NR 664.1084(3)(b)3.3. Each opening in the fixed roof, and any manifold system associated with the fixed roof, shall be any of the following: NR 664.1084(3)(b)3.a.a. Equipped with a closure device designed to operate such that when the closure device is secured in the closed position there are no visible cracks, holes, gaps or other open spaces in the closure device or between the perimeter of the opening and the closure device. NR 664.1084(3)(b)3.b.b. Connected by a closed-vent system that is vented to a control device. The control device shall remove or destroy organics in the vent stream, and shall be operating whenever hazardous waste is managed in the tank, except as follows: 1) During periods when it is necessary to provide access to the tank for performing the activities of subd. 3. b.2), venting of the vapor headspace underneath the fixed roof to the control device is not required, opening of closure devices is allowed and removal of the fixed roof is allowed. After completing the activity, promptly secure the closure device in the closed position or reinstall the cover, as applicable, and resume operation of the control device.
2) During periods of routine inspection, maintenance or other activities needed for normal operations, and for removal of accumulated sludge or other residues from the bottom of the tank.
NR 664.1084(3)(b)4.4. Make the fixed roof and its closure devices of suitable materials that will minimize exposure of the hazardous waste to the atmosphere, to the extent practical, and will maintain the integrity of the fixed roof and closure devices throughout their intended service life. Factors to consider when selecting the materials for and designing the fixed roof and closure devices shall include organic vapor permeability, the effects of any contact with the hazardous waste or its vapors managed in the tank, the effects of outdoor exposure to wind, moisture and sunlight and the operating practices used for the tank on which the fixed roof is installed. NR 664.1084(3)(c)(c) Whenever a hazardous waste is in the tank, install the fixed roof with each closure device secured in the closed position except as follows: NR 664.1084(3)(c)1.1. Opening of closure devices or removal of the fixed roof is allowed at the following times: NR 664.1084(3)(c)1.a.a. To provide access to the tank for performing routine inspection, maintenance or other activities needed for normal operations. Examples of those activities include those times when a worker needs to open a port to sample the liquid in the tank, or when a worker needs to open a hatch to maintain or repair equipment. After completing the activity, promptly secure the closure device in the closed position or reinstall the cover, as applicable, to the tank. NR 664.1084(3)(c)2.2. Opening of a spring-loaded pressure-vacuum relief valve, conservation vent or similar type of pressure relief device which vents to the atmosphere is allowed during normal operations for the purpose of maintaining the tank internal pressure according to the tank design specifications. Design the device to operate with no detectable organic emissions when the device is secured in the closed position. Establish the settings at which the device opens such that the device remains in the closed position whenever the tank internal pressure is within the internal pressure operating range determined by the owner or operator based on the tank manufacturer recommendations, applicable rules, fire protection and prevention codes, standard engineering codes and practices or other requirements for the safe handling of flammable, ignitable, explosive, reactive or hazardous materials. Examples of normal operating conditions that may require these devices to open are during those times when the tank internal pressure exceeds the internal pressure operating range for the tank as a result of loading operations or diurnal ambient temperature fluctuations. NR 664.1084(3)(c)3.3. Opening of a safety device, as defined in s. NR 665.1081, is allowed at any time conditions require doing so to avoid an unsafe condition. NR 664.1084(3)(d)(d) Inspect the air emission control equipment according to all of the following requirements: NR 664.1084(3)(d)1.1. Visually inspect the fixed roof and its closure devices to check for defects that could result in air pollutant emissions. Defects include, but are not limited to, visible cracks, holes or gaps in the roof sections or between the roof and the tank wall, broken, cracked or otherwise damaged seals or gaskets on closure devices and broken or missing hatches, access covers, caps or other closure devices. NR 664.1084(3)(d)2.2. Perform an initial inspection of the fixed roof and its closure devices on or before the date that the tank becomes subject to this section. Thereafter, perform the inspections at least once every year except under the special conditions provided for in sub. (12). NR 664.1084(4)(4) Owners and operators controlling air pollutant emissions from a tank using Tank Level 2 controls shall use one of the following tanks: NR 664.1084(4)(a)(a) A fixed-roof tank equipped with an internal floating roof according to sub. (5). NR 664.1084(4)(c)(c) A tank vented through a closed-vent system to a control device according to sub. (7). NR 664.1084(4)(e)(e) A tank located inside an enclosure that is vented through a closed-vent system to an enclosed combustion control device according to sub. (9). NR 664.1084(5)(5) The owner or operator who controls air pollutant emissions from a tank using a fixed roof with an internal floating roof shall meet pars. (a) to (c). NR 664.1084(5)(a)(a) Equip the tank with a fixed roof and an internal floating roof according to all of the following requirements: NR 664.1084(5)(a)1.1. Design the internal floating roof to float on the liquid surface except when the floating roof must be supported by the leg supports. NR 664.1084(5)(a)2.2. Equip the internal floating roof with a continuous seal between the wall of the tank and the floating roof edge that meets any of the following requirements: NR 664.1084(5)(a)2.b.b. Two continuous seals mounted one above the other. The lower seal may be a vapor-mounted seal.