2.4 Fueling Systems Management
2.4.1 Underground Storage Tanks (UST)
2.4.1.1 Conformance with Regulations, Codes, Standards, and Specifications
Underground Fuel Storage Tanks (UST) containing fuels or chemicals designated hazardous by the United States Environmental Protection Agency (U.S. EPA) or by the applicable codes and standards, shall be approved secondary containment systems and shall be in strict conformance with the most recent applicable regulations, manufacturer’s recommendations, codes, and standards.
A. U.S. EPA Final Rule; Federal Relations: Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks. Title 40, Code of Federal Regulations, Part 280 (40 CFR Part 280).
B. State of Maryland, Department of Environment (MDE), Title; 26, Subtitle 10, Oil Pollution and Tank Management (COMAR 26.10).
C. State of Maryland, Department of Public Safety and Correctional Services, Title; 12, Subtitle 03, Fire Prevention Commission (COMAR 12.03).
D. National Fire Prevention Association (NFPA) Standards:
1. NFPA 30: Flammable and Combustible Liquids Code.
2. NFPA 30A: Motor Fuel Dispensing Facilities and Repair Garage.
3. NFPA 31: Standard for Installation of Oil-Burning Equipment.
4. NFPA 70: National Electric Code.
E. Petroleum Equipment Institute (PEI) Recommended Practice (RP) For the Installation of Underground Liquid Storage Systems (PEI/RP 100-05).
F. American Petroleum Institute (API) Recommended Practice (RP) For the Installation of Underground Petroleum Storage Systems (API/RP 1615).
G. American Petroleum Institute (API) Standard 2000, Venting Atmospheric and Low-Pressure Storage Tanks.
H. Listing and Labeling: Provide equipment and accessories that are listed and labeled as defined in the National Electric Code (NEC), Article 100.
2.4.1.2 Underground Fuel Storage Tank Requirements
Underground storage tanks shall be warranted for 30 years against failure due to internal/external corrosion and when properly installed, against structural failure. Underground storage tanks shall also be UL listed of one of the following type:
A. Fiberglass Reinforced Polyester UST
1. The underground storage tank shall be constructed of double-walled, fiberglass reinforced polyester (FRP).
2. Tank shall be manufactured with 100% resin and glass-fiber reinforcement. Tank shall include an integral fiberglass-reinforced polyester (FRP) secondary containment.
3. The tank shall be double wall construction for containment of leaks with interstitial space between primary (internal) and secondary (external) tank walls to allow for free flow of all leaked product from the primary tank. The entire tank system shall be fabricated as a single unit and delivered to the job site as a complete assembly.
4. Both the primary storage tanks and secondary containment shall be UL approved for their use and shall be compatible with gasoline, gasohol, ethanol, E85, methanol, oxygenated fuels, jet fuel, av-gas, kerosene, diesel fuel, bio-diesel, and motor oil (new or used) at ambient underground temperature or fuel oil stored at temperatures not to exceed 100ºF. Tanks shall be chemically inert to petroleum products.
5. Tank shall be designed with one 4-inch fitting that will access the tank bottom between the primary and secondary walls (annular space).
6. Tanks with a 6-foot diameter or larger shall have a UL approved, integrally mounted reservoir installed on the tank for hydrostatic monitoring of the interstitial space. The reservoir shall be constructed of fiberglass reinforced plastic materials and warranted for 30 years against failure due to internal/external corrosion and when properly installed, against structural failure (same as tank warranty).
7. The annular space of the tank shall be filled with a Brine Antifreeze solution provided by the tank manufacturer.
8. The tank shall have one (1) 22-inch I.D. flanged manway complete with UL listed gaskets, bolds and cover and appropriate hold-down straps and lifting lugs.
9. Each tank shall be provided with glass fiber reinforced plastic anchor straps for each tank. The number and location of straps shall be as specified by manufacturer. Each strap shall be capable of withstanding a maximum load for each tank diameter per the manufacturer’s specifications. Straps shall be standard as supplied by the tank manufacturer.
