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SynC · Editorial revision

Fuel Storage Tanks

Revision5
EditedOct 12, 2026
StatusCurrent
Contents

View changes in this revision   Revision history

Current revision. This is editorial revision 5, the current text of this standard. Read it on the standard's page.

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)
P1 batch 3: knife gate valves, water storage tanks, water wells, cathodic protection and instrumentation cable now owned; bare-text mentions re-pointed to the new standards

1 Scope

NOTE This standard covers the fuel storage tank as a vessel, from the shell and its secondary containment to the appurtenances mounted on the tank itself: the fill connection with its spill container and overfill prevention device, the normal and emergency vent devices at the tank openings, the leak detection sensors in the interstitial space or the containment, the level gauge and its alarm contacts, the manway and the nozzles, the saddles, skid, or legs, the corrosion protection, and the anchorage to the foundation or the flotation restraint in the excavation. (1.1)
NOTE A tank belongs to this standard in any of four roles: a bulk storage tank remote from the equipment it serves, a sub-base tank built into the base of a packaged engine-generator, a day tank at the equipment, or an ASME container storing propane for on-site equipment. The role decides which articles apply and what the capacity follows from, so the role is the first selection on the datasheet. (1.2)
NOTE The boundary with the fuel-oil system is the face of the tank nozzle. Everything that connects to a nozzle and carries fuel, vapor, or a signal away from the tank, including the fill piping to a remote fill station, the vent piping to its termination, the supply and return piping, the pumps and their controls, fuel polishing, tank heating, and the fuel-oil monitoring console, is furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems. For a propane container the boundary is the outlet of the container service valve, and the first-stage regulator mounted there begins the system furnished under Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping. (1.3)
NOTE The following are governed elsewhere and are outside this standard. (1.4)
  • The engine, the alternator and its excitation, the governor and voltage regulator, the exhaust silencer, the enclosure, and the starting batteries of the engine-generator (GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators)
  • The burner, the oil train downstream of the appliance shutoff valve, and the venting of a boiler (BoilersBoilersResolves to the current adopted revision.sync/boilers)
  • The class and runtime of an emergency or standby power system and the capacity its alternate source carries (Emergency And Standby PowerEmergency and Standby Power SystemsResolves to the current adopted revision.sync/emergency-and-standby-power)
  • Motor-vehicle dispensing stations, aviation and marine fueling, and the Class I liquid tanks that serve them under NFPA 30A
  • Field-erected tanks built to API 650 or API 620, oil-water separators, and chemical storage tanks
  • Water storage tanks: Water Storage TanksWater Storage TanksResolves to the current adopted revision.sync/water-storage-tanks
  • The concrete pad or foundation as a structure (Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads, Shallow FoundationsShallow Foundations (Spread and Strip Footings)Resolves to the current adopted revision.sync/shallow-foundations), the anchor rods cast into it (Structural Steel Anchor BoltsAnchor Rods and Embedded SteelResolves to the current adopted revision.sync/structural-steel-anchor-bolts), and the anchors drilled into it (Post Installed AnchorsPost-Installed Concrete and Masonry AnchorsResolves to the current adopted revision.sync/post-installed-anchors)
  • Excavation for an underground tank, worker protection, construction groundwater control, and backfill above the tank excavation (EarthworkEarthworkResolves to the current adopted revision.sync/earthwork, Excavation Support And DewateringExcavation Support and DewateringResolves to the current adopted revision.sync/excavation-support-and-dewatering)
  • Grading and drainage of the tank area so that a release is held away from storm inlets (Site Rough GradingSite Grading and Subgrade PreparationResolves to the current adopted revision.sync/site-rough-grading), and the spill-control shutoff at the outlet of a stormwater facility (Stormwater Management SystemsStormwater Management and Detention SystemsResolves to the current adopted revision.sync/stormwater-management-systems)
  • The grounding electrode system and the bonding of the tank and its piping (Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding)
  • The bollards and barriers that protect an aboveground tank or container from vehicle impact (Site Furnishings And BollardsSite Furnishings and BollardsResolves to the current adopted revision.sync/site-furnishings-and-bollards)
  • The raceway and cable that carry the leak, level, and alarm signals from the tank (Raceways And ConduitRaceways and ConduitResolves to the current adopted revision.sync/raceways-and-conduit, Conductors And CablesConductors and CablesResolves to the current adopted revision.sync/conductors-and-cables)
  • The output signal type and the hazardous-location protection of a level transmitter or temperature element that reports to a plant monitoring system (Pressure InstrumentationPressure InstrumentationResolves to the current adopted revision.sync/pressure-instrumentation, Temperature InstrumentationTemperature InstrumentationResolves to the current adopted revision.sync/temperature-instrumentation)
1.5 The location of each tank, whether outdoors, inside a building, or below grade, shall be as indicated on the contract drawings.
1.6 The Contractor shall coordinate the nozzle schedule, the fill point, the vent terminations, the signal destinations, and the anchorage of each tank with the standards named in this section before the tank is released for fabrication.

