Wisconsin Legislature: ATCP 93.350(6)(d)1.f.

a. Tanks shall be protected from over-pressurization and excessive vacuum that may be caused by operator error, filling, emptying, atmospheric temperature changes, pumping, refrigeration, heating, and fire exposure.

b. Tanks subject to failure due to pressure or vacuum shall be provided with pressure control devices as determined by the qualified engineer.

c. Protection shall be provided by vents, rupture discs, pressure or vacuum relief devices, controllers, fail-safe vessel designs, or other means determined by a qualified engineer.

2. If a pilot-operated relief valve is used, it shall be designed so the main valve will open automatically and will protect the tank in the event of failure of the pilot valve or other device.

3. Venting used on a tank containing a flammable or combustible hazardous substance shall follow the requirements of NFPA 30 sections 21.4.3 and 22.7.

4. Vent discharge openings shall be designed and constructed to prevent interference of operation due to precipitation.

5. Vents shall have provisions for draining any condensate that may accumulate.

6. Vents shall be protected from tampering.

7. Vents shall have direct contact with the vapor space of the tank.

8. Venting shall be sized to limit the back pressure to less than the maximum pressure allowed by the design of the system.

9. Tanks fitted with relief valves may not be equipped with an isolation valve below the relief valve unless 2 or more relief valves are provided, and isolation valves are interlocked.

10. Cooled tanks with sealed double-wall construction shall have a pressure relief valve on the outer wall in addition to a pressure relief valve or safety disk on the inner tank.

(b) Normal venting. Closed-roof atmospheric tanks and low-pressure tanks shall be equipped with normal vents designed to accommodate all of the following conditions:

1. Inbreathing resulting from maximum outflow of liquid from the tank.

2. Inbreathing resulting from contraction of vapors caused by a decrease in atmospheric temperature.

3. Outbreathing resulting from maximum inflow of liquid into the tank and maximum evaporation caused by the inflow.

4. Outbreathing resulting from expansion and evaporation that result from maximum increase in atmospheric temperature.

Note: Examples of normal venting include pilot-operated relief valves, pressure relief valves, pressure-vacuum valves, conservation vents, open vents, or a combination of devices.

1. Atmospheric, low-pressure and high-pressure aboveground tanks shall have emergency venting to ensure that the maximum pressure for the tank is not exceeded.

2. Emergency venting shall be designed by a qualified engineer in accordance with good engineering practices.

Note: Examples of emergency venting include larger or additional open vents, pressure-vacuum valves, pressure relief valves, a gauge hatch that permits the cover to lift under abnormal internal pressure or a manhole cover that lifts when exposed to abnormal internal pressure.

(d) Labeling of pressure relief valves.

1. Where safety, pressure relief or vacuum relief valves are used, each valve shall be permanently labeled with all of the following information:

a. The name or identifying trademark of the manufacturer.

b. The manufacturer’s design or type number.

c. The pipe size of the inlet.

d. The set pressure or vacuum, in pounds per square inch gauge.

e. The full open pressure or vacuum, in pounds per square inch gauge.

f. The capacity at the indicated pressure or full open vacuum, in either cubic feet of gas per minute or cubic feet of gas per hour.

2. The labeling shall be provided either on the valve itself or on a plate securely fastened to the valve.

(7) Temperature monitoring.

(a) Temperature indicators and corresponding alarms shall be provided for storage tanks where heat from a reaction could cause damage to the system or a release to the environment.

(b) Heated or cooled tanks shall be equipped with appropriate thermal controls and gauges.

(c) Protection against overheating or overcooling shall be provided for heated or cooled tanks in accordance with generally accepted engineering practices.

Note: Means of protection may include temperature controllers, insulation, alarms, cooling systems, and special material selection.

(8) Leak detection for underground tank systems.

(a) Underground storage tank systems that contain federally regulated hazardous substances shall be equipped with a leak detection system which will detect a leak in the primary containment of the tank and piping.

(b) The leak detection method shall be capable of meeting the requirements in s. ATCP 93.510, except as provided in par. (c).

(c) Other methods of leak detection may be used if approval from the department is obtained before the installation and operation of the new UST system.

(9) Corrosion protection. Corrosion protection shall be provided in accordance with s. ATCP 93.520 for underground storage tank systems or s. ATCP 93.400 for aboveground storage tank systems.

(10) Identification and labeling.

(a) Transfer points shall be labeled with the name of the substance transferred.

(b) Aboveground tanks storing hazardous substances within the scope of this section shall be identified and labeled in accordance with s. ATCP 93.400 (7).

Note: Section ATCP 93.400 (7) requires conformance with NFPA 704.

(c) All tanks on a property shall have a unique tank identification number that is readily visible to emergency response personnel.

(11) Inspections, changes in service, tank closure, and releases from a tank.

(a) Aboveground storage tanks.

1. Aboveground storage tanks shall comply with ss. ATCP 93.440 to 93.470, except as provided in subd. 2.

2. Periodic inspections of aboveground tanks may be conducted in accordance with any nationally recognized standard that is more applicable to hazardous tanks than STI SP001.

3. Existing and new aboveground fiberglass storage tanks shall have certified external tank inspections and certified tank integrity inspections in accordance with HIR FTV RP 2007.

