Section ATCP 93.420 - Secondary containment(1) APPLICATION. Aboveground storage tanks using secondary containment as a method of spill control shall comply with the secondary containment requirements in NFPA 30 section 22.11 and this section, except this requirement does not apply to any of the following tanks: (a) Tanks covered in ss. ATCP 93.610(1) to (3) and 93.630. Note: Sections ATCP 93.610(1) to (3) and 93.630 cover tank wagons, movable tanks, tank vehicles, and aboveground farm tanks.
(b) Tanks storing Class IIIB liquids other than used oil. Note: Federal regulations, such as the Spill Prevention Control and Countermeasure requirements in 40 CFR part 112, may also apply to these tanks and be more restrictive but are not enforced by the department.
(c) Tanks storing Class IIIB liquids that are not in the same diked area as a tank containing Class I, II, or IIIA liquids.(2) DIKE SYSTEMS FOR TANKS. (a)Weather exposure. Where a dike system is used to provide secondary containment for a tank system that is exposed to the weather, the dike system shall be constructed in accordance with NFPA 30 section 22.11; ACI 350.2R, if concrete is used; and this subsection.(b)Capacity. The capacity of a dike system open to the weather shall be 25 percent larger than required under NFPA 30 section 22.11.1.2 or 22.11.2.2.(c)Construction. The walls and floor of the dike system shall be constructed of earth, solid masonry, steel, precast concrete, engineered poured concrete, or other materials approved by the department.(d)Sealing. Dike systems with the walls and floor made of steel or poured or precast concrete shall have all cracks, seams, and joints sealed to be liquid-tight.(e)New earthen or masonry dikes.1. New dike systems that have walls or floor made of earth or masonry shall be lined with a synthetic material having a permeability of no faster than 10 -6 centimeters per second for the substance stored, except as provided in subd. 2.2.a. Tanks included in either subd. 2. b. or c. may have dike systems designed by an engineer, with the walls and floor made of clay material having a permeability of no faster than 10 -6 centimeters per second for the substance stored. The dike system shall be designed to maintain the permeability for a minimum of 35 years.b. Tanks that have a double bottom which includes interstitial monitoring.c. Single-bottom tanks that are constructed to ensure that any leaks from the bottom will drain to a conspicuous location and be contained there.3. All piping shall be routed over the top of the dike wall. Note: A method to achieve compliance with subd. 2. c. could include placing a tank over coarse aggregate that rests on a concrete base which is configured to provide the specified drainage and containment.
Note: As applied under s. ATCP 93.440(2) and (3), API 653 requires routine inspection of field-erected tanks, and STI SP001 requires periodic inspection of shop-built tanks for evidence of leaks.
(f)Existing earthen or masonry dikes.1. Tanks may be installed within an existing dike system that has walls or floor made of earth or masonry only if all of the following conditions are met: a. The dike system complies with par. (b).b. The new tanks comply with par. (e) 2. b. or c.c. All other tanks within the dike system have overfill protection as specified in NFPA 30 section 21.7.1.2. An existing dike system that has walls or floor made of earth or masonry may be expanded with materials which are similar to the materials in the existing walls and floor. After that expansion, tanks may be installed within the dike system only if all of the conditions in subd. 1. a. to c. are met.3. Tanks within an existing dike system that has walls or floor made of earth or masonry may be converted from storing an unregulated substance to storing a regulated substance only if all of the following conditions are met: a. The dike system complies with par. (b).b. The converted tanks comply with par. (e) 2. b. or c.c. All other tanks within the dike system have overfill protection as specified in NFPA 30 section 21.7.1.4. All new or replacement piping shall be routed over the top of the dike wall.(g)Approval and installation of synthetic liners. Synthetic liners shall be approved in accordance with s. ATCP 93.130 and installed under the direct supervision of a qualified representative of the manufacturer(h)Testing and maintenance. All new and existing synthetic liners and their seams shall be tested and maintained in accordance with the manufacturer's recommendations.(i)Inspection of seams. Dike systems shall be constructed and maintained such that the liquid-tight seams can be visually inspected, except as provided in pars. (j) and (k).(j)Seam exceptions. The following dike systems are not required to have seams that can be visually inspected: 1. Concrete or steel systems that are coated with a liquid-proof sprayed coating.2. Systems using an additional synthetic liner.3. Systems using a synthetic liner that is covered with earthen material.(k)Existing seams. For existing dike systems, the seams directly under the tank are not required to be visible for inspection.(l)Separation. A separation of at least 2 feet shall be provided between any new tank and the toe of any new or existing dike wall, and a minimum of 3 inches shall be provided between the bottom of any new tank and the dike floor, to allow for visual inspection of the exterior tank surface - except this 3-inch requirement does not apply to tanks that comply with par. (e) 2. b. or c., or where otherwise approved by the department.(m)Drainage. Permanent containment structures shall be designed with a manually controlled drainage system to permit the drainage of liquids resulting from leaks, spills, and precipitation, such as a manually controlled pump or siphon or a manually controlled dike valve.(n)Dike maintenance. Dikes shall be maintained in accordance with API 2610 and s. ATCP 93.400(8) (e).(3) SECONDARY CONTAINMENT TANKS. (a) The department may accept secondary containment tanks of any size as providing acceptable secondary containment, except where dike systems are specifically required by this chapter.(b) Secondary containment tanks shall be provided with an approved method of interstitial leak detection.(c) For electronic interstitial monitoring, the sensor shall be of a normally-closed type.(d) Interstitial leak detection devices shall be tested for operability and functionality at installation.(4) PIPING. All underground piping connected to an aboveground tank shall comply with the secondary containment requirements in s. ATCP 93.400(3).(5) TRANSFER OPERATIONS. In order to prevent a spill from moving beyond the loading or unloading area, any tank which has a capacity of 5,000 gallons or more and which is involved in transfer operations for bulk loading and unloading of tank cars or tank vehicles at facilities that refine, process, distribute, or manufacture liquids regulated under this code shall be provided with a catchment basin or treatment facility to contain the maximum capacity of the largest compartment of a tank car or tank vehicle loaded or unloaded at the facility. Note: This transfer requirement does not apply to transfers of used oil or fuel oil for heating or other burning purposes.
Wis. Admin. Code Department of Agriculture, Trade and Consumer Protection ATCP 93.420
CR 07-029: cr. Register November 2008 No. 635, eff. 2-1-09; correction in (2) (L) made under s. 13.92(4) (b) 7, Stats., Register November 2008 No. 635; CR 09-017: am. (5) Register July 2009 No. 643, eff. 8-1-09; correction in (1) (a), (4) made under s. 13.92(4) (b) 7, Stats., Register December 2011 No. 672; corrections in (1) (a), (4) made under s. 13.92(4) (b) 7, Stats., Register October 2013 No. 694.Adopted by, CR 17-092: cr. Register October 2019 No. 766, eff. 11/1/2019For further information on industry practices for preventing or detecting releases with aboveground storage systems, and for protecting groundwater, surface water and soil in the event of a liquid release, see API Publication 340 - Liquid Release Prevention and Detection Measures for Aboveground Storage Facilities.