Wisconsin Administrative Code
Department of Natural Resources
NR 400-499 - Environmental Protection - Air Pollution Control
Chapter NR 420 - Control Of Organic Compound Emissions From Petroleum And Gasoline Sources
Section NR 420.03 - Storage of petroleum liquids

Universal Citation: WI Admin Code ยง NR 420.03

Current through August 26, 2024

(1) APPLICABILITY. The storage, recordkeeping and maintenance requirements of subs. (2), (3) and (4) apply to all storage vessels for petroleum liquids of more than 151,412 liter (40,000 gallon) capacity on which construction or modification is commenced after July 1, 1975, with the exception of:

(a) Storage vessels being used for number 2 through number 6 fuel oils as specified in ASTM D396-02, gas turbine fuel oils numbers 2-GT through 4-GT as specified in ASTM D2880-00, or diesel fuel oils numbers 2-D and 4-D as specified in ASTM D975-02. These ASTM standards are incorporated by reference in s. NR 484.10(8), (13) and (40).

(b) Storage vessels for the crude petroleum or condensate stored, processed or treated at a drilling and production facility outside a metropolitan county prior to custody transfer.

(c) Pressure vessels which are designed to operate at pressures in excess of 104 kPa (15 psig) without emissions except under emergency conditions.

(d) Subsurface caverns or porous rock reservoirs.

(e) Horizontal underground storage tanks used to store JP-4 jet fuel.

(2) STORAGE REQUIREMENTS. The owner or operator of any storage vessel to which this section applies shall store petroleum liquids as follows:

(a) If the true vapor pressure of the petroleum liquid, as stored, is equal to or greater than 10.5 kPa (1.52 psia) but not greater than 77 kPa (11.1 psia), the storage vessel shall be equipped with a floating roof, a vapor recovery system or an equally effective alternative control method approved by the department.

(b) If the true vapor pressure of the petroleum liquid, as stored, is greater than 77 kPa (11.1 psia), the storage vessel shall be equipped with a vapor recovery system or an equally effective alternative control method approved by the department.

(3) RECORDKEEPING.

(a) General records. The owner or operator of any storage vessel to which this section applies shall, for each such storage vessel, maintain a file of each type of petroleum liquid stored, the typical Reid vapor pressure of each type of petroleum liquid stored and the dates of storage. Dates on which the storage vessel is empty shall be indicated.

(b) Vapor pressure dependent records. The owner or operator of any storage vessel to which this section applies shall, for each such storage vessel, determine and record the average monthly storage temperature and true vapor pressure of the petroleum liquid stored at that temperature if one of the following applies:
1. The petroleum liquid has a true vapor pressure, as stored, greater than 3.5 kPa (0.51 psia) but less than 10.5 kPa (1.52 psia) and is stored in a vessel other than one equipped with a floating roof, a vapor recovery system or their equivalents.

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.

(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.

(4) EQUIPMENT MAINTENANCE.

(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.

(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:
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.

2. The seals of any floating roof are maintained so as to minimize emissions.

3. All gauging and sampling devices are vapor tight except when gauging or sampling is taking place.

(5) FIXED ROOF VESSELS.

(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.

(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:
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.

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.

4. All openings, except stub drains, are equipped with covers, lids, or seals such that:
a. The cover, lid or seal is in the closed position at all times except when in actual use.

b. Automatic bleeder vents are closed at all times except when the roof is floated off or landed on the roof leg supports.

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.

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.

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.

7. A complete inspection of cover and seal is conducted periodically as required by par. (c)

8. Records are maintained and retained for a minimum of 5 years, unless otherwise noted, that shall include both of the following:
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.

b. The information required under sub. (3).

(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:
1. Whenever a fixed roof storage vessel is emptied and degassed or at least every 5 years, whichever is more frequent.

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:
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.

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.

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.

(d) Notification and change of compliance method requirements. All existing facilities which have one or more storage vessels subject to par. (c) shall notify the department in writing, by January 3, 2000, as to whether the facility will comply with this section under the provisions of par. (c) 1. or 2. After January 3, 2000, a facility owner or operator may only change the compliance option from par. (c) 1. to par. (c) 2. after completing a complete inspection of every affected fixed roof storage vessel at the facility. For any newly constructed facility, the owner or operator shall notify the department prior to commencing operation as to which compliance option will be used. A facility owner or operator may at any time elect to change the compliance option from par. (c) 2. to par. (c) 1. provided the following conditions are met:
1. The facility owner or operator notified the department, in writing, at least 30 days prior to the date on which the facility owner or operator plans to begin meeting the requirements of par. (c) 1.

