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ATCP 93.050(109)(b) (b) A violation that substantially deviates from a requirement of this chapter.
ATCP 93.050(109)(c) (c) A violation that includes failure to install, maintain or operate equipment essential to preventing or detecting leaks.
ATCP 93.050(109)(d) (d) A violation that is observed to reoccur repeatedly as a result of intentional or unintentional administrative or operational oversight.
ATCP 93.050(110) (110) “ Space heating” means heating of areas intended for occupancy or storage.
ATCP 93.050(111) (111) “ Storm water or wastewater collection system” means piping, pumps, conduits, and any other equipment necessary to collect and transport the flow of surface water run-off resulting from precipitation, or domestic, commercial, or industrial wastewater to and from retention areas or any areas where treatment is designated to occur. The collection of storm water and wastewater does not include treatment except where incidental to conveyance.
ATCP 93.050(112) (112) “ Structure” means an assembly of materials forming a construction for occupancy, storage, use, shelter or weather protection meeting the definition of place of employment under sub. (88) or public building under sub. (95).
ATCP 93.050 Note Note: The department does not consider a tank to be a structure although local or municipal regulations may classify a tank as a structure.
ATCP 93.050(113) (113) “ Suspected release” means either of the following:
ATCP 93.050(113)(a) (a) There is indication that a tank system or dispensing system has leaked — such as inventory losses; observable free product or evidence of free product in secondary containment at dispensers, submersible pumps or spill buckets; petroleum odors; unexplained presence of water in a tank; or activation of a leak detection alarm system — but there is no observable environmental evidence of a release.
ATCP 93.050(113)(b) (b) There is observable environmental evidence of a release, such as soil discoloration or free product, but the source is unknown.
ATCP 93.050 Note Note: See sub. (62) for a definition of “leak,” sub. (76) for a definition of “obvious release” and sub. (103) for a definition of “release.”
ATCP 93.050(114) (114) “ Tank” means a device designed to contain an accumulation of regulated substance and constructed of non-earthen materials such as concrete, steel, fiberglass or plastic, and including the following types of tanks, which have the following meanings:
ATCP 93.050(114)(a) (a) “Abandoned tank” means an aboveground or underground tank with or without product that is not recognized by this chapter as in-use, temporarily out of service, or closed.
ATCP 93.050(114)(b) (b) “Accumulator tank” or “accumulator reservoir” means a container that is integral to a closed-loop mechanical-system operation of equipment, and that is used either to provide a regulated substance on demand, such as a fluid that is used as a heating or cooling media, or to store a regulated substance that is displaced from the functioning equipment, such as from an elevator or hydraulic lift.
ATCP 93.050 Note Note: Accumulator tanks are outside the scope of this chapter.
ATCP 93.050(114)(c) (c) “Breakout tank” means a tank that is used to relieve surges in an oil pipeline system or to receive and store oil transported by a pipeline for reinjection and continued transportation by a pipeline. Tanks considered by this chapter to be breakout tanks do not have piping that transfers product directly to or from a loading rack.
ATCP 93.050(114)(d) (d) “Day tank” means an intermediate tank in a product transfer system between a storage tank and the end use of the product, usually a generator. The purpose of a day tank is to provide immediate product to the end source where the supply may otherwise be influenced by product temperature, viscosity or inadequate supply pressure.
ATCP 93.050(114)(e) (e) “Farm tank” means a tank that is constructed in accordance with NFPA 30A section 13.2 and installed on a farm premises.
ATCP 93.050(114)(f) (f) “Field-erected tank” means an aboveground tank that is built on the site from sections and components.
ATCP 93.050 Note Note: See par. (p) for a definition of “fixed tank.”
ATCP 93.050(114)(g) (g) “Gravity tank” means a supply tank from which the product is delivered directly by gravity.
ATCP 93.050(114)(h) (h) “Integral tank” means a vessel with a liquid capacity of less than 110 gallons, which supplies fuel to an engine and which is assembled and used with the engine as a single unit of equipment.
ATCP 93.050 Note Note: Vessels with a capacity of 110 gallons or more are included in the definition of storage tank in par. (q).
ATCP 93.050(114)(i) (i) “Movable tank” means an aboveground storage tank that meets all of the following:
ATCP 93.050(114)(i)1. 1. Has a liquid capacity of 110 gallons or more, and is used for storing and dispensing liquid motor vehicle fuel.
