ATCP 93.350(5)(b)7.c.c. All drainage systems shall be locked in a closed position when a transfer of a hazardous substance is in progress. ATCP 93.350(5)(b)7.d.d. Spilled or leaked substances shall be removed from the containment system to prevent a release to the waters of the state. ATCP 93.350(6)(a)1.a.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. ATCP 93.350(6)(a)1.b.b. Tanks subject to failure due to pressure or vacuum shall be provided with pressure control devices as determined by the qualified engineer. ATCP 93.350(6)(a)1.c.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. ATCP 93.350(6)(a)2.2. 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. ATCP 93.350(6)(a)3.3. 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. ATCP 93.350(6)(a)4.4. Vent discharge openings shall be designed and constructed to prevent interference of operation due to precipitation. ATCP 93.350(6)(a)5.5. Vents shall have provisions for draining any condensate that may accumulate. ATCP 93.350(6)(a)8.8. Venting shall be sized to limit the back pressure to less than the maximum pressure allowed by the design of the system. ATCP 93.350(6)(a)9.9. 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. ATCP 93.350(6)(a)10.10. 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. ATCP 93.350(6)(b)(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: ATCP 93.350(6)(b)2.2. Inbreathing resulting from contraction of vapors caused by a decrease in atmospheric temperature. ATCP 93.350(6)(b)3.3. Outbreathing resulting from maximum inflow of liquid into the tank and maximum evaporation caused by the inflow. ATCP 93.350(6)(b)4.4. Outbreathing resulting from expansion and evaporation that result from maximum increase in atmospheric temperature. ATCP 93.350 NoteNote: Examples of normal venting include pilot-operated relief valves, pressure relief valves, pressure-vacuum valves, conservation vents, open vents, or a combination of devices.
ATCP 93.350(6)(c)1.1. Atmospheric, low-pressure and high-pressure aboveground tanks shall have emergency venting to ensure that the maximum pressure for the tank is not exceeded. ATCP 93.350(6)(c)2.2. Emergency venting shall be designed by a qualified engineer in accordance with good engineering practices. ATCP 93.350 NoteNote: 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.