10. Precast concrete deadman anchors or poured-in-place concrete hold down slab shall be compatible with the manufacturers anchor straps. The concrete deadman or hold down slab and anchor straps shall prevent the fiberglass tank from floating out of the ground when the tank installation in an area of high groundwater or saturated soil conditions.
11. The tank shall support accessory equipment such as ladders, submersible pumps, containment sumps, drop tubes, etc. when properly installed.
12. Threaded fittings and optional equipment shall be consistent for use as directed by the Engineer.
13. Striker plates shall be installed under each service fitting and manway opening.
14. The Underwriters Laboratories (UL) label shall be permanently affixed to each tank.
15. Provide lifting lug(s) on all tanks. Lifting lug system shall be capable of withstanding weight of tank with a sufficient safety factor.
16. The tank shall withstand surface H-20 axle loads when properly installed according to manufacturer’s installation instructions. The tank shall withstand aircraft loading if the proposed location requires such loading.
B. HMW Polymer Extruded Double-wall Steel UST
1. The underground storage tank shall be double-walled steel with a primary steel storage tank contained in a 360º, air-pressure testable and unbreakable jacket, bonded together and sealed off at the fittings. The secondary containment tank wall shall be made of high molecular weight (HMW) polymer extruded and applied at the tank factory. The tank shall be designed with one (1) 22-inch I.D. flanged manway complete with UL listed gaskets, bolts and cover, and appropriate hold-down straps and lifting lugs.
2. The tank shall be double wall construction for containment of leaks with interstitial space between primary (internal) and secondary (external) tank walls to allow for free flow of all leaked product from the primary tank.
3. Tank shall be designed with one 2-inch fitting that will provide access to the tank bottom between the primary and secondary walls (annular space).
4. The tank shall withstand surface H-20 axle loads when properly installed according to manufacturer’s installation instructions. The tank shall withstand aircraft loading if the proposed location requires such loading.
5. The tank shall be shipped, delivered, installed and 75% backfilled while maintaining a constant vacuum (minimum 12 inches of mercury vacuum) on the interstitial space to assure integrity of both the primary storage tank and secondary containment tank wall simultaneously.
6. Each tank shall be provided with appropriate anchor straps, per the manufacturer’s recommendations. The number and location of straps shall be as specified by manufacturer. Each strap shall be capable of withstanding a maximum load for each tank diameter per the manufacturer’s specifications. Straps shall be standard as supplied by the tank manufacturer.
7. Precast concrete deadman anchors or poured-in-place concrete hold down slab shall be compatible with the manufacturers anchor straps. The concrete deadmen or hold down slab and anchor straps shall prevent the tank from floating out of the ground when the tank installation in an area of high groundwater or saturated soil conditions.
8. The tank shall support accessory equipment such as ladders, submersible pumps, containment sumps, drop tubes, etc. when properly installed.
9. Threaded fittings and optional equipment shall be consistent for use as directed by the Engineer.
10. Striker plates shall be installed under each service fitting and manway opening.
11. The Underwriters Laboratories (UL) label shall be permanently affixed to each tank.
12. Provide lifting lug(s) on all tanks. Lifting lug system shall be capable of withstanding weight of tank with a significant safety factor.
C. Double-wall Polyurethane-coated Steel UST
1. The underground storage tank shall be double-walled steel, externally protected with 75mils thick of Polyurethane Coating System per corrosion control system specifications, and built in accordance with UL 58 Type I Construction criteria.
2. The corrosion control system shall have a minimum of 30-year warranty against failure due to exterior corrosion and internal corrosion when used with compatible petroleum products. The tank will not require sacrificial anodes and therefore will not require cathodic monitoring.
3. The tank shall be double wall construction for containment of leaks with interstitial space between primary (internal) and secondary (external) tank walls to allow for free flow of all leaked product from the primary tank.
4. Tank shall be designed with one 2-inch fitting that will provide access to the tank bottom between the primary and secondary walls (annular space).
5. The tank shall withstand surface H-20 axle loads when properly installed according to manufacturer’s installation instructions. The tank shall withstand aircraft loading if the proposed location requires such loading.