2 Referenced Standards

2.1 Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
2.2 Where the contract documents, the adopted codes, the Authority Having Jurisdiction, or two referenced standards impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
Standard Title
NFPA 30 Flammable and Combustible Liquids Code
NFPA 31 Standard for the Installation of Oil-Burning Equipment
NFPA 37 Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines
NFPA 58 Liquefied Petroleum Gas Code
NFPA 70 National Electrical Code (Articles 500 through 505, hazardous locations)
NFPA 110 Standard for Emergency and Standby Power Systems
NFPA 704 Standard System for the Identification of the Hazards of Materials for Emergency Response
IFC International Fire Code (Chapter 57 and Chapter 61)
UL 58 Steel Underground Tanks for Flammable and Combustible Liquids
UL 80 Steel Tanks for Oil-Burner Fuels and Other Combustible Liquids
UL 142 Steel Aboveground Tanks for Flammable and Combustible Liquids
UL 1316 Fibre Reinforced Underground Tanks for Flammable and Combustible Liquids
UL 1746 External Corrosion Protection Systems for Steel Underground Storage Tanks
UL 2080 Fire Resistant Tanks for Flammable and Combustible Liquids
UL 2085 Protected Aboveground Tanks for Flammable and Combustible Liquids
UL 2245 Below-Grade Vaults for Flammable Liquid Storage Tanks
UL 2258 Nonmetallic Tanks for Oil-Burner Fuels and Other Combustible Liquids
UL 50E Enclosures for Electrical Equipment, Environmental Considerations
NEMA 250 Enclosures for Electrical Equipment (1000 Volts Maximum)
ASME BPVC Section VIII, Division 1 Rules for Construction of Pressure Vessels
API Std 2000 Venting Atmospheric and Low-Pressure Storage Tanks
PEI RP100 Recommended Practices for Installation of Underground Liquid Storage Systems
PEI RP200 Recommended Practices for Installation of Aboveground Storage Systems for Motor Vehicle Fueling
STI SP001 Standard for the Inspection of Aboveground Storage Tanks
STI R051 Cathodic Protection Testing Procedures for sti-P3 USTs
NACE SP0285 External Corrosion Control of Underground Storage Tank Systems by Cathodic Protection
ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures
ASTM D975 Standard Specification for Diesel Fuel Oils
ASTM D396 Standard Specification for Fuel Oils
ASTM D7467 Standard Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20)
ASTM D1835 Standard Specification for Liquefied Petroleum (LP) Gases
40 CFR Part 280 Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks
40 CFR Part 112 Oil Pollution Prevention

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer's review and return before any tank is released for fabrication:
  • Product data for each tank, giving the listing standard and the listing file number, the shell and head material and thickness, the containment construction, the nominal and the usable capacity, the fill limit, the operating and the empty weight, and the published fuel compatibility
  • Shop drawings for each tank showing the dimensions, the nozzle schedule with each nozzle's size, service, and location, the manway, the lifting lugs, the saddles, skid, or legs, the anchor bolt pattern, and the location of every appurtenance on the tank
  • A capacity statement for each tank reconciling the nominal capacity to the capacity the served equipment standard derives or the drawings indicate, with the fill limit and the unusable volume subtracted
  • Normal and emergency vent sizing for the primary tank and for the interstitial space, stating the fill rate, the withdrawal rate, and the wetted area used
  • Anchorage calculations for each aboveground tank, giving the seismic and wind reactions at the anchors and the anchor size and embedment, sealed by a professional engineer where required under Anchorage and Flotation
  • A flotation calculation for each underground tank, giving the buoyant force of the empty tank at the seasonal high groundwater elevation and the anchorage or ballast that resists it
  • Product data for the overfill prevention device, the spill container, the vent devices, the leak detection sensors, the level gauge, and the alarm contacts, with the wiring interface of every electrical device
  • A statement of compatibility of the shell, the lining, the gaskets, and the sensor materials with the fuel selected on the datasheet
  • For a propane container, the ASME data report, the NFPA 58 siting plan showing the separation distances from the container to buildings, property lines, and sources of ignition, and the container valve schedule
Required Action Submittalscheckbox
☑ Tank product data with listing and capacity
☑ Tank shop drawings with nozzle schedule
☑ Capacity statement against the derived capacity
☑ Normal and emergency vent sizing
☑ Anchorage calculations
☐ Flotation calculation for underground tanks
☑ Appurtenance product data with wiring interfaces
☑ Fuel compatibility statement
☐ Propane container data report, siting plan, and valve schedule
3.1.2 A tank shall not be released for fabrication until its shop drawings have been reviewed and returned without exception, and a tank fabricated before that return shall be modified or replaced at the Contractor's expense where the review requires a change.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following for information before the tank is delivered to the site:
  • The manufacturer's factory tightness test certificate for each tank, stating the test pressure, the duration, and the result for the primary tank and for the interstitial space
  • Mill certificates for the steel of a steel tank, or the resin and glass certifications for a fiberglass tank
  • Welder qualifications and the welding procedure specifications for a steel tank
  • The manufacturer's installation instructions for each tank, including the bedding and backfill requirements of an underground tank and the lifting instructions of every tank
  • The manufacturer's warranty terms and the installation conditions the warranty requires
  • For a steel underground tank with sacrificial anodes, the anode design and the manufacturer's test station instructions
Required Informational Submittalscheckbox
☑ Factory tightness test certificates
☑ Mill or resin certifications
☐ Welder qualifications and welding procedures
☑ Installation instructions
☑ Warranty terms and installation conditions
☐ Sacrificial anode design and test station instructions

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following before the tank is accepted:
  • Field tightness test reports for the primary tank and for the interstitial space, with the test method, the pressure or vacuum, the duration, and the result
  • The leak detection, overfill alarm, and level alarm functional test record, showing each sensor and contact exercised and the alarm received where the datasheet sends it
  • The cathodic protection commissioning record for a steel underground tank, with the structure-to-soil potentials and the test station location
  • The state registration or notification for an underground tank, where the state program requires one, and the installer certification the state program requires
  • The Spill Prevention, Control, and Countermeasure determination for the site, stating the aggregate oil storage and whether a plan is required
  • Operation and maintenance data for the tank and its appurtenances, including the inspection schedule under STI SP001 for an aboveground tank, the release detection and spill container testing schedule under 40 CFR Part 280 for an underground tank, and the part numbers of every sensor, gasket, and vent device
  • Warranty documentation
Required Closeout Submittalscheckbox
☑ Field tightness test reports
☑ Leak, overfill, and level alarm functional test record
☐ Cathodic protection commissioning record
☐ State underground tank registration and installer certification
☑ SPCC determination
☑ Operation and maintenance data with inspection schedules
☑ Warranty documentation

4 Quality Assurance

4.1 Listing and Manufacturer Qualifications

4.1.1 Each liquid fuel tank shall bear the listing mark of a Nationally Recognized Testing Laboratory for the listing standard selected under this standard, and each propane container shall bear the ASME Code symbol stamp and the nameplate NFPA 58 requires.
NOTE The listing mark is the evidence the Authority Having Jurisdiction accepts that the tank's steel thickness, weld design, containment, and venting openings meet the construction rules of the adopted fire code, and an unlisted shop-built tank cannot be permitted for combustible liquid service without an engineering evaluation the code does not otherwise require. (4.1.2)
4.1.3 The tank manufacturer shall have fabricated listed tanks of the selected listing standard and of the specified capacity for not less than five years.
4.1.4 Welding of a steel tank shall be performed by welders qualified to the procedure specifications submitted under this standard.
4.1.5 Where a listing standard other than the one selected on the datasheet is required by the Authority Having Jurisdiction for the tank's location, the Contractor shall report the requirement to the Engineer in writing before fabrication, and the Engineer shall direct the selection.