Note: Aboveground storage tanks which store hazardous substances and which have a capacity of less than 5,000 gallons are exempt from this chapter unless the substance is also flammable or combustible.

Note: Sections ATCP 93.440 to 93.470 address inspections; seldom-used and temporarily out of service tanks; change in service to store a non-regulated substance; tank closures; tank-system site assessment; and confirming and responding to leaks, spills, overfills and releases.

Note: The department accepts use of the following standard for performing periodic inspections under this subdivision: HIR FTV RP 2007, In-Service Inspection of Aboveground Atmospheric Fiberglass Reinforced Plastic Tanks and Vessels, as published by HIR Technical Services. This standard is available by contacting FTPI at http://www.storagetanks.info/FTVRP2007.html.

(b) Underground storage tanks. Underground storage tanks shall comply with ss. ATCP 93.545 to 93.585.

Note: Sections ATCP 93.545 to 93.585 address seldom-used and temporarily out of service tanks; change in service to store a non-regulated substance; tank system closures; conditions indicating releases; tank system integrity assessments; tank system site assessments; and responding to leaks, spills, overfills and releases.

(13) Security at chemical storage facilities. Owners and operators shall be aware of regulations, standards and operating practices that relate to facility security.

Note: Information on how to develop a comprehensive site security program is available in the API document Security Guidelines for the Petroleum Industry, or the American Chemistry Council document, Site Security Guidelines for the U.S. Chemical Industry.

History: CR 17-092: cr. Register October 2019 No. 766, eff. 11-1-19; correction in (1) (b) 5., (4) (b) made under s. 35.17, Stats., Register October 2019 No. 766.

ATCP 93.360 Storage of Class IA flammable liquids.

(1) All storage, whether new or existing, of Class IA flammable liquids with a Reid vapor pressure not exceeding 25.3 psig (40 psia) and a boiling point of less than 100o F shall comply with the applicable requirements of NFPA 30 and this chapter, except as provided in sub. (2).

(2) Design standards for new tank systems do not apply to existing tank systems unless specified otherwise.

Note: See ch. SPS 341 for additional requirements that may apply to flammable liquid storage in pressure vessels at pressures greater than 15 psig.

History: CR 17-092: cr. Register October 2019 No. 766, eff. 11-1-19.

ATCP 93.370 Emergency shutoff for transfers.

(1) An emergency electrical shutoff shall be installed in accordance with NFPA 30A section 6.7 on any new or existing system that provides for the transfer of product from a fixed storage tank system to a tank vehicle rail tank car or vehicle fuel tank.

(2) The emergency electrical shutoff shall be tested annually. Annual testing for UST systems shall be documented on the functionality verification form, TR-WM-139.

History: CR 17-092: cr. Register October 2019 No. 766, eff. 11-1-19.

Subchapter IV — General AST Storage

Note: The requirements in this subchapter are general requirements. Under s. ATCP 93.020 (7) (b), wherever subchapter III prescribes a specific or more detailed requirement regarding the same subject, that subchapter III requirement governs instead of the requirement in this subchapter.

ATCP 93.400 General requirements.

(1) Aboveground tank design.

(a) General. Tanks designed and built for underground use may not be used aboveground.

(b) Tanks for Class I, II, or IIIA liquids. Tanks used for aboveground storage of Class I, II, or IIIA liquids shall comply with the tank construction and marking requirements in s. ATCP 93.250.

(c) Tanks for Class IIIB liquids. Tanks which have a capacity of 1,100 gallons or more and which are used for aboveground storage of Class IIIB liquids shall be listed or shall be acceptable to the department.

Note: See s. ATCP 93.130 (5) for listing and labeling requirements for aboveground tanks.

(d) Tank foundations. Tank foundations shall be designed to prevent uneven settling of the tank. Tank supports shall be placed on a prepared, flat, smooth, and solid surface.

(2) Corrosion protection.

(a) General. Aboveground storage tank systems shall be protected from excessive external corrosion through the use of paint, protective coatings, or corrosion resistant materials that are applied after the surface has been prepared in accordance with the manufacturer’s recommendations.

(b) Tank systems. Any portion of an aboveground tank system that is in contact with the ground shall be protected from corrosion by one of the following methods:

1. The tank system is constructed of an inherently corrosion-resistant material.

2. The tank system is isolated from the ground by a method acceptable to the department.

Note: Methods of isolation acceptable to the department include dielectric coating, placement on clean concrete, placement on an elevated ring wall, or mounting on listed saddles.

3. The tank system is protected by a sacrificial anode or impressed current system.

a. Single- or double-wall tanks which are constructed of material subject to corrosion and which are supported on runners or tank supports shall be constructed such that the bottom of the tank shell is at least 3 inches but no more than 12 inches above grade, as measured from the lowest point of the tank shell, except the 12-inch maximum does not apply where subd. 4. b. is met.

b. The 12-inch maximum in subd. 4. a. may be exceeded where structural fire resistance is provided that complies with NFPA 30 section 22.5.2.4.

(c) Underground piping. All new and existing underground piping connected to an aboveground tank shall be protected from corrosion using one of the methods in s. ATCP 93.520 (1).

(d) Designed corrosion protection systems.