Aboveground Class IIIB liquid storage tanks are not required to be electrically grounded.
  • Aboveground Class IIIB liquid storage tanks are required to be separated from combustible material by a minimum separation distance of 5 ft.
  • Aboveground Class IIIB liquid storage tanks of less than 12,000 gallons are required to be separated from buildings, property lines that are, or can be, built upon and from any public way by only 5 feet.
  • Aboveground Class IIIB liquid storage tanks are required to be separated by only 3 ft. from other tanks storing Class IIIB liquids. (Tank-to-tank separation distances from Part 160 rules would continue to apply if the adjacent tank is other than a Class IIIB liquid storage tank).
  • Aboveground indoor Class IIIB liquid storage tanks are not required to be physically separated from other areas of an occupancy by fire rated barriers or by fire-rated tank design (regardless of occupancy classification). Aboveground indoor Class IIIB liquid storage tanks are not required to have vent piping extend to outside the building enclosure.
  • Aboveground indoor Class IIIB liquid storage tanks are not required to be filled or emptied from connections located outside the building.
  • Aboveground indoor Class IIIB liquid storage tanks are allowed to be located in the basement of buildings. Aboveground indoor Class IIIB liquid storage tanks are allowed to be located in buildings of combustible construction.
Aboveground Class IIIB liquid storage tanks continue to be required to:
  • Complete and submit an OSFM "bulk storage" AST application and undergo field inspection processes for new or relocated tank installations;
  • Comply with UL listing requirements appropriate for the aboveground storage of combustible liquids;
  • Be provided with proper regular and emergency venting applicable to the AST;
  • Comply with collision protection requirements;
  • Have any attached product piping testing upon installation in accordance with Part 160 rule requirements;
  • Have each connection below normal liquid level through which liquid can normally flow equipped with an internal or external valve located as close as practical to the shell of the tank.


Question: 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?

Answer: 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 are regulated and sub-classified as follows:

Classification Flash Point (°F)
Flammable Liquid Less than 100
Combustible Liquid  
Class II At or above 100 and below 140
Class III-A At or above 140 and below 200
Class III-B Above 200


Question: What class of liquid is Waste Oil? Diesel Fuel? Gasoline?

Answer: Waste oil is normally considered a Class III-B combustible liquid by the OSFM. (Although please see Q#21 which addresses public waste oil collection sites). As a Class IIIB combustible liquid, it is subject to several relaxed requirements (e.g., absence of secondary containment, less restrictive tank-to-tank and tank-to-property separation distances, not being required to be filled from or vented to the exterior of a building, etc.). Gasoline, with a flash point well below 100°F, is classified as a Class I Flammable liquid. Diesel fuel, commonly having a flash point range of 105-120°F is classified as a Class II combustible liquid.


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

Answer: Facilities that allow the public to drop off or deposit waste oil into their aboveground storage tanks may be subject to having the contents of the tank regulated as other than a Class IIIB combustible liquid (and thereby losing several of the relaxed restrictions that are allowed by the OSFM for Class IIIB liquid storage tanks). The OSFM has concerns regarding the contents of liquids being deposited by the public and specifically about the possibility that the liquids being deposited may not contain only waste motor oil but may also contain flammable liquids that will lower the flash point of the overall AST contents and thus make it more volatile. However, the OSFM also recognizes the existence of programs that impose specific requirements for accepting public waste oil and ensuring the contents of the storage tank to remain as Class IIIB. Therefore, the OSFM will consider public waste oil collection tanks as Class IIIB combustible liquid storage tanks if:

  • Acceptable products for deposit are limited to waste motor oil, waste transmission fluid, waste hydraulic fluid. The aboveground waste oil collection tanks are not accessible to the general public during times that an attendant/employee is not present to monitor the liquids being placed in the AST.
  • Visual examination of the liquid to be deposited in the AST is conducted by an attendant/employee of retail occupancy accepting the product (this is primarily to check for separation of product - oil does not separate).
  • A written log is maintained to indicate the name and address of the person depositing waste oil products into the AST.
  • Tanks are marked with signage that indicates "Used Oil Only". Customers are limited to depositing no more than 5 gallons per visit.
  • A program approved by the OSFM is in place either by the vendor where the AST is located or by the company that collects product from the AST to conduct periodic testing of deposited liquids to ensure that the flash point is greater than 200° F (and thus qualifies as a Class IIIB liquid). Records of these periodic tests must be maintained for the past year of operation and be available for submittal to the OSFM if requested.


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

Answer: No. The OSFM has not been requiring such deep-poured footings on concrete dikes that surround relatively small installations. Plan reviewers will note the need to have dike footings installed below the frost line if necessary.


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

Answer: The applicable standards are:

  • U.L. 142 Aboveground Steel Storage Tanks for Flammable and Combustible Liquids
  • U.L. 2080 Fire Resistant Aboveground Tanks for Flammable and Combustible Liquids
  • U.L. 2085 Protected Aboveground Tanks for Flammable and Combustible Liquids
  • U.L. 2245 Vaulted Tanks U.L. U.L. 2244 Tank Systems


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

Answer: U.L. 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.

U.L. 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.


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

Answer: 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).