4.2 Regulatory Determinations

4.2.1 The Contractor shall sum the capacity of every oil-storing tank on the site, including each generator sub-base tank and each day tank, and shall report the aggregate aboveground and the aggregate underground oil storage to the Owner in the SPCC determination.
NOTE The oil pollution prevention rule in 40 CFR Part 112 applies to a facility whose aggregate aboveground oil storage exceeds 1,320 gallons, counting every container of 55 gallons or more, or whose aggregate underground storage exceeds 42,000 gallons. The threshold is a site total, so a plant of three generators with 500-gallon sub-base tanks crosses it with no single tank that looks large, and the plan that follows is the Owner's obligation before the tanks are filled. (4.2.2)
4.2.3 Where an underground tank is regulated under 40 CFR Part 280 or the state program that implements it, the Contractor shall file the notification or registration the program requires before the tank is backfilled, and shall employ an installer certified as the state program requires.
NOTE The federal underground tank rule exempts a tank storing heating oil for consumptive use on the premises, and until 2018 it exempted an emergency generator tank from release detection; many states regulate both, and a state program is often stricter than the federal rule it implements. A tank backfilled before its registration is accepted has in some jurisdictions been ordered excavated, so the registration is a precondition to burial rather than a closeout item. (4.2.4)
4.2.5 Where a tank is installed inside a building, the Contractor shall confirm that the tank's capacity, its listing, and the construction of the room satisfy NFPA 30 Chapter 24, NFPA 37 where the tank serves an engine, and NFPA 31 where it serves a burner, and shall report any conflict with the datasheet selection to the Engineer before fabrication.

4.3 Identification

4.3.1 Each tank shall be marked on the shell, in letters legible from the fill point, with the fuel stored, the nominal capacity in gallons, and the hazard identification NFPA 704 requires in the form the adopted fire code prescribes.
4.3.2 Each fill connection shall carry a permanent tag naming the fuel and the tank it fills, and where more than one tank is filled from one location, the tags shall also carry the tank designation shown on the shop drawings.
NOTE A delivery driver who cannot tell a diesel fill from a heating oil fill, or one tank's fill from another's, is how the wrong tank gets the product, and the tag at the fill is read in the dark from a hose reel. (4.3.3)

5 Tank Service and Configuration

5.1 Stored Fuel

5.1.1 The fuel each liquid fuel tank stores shall be as indicated in the datasheet.
Stored Fuelselect
No. 2 ultra-low-sulfur diesel to ASTM D975
Biodiesel blend B6 to B20 to ASTM D7467
No. 2 heating fuel oil to ASTM D396
No. 1 diesel or kerosene to ASTM D975 or ASTM D396
Winter-blended No. 1 and No. 2 diesel to ASTM D975
NOTE No. 2 ultra-low-sulfur diesel is the fuel the engine manufacturers rate their stationary sets on and the fuel the road supply chain delivers, which is why it is the default; a biodiesel blend is the fuel where a procurement policy or a state blending mandate supplies it, and blends above B5 attack nitrile elastomers and some interior coatings and hold more water, so the blend has to be declared for the manufacturer to select compatible gaskets and a lining; No. 2 heating oil is the fuel of an oil-fired boiler and is exempt from the federal underground tank rule when burned on the premises; No. 1 oil and kerosene gel at a lower temperature at a higher price per gallon and a lower energy content; a winter blend buys cold-flow margin for a tank in an unheated outdoor location without going to straight No. 1. (5.1.2)
5.1.3 The shell, the interior lining where one is selected, the gaskets, the sensor bodies, and the float materials shall be rated by their manufacturers for the fuel selected, including the biodiesel content of a blend.
5.1.4 A tank storing a biodiesel blend shall be furnished with a water draw-off at the low point of the shell, and the operation and maintenance data shall state the bottom-water draining interval the fuel supplier recommends.

5.2 Tank Role

5.2.1 The role each tank serves shall be as indicated in the datasheet.
Tank Roleradio
○ Bulk storage tank remote from the served equipment
○ Generator sub-base tank
○ Day tank at the served equipment
NOTE A bulk tank holds the site's fuel where the site can hold it and feeds the equipment through the pumps and piping of the fuel-oil system, so it can be as large as the runtime demands and is the one role a buried tank serves; a sub-base tank is bought with the generator as part of its UL 2200 assembly, carries the set's weight, and holds what the base can hold, which fixes the runtime at the set unless a bulk tank makes it up; a day tank at the equipment holds a few hours of fuel at the head and pressure the engine or burner needs and is filled from a bulk tank, so its capacity follows from the fuel-oil system's controls rather than from the runtime. The role follows the fuel storage arrangement of the served equipment, so no role is the norm across projects. (5.2.2)
5.2.3 Where the tank serves an engine-generator, its role shall agree with the diesel fuel storage arrangement selected under GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators, and the Contractor shall report any disagreement to the Engineer before fabrication.
5.2.4 A generator sub-base tank shall be furnished by the generator manufacturer as part of the UL 2200 assembly as GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators requires, and the construction, containment, venting, overfill prevention, and leak detection selected under this standard shall be furnished on it.
5.2.5 A generator sub-base tank shall additionally carry the fuel level sender, the low-fuel contact, and the shutoff valve at the supply outlet that GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators requires of it, wired as that standard directs.
5.2.6 A day tank inside an engine room shall not exceed the capacity NFPA 37 permits at its location, and a day tank serving a burner shall not exceed the capacity NFPA 31 permits at its location.