ATCP 93.050(114)(i)2. 2. Is supported on skids, wheels without axles, or similar means and is not mounted upon a tank vehicle or chassis capable of road travel.
ATCP 93.050(114)(i)3. 3. Is designed and constructed in accordance with s. ATCP 93.250.
ATCP 93.050(114)(i)4. 4. Is not intended for permanent placement.
ATCP 93.050 Note Note: Movable tanks are acceptable for use at construction projects, farms, and other locations recognized in subch. VI, where it is more practical to move the tank, typically by lifting equipment, to off-road motorized equipment for dispensing, rather than drive the motorized equipment to the tank.
ATCP 93.050(114)(j) (j) “Multi-compartment tank” or “multi-chamber tank” means a vessel that contains 2 or more compartments created by the presence of an interior wall so that 2 or more substances can be stored at the same time within a single tank shell.
ATCP 93.050 Note Note: In accordance with s. ATCP 93.250, each compartment of a multi-compartment tank is considered a separate tank, even if the same substance is stored in more than one compartment.
ATCP 93.050(114)(k) (k) “Portable tank” means an aboveground closed vessel that has a liquid capacity of 110 gallons or more; is not otherwise defined in this chapter; is equipped with skids, mountings or accessories to facilitate handling of the tank by mechanical means; and is not intended for fixed installation or for highway vehicle fueling. “Portable tank” includes intermediate bulk containers.
ATCP 93.050(114)(L)1.1. “Process tank” or “flow-through process tank” means a tank that forms an integral part of a production process through which there is a steady, variable, recurring, or intermittent flow of materials during the operation of the process and the tank is utilized to carry out or control the heating, cooling, mixing, blending, separating, metering, or chemical action of materials. The processing is done on a regular basis and it is the primary function of the tank.
ATCP 93.050(114)(L)2. 2. “Process tank” or “flow-through process tank” does not include a tank that is used for the storage of materials before their introduction into the production process or for the storage of finished products or by-products from the production process, or a tank that is only used to recirculate materials. A process tank would be considered a storage tank if the vessel is used as storage for a period exceeding 96 hours after the processing ends.
ATCP 93.050 Note Note: Process tanks are outside the scope of this chapter.
ATCP 93.050(114)(m) (m) “Product recovery tank” means a tank that forms an integral part of a ch. ATCP 93 regulated substance spill control system for a storage, processing or transfer area. The purpose of the tank is spill recovery and temporary containment. A product recovery tank does not include a tank that is used for the storage of materials or by-products from a flow-through reclamation process. A product recovery tank will be considered a storage tank if the vessel is used as storage for a period exceeding 96 hours after the control of a release or spill.
ATCP 93.050 Note Note: Product recovery tanks are outside the scope of this chapter.
ATCP 93.050(114)(n) (n) “Residential tank” means a tank located on the same property as a 1- or 2-family dwelling or a residential building that falls within the scope of chs. SPS 361 to 366 and used only by the residents of the property or for the maintenance of the property.
ATCP 93.050(114)(o) (o) “Service tank” means a tank that is used for a limited period of time during the servicing of liquid-bearing equipment, to hold liquids temporarily during the servicing, cleaning or relocation of the equipment.
ATCP 93.050 Note Note: Service tanks are outside the scope of this chapter. Service tanks include the defueling and refueling tanks that are used in commercial aviation environments. These tanks are used for removal of fuel from an aircraft to facilitate other maintenance for the aircraft and for return of that fuel to the aircraft immediately thereafter. They are typically not moved from one site to another and are operated by employees of an aviation service company under aviation service protocols and monitored situations.
ATCP 93.050(114)(p) (p) “Stationary tank” or “fixed tank” means a storage vessel intended for stationary installation and not intended for relocation, loading, unloading, or attachment to a transport vehicle, as part of its normal operation in the process of use.
ATCP 93.050(114)(q) (q) “Storage tank” means a liquid-tight vessel that is intended for fixed or stationary use or a tank that is used for fuel dispensing under subch. VI but is not used for any of the excepted purposes in s. ATCP 93.020 (6). This term includes a vessel which has a liquid capacity of 110 gallons or more and which is assembled and used with an engine as a single unit of equipment.
ATCP 93.050(114)(r) (r) “Work-top tank” means an aboveground steel rectangular tank for combined use as a working surface and a storage tank for Class IIIB liquids.