6. The tank shall be shipped, delivered, installed and 75% backfilled while maintaining a constant vacuum (minimum 12 inches of mercury vacuum) on the interstitial space to assure integrity of both the primary storage tank and secondary containment tank wall simultaneously.
7. Each tank shall be provided with appropriate anchor straps, per the manufacturer’s recommendations. The number and location of straps shall be as specified by manufacturer. Each strap shall be capable of withstanding a maximum load for each tank diameter per the manufacturer’s specifications. Straps shall be standard as supplied by the tank manufacturer.
8. Precast concrete deadman anchors or poured-in-place concrete hold down slab shall be compatible with the manufacturer’s anchor straps. The concrete deadman or hold down slab and anchor straps shall prevent the tank from floating out of the ground when the tank installation in an area of high groundwater or saturated soil conditions.
9. The tank shall support accessory equipment such as ladders, submersible pumps, containment sumps, drop tubes, etc. when properly installed.
10. Threaded fittings and optional equipment shall be consistent for use as directed by the Engineer.
11. Striker plates shall be installed under each service fitting and manway opening.
12. The Underwriters Laboratories (UL) label 58 Type I Construction label shall be permanently affixed to each tank.
13. Provide lifting lug(s) on all tanks. Lifting lug system shall be capable of withstanding weight of tank with a significant safety factor.
2.4.1.3 Underground Storage Tank Piping
All product piping that is buried underground shall be made of non-ferrous materials and shall be designed as double containment components.
A. Double-Wall Flexible Plastic
1. Underground piping shall be 1-inch – 1.5-inch diameter Flexible, Double-Containment Piping and MUST comply with UL 971 (2004).
2. Ducting for flexible double wall pipe shall be 4” nominal diameter HDPE duct utilized as a carrier for double wall pipe to allow ease of replacement of double wall pipe if leakage is detected. Duct shall be a minimum SDR of 11 with a wall thickness of 0.409”. Bends within the duct shall be limited to a bend radius that is greater than or equal to the bend radius of the flexible double containment product piping.
3. Flexible plastic piping systems shall not be utilized as direct fill lines, vent lines, stage II vapor recovery lines or aboveground.
4. An automatic line leak detector must be installed on each fuel supply line that conveys product under pressure.
B. Coaxial Fiberglass Pipe
1. An automatic line leak detector must be installed on each fuel supply line that conveys product under pressure.
2. FRP piping shall not be utilized as direct fill lines or aboveground.
2.4.2 Aboveground Storage Tanks
2.4.2.1 Conformance with Regulations, Codes, Standards, and Specifications
Aboveground Storage Tanks (AST) containing fuels or chemicals designated hazardous by the EPA or by the applicable codes and standards, shall be approved secondary containment systems and shall be in strict conformance with the most recent applicable regulations, manufacturer’s recommendations, codes, and standards.
A. U.S. EPA Spill Prevention Control and Countermeasure Plans. 40 CFR Part 112 as approved by MDOT MAA Manager of Environmental Compliance.
B. State of Maryland, Department of Public Safety and Correctional Services, Title; 12, Subtitle 03, Fire Prevention Commission (COMAR 12.03).
C. State of Maryland, Department of the Environment (MDE), Title; 26, Subtitle 10, Oil Pollution and Tank Management (COMAR 26.10).
D. National Fire Prevention Association (NFPA) Standards:
2. NFPA 30: Flammable and Combustible Liquids Code.
3. NFPA 30A: Motor Fuel Dispensing Facilities and Repair Garage.
4. NFPA 31: Standard for Installation of Oil-Burning Equipment.
5. NFPA 58: Liquefied Petroleum Gas Code.
6. NFPA 59: Utility LP-Gas Code
7. NFPA 59A: Standard for the Production, Storage, and Handling of Liquefied Natural Gas (LNG).
8. NFPA 70: National Electric Code.
9. NFPA 385: Standard for Tank Vehicles for Flammable and Combustible Liquids.
10. NFPA 395: Standard for the Storage of Flammable and Combustible Liquids at Farms and Isolated Sites.
11. NFPA 704: Standard System for Identification of Hazards of Materials for Emergency Response.
12. NFPA 780: Standard for the Installation of Lightning Protection Systems.
E. Petroleum Equipment Institute (PEI) Recommended Practice (RP) For the Installation of Aboveground Storage Systems for Motor-Vehicle Fueling (PEI/RP 200-03).