5.3 Tank Placement

5.3.1 Each tank shall be placed aboveground, underground, or within a below-grade vault as indicated in the datasheet.
Tank Placementradio
● Aboveground
○ Underground
○ Aboveground tank within a below-grade vault
NOTE An aboveground tank is inspected by walking around it, its leak goes where it can be seen, and its listing, containment, and registration burden are the lightest, at the cost of the site area the fire code setbacks consume and a shell exposed to weather and vehicles; an underground tank gives the site surface back and takes the tank out of the fire exposure, at the cost of excavation, flotation restraint, corrosion protection, the federal and state release detection program, and the registration that precedes burial; a tank in a below-grade vault listed to UL 2245 stays an aboveground tank in the eyes of the code while sitting below grade, and is the arrangement for a site that can give up neither its surface nor the inspectability of an aboveground tank. Aboveground placement is the default because it is what most new fuel-oil installations now choose. (5.3.2)
5.3.3 A tank within a below-grade vault shall be a tank listed for aboveground service set in a vault listed to UL 2245, with the vault's drainage, ventilation, and access as NFPA 30 requires of a vaulted tank.

5.4 Nominal Capacity

5.4.1 The nominal capacity of each tank shall be as indicated in the datasheet.
Nominal Tank Capacityrange
gal
2560000
Derived — the runtime or delivery interval established under the served equipment standard or indicated on the drawings, the full-load fuel consumption of the served equipment, and the fill limit and unusable volume the tank listing and its overfill prevention device impose (by default)
NOTE Nominal capacity is the volume of the shell. The overfill prevention device stops the fill at or below 95 percent of it, and the suction nozzle leaves a dead volume at the bottom that the engine never draws, so the usable volume is about 85 to 90 percent of the nominal and the runtime calculation is done on the usable volume. The capacity is not a decision made at the tank: for a generator it follows from the runtime class the emergency power system assigns and the fuel the set burns at full load, and for a burner it follows from the delivery interval the Owner can live with and the firing rate, so the field points at that basis rather than carrying a number of its own. (5.4.2)
5.4.3 Where the tank is a generator sub-base tank or a day tank serving an engine-generator, its usable capacity shall be the usable fuel capacity at the set derived under GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators.
5.4.4 Where the tank is a bulk storage tank, the Contractor shall state on the capacity statement the fuel consumption figure used and the document it came from.

5.5 Tank Form

5.5.1 Each tank shall be of the form indicated in the datasheet.
Tank Formradio
○ Horizontal cylindrical
○ Vertical cylindrical
○ Rectangular
NOTE A horizontal cylinder is the lowest-cost form per gallon above a few hundred gallons, puts its weight on two saddles, and is the form of nearly every underground tank; a vertical cylinder holds the same volume in the smallest footprint and raises the suction and the gauge, at the cost of a taller fill and a higher center of gravity to anchor; a rectangular tank fits under a generator base, against a wall, or inside a room where a cylinder wastes the corners, and is the form of the sub-base tank, the day tank, and the small oil-burner tank. The form follows the role and the space, so no form is the norm across the standard. (5.5.2)
5.5.3 Nozzle sizes, services, and locations on each tank shall be as indicated on the fuel system flow diagram.
5.5.4 Each tank shall be furnished with a bolted manway as indicated in the datasheet.
Bolted Manwayradio
○ Bolted manway not smaller than 18 in.
○ No manway, threaded inspection openings only
NOTE A manway is how a tank that stores fuel for years is entered to remove the sludge and water that settle under a stored distillate, and how a damaged interior lining or a failed sensor is reached; it adds a flanged opening, a gasket, and a cover to a tank that otherwise has only threaded nozzles, and a tank of a few hundred gallons is cleaned through a 4 in. opening with a wand. (5.5.5)
5.5.6 Each tank shall be furnished with a threaded nozzle for a water draw-off or a stick-gauge opening that reaches the lowest point of the shell, in addition to the nozzles the flow diagram shows.

6 Aboveground Tanks

6.1 Aboveground Tank Listing

6.1.1 Requirements in this article apply where the datasheet selects aboveground placement, including a tank within a below-grade vault.
6.1.2 An aboveground tank shall be listed to the standard indicated in the datasheet.
Aboveground Tank Listingradio
● UL 142 steel aboveground tank
○ UL 2080 fire resistant tank
○ UL 2085 protected tank
○ UL 80 steel oil-burner fuel tank
○ UL 2258 nonmetallic oil-burner fuel tank
NOTE UL 142 is the construction standard for the shop-built steel tank, and it is the listing of the sub-base tank, the day tank, and most bulk tanks, which is why it is the default; UL 2080 adds a two-hour fire test to a UL 142 tank and buys a reduction in the separation distances the fire code requires; UL 2085 adds to the fire test the insulation that limits the heat reaching the primary tank, a vehicle impact test, and a ballistics test, which is what the fire code and most Authorities Having Jurisdiction require where a tank sits close to a building, a property line, or a public way, at roughly twice the weight and a higher price than the same gallons in UL 142; UL 80 and UL 2258 are the listings of the steel and the polyethylene oil-burner tank of 660 gallons and less that sits in a basement or a utility room feeding a boiler or furnace, and neither is a listing for an engine fuel tank. (6.1.3)
6.1.4 Where the separation distances NFPA 30 and the adopted fire code require for a UL 142 tank at its location cannot be met, the tank shall be listed to UL 2085 or shall be protected as the Authority Having Jurisdiction accepts in writing, whatever the datasheet selects.
6.1.5 The shell and head thickness of a steel aboveground tank shall be not less than the minimum the listing standard assigns for the tank's capacity, and the thickness shall be stated on the shop drawings.