ATCP 93.050(115) (115) “ Tank system” includes the primary tank and pipe, integral secondary containment, integral supports, leak detection, overfill prevention, spill containment, anti-siphon devices, any vapor-recovery system connected to the tank, and the necessary core components that allow the tank system to function as intended and in accordance with the installation requirements. Tank system configurations include onshore underground storage tanks, onshore aboveground storage tanks, and storage tanks over water that are integral with a stationary pier, floating vessel or floating structure for the purpose of storage or vehicle fueling.
ATCP 93.050 Note Note: In a typical fueling island, the dispensing system, as defined in sub. (41), begins immediately downstream of the emergency shutoff valve, and all components upstream of that point, including the shutoff valve, are part of the tank system.
ATCP 93.050(116) (116) “ Tank-system integrity assessment” or “TSIA” means the process by which the department seeks to determine if the integrity of a tank system or any component thereof has been compromised. This process includes precision tightness testing, inventory reconciliation, visual inspection of system components, and calibration checks of dispensers and automatic tank gauges.
ATCP 93.050 Note Note: In general, TSIAs are to be performed if there are indications that the integrity of a system has been compromised.
ATCP 93.050(117) (117) “ Tank-system site assessment” or “TSSA” means the process by which the department expects tank-system owners or operators to determine if a tank system or any component of that system has released petroleum products or other hazardous substances into the soil, groundwater or surface waters. This process includes all of the following:
ATCP 93.050(117)(a) (a) Observation of field conditions, such as stained soils; odors; pitting, holes or cracks in tank system components; observable leaks; and elevated in-field soil-gas readings.
ATCP 93.050(117)(b) (b) Collection of soil samples for laboratory analysis of petroleum products or other hazardous substances, as prescribed in the department's Tank System Assessment: A Guide to the Assessment and Reporting of Suspected or Obvious Releases From Underground and Aboveground Storage Tank Systems.
ATCP 93.050(117)(c) (c) Reporting of the field observations and sampling results in a format prescribed by the department.
ATCP 93.050 Note Note: In general, TSSAs are to be performed at the time a storage tank system, or some component thereof, is to be permanently closed, upgraded or repaired, or if a change in service is to take place.
ATCP 93.050 Note Note: Tank System Site Assessment: A Guide to the Assessment and Reporting of Suspected or Obvious Releases From Underground and Aboveground Storage Tank Systems is available from the department's Web site at
ATCP 93.050(118) (118) “ Tank vehicle” means a tank truck or trailer system designed and constructed to comply with NFPA 385.
ATCP 93.050 Note Note: NFPA 385 recognizes 3 types of tank vehicles: (1) a tank truck in which the cargo tank is supported entirely on the truck chassis, (2) a tank semi-trailer in which the cargo tank is supported by both the truck chassis and trailer chassis, and (3) a tank full-trailer in which the cargo tank is supported entirely on the trailer chassis.
ATCP 93.050(119) (119) “ Tank wagon” means a tank that is affixed to a trailer system with at least one axle, is constructed in accordance with s. ATCP 93.610 (1), has a liquid capacity of 1,100 gallons or less, and is used for storing and dispensing liquid motor vehicle fuel for equipment used on the site, or is used for storing other liquids regulated under this chapter. A tank wagon is not constructed to comply with NFPA 385.
ATCP 93.050 Note Note: Since a tank wagon is not designed and constructed under NFPA 385 criteria, it shall be towed empty on the road for transport and placement in accordance with s. ATCP 93.610 (1).
ATCP 93.050(120) (120) “ Temporarily out of service” or “TOS” means a storage tank system that is not in use meets the requirements of s. ATCP 93.445 (1) or 93.545 (1) and is intended to be placed back into use within 24 months.
ATCP 93.050 Note Note: Temporarily out of service does not apply to stationary tanks that are of seasonal use, such as heating fuel storage tanks.
ATCP 93.050(121) (121) “ Transfer area” means the area where product is transferred, commonly referred to as loading or unloading, between a storage tank and a transport vehicle. Transfer areas are located at terminals, as well as at end-user and intermediate vendors in the product distribution stream. The transfer area may involve loading racks, pipe stands, or direct hose-to-valve connections, and accommodate top or bottom transfer.
ATCP 93.050(121m) (121m) “Underground storage tank” or “underground tank” has the meaning given in sub. (122) unless the context requires otherwise.
ATCP 93.050(122)(a) (a) “Underground storage tank system” or “UST system” means any one or combination of tanks, including connected pipes, that is used to contain an accumulation of regulated substances, and the volume of which, including the volume of connected underground pipes, is 10 percent or more beneath the surface of the ground.