F. Underwriters Laboratories Inc. (UL) listing required – UL 142 – Standards for Steel Aboveground Tanks for Flammable and Combustible Liquids.
G. Underwriters Laboratories Inc. (UL) listing required – UL 2085 – Standards for Protected Aboveground Tanks for Flammable and Combustible Liquids.
H. American Petroleum Institute (API) Standard 2000, Venting Atmospheric and Low-Pressure Storage Tanks.
I. Steel Tanks Institute (STI), Shop Fabricated Atmospheric Tank Documents.
2.4.2.2 Aboveground Fuel Storage Tank Requirements
A. Storage tanks shall be warranted for 30 years against failure due to internal/external corrosion and when properly installed, against structural failure.
B. Aboveground storage tanks shall be UL-2085 or UL-142 listed and shall be equipped with the following design parameters:
1. “Protected” Aboveground Storage Tank System (UL-2085)
a. The storage tank shall be a UL-2085 thermally insulated double-walled, steel aboveground storage tank designed for the storage of flammable and combustible liquids at atmospheric pressure. The tank shall include steel primary tank, integral steel secondary containment and thermal insulation that provides a minimum two-hour fire rating. The entire tank system shall be factory fabricated as a single unit and delivered to the job site as a complete assembly. Secondary containment shall be a minimum 110% of the primary containment volume.
b. Inner and outer tank shall be manufactured in accordance with UL-142 Standard for Steel Aboveground Tanks for Flammable and Combustible Liquids. Entire tank shall be labeled for Underwriters Laboratories UL-2085 Standard for Insulated Secondary Containment Aboveground Tank for Flammable Liquids. The tank design shall comply with UL-2085 “Protected” Tank standard and shall be tested for Ballistics, Impact, Hose Stream, and Pool Fire UL-2085 performance standards. Each tank shall be delivered as a completed UL-listed assembly.
c. Tank shall be manufactured and labeled per NFPA 704 for type of hazardous material stored and in strict accordance with Steel Tank Institute (STI) Fireguard® Thermally Insulated, Double Wall Steel Aboveground Storage Tank standards as applied by a license of the STI. Tanks shall be subject to STI’s Quality Assurance program and backed by the STI 30-year limited warranty.
d. Tank shall be fabricated per UL-142 of mild carbon steel with shall seams of continuous lap weld construction. Tank shall be of double wall construction and provide complete secondary containment of the primary storage tank’s contents by an impervious steel outer wall. A minimum of 3-inches of porous, lightweight monolithic thermal insulation material shall be installed at the factory within the interstitial space between the inner and outer wall. The thermal insulating material shall be in accordance with American Society of Testing Materials (ASTM) Standards C-332 and C-495. The thermal insulating material shall allow liquid to migrate through it to the monitoring point. The thermal insulating material shall not be exposed to weathering and shall be protected by the steel secondary containment outer wall.
2. Aboveground Storage Tank System (UL-142)
a. The storage tank shall be a UL-142 double-walled, steel aboveground storage tank designed for the storage of flammable and combustible liquids at atmospheric pressure. The tank shall include steel primary tank and integral steel secondary containment. The entire tank system shall be factory fabricated as a single unit and delivered to the job site as a complete assembly. Secondary containment shall be a minimum of 110% of the primary containment volume. The tank shall be designed for possible relocation at a future date.
b. Inner and outer tank shall be manufactured in accordance with UL-142 Standard for Steel Aboveground Tanks for Flammable and Combustible Liquids. Each tank shall be delivered as a completed UL-listed assembly.
c. Tank shall be fabricated per UL-142 of mild carbon steel with shall seams of continuous lap weld construction. Tank shall be of double wall construction and provide complete secondary containment of the primary storage tank’s contents by an impervious steel outer wall.
C. Each tank shall be designed for possible relocation at a future date. Concrete encased tank designs are not recommended.
