NR 420.03(3)(b)2.2. The petroleum liquid has a true vapor pressure, as stored, greater than 63 kPa (9.1 psia) and is stored in a storage vessel other than one equipped with a vapor recovery system or its equivalent. NR 420.03(3)(c)(c) Vapor pressure determination. The true vapor pressure shall be determined by application of the procedures in API Publication 2517, 3rd edition, incorporated by reference in s. NR 484.11 (5), in accord with this paragraph. This procedure is dependent upon determination of the average monthly storage temperature and the Reid vapor pressure, which requires sampling of the petroleum liquids in the storage vessels. Unless the department requires in specific cases that the stored petroleum liquid be sampled, the true vapor pressure may be determined by using the average monthly storage temperature and the typical Reid vapor pressure. For those liquids for which certified specifications limiting the Reid vapor pressure exist, that Reid vapor pressure may be used. For other liquids, supporting analytical data shall be made available on request to the department when typical Reid vapor pressure is used. NR 420.03(4)(a)(a) Applicability. In addition to the vessels identified in sub. (1) this subsection applies to all storage vessels for petroleum liquids of more than 7,571 liter (2,000 gallon) capacity. NR 420.03(4)(b)(b) Requirements. No person may place, hold or store in a storage vessel any petroleum liquid which has a true vapor pressure as stored greater than 10.5 kPa (1.52 psia) unless all of the following requirements are met: NR 420.03(4)(b)1.1. Any tank surface exposed to the rays of the sun is painted and maintained white so as to prevent excessive temperature and vapor pressure increases. NR 420.03(4)(b)2.2. The seals of any floating roof are maintained so as to minimize emissions. NR 420.03(4)(b)3.3. All gauging and sampling devices are vapor tight except when gauging or sampling is taking place. NR 420.03(5)(a)(a) Applicability. This subsection applies, subject to the provisions of s. NR 425.03, to all fixed roof storage vessels with capacities greater than 151,412 liters (40,000 gallons) with the exception of those having capacities less than 1,600,000 liters (416,000 gallons) used to store crude petroleum and condensate prior to custody transfer. NR 420.03(5)(b)(b) Storage requirements. No owner or operator of a fixed roof storage vessel to which this subsection applies may permit the storage vessel to be used for storing any petroleum liquid which has a true vapor pressure as stored greater than 10.5 kPa (1.52 psia), unless all of the following requirements are met: NR 420.03(5)(b)1.1. The vessel has been retrofitted with an internal floating roof equipped with a closure seal, or seals, to close the space between the roof edge and tank wall, or with equally effective alternative controls approved by the department. NR 420.03(5)(b)3.3. The vessel is maintained such that there are no visible holes, tears, or other openings in the seal or any seal fabric or materials. NR 420.03(5)(b)4.4. All openings, except stub drains, are equipped with covers, lids, or seals such that: NR 420.03(5)(b)4.a.a. The cover, lid or seal is in the closed position at all times except when in actual use. NR 420.03(5)(b)4.b.b. Automatic bleeder vents are closed at all times except when the roof is floated off or landed on the roof leg supports. NR 420.03(5)(b)4.c.c. Rim vents, if provided, are set to open when the roof is being floated off the roof leg supports or at the manufacturer’s recommended setting. NR 420.03(5)(b)5.5. Routine inspections are conducted through roof hatches at monthly intervals during the ozone season. These routine inspections shall include, at a minimum, a visual examination to determine that the roof is resting on the liquid surface, no liquid has accumulated on the roof, no seal is detached and that there are no tears or holes in the seal material. NR 420.03(5)(b)6.6. The vessel is repaired or removed from service as expeditiously as practicable, but no later than 45 days after any routine inspection in which any of the defects described in subd. 5. are found, unless an extension is granted by the department. If a defect identified in subd. 5. cannot be repaired or the vessel removed from service within 45 days, a one time 30 day extension may be requested by the owner or operator. The department may grant such a request if the owner or operator demonstrates that alternative storage capacity is not available or that repair or removal of the tank from service is infeasible for reasons beyond the control of the owner or operator. NR 420.03(5)(b)7.7. A complete inspection of cover and seal is conducted periodically as required by par. (c) NR 420.03(5)(b)8.8. Records are maintained and retained for a minimum of 5 years, unless otherwise noted, that shall include both of the following: NR 420.03(5)(b)8.a.a. The results of inspections conducted under subds. 5. and 7., including LEL readings, if applicable. All LEL readings and inspection report records shall be maintained for a minimum of 10 years if the facility elects to comply with par. (c) through use of par. (c) 2. NR 420.03(5)(c)(c) Complete inspection requirements. All fixed roof storage vessels at a facility to which this subsection applies are required to periodically undergo a complete inspection of cover and seal, and all shall use either subd. 1. or 2. to demonstrate compliance. No facility may use different compliance methods for different fixed roof storage vessels to comply with this paragraph. The complete inspection shall be conducted according to one of the following schedules: NR 420.03(5)(c)1.1. Whenever a fixed roof storage vessel is emptied and degassed or at least every 5 years, whichever is more frequent. NR 420.03(5)(c)2.2. Whenever a fixed roof storage vessel is emptied and degassed or at least every 10 years, whichever is more frequent, if all of the following requirements are met: NR 420.03(5)(c)2.a.a. The routine monthly inspections during the ozone season, in addition to meeting the requirements of par. (b) 5., include the measurement with an explosimeter of the organic vapor space above the internal floating roof to demonstrate that the organic vapor concentration does not exceed 50% of the lower explosive limit (LEL) for the stored petroleum liquid. NR 420.03(5)(c)2.b.b. The fixed roof storage vessel is repaired or removed from service as expeditiously as practicable, but no later than 45 days after the completion of the routine inspection, if any of the defects described in par. (b) 5. are found or if the measurement required under subd. 2. a. exceeds 50% of the LEL. NR 420.03(5)(c)2.c.c. Repair steps meeting the requirements of subd. 2. b. may include tests, maintenance or inspections followed by LEL measurements below 50% within 45 days of the initial LEL reading exceeding 50% that confirm further repair or removal of the tank from service is not warranted.