6.2 Aboveground Tank Support

6.2.1 An aboveground tank shall be supported as indicated in the datasheet.
Aboveground Tank Supportradio
○ Integral steel saddles
○ Integral steel skid base
○ Steel legs
○ Flat bottom set directly on the foundation
NOTE Saddles carry a horizontal cylinder at two lines and lift the shell off the foundation where the bottom can be inspected and water cannot stand against it; a skid base ties the saddles into a frame that is lifted, set, and anchored as one piece and carries a stair or a pump cabinet, at the cost of steel; legs lift a small tank for gravity feed to a burner and are the support UL 80 and UL 2258 tanks ship with; a flat-bottom tank set directly on the foundation puts the whole bottom on concrete where it cannot be inspected, which is why the fire code and STI SP001 treat it as a different inspection category. (6.2.2)
6.2.3 Saddles, skids, and legs shall be welded to the shell by the tank manufacturer, and the shell at the support shall carry the reinforcing pad the listing requires.
6.2.4 A tank set on saddles or legs shall rest on a reinforced concrete pad constructed under Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads that extends not less than 6 in. beyond the supports on every side and stands not less than 4 in. above the finished surface, and a flat-bottom tank shall rest on a foundation constructed under Shallow FoundationsShallow Foundations (Spread and Strip Footings)Resolves to the current adopted revision.sync/shallow-foundations or Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads that sheds water away from the bottom.

6.3 Aboveground Tank Exterior Coating

6.3.1 An aboveground steel tank shall be furnished with the shop-applied exterior coating system indicated in the datasheet.
Aboveground Tank Exterior Coatingselect
Alkyd enamel over a rust-inhibitive primer
Epoxy primer with an aliphatic polyurethane topcoat
Powder coating over a blasted and primed surface
Hot-dip galvanized shell with no topcoat
Manufacturer's standard (by default)
NOTE The manufacturer's standard coating is acceptable because the tank's listing does not depend on it and because every manufacturer finishes a tank to a system that holds up in an ordinary exterior exposure; an alkyd enamel is that standard system and chalks and fades in a few years of sun; an epoxy and polyurethane system holds its gloss and resists salt air and chemical fumes for a decade or more and is specified at a coastal or industrial site; powder coating gives a hard, uniform film on a tank small enough to fit the oven; a galvanized shell is the finish of some small outdoor burner tanks and takes no topcoat. (6.3.2)
6.3.3 The exterior topcoat color shall be the manufacturer's standard white or light reflective color unless another color is indicated on the mechanical equipment schedule.
6.3.4 An aboveground steel tank shall be furnished with the interior surface indicated in the datasheet.
Aboveground Tank Interior Surfaceradio
● Bare steel
○ Fuel-compatible epoxy lining
NOTE Bare steel holds distillate fuel indefinitely and is the interior of nearly every diesel and heating oil tank, which is why it is the default; a lining is what a biodiesel blend above B5 or a fuel that will be polished and held for years calls for, because it keeps the water that settles in a stored fuel from pitting the bottom and keeps rust scale out of the fuel, at the cost of a lining that has to be rated for the blend. (6.3.5)

7 Underground Tanks

7.1 Underground Tank Construction

7.1.1 Requirements in this article apply where the datasheet selects underground placement.
7.1.2 An underground tank shall be of the construction and listing indicated in the datasheet.
Underground Tank Construction and Listingradio
○ Steel to UL 58 with UL 1746 Part I sacrificial anode cathodic protection
○ Steel to UL 58 with UL 1746 Part II fiberglass-clad composite exterior
○ Steel to UL 58 with UL 1746 Part III fiberglass or polyethylene jacket
○ Fiberglass-reinforced plastic to UL 1316
NOTE A cathodically protected steel tank is the lowest-cost steel construction and depends for its life on anodes that are tested after backfill and every three years and replaced when consumed; a composite tank bonds a fiberglass laminate to the steel so the steel never touches the soil and needs no anodes, at a higher price; a jacketed tank wraps the steel in a fiberglass or polyethylene outer shell that is also the secondary containment, so the interstice is the space between steel and jacket; a fiberglass tank has no steel to corrode and carries the longest corrosion warranty, deflects under backfill load so its bedding and backfill are gradation-controlled, and is lighter to set. Steel and fiberglass each hold about half of the new installations, so the field carries no default. (7.1.3)
7.1.4 An underground tank shall be of double-wall construction with an interstitial space that can be monitored over the whole bottom of the tank, whatever the secondary containment selection under Secondary Containment, as 40 CFR Part 280 requires of a new or replaced underground tank.
7.1.5 A steel underground tank protected by sacrificial anodes shall be furnished with the anodes, the dielectric nozzle bushings, and the test station lead the UL 1746 Part I listing requires, and the structure-to-soil potential shall satisfy NACE SP0285 when tested under STI R051 after backfill.
7.1.6 The exterior coating of a steel underground tank shall be inspected for holidays with a wet-sponge or a high-voltage holiday detector at the manufacturer's stated voltage after the tank is set and before backfill, and every holiday shall be repaired with the manufacturer's repair material before backfill proceeds.
7.1.7 A fiberglass tank shall be furnished with the deflection gauge or measurement the manufacturer requires, and the vertical deflection of the shell after backfill shall not exceed the manufacturer's published limit.

7.2 Underground Tank Burial and Flotation

7.2.1 An underground tank shall be bedded on and surrounded by the backfill material the tank listing and the manufacturer's installation instructions specify, placed in the lifts and to the compaction those instructions state, from the bottom of the excavation to not less than 12 in. over the top of the tank.
7.2.2 Excavation of the tank pit, worker protection, and construction groundwater control shall conform to EarthworkEarthworkResolves to the current adopted revision.sync/earthwork, any engineered excavation support or designed dewatering system shall conform to Excavation Support And DewateringExcavation Support and DewateringResolves to the current adopted revision.sync/excavation-support-and-dewatering, and backfill above the tank backfill zone shall conform to EarthworkEarthworkResolves to the current adopted revision.sync/earthwork for the area in which the tank falls.
NOTE The bedding and the backfill against the shell are within this standard because the listing of a buried tank is conditioned on them: a fiberglass tank that is backfilled with the native clay deflects past its limit, and a steel tank bedded on a rock shears its coating at the first point load. EarthworkEarthworkResolves to the current adopted revision.sync/earthwork resumes above the tank backfill zone with the class and compaction for the paving or the lawn above. (7.2.3)
7.2.4 The cover over the tank shall be not less than NFPA 30 requires for the surface above it, and where vehicles pass over the tank, the cover shall include the reinforced concrete or asphalt slab NFPA 30 requires for traffic loading.
7.2.5 Where the top of the backfill is within Frost DepthFrost DepthParameterEach project supplies its own value.frost-depth of the tank, the manufacturer shall confirm in writing that the tank, its risers, and its spill containers are rated for the frost heave the burial depth exposes them to.
7.2.6 An underground tank shall be restrained against flotation as indicated in the datasheet.
Underground Tank Flotation Restraintradio
○ Precast or cast-in-place deadman anchors with hold-down straps
○ Reinforced concrete hold-down pad beneath the tank with hold-down straps
○ None, backfill weight alone
NOTE Deadman anchors are concrete beams set in the excavation beside the tank, placed and strapped before backfill with no cure time on the critical path; a hold-down pad is a slab the tank sits on and is strapped down to, which also gives a flat bed in a wet or soft excavation at the cost of a pour and a cure before the tank is set; no restraint is the arrangement where the groundwater stays below the tank through the seasonal high and the backfill alone outweighs the empty tank's buoyancy with the margin the manufacturer requires. (7.2.7)
7.2.8 The flotation restraint shall resist the buoyant force of the empty tank with groundwater at Seasonal High Groundwater ElevationSeasonal High Groundwater ElevationParameterEach project supplies its own value.seasonal-high-groundwater-elevation with the factor of safety the tank manufacturer requires, and the calculation shall be submitted under this standard.
7.2.9 Hold-down straps shall be of the material, number, and spacing the tank manufacturer specifies for the tank, shall bear on the shell through the manufacturer's isolating pads, and shall not be welded to a steel tank or drawn tight enough to deflect a fiberglass tank.