D. Each tank shall be equipped with OSHA approved stairs and platforms with handrails, supplied by the manufacturer. For tanks without remote fill assemblies, stairs shall be located at same end of tank as fill pipe, fill pipe shall be fully accessible to fuel delivery operator.
E. Lifting lugs shall be provided at balancing points to facilitate handling and installation of the tank.
F. Exterior protective coatings shall be applied per manufacturer’s recommendations.
G. The interstitial space between tanks must be able to be monitored for leaks.
H. Tank Appurtenances – At a minimum each tank shall be equipped with the following. Any deviations from this requirement must be approved by the Engineer in writing. All tank appurtenances must meet the requirements of NFPA 30 and NFPA 30A.
1. Normal vent;
2. Emergency vent(s);
3. Spill catchment basin;
4. Site gauge capable of providing the level of liquid within the tank to the nearest inch (minimum);
5. Overfill prevention valve;
6. Vent whistle / high level alarm;
7. Fire valve;
8. Ball valve(s);
9. Antisiphon valve / solenoid valve that will prevent the release of liquid from the tank by siphon flow; and
10. Annular space leak detection gauge that will visually alert facility personnel to the presence of liquid within the annular space.
11. Minimum 30” diameter flanged manway access at top centerline of tank for tanks over 5,000gallon capacity.
I. The tank’s primary and secondary containments must be tested for tightness in the factory and in the field (following installation of all components) before commissioning.
2.4.2.3 Aboveground Storage Tank Venting (Normal Vent)
A. Storage tank shall be adequately vented to prevent the development of pressure or vacuum that can damage the tank or exceed the tank’s design pressure during filling or emptying of the tank. Each compartment of the primary tank shall be equipped with a normal venting device sized and installed in accordance with the requirements of NFPA 30, NFPA 30A, and API Standard 2000.
B. The normal vent shall be at least as large as the largest filling or withdrawal connection but shall not be less than 1.25-inches nominal inside diameter.
C. The normal vent for an AST system storing a flammable liquid shall extend a minimum of twelve (12) feet above the ground. The normal vent for an AST system storing a combustible liquid shall extend a minimum of three (3) feet above the top of the tank.
D. The venting device(s) shall be designed so vapors exhaust upward. Vent outlets shall be installed so that vapors will not be trapped by eaves or other obstructions, all vent outlets shall be a minimum of five (5) from building openings and air intakes.
E. Tank vents that are installed within or attached to a canopy shall extend a minimum of five (5) feet above the highest projection of the canopy.
F. Normal vents shall NOT be installed on any compartment of the tank that does not routinely contain petroleum products (i.e., interstitial spaces, closed portions of closed-top dike tanks).
G. Ball float vent checks shall NOT be used with an AST system.
2.4.2.4 Aboveground Storage Tank Venting (Emergency Vents)
A. Every aboveground storage tank shall have emergency relief venting (either through construction of device(s)) that will relieve excessive pressure caused by exposure to fire. This applies to every compartment of the primary tank, the interstitial space of the secondary tank, and the enclosed space of tanks of closed-top dike construction.
B. The necessary emergency relief venting capacity for a tank system shall be in accordance with NFPA 30, NFPA 30A, and the manufacturer’s recommendations.
2.4.2.5 Aboveground Storage Tank Piping
A. Aboveground piping shall be minimum Schedule 40 galvanized steel for ground product fuels and internally lined epoxy-coated or stainless steel for jet fuel. Galvanized piping shall not be used for diesel or aviation fuels.
B. Underground product piping shall be one of the following: UL approved double-walled fiberglass, or UL approved double-walled corrosion resistant flexible petroleum fuel piping including polyethylene conduit, or equal, including the installation of product containment sumps for dispensing units and transition points from aboveground to underground piping.
C. Piping systems of aboveground storage tanks in connection with pumps shall contain a sufficient number of control valves and check valves to control the flow of liquids properly in normal operation and in the event of physical damage or fire exposure.
D. Piping systems affiliated with aboveground storage tanks shall be protected and supported in a way that it will be protected from physical damage and excessive stresses arising from settlement, vibration, expansion, contraction, or exposure to fire.
