NR 661.1084(6)(a)3.3. The external floating roof shall meet all of the following specifications: NR 661.1084(6)(a)3.a.a. Except for automatic bleeder vents, vacuum breaker vents, and rim space vents, each opening in a noncontact external floating roof shall provide a projection below the liquid surface. NR 661.1084(6)(a)3.b.b. Except for automatic bleeder vents, rim space vents, roof drains, and leg sleeves, each opening in the roof shall be equipped with a gasketed cover, seal, or lid. NR 661.1084(6)(a)3.c.c. Each access hatch and each gauge float well shall be equipped with a cover designed to be bolted or fastened when the cover is secured in the closed position. NR 661.1084(6)(a)3.d.d. Each automatic bleeder vent and each rim space vent shall be equipped with a gasket. NR 661.1084(6)(a)3.e.e. Each roof drain that empties into the liquid managed in the tank shall be equipped with a slotted membrane fabric cover that covers at least 90 percent of the area of the opening. NR 661.1084(6)(a)3.f.f. Each unslotted and slotted guide pole well shall be equipped with a gasketed sliding cover or a flexible fabric sleeve seal. NR 661.1084(6)(a)3.g.g. Each unslotted guide pole shall be equipped with a gasketed cap on the end of the pole. NR 661.1084(6)(a)3.h.h. Each slotted guide pole shall be equipped with a gasketed float or other device that closes off the liquid surface from the atmosphere. NR 661.1084(6)(b)(b) The remanufacturer or other person that stores or treats the hazardous secondary material shall operate the tank in accordance with all of the following requirements: NR 661.1084(6)(b)1.1. When the floating roof is resting on the leg supports, the process of filling, emptying, or refilling shall be continuous and shall be completed as soon as practical. NR 661.1084(6)(b)2.2. Except for automatic bleeder vents, rim space vents, roof drains, and leg sleeves, each opening in the roof shall be secured and maintained in a closed position at all times except when the closure device must be open for access. NR 661.1084(6)(b)3.3. Covers on each access hatch and each gauge float well shall be bolted or fastened when secured in the closed position. NR 661.1084(6)(b)4.4. Automatic bleeder vents shall be set closed at all times when the roof is floating, except when the roof is being floated off or is being landed on the leg supports. NR 661.1084(6)(b)5.5. Rim space vents shall be set to open only at those times that the roof is being floated off the roof leg supports or when the pressure beneath the rim seal exceeds the manufacturer’s recommended setting. NR 661.1084(6)(b)6.6. The cap on the end of each unslotted guide pole shall be secured in the closed position at all times except when measuring the level or collecting samples of the liquid in the tank. NR 661.1084(6)(b)7.7. Except when the hatch or well must be opened for access, the cover on each gauge hatch or sample well shall be secured in the closed position at all times. NR 661.1084(6)(b)8.8. Except during inspections, both the primary seal and the secondary seal shall completely cover the annular space between the external floating roof and the wall of the tank in a continuous fashion. NR 661.1084(6)(c)(c) The remanufacturer or other person that stores or treats the hazardous secondary material shall inspect the external floating roof in accordance with all of the following procedures: NR 661.1084(6)(c)1.1. The remanufacturer or other person that stores or treats the hazardous secondary material shall measure the external floating roof seal gaps in accordance with all of the following requirements: NR 661.1084(6)(c)1.a.a. The remanufacturer or other person that stores or treats the hazardous secondary material shall perform measurements of gaps between the tank wall and the primary seal within 60 calendar days after initial operation of the tank following installation of the floating roof and, thereafter, at least once every 5 years. NR 661.1084(6)(c)1.b.b. The remanufacturer or other person that stores or treats the hazardous secondary material shall perform measurements of gaps between the tank wall and the secondary seal within 60 calendar days after initial operation of the tank following installation of the floating roof and, thereafter, at least once every year. NR 661.1084(6)(c)1.c.c. If a tank ceases to hold hazardous secondary material for a period of one year or more, subsequent introduction of hazardous secondary material into the tank shall be considered an initial operation for the purposes of subd. 1. a. and b. NR 661.1084(6)(c)1.d.d. The remanufacturer or other person that stores or treats the hazardous secondary material shall determine the total surface area of gaps in the primary seal and in the secondary seal individually using the following procedure: 1) The seal gap measurements shall be performed at one or more floating roof levels when the roof is floating off the roof supports.
2) Seal gaps, if any, shall be measured around the entire perimeter of the floating roof in each place where a 0.32-centimeter diameter uniform probe passes freely, without forcing or binding against the seal, between the seal and the wall of the tank and the circumferential distance of each such location shall be measured.
3) For a seal gap measured under par. (c), the gap surface area shall be determined by using probes of various widths to measure accurately the actual distance from the tank wall to the seal and multiplying each width by its respective circumferential distance.
4) The total gap area shall be calculated by adding the gap surface areas determined for each identified gap location for the primary seal and the secondary seal individually, and then dividing the sum for each seal type by the nominal diameter of the tank. The total gap areas for the primary seal and secondary seal shall be compared to the respective standards for the seal type as specified in par. (a) 2.