8 Secondary Containment

8.1 Containment Construction

8.1.1 Each tank shall have the secondary containment indicated in the datasheet.
Secondary Containmentradio
● Double-wall tank with a monitored interstitial space
○ Single-wall tank within an open diked enclosure
○ Single-wall tank within a closed containment vault
NOTE A double-wall tank carries its containment in its own shell, so the footprint is the tank's, the interstice is monitored by one sensor, and rain never enters the containment, which is why it is the default; an open dike holds a release from a single-wall tank in a bund that also collects rain and has to be drained through a valve that someone is responsible for, and it suits a large tank or a group of tanks where a double-wall shell would be heavier than a dike is costly; a closed containment vault encloses the tank in a concrete or steel enclosure that keeps rain out and adds impact and fire protection, and is the construction of the UL 2085 protected tank. (8.1.2)
8.1.3 Secondary containment shall hold not less than the full capacity of the largest tank within it, and where the containment is open to rainfall it shall also hold the precipitation the adopted fire code and 40 CFR Part 112 require it to retain.
8.1.4 The secondary containment of a double-wall tank shall be of the same listing as the primary tank and shall be tight to the test pressure or vacuum the listing assigns to the interstitial space.
8.1.5 An open diked enclosure shall drain through a normally closed valve that is locked closed, and the drain shall not discharge to a storm inlet or a watercourse except through the oil-water separation the adopted codes require.
8.1.6 The interstitial space of a double-wall tank shall be provided with a monitoring opening at the lowest point of the interstice and an emergency vent opening of the capacity the listing requires.
NOTE An interstice that cannot vent is a sealed annulus that over-pressures when the primary tank is engulfed in fire; the listing standards require the secondary to relieve the same fire exposure as the primary, which is why the emergency vent count on a double-wall tank is two. (8.1.7)

8.2 Leak Detection

8.2.1 The interstitial space or the containment of each tank shall be monitored by the method indicated in the datasheet.
Leak Detection Methodselect
Liquid sensor in a dry interstitial space
Hydrostatic brine-filled interstitial space with a reservoir level sensor
Vacuum-monitored interstitial space
Pressure-monitored interstitial space
Liquid sensor in the dike or vault sump
Groundwater or vapor monitoring wells around the excavation
NOTE A liquid sensor at the low point of a dry interstice alarms when fuel from the primary or water from the secondary reaches it, costs one sensor and one pair of wires, and is the method on most double-wall tanks, which is why it is the default; a brine-filled interstice reads a leak in either wall as a change of level in a reservoir on top of the tank and detects an outer-wall breach that a dry sensor cannot see, at the cost of a reservoir to keep filled; vacuum and pressure monitoring hold the interstice at a set vacuum or pressure and alarm on a loss, which proves the integrity of both walls continuously rather than waiting for liquid to arrive, at the cost of a pump or a gas supply and a gauge to watch; a sump sensor is the method for a single-wall tank in a dike or vault, where there is no interstice; monitoring wells sample the groundwater or the soil vapor around an underground tank and are a method the federal rule accepts only where the site hydrogeology allows, so they are chosen for a single-wall or an existing tank rather than for new work. (8.2.2)
8.2.3 Groundwater or vapor monitoring wells shall be used only where the datasheet selects underground placement and where the Contractor submits the site assessment 40 CFR Part 280 requires for that method.
8.2.4 A leak detection sensor and the device that reads it shall alarm a release within the time 40 CFR Part 280 allows for the method where the tank is a regulated underground tank, and continuously where the datasheet selects an electronic sensor.
8.2.5 Each leak detection sensor shall be removable through its riser or opening for test and replacement without entering the interstice or draining the tank.
8.2.6 Leak detection sensors shall be wired to the monitoring console indicated in the datasheet.
Tank Monitoring Consoleradio
○ Monitoring console furnished with the tank
○ No console with the tank, sensors terminated in a junction box at the tank for the fuel-oil system console
NOTE A console furnished with the tank arrives matched to the tank's sensors, reads the leak sensor and the level probe on one display, logs the alarms the state program requires an underground tank to keep, and is the arrangement for a bulk tank that is the only tank at the site; a junction box hands the sensors to the console the fuel-oil system furnishes where several tanks, the pumps, and the day-tank levels are monitored together, so that the plant has one console rather than one per tank. The choice follows the number of tanks and who furnishes the pumps, so the field carries no default. (8.2.7)
8.2.8 Where the tank is a generator sub-base tank, the leak detection sensor shall be wired to the generator controller and annunciated as GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators requires, whatever the console selection above.
8.2.9 Where a console is furnished with the tank, it shall display the state of each sensor, shall alarm audibly and visually at the console, shall provide a dry contact for each alarm for connection to the plant monitoring system, and shall retain an alarm log where the tank is a regulated underground tank.