E. Aboveground product supply piping shall be equipped with the following components, which shall be installed in the following order moving downstream from the tank (unless otherwise specified by the Engineer in writing):
1. Block valve / Ball valve – capable of isolating the tank from the piping.
2. Fire / Emergency valve – capable of automatically closing and isolating the tank and piping in the event of a fire. The fire / emergency valve shall be constructed of steel of nodular iron to prevent failure under fire conditions.
3. Anti-siphon valve / solenoid valve – capable of preventing gravity-discharge / siphon flow of product from damaged piping. The anti-siphon valve may be electrically operated solenoid valves or mechanical check valves that open or close simultaneously with the operation of the pump motor. Anti-siphon valves are only required on tanks where the liquid level in the tank (at any point) is higher than the supply piping or dispensing unit. Where permitted, mechanical anti-siphon valves shall be installed in lieu of electric solenoid valves.
2.4.3 Storage Tanks Associated with Gasoline Dispensing/Motor Vehicle Refueling Facilities (GD/MVRFs)
Please see Chapter 1.6 Gasoline Dispensing/Motor Vehicle Refueling Facilities Permitting Process regarding the Gasoline Dispensing/Motor Vehicle Refueling Facilities Permitting Process and Design Requirements.
For the purposes of this section and all subsequent subsections, “Owner” refers to the Maryland Aviation Administration (MDOT MAA), or either of BWI Marshall and/or Martin State Airports as determined by the context. “Consultant” refers to any entity commissioned to design and/or specify equipment described herein for construction and/or installation at any MDOT MAA facility or location within the BWI Marshall and/or Martin State Airports.
Owner must ensure that proper procedures are followed during product transfer from cargo tanks to storage tanks to minimize vapor releases, such as minimizing gasoline spills, expeditiously cleaning up gasoline spills, using gasketed seals for gasoline containers and storage tank fill pipes, and minimizing product being sent to open waste collection systems that collect and transport gasoline to reclamation and recycling devices such as oil/water separators.
Owner must not permit cargo (delivery) trucks/tanks to unload gasoline into a storage tank unless proper connections in the vapor balance system are established, vapor-tight equipment and connections are used, and the tank truck vapor return equipment/hatches/seals are vapor- tight and compatible with the storage tank vapor balance equipment. Additionally, the cargo tank must carry documentation that it has met specifications of EPA method 27.
Owner must comply with general requirements pertaining to permit duration, availability of permit at permitted location, modifications, inspections, right of entry, violations, and penalties as outlined in Part III of MDE/ARMA’s Air Quality General Permit to Construct Application Package for Motor Vehicle Refueling Facilities.
In addition, the following recordkeeping, testing, notification, and reporting procedures are required for GD/MVRF storage tanks:
A. Recordkeeping
1. For tanks with a monthly throughput of less than 100,000 gallons and Stage I vapor recovery equipment, owner must make gasoline throughput, gasoline spills and cleanups, and maintenance records available within 24 hours of a Maryland Department of the Environment’s Air and Radiation Management Administration (MDE/ARMA) request.
2. For tanks with monthly throughput of 100,000 gallons or more and Stage I vapor recovery equipment, owner must make those records outlined in item 1.a., above, as well as records of all tests performed and all notifications or reports submitted to the EPA or MDE/ARMA available within 24 hours of a MDE/ARMA request.
3. All records must be kept by owner for a period of five years.
4. Additional recordkeeping requirements are outlined for tanks with Stage II vapor recovery equipment (required for all new sources at BWI Marshall and Martin State Airports) in Part II, Section E(2) of MDE/ARMA’s Air Quality General Permit to Construct Application Package for Motor Vehicle Refueling Facilities.
B. Testing
1. For tanks with a monthly throughput of 100,000 gallons or more and Stage I vapor recovery equipment, owner must demonstrate compliance at the time of installation and every three years thereafter with those tests outlined in Section 4.8.5.2, subsection 5(d-g) and in Part II, Section B(1)(c) of MDE/ARMA’s Air Quality General Permit to Construct Application Package for Motor Vehicle Refueling Facilities.