ATCP 93.050(122)(b) (b) “Underground storage tank system” or “UST system” does not include any of the following or pipes connected to any of the following:
ATCP 93.050(122)(b)1. 1. A surface impoundment, pit, pond, or lagoon.
ATCP 93.050(122)(b)2. 2. A storm water or wastewater collection system.
ATCP 93.050(122)(b)3. 3. A liquid trap or associated gathering lines directly related to oil or gas production and gathering operations.
ATCP 93.050(122)(b)4. 4. A storage tank situated in an underground area, such as a basement, cellar, mine shaft or tunnel, if the storage tank is situated upon or above the surface of the floor and not surrounded by earth.
ATCP 93.050(123) (123)“Upgrade” means the addition to or retrofit of some part of a storage tank system, such as cathodic protection, leak detection, lining, or spill and overfill controls, to improve the ability of a storage tank system to prevent the release of product.
ATCP 93.050(124) (124) “ Used oil” or “waste oil” means any oil refined from crude oil, or any synthetic oil, that has been used and as a result of such use is contaminated by physical or chemical impurities; and means used cooking oils that are used as fuel for purposes such as space heating or fueling motor vehicles.
ATCP 93.050 Note Note: See ch. NR 679 and s. 287.15, Stats., for other definitions of used oil and waste oil, and for requirements relating to those definitions, such as criteria for transporting or recycling these liquids.
ATCP 93.050(125) (125) “ Vehicle collision protection” means a structure or mechanism to protect a tank or system component from vehicle impact.
ATCP 93.050(126) (126) “ Vehicle fueling” means the process of adding motor fuel to the engine fuel supply tank for motor driven vehicles, including aircraft, watercraft, on- or off-road vehicles and vehicles on rails.
ATCP 93.050(127) (127) “ Watercraft” or “marine craft” means a vehicle designed to operate on rivers, streams or lakes for the transport of people or goods for recreation, business or commerce purposes.
ATCP 93.050(128) (128) “ Watercraft fueling” means the storage and fueling system and activities associated with shoreline fuel transfer into watercraft and aircraft while moored on the water to be fueled.
ATCP 93.050 Note Note: Further information relating to terms associated with petroleum storage facilities, petroleum equipment and petroleum-based fuels is available at the Petroleum Equipment Institute's Web site at
ATCP 93.050 History History: CR 17-092: cr. Register October 2019 No. 766, eff. 11-1-19; correction in (2), (10), (26), (64) (a), (89), (114) (k), (120), (122) (b) 1., 2. made under s. 35.17, Stats., and (13), (87) renum. (9m), (85m) under s. 13.92 (4) (b) 1., Stats., Register October 2019 No. 766.
subch. I of ch. ATCP 93 Subchapter I — Administration and Enforcement
ATCP 93.100 ATCP 93.100 Plan review.
ATCP 93.100(1)(1)General.
ATCP 93.100(1)(a)(a) Plan review and written approval from the authorized agent or the department shall be obtained before any of the following activities are performed on storage tank systems used to store a regulated substance, except where exempted under par. (b):
ATCP 93.100(1)(a)1. 1. Commencing any construction of new or additional tank or piping installation.
ATCP 93.100(1)(a)2. 2. Changing the operation of a tank system from storage of a non-regulated substance to a regulated substance.
ATCP 93.100(1)(a)3. 3. Adding or modifying tank or pipe corrosion protection.
ATCP 93.100(1)(a)4. 4. Adding leak detection or modifying leak detection as specified in s. ATCP 93.110 (3) (e) when performed in conjunction with other changes that require plan review. A certified installer is not required to perform the modification of leak detection.
ATCP 93.100 Note Note: Under sub. (3) (a) 5. c., the department's leak detection installation form, TR-WM-133, must be filled out and submitted anytime leak detection equipment is added or modified, whether or not plan review is required. This form is available from the Bureau of Weights and Measures, PO Box 8911, Madison, WI 53708-8911, or at telephone (608) 224-4942, or from the Bureau's Web site at
ATCP 93.100(1)(a)5. 5. Upgrading or modifying spill or overfill protection, except this requirement does not apply where drop tube overfill protection is added or modified for existing underground fill piping that drops vertically into a tank.
ATCP 93.100(1)(a)6. 6. Lining or relining of underground tanks.
Published under s. 35.93, Stats. Updated on the first day of each month. Entire code is always current. The Register date on each page is the date the chapter was last published.