9 Fill Connection and Overfill Prevention

9.1 Fill Point

9.1.1 Each tank shall be filled through the fill point indicated in the datasheet.
Fill Point Locationradio
● Fill connection on the tank
○ Remote fill station
NOTE A fill connection on the tank puts the driver, the spill container, the gauge, and the overfill alarm in one place where the driver can watch all of them, and is the arrangement of nearly every tank a delivery truck can reach, which is why it is the default; a remote fill station is a cabinet at the curb or on an exterior wall piped to a tank the truck cannot reach, and it moves the spill container and the overfill alarm to the cabinet and adds fill piping furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems. (9.1.2)
9.1.3 The fill connection shall be of the nominal size indicated in the datasheet, threaded or flanged to match the fill adapter.
Fill Connection Sizerange
in.
234
NOTE A 2 in. fill matches the hose and the tight-fill adapter of the fuel delivery trucks that serve generator and heating oil tanks and is the size on nearly every such tank; a 3 in. or 4 in. fill is used on a bulk tank of several thousand gallons filled by transport trailer at a rate a 2 in. fill would throttle, and the vent has to be sized for that fill rate. (9.1.4)
9.1.5 The fill connection shall be furnished with a tight-fill adapter of the pattern the fuel supplier's delivery hose uses, a lockable dust cap, and a drop tube extending to within 6 in. of the bottom of the tank.
NOTE A drop tube that ends above the liquid lets the fuel fall through the vapor space, which splashes, aerates the fuel, and builds a static charge; one that reaches near the bottom fills from below the surface and keeps the water and sludge there from being stirred into suspension. (9.1.6)
9.1.7 Where the datasheet selects a remote fill station, the station shall house the spill container, the fill adapter and cap, the overfill alarm indicator, and the gauge or indicator the driver reads, in a lockable weatherproof cabinet, and the fill piping from the station to the tank shall be furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems.

9.2 Spill Containment at the Fill

9.2.1 Each fill connection shall be furnished with a spill container around the fill adapter of the capacity indicated in the datasheet.
Spill Container Capacityrange
Not less than
gal
571525
NOTE Five gallons is the minimum the fire code accepts at an aboveground fill, the usual size of the catchment basin the federal underground tank rule requires, and holds the drain-back of a 2 in. delivery hose; a 7 gal container is the capacity of the fill box on most aboveground tanks; 15 and 25 gal containers hold the drain-back of a transport hose or the spill of a fill that was not shut off at the alarm, and they are the containers at a bulk tank filled by trailer. The capacity follows the hose and the fill rate, so the field carries no default. (9.2.2)
9.2.3 Spill containers shall be of the construction indicated in the datasheet.
Spill Container Constructionradio
○ Single-wall
○ Double-wall with an interstitial test port
NOTE A single-wall spill container on an underground tank is tested for tightness every three years under the federal rule; a double-wall container with a monitored or testable interstice is exempt from that test, so the second wall is bought against a recurring test on a part that sits in traffic and ice. On an aboveground tank the container is in sight and is emptied by hand, so a second wall buys little. (9.2.4)
9.2.5 Each spill container shall drain to the tank through a normally closed drain valve or be emptied by hand, shall have a liquid-tight lid that excludes rain, and shall be of a material rated for the fuel.

9.3 Overfill Prevention

9.3.1 Each tank filled by pump from a delivery vehicle shall be furnished with the overfill prevention indicated in the datasheet.
Overfill Preventionradio
○ High-level alarm at the fill point, audible and visible to the delivery operator
○ Automatic shutoff valve in the fill line
○ High-level alarm at the fill point and automatic shutoff valve in the fill line
NOTE A high-level alarm at the fill point warns the driver at the level NFPA 30 sets and relies on the driver to close the delivery valve, which is the arrangement where the fuel supplier's own procedure is trusted and the valve is in reach; an automatic shutoff valve in the fill line closes on its own at the fill limit and is what protects a tank filled by a driver who has walked away, but a valve that closes against a pumping truck sends a pressure surge back up the hose, so it is paired with an alarm that warns the driver first on most tanks that take both. The fire code accepts any of the three for a tank that receives fuel by pump, and a state program or an Authority Having Jurisdiction sometimes requires the valve, so the field carries no default. (9.3.2)
9.3.3 The high-level alarm shall actuate at not more than 90 percent of the nominal capacity, shall be independent of the level gauge, and shall sound and light at the fill point until acknowledged there.
9.3.4 The automatic shutoff valve shall close at not more than 95 percent of the nominal capacity, shall be listed for the fuel, and shall be of a type that can be tested in place without filling the tank to the shutoff level.
9.3.5 A ball-float vent valve shall not be used as the overfill prevention device on a new tank.
NOTE An overfill alarm that is lit at the console in a room the driver cannot see protects nothing at the fill; the alarm the fire code intends is the one the person holding the hose hears, which is why the alarm is placed at the fill point and why the console alarm is an additional contact rather than a substitute. (9.3.6)

10 Venting

10.1 Normal Venting

10.1.1 Each tank shall be furnished with a normal vent opening and vent device sized under API Std 2000 or NFPA 30 for the greater of the maximum fill rate and the maximum withdrawal rate, and the normal vent shall be not smaller than 1-1/4 in. nominal.
10.1.2 The normal vent device shall be as indicated in the datasheet.
Normal Vent Deviceradio
● Open vent with weatherproof cap and insect screen
○ Pressure-vacuum vent
NOTE An open vent lets the tank breathe freely as it fills, empties, and warms, and is the vent on nearly every diesel and heating oil tank because a Class II or Class III liquid gives off too little vapor at ambient temperature for the vent to matter, which is why it is the default; a pressure-vacuum vent holds a small pressure and vacuum before it opens, which limits evaporative loss and keeps moist air out of a tank that is stored full for long periods, at the cost of a device that has to be sized for the fill rate and inspected. (10.1.3)
10.1.4 The normal vent opening on a double-wall tank shall be on the primary tank, and the interstitial space shall not be vented through the primary tank's normal vent.