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

Answer: 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.


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

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


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

Answer: The OSFM does not require the 5-foot separation distance for smaller capacity tanks, such as waste or fresh motor oil tanks under 1,000 gallons capacity. It should be noted that NFPA Standard #30 requires only 3-foot separation distances, even for large volume storage tanks. It has been the policy of the office to allow the 3-foot separation distance allowed by NFPA #30, if the entire project complies with other NFPA #30 requirements, and if the local fire department indicates no objection to such tank-to-tank spacing. (Such alternatives are usually reserved for the re-installation of tanks at existing tank sites where the pads are already in-place).


Question: Are tanks allowed to be multi-compartmented?

Answer: 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 restrict the number of aboveground fuel dispensing storage tanks to two tanks of up to 2,500 gallons capacity at a facility. The installation of two dual- compartmented tanks containing 1,500 gallons of diesel fuel and 1,000 gallons of gasoline in each tank would be within the rules and would count as a total of two ASTs, not four ASTs.


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

Answer: 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.


Question: Can a listed UST be installed as an AST?

Answer: 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.


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

Answer: 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 are not U.L. listed ASTs. The State Administrative Rules prohibit off-loading directly from a tank car to a tank truck or other vehicle.


Question: What are the types of emergency venting devices?

Answer: 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).


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

Answer: Yes. Part 160 rules reference NFPA Standard #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 (with larger tanks requiring more emergency venting capacity). This results in smaller tanks sometimes being able to comply with emergency venting requirement simply by the size of the normal vent piping placed on the tank. Essentially, the code is recognizing that the venting capacity offered by the normal vent that is designed to allow the tanks to breathe during filling or off-loading operations, is sufficient to provide venting of vapors under emergency conditions. Caution should be used however when installing an aboveground tank installation that does not present an emergency vent, separate from the normal vent. While indeed this may be a legitimate arrangement, the owner should ensure that normal venting is sufficient to serve as emergency venting.


Question: Must emergency vents for indoor tanks terminate outside of buildings?

Answer: Yes. Part 160.90 of the Administrative Rules requires that emergency venting must be installed in accordance with NFPA Standard #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. Therefore, all indoor storage tanks, other than those storing exclusively Class III-B liquids, must have regular and emergency vent piping terminate outside of the building.


Question: What is special about kerosene storage tanks?

Answer: 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.)


Question: What is special about airport dispensing tanks?

Answer: 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.


Question: What is special about marina dispensing tanks?

Answer: Marina facility tanks that will be used to pipe fuel to piers for dispensing into 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. (Self-service is prohibited). The application must indicate that the tank is to be installed above the high-water mark for the area, or indicate a method of anchoring to prevent tank flotation.


Question: Are rainshields allowed on aboveground tanks?

Answer: Yes, but only if installed in accordance with certain parameters. The rainshields cannot prevent methods of secondary containment from being effective.


Question: What is the A.P.I.?

Answer: American Petroleum Institute. This is an organization made up of petroleum processors and equipment manufacturers. Similar to the NFPA, the A.P.I. develops and publishes standards relating to their industry. A.P.I. #650 is referenced by Part 160 as the standard for the installation of field-erected ASTs.


Question: What is the S.T.I.?

Answer: Steel Tank Institute. This is a trade organization made up of steel tank manufacturers. You may be familiar with an 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. Manufacturers who constructed tanks to the S.T.I. specifications were allowed to place the STI-P3 mark on the tank. Likewise, the S.T.I. has developed standards for aboveground flammable liquid storage tanks.


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

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


Question: Can combustible/flammable liquids be stored inside a building?

Answer: 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. (All nationally recognized codes allow for the storage of indoor flammable and combustible liquid storage tanks, and the OSFM, in an attempt to allow reasonable business practice while ensuring fire safety, also allows such storage with particular restrictions). Indoor storage tanks 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.


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

Answer: 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.


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

Answer: 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.


Question: Are fuel dispensing tanks for mines and quarry sites addressed any differently by the applicable AST rules?

Answer: Yes. Recent rule modifications allow for aboveground fuel dispensing storage tanks at mining, quarry, or coal- fired electrical generating facilities to be up to 12,000 gallons in capacity. This allowance is made only for the storage of diesel fuel and only for the fueling of equipment that is not capable of being driven to a service station. Furthermore, the local fire department having response jurisdiction over the tanks location must offer written agreement to the oversized aboveground tanks. Setback distances for these over-capacity tanks are also increased when compared to the normally allowed 2,500-gallon capacity aboveground tank.


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

Answer: 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.


Question: Can a previously used AST be installed?

Answer: 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.


Question: 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.


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

Answer: 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.


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

Answer: 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.


Question: What is a vaulted AST?

Answer: 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 Illinois 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, methods of fire suppression agent delivery into the vault and construction standards for vault tops, etc. Although the NFPA rules on vaulted tanks have not been formally adopted in Illinois Administrative Code, the OSFM uses the NFPA rules as a guideline, considering the absence of rules within the administrative code pertaining specifically to vaulted tanks. Vaulted tanks are listed by Underwriters Laboratories in accordance with U.L. Standard 2245 Vaulted Tanks.