2. Testing frequency as well as additional testing requirements for tanks with Stage II vapor recovery equipment are outlined in Part II, Section B(2) of the Application Package.
3. Owner must ensure that all Stage II equipment is inspected at least daily, and that at least one employee shall be trained to conduct inspections through an approved training course.
C. Notifications
1. Regulatory notifications are required for tanks with monthly throughput of 10,000 gallons or more and Stage I vapor recovery equipment. Notification types include Initial, Compliance, Change in Information, and Performance Test, and requirements increase for tanks with a monthly throughput of 100,000 gallons or more. These notification requirements and procedures are outlined in Part II, Section C of the Application Package.
2. Except for Performance Test notifications, there are no other notification requirements for tanks of any size with Stage II vapor recovery equipment (see Part II, Section C(2) and Section D(2) of the Application Package). Owner must notify MDE/ARMA of any Stage II vapor recovery equipment performance tests at least 5 days before conducting the test. Copies of all test results and reports of test failures must be forwarded to MDE/ARMA within 45 days per Part II, Section D(2) of the Application Package.
D. Reporting
1. There are no reporting requirements for tanks with monthly throughput of less than 100,000 gallons and Stage I vapor recovery equipment. For tanks with monthly throughput of 100,000 gallons or more and Stage I vapor recovery equipment, owner must report results of tests to EPA Region III and the MDE/ARMA within 180 days of test completion (see Part II, Section D(1) of the Application Package).
2.4.4 Oil Water Separator (OWS)
Oil/Water Separators offer environmental protection from surface water pollution meeting the needs of a wide variety of run-off applications. Oil/water separators serving as secondary containment as defined by 40 CFR Part 112.8 must be constructed to contain 110% of the volume of the largest oil storage container. This often includes mobile fuelers and bulk fuel storage containers.
Construction and performance of the oil/water separators must be in accordance with UL SU-2215. Oil/Water separators shall be listed to Underwriter’s Laboratories UL SU-2215. Manufacturer must provide certification documentation detailing criteria under which the system was tested. UL SU-2215 label shall be prominently displayed on manway covers.
Capacities, dimensions, construction, and thickness of separators shall be in strict accordance with UL 58, double-walled construction with 360-degree steel secondary containment. The inner steel tank shall be completely contained within the outer tank, enclosing 100% of the tank volume. The tank must have a double steel shell with a space between the layers. The space between the inner and outer steel walls shall be monitored with an approved leak detection device.
Oil/Water separators shall have the structural strength to withstand static and dynamic hydraulic loading while empty and during operating conditions. The oil/water separators dimensions and thickness shall be in strict compliance with Roark’s Formulas for Stress and Strain as presented in UL 58. Calculations shall be submitted to project Design Engineer to document structural strength under specified overbearing or external pressure. These calculations shall be included in the submittal for the Oil/water separator. The separator shall be installed in accordance with manufacturer’s recommendations. Oil/water separators installed below ground shall be installed to withstand H-20 or aircraft rated loading depending on location.
Coalescer area calculations also must be provided during the submittal process and should illustrate specified performance under laminar flow conditions. Submitted calculations shall take into account the rate of flow, potential surge flow, influent concentration, particle characteristics (20-micron), fluid temperature, fluid specific gravity and pH.
Separators must be designed to remove all free oil droplets equal or greater than 20 microns. In addition, the effluent quality must meet a discharge limit of 15mg/L Oil and grease.
Corrosion control systems for separators shall be in accordance with UL 1746 standard for external corrosion protection systems for steel underground tanks. Accepted exterior surfaces include: polyurethane (PUR), polyurea, or fiber-reinforced plastic (FRP) coated systems. Galvanic-type cathodic protection systems are not acceptable. Each separator STI corrosion control system shall include a 15 mil thick interior polyurethane coating and all interior seams shall be steel welded before sand blasting and interior coating.
Oil/water separators may provide treatment with flow-through or actuated inlet tanks. Oil/water separator systems shall be fabricated, inspected and tested for leakage before shipment from the manufacturer as completely assembled units. The oil/water separator shall be tested in accordance with NFPA 30 Chapter 21.5.2 before being placed into service.
