Wisconsin Legislature: ATCP 93.350(5)(b)1.

9. Refrigerated piping systems shall be constructed of materials suitable for extreme temperatures and pressures in the storage system.

(b) National standards. Hazardous substance piping systems serving storage tanks shall be designed, constructed and installed or certified by a qualified engineer in accordance with a standard, as recognized by the department, that is developed by a nationally recognized association or independent testing laboratory.

Note: Examples of recognized standards include ORD-C107.7 — Glass-Fibre Reinforced Plastic Pipe and Fittings; and ASTM D 2996 — Standard Specification for Filament-Wound “Fiberglass” (Glass-Fiber-Reinforced Thermosetting Resin) Pipe.

(5) Secondary containment.

(a) General.

1. All new and existing tank systems used to store hazardous liquids shall be provided with secondary containment.

2. Secondary containment systems shall be designed, constructed and installed to prevent the release of regulated substances to the environment at any time during the operational life of a tank system by containing a leak or spill from the system until the leak or spill is detected and removed.

3. A building may serve as secondary containment if at least one of the following requirements is met:

a. The building is an enclosed structure resting on or above impermeable surfaces from which a discharge of the entire contents of the largest tank would not escape through any doorway, floor drain or other means.

b. The building drains and spillways are connected to an onsite wastewater treatment facility and are designed and maintained such that any leak or spill cannot drain elsewhere.

c. The building drains and spillways are connected to a municipal wastewater treatment facility with agreement of the municipality on the specific materials stored, and drains and spillways are designed and maintained such that any leak or spill cannot drain elsewhere.

4. Secondary containment systems shall be checked for evidence of a leak or spill at least every 30 days.

5. Double-walled tanks shall be designed, constructed, and installed to contain a leak from any portion of the inner tank and to detect a failure of the inner or outer wall.

6. Capacity requirements for secondary containment structures may be reduced by the amount of available treatment plant capacity that is directly accessible to the tank.

7. Secondary containment, including liners and vaults, shall be designed, constructed, and installed to do all of the following:

a. Contain 100 percent of the capacity of the largest tank within the containment area, except as provided in subd. 8.

b. Prevent precipitation or groundwater intrusion from interfering with the ability to contain or detect a leak or spill of a regulated substance.

c. Surround the tank completely and be capable of preventing migration of a regulated substance.

d. Use materials that are compatible with the substances stored and the environment.

e. Isolate incompatible liquids and tank materials from each other and from the environment.

a. Permanent containment structures that are not protected from the weather shall be designed and maintained to allow for the containment of 125 percent of the volume of the largest tank within the containment area.

b. Precipitation and debris shall be removed from the containment structure on a regular basis.

c. No precipitation, ice, or debris that is noticeably contaminated may be discharged to the environment.

9. Underground piping shall be provided with secondary containment and leak detection in accordance with sub. (8).

10.

a. Connections to tanks shall be located within a containment structure constructed of compatible material and capable of containing leaks from the connections.

b. The containment structure for underground tanks shall have an access way so connections can be inspected and repaired.

(b) Secondary containment systems for product transfers. Transfer of hazardous substances shall take place within a secondary containment system that meets all of the following requirements:

a. For facilities that are designed on or after February 1, 2009, the system shall be capable of containing leaks and spills from the largest compartment of the vehicle being loaded or unloaded, including leaks or spills from connections, couplings, vents, pumps and valves, hose failure, or overturning of a container.

b. For facilities designed or installed before February 1, 2009, the system shall be capable of containing the volume of any leak or spill deemed likely to occur, in the professional judgment of a qualified engineer.

c. Open-ended fill lines shall be located within the secondary containment system.

a. The system shall be designed, installed, and operated to prevent any migration of hazardous substances into the soil or the waters of the state, before cleanup occurs, except as allowed in subd. 2. b.

b. The system may allow migration of the gaseous component of a spill.

3. The system shall be constructed, coated, or lined with materials that are compatible with the substances to be transferred and the environment.

a. Product transfers using temporary containment structures shall be constantly attended.

b. The attendant shall be familiar with emergency procedures such that the secondary containment capacity will not be exceeded in the event of a leak or spill.

a. Permanent containment structures shall have sufficient strength and thickness to withstand wear, hydrostatic forces, frost heaving, and weathering.

b. The structure shall support any vehicle brought into the transfer area.

6. Permanent containment structures shall have a foundation that prevents failure due to settlement, compression, or uplift.

a. 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.

b. Pump, siphon and valve controls shall be located outside of the diked area.

c. All drainage systems shall be locked in a closed position when a transfer of a hazardous substance is in progress.

d. Spilled or leaked substances shall be removed from the containment system to prevent a release to the waters of the state.

(6) Pressure relief and venting.

(a) General pressure relief and venting requirements.

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.