2. All tanks at the facility were found to be in compliance with the 50% LEL requirement of par. (c) 2. during their last LEL measurement.

(6) EXTERNAL FLOATING ROOF VESSELS.

(a) Applicability. This subsection applies, subject to the provisions of s. NR 425.03(4) or (5), to all storage vessels equipped with external floating roofs having capacities greater than 151,412 liters (40,000 gallons) with the exception of:
1. Storage vessels having capacities less than 1,500,000 liters (396,270 gallons) used to store crude petroleum and condensate prior to custody transfer.

2. Storage vessels used to store waxy, heavy pour crude petroleum.

3. Storage vessels used solely for petroleum liquids with a true vapor pressure of less than 10.5 kPa (1.52 psia).

4. Storage vessels used solely for petroleum liquids with a true vapor pressure of less than 27.6 kPa (4.0 psia), and which are of welded construction, and presently possess a metallic-type shoe seal, a liquid-mounted foam seal, a liquid-mounted liquid filled type seal, or equally effective alternative control, approved by the department.

5. Storage vessels of welded construction, equipped with metallic-type shoe primary seal which has a secondary seal from the top of the shoe seal to the tank wall.

(b) Storage requirements. No owner or operator of a storage vessel equipped with an external floating roof to which this subsection applies may permit such storage vessel to be used for storing any petroleum liquid unless all of the following requirements are met:
1. The vessel has been fitted with a continuous secondary seal extending from the floating roof to the tank wall, or the vessel has been fitted with an equally effective alternative control, approved by the department.

2. The vessel is maintained such that all seal closure devices meet the following requirements:
a. There are no visible holes, tears, or other openings in the seal or any seal fabric or material.

b. The seal or seals are intact and uniformly in place around the circumference of the floating roof between the floating roof and the tank wall.

c. For vapor-mounted seals, the accumulated area of gaps exceeding 0.32 cm (1/8 in) in width between the secondary seal and tank wall may not exceed 21.2 cm2 per meter (1.00 in2 per foot) of tank diameter.

3. All openings in the external floating roof, except for automatic bleeder vents, rim space vents, and leg sleeves, are:
a. Equipped with covers, seals, or lids kept in the closed position except when in actual use.

b. Equipped with projections into the tank which remain below the liquid surface at all times.

4. Automatic bleeder vents are closed at all times except when the roof is floated off or landed on the roof leg supports.

5. Rim vents are set to open only when the roof is being floated off the leg supports or at the manufacturer's recommended setting.

6. Emergency roof drains are provided with slotted membrane fabric covers or equivalent covers which cover at least 90% of the area of the opening.

7. Routine visual inspections are conducted of all seals and seal closure devices at monthly intervals during the ozone season.

8. The secondary seal gap of vapor-mounted seals is measured annually, in a manner approved by the department.

9. The vessel is repaired or removed from service as expeditiously as practicable, but no later than 45 days after the completion of the routine inspection under subd. 7. or the annual inspection under subd. 8., if the inspection reveals a failure to meet any of the requirements of subd. 2.

10. Records are maintained and retained for a minimum of 5 years that shall include:
a. The results of inspections conducted under subds. 7. and 8.

b. The information required under sub. (3) (a) and (b) (intro.).

(7) EXTERNAL FLOATING ROOF VESSELS WITH NO SECONDARY SEAL REQUIREMENT.

(a) Applicability. This subsection applies to all storage vessels with capacities greater than 151,412 liters (40,000 gallons) equipped with external floating roofs operating without secondary seals or their approved equivalent pursuant to sub. (6) (a) 1. to 4.

(b) Recordkeeping. The owner or operator of a petroleum liquid storage vessel with an external floating roof not covered under sub. (6) but containing a petroleum liquid with a true vapor pressure greater than 7.0 kPa (1.0 psia), shall maintain and retain for at least 2 years records of the average monthly storage temperature, the type of liquid, throughput quantities and the maximum true vapor pressure for all petroleum liquids with a true vapor pressure greater than 7.0 kPa (1.0 psia).

(8) ALTERNATIVE CONTROL. Any alternative control method approved by the department under sub. (2), (5) (b) 1. or (6) (b) 1. shall be submitted to, and will not become effective for federal purposes until approved by, the administrator or designee as a source-specific revision to the department's state implementation plan for ozone.

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