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. Following completion of the activity, the remanufacturer or other person that stores or treats the hazardous secondary material shall 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 661.1084(3)(b)4.4. The fixed roof and its closure devices shall be made of suitable materials that will minimize exposure of the hazardous secondary material 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 be considered 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 secondary material 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 661.1084(3)(c)(c) Whenever a hazardous secondary material is in the tank, the fixed roof shall be installed with each closure device secured in the closed position except as follows: NR 661.1084(3)(c)1.1. Opening of closure devices or removal of the fixed roof is allowed at the following times: NR 661.1084(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 such 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. Following completion of the activity, the remanufacturer or other person that stores or treats the hazardous secondary material shall promptly secure the closure device in the closed position or reinstall the cover, as applicable, to the tank. NR 661.1084(3)(c)2.2. Opening of a spring-loaded pressure-vacuum relief valve, conservation vent, or similar type of pressure relief device that vents to the atmosphere is allowed during normal operations for the purpose of maintaining the tank internal pressure in accordance with the tank design specifications. The device shall be designed to operate with no detectable organic emissions when the device is secured in the closed position. The settings at which the device opens shall be established such that the device remains in the closed position whenever the tank internal pressure is within the internal pressure operating range determined by the remanufacturer or other person that stores or treats the hazardous secondary material based on the tank manufacturer recommendations, applicable regulations, 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 661.1084(3)(c)3.3. Opening of a safety device, as defined in s. NR 661.1081, is allowed at any time conditions require doing so to avoid an unsafe condition. NR 661.1084(3)(d)(d) The remanufacturer or other person that stores or treats the hazardous secondary material shall inspect the air emission control equipment according to all of the following requirements: NR 661.1084(3)(d)1.1. The fixed roof and its closure devices shall be visually inspected by the remanufacturer or other person that stores or treats the hazardous secondary material to check for defects that could result in air pollutant emissions. Defects include 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 661.1084(3)(d)2.2. The remanufacturer or other person that stores or treats the hazardous secondary material shall 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, the remanufacturer or other person that stores or treats the hazardous secondary material shall perform the inspections at least once every year except under the special conditions provided for in sub. (12). NR 661.1084(3)(d)3.3. In the event that a defect is detected, the remanufacturer or other person that stores or treats the hazardous secondary material shall repair the defect in accordance with the requirements under sub. (11). NR 661.1084(3)(d)4.4. The remanufacturer or other person that stores or treats the hazardous secondary material shall maintain a record of the inspection in accordance with the requirements specified in s. NR 661.1089 (2). NR 661.1084(4)(4) The remanufacturer or other person that stores or treats the hazardous secondary material controlling air pollutant emissions from a tank using Tank Level 2 controls shall use one of the following tanks: NR 661.1084(4)(a)(a) A fixed-roof tank equipped with an internal floating roof in accordance with the requirements specified in sub. (5). NR 661.1084(4)(b)(b) A tank equipped with an external floating roof in accordance with the requirements specified in sub. (6). NR 661.1084(4)(c)(c) A tank vented through a closed-vent system to a control device in accordance with the requirements specified in sub. (7). NR 661.1084(4)(d)(d) A pressure tank designed and operated in accordance with the requirements specified in sub. (8). NR 661.1084(4)(e)(e) A tank located inside an enclosure that is vented through a closed-vent system to an enclosed combustion control device in accordance with the requirements specified in sub. (9). NR 661.1084(5)(5) The remanufacturer or other person that stores or treats the hazardous secondary material who controls air pollutant emissions from a tank using a fixed roof with an internal floating roof shall meet the requirements specified in pars. (a) to (c). NR 661.1084(5)(a)(a) The tank shall be equipped with a fixed roof and an internal floating roof in accordance with all of the following requirements: NR 661.1084(5)(a)1.1. The internal floating roof shall be designed to float on the liquid surface except when the floating roof shall be supported by the leg supports. NR 661.1084(5)(a)2.2. The internal floating roof shall be equipped with a continuous seal between the wall of the tank and the floating roof edge that meets any of the following requirements: NR 661.1084(5)(a)2.b.b. Two continuous seals mounted one above the other. The lower seal may be a vapor-mounted seal. NR 661.1084(5)(a)3.3. The internal floating roof shall meet all of the following specifications: NR 661.1084(5)(a)3.a.a. Each opening in a noncontact internal floating roof except for automatic bleeder vents, vacuum breaker vents, and the rim space vents shall provide a projection below the liquid surface. NR 661.1084(5)(a)3.b.b. Each opening in the internal floating roof shall be equipped with a gasketed cover or a gasketed lid except for leg sleeves, automatic bleeder vents, rim space vents, column wells, ladder wells, sample wells, and stub drains.