Separators shall never be intended for use with hazardous chemicals. Oil/water separators should not be used with additional tanks for collection of oil effluent downstream of the unit discharge.
The source of the influent to the separator shall be gravity flow from storm water runoff, hydrocarbon spills, and/or cleaning/maintenance operations.
Oil/water separator local alarm control panel shall consist of audible and visual alarms generated. Alarms shall consist of “high” oil level, “high, high” oil level, and “leak” detection. Control panel shall consist of NEMA 4 enclosure and level sensors shall be intrinsically safe. Liquid level sensing device shall comply with the Standard for Liquid Level Indicating Gauges for Oil Burner Fuels, UL 180, or Control Equipment for use with Flammable Liquid Dispensing Devices, UL 1238.
Separators shall be furnished with flanged inlet and outlet pipe connections.
Separators shall utilize necessary appurtenances, including, but not limited to, liquid level devices, overpressure devices, venting, heaters, pumps, monitors, shutoff valves, control panels, or other individual mechanical or electrical components.
Oil/water separators shall meet the following requirements:
A. Must comply with Standard for External Corrosion Protection Systems for Steel Underground Storage Tanks—UL 1746
B. Normal Venting for Underground Storage Tanks—National Fire Protection Association NFPA 30, 2012. Flammable and Combustible Liquids Code.
C. Erosion and Sediment Control—COMAR 26.17
D. Gaskets and Seals—UL 157
E. Underwriter’s Laboratories UL SU-2215
Design must maintain positive drainage through the unit. Piping utilized for drainage from the unit shall be sized based on maximum discharge flowrates from the unit, pipe capacity, and necessary pipe strength based on depth of below ground pipe placement. Piping shall be installed with all necessary appurtenances, including seals at piping connections to prevent contamination by unit, cleanouts to allow access to entire length of installed piping, and necessary valves. Oil/water separator inlet and outlet piping shall be installed with a minimum slope of 1 percent, and to discharge non-erosively.
Oil water separator must be properly vented to prevent flow siphoning through the tank. Comply with oil/water separator manufacturer recommendations for vent pipe size and locations.
Oil/water separator must contain a minimum of two manways. One manway shall be directly above coalescers (either parallel plates or coalescer balls acceptable) to provide easy access during maintenance. The second manway shall be directly above either a final polishing coalescer, if applicable, or the sludge chamber. Each manway dimensions shall facilitate easy removal of either device during maintenance. No manway shall be less than ID 30 inches in size. The manway covering must be in accordance with Volume 2, Section 6.2.2 Manhole/Handhole Covers/LIDS.
Each separator shall be provided with a minimum warranty of one year material and workmanship against structural failure following placement into service.
Separators must be designed to remove all free oil droplets equal or greater than 20 microns. In addition, the effluent quality must meet a discharge limit of 15mg/L oil and grease.
Selected oil/water separator manufacturer shall have at least 5 years of experience in manufacturing similar units for comparable applications.
If there is a conflict between the MDOT MAA design standards and federal, state, or local code, the latest code or policy will govern.
2.4.5 Fuel Truck Parking
The design of all facilities at BWI Marshall and MTN, involving fuel loading and/or parking areas for mobile or portable fuel/oil storage containers must comply with NFPA 407, and must meet 40 CFR, Part 112 requirements of the Environmental Protection Agency’s Spill Prevention and Control Countermeasures (SPCC).
The MDOT MAA requires all owners of existing fuel operations at BWI Marshall and MTN to construct the secondary containment. New facilities must construct the required secondary containment prior to beginning operation. The requirement for secondary containment applies but is not limited to, the following conditions:
A. Fuel truck parking areas where filled and parked fuel trucks are left unattended. The fuel truck parking areas must be provided with secondary containment capable of holding the volume of the largest tank.
B. Truck loading/unloading areas. Areas where fuel is loaded or unloaded from a tank truck to a storage tank, or vice-versa, must be provided with secondary containment capable of holding at least the maximum capacity of any single compartment of a truck using the facility.