10.2 Emergency Venting

10.2.1 Each aboveground tank, and the interstitial space of each double-wall aboveground tank, shall be furnished with an emergency vent opening and device sized under NFPA 30 for the wetted area of the tank, and the emergency vent shall be of the type indicated in the datasheet.
Emergency Vent Deviceradio
● Spring-loaded emergency vent
○ Long-bolt manway cover
NOTE A spring-loaded vent lifts at a set pressure, reseats when the pressure falls, and is the device the manufacturers fit to the emergency vent opening of nearly every shop-built tank, which is why it is the default; a long-bolt manway cover lifts on its bolts under fire pressure and serves a large tank whose manway is already the largest opening on the shell, and it does not reseat. (10.2.2)
10.2.3 An emergency vent shall relieve at a pressure not exceeding the design pressure of the tank and shall be marked with its relieving capacity.
NOTE The emergency vent relieves the vapor a tank generates when a fire boils the fuel inside it, a rate hundreds of times the normal breathing rate; a tank without one ruptures at the weld in that fire, and a double-wall tank whose interstice has none ruptures the outer shell. Neither vent is a substitute for the other. (10.2.4)
10.2.5 An underground tank shall not be furnished with an emergency vent, and its normal vent shall be sized for the fill rate as NFPA 30 requires of a buried tank.

10.3 Vent Terminations

10.3.1 Vent openings and devices shall be located on the tank so that the vent piping furnished under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems can terminate outdoors, above the fill opening, and at the height above grade and the distance from building openings, air intakes, and sources of ignition that NFPA 30 requires for the tank's placement and the fuel's class.
10.3.2 A sub-base tank and a day tank whose vents terminate at the tank shall have those vents terminate as the preceding clause requires, with the termination fitting furnished on the tank.

11 Level Gauging and Alarms

11.1 Level Gauging

11.1.1 Each tank shall be furnished with the level gauging indicated in the datasheet.
Level Gaugingselect
Direct-reading mechanical float gauge at the tank
Magnetostrictive probe with the monitoring console
Hydrostatic pressure level transmitter
Ultrasonic level transmitter
Guided-wave radar level transmitter
Point-level switches only, no continuous gauge
NOTE A mechanical float gauge reads with no power at the tank and nothing anywhere else, and is the gauge the delivery driver reads before the hose is connected; a magnetostrictive probe reads level and bottom water to a fraction of an inch into a console that also runs the leak detection and the inventory record the state program requires of an underground tank, so it is the gauge of the regulated tank; a hydrostatic transmitter reads the head at the bottom nozzle on a two-wire loop and is the lowest-cost continuous signal to a remote system; an ultrasonic transmitter reads from the top with nothing in the fuel and loses its echo in foam and vapor; a guided-wave radar reads along a probe unaffected by vapor, density, or foam at the highest price of the group; point switches alone give the alarms and no inventory, for a day tank whose level is run by its own controls. Which gauge a tank gets follows from who reads it and what the record has to show, so the field carries no default. (11.1.2)
11.1.3 Where the level gauge provides an analog output to a plant monitoring system, the output signal and the hazardous-location protection shall be as selected under Pressure InstrumentationPressure InstrumentationResolves to the current adopted revision.sync/pressure-instrumentation.
11.1.4 Where temperature elements are furnished on a tank for fuel temperature monitoring, their output signal and hazardous-location protection shall be as selected under Temperature InstrumentationTemperature InstrumentationResolves to the current adopted revision.sync/temperature-instrumentation.
11.1.5 A level gauge shall be readable from grade or from the fill point without a ladder, and a mechanical gauge shall be graduated in gallons or in fractions of the nominal capacity.

11.2 Level and Leak Alarm Contacts

11.2.1 Each tank shall be furnished with the alarm contacts indicated in the datasheet, each as a dry contact wired to the console or junction box selected under Leak Detection.
Alarm Contactscheckbox
☑ High level
☑ Low level
☐ Critical low level
☑ Interstitial or containment leak
☐ Bottom water
NOTE The high-level contact is the overfill alarm's contact and reports at the console that a fill approached the limit; the low-level contact is the fuel-ordering alarm that keeps a generator tank from being found empty at the start of an outage; a critical-low contact at a level above the suction dead volume warns that the engine is about to lose fuel and is set below the low-level alarm; the leak contact is the leak detection sensor's; a bottom-water sensor reports the water that collects under a stored distillate and feeds the microbial growth that plugs filters, and is the contact a tank that stores fuel for years benefits from. (11.2.2)
11.2.3 Alarm setpoints shall be as indicated on the fuel system flow diagram, and the set levels shall be recorded on the functional test record.
11.2.4 Where the tank serves an engine-generator, the low-fuel pre-alarm level shall be the level GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators requires for the set's runtime, and the contact shall also be wired to the generator controller as that standard requires.

12 Electrical Devices on the Tank

12.1 Enclosure Rating

12.1.1 Junction boxes, alarm indicators, sensor housings, and the monitoring console where one is furnished with the tank shall carry at least the enclosure rating indicated in the datasheet, rated under NEMA 250 or UL 50E.
Minimum Enclosure Ratingselect
NEMA Type 1
NEMA Type 3R
NEMA Type 4
NEMA Type 4X
NEMA Type 12
NEMA Type 7
NOTE Type 3R is the default because the fuel tank and the devices on it normally sit outdoors, and it excludes rain and sleet and lets condensation drain; Type 1 serves a console or a day-tank junction box inside a dry room; Type 4 excludes hose-directed water and wind-driven rain for a device at grade where a truck apron is washed down; Type 4X adds corrosion resistance for salt air and chemical fumes; Type 12 excludes dust and dripping non-corrosive liquid indoors; Type 7 is the explosion-proof construction for a Class I, Division 1 location. The clauses that follow raise the rating for the locations that need more, whatever the datasheet selects. (12.1.2)
12.1.3 Enclosures mounted outdoors shall be rated NEMA Type 3R, Type 4, or Type 4X.
12.1.4 Enclosures mounted where they are subject to washdown or hose-directed water shall be rated NEMA Type 4 or Type 4X.
12.1.5 Enclosures mounted where they are exposed to salt air, corrosive fumes, or washdown chemicals shall be rated NEMA Type 4X.
12.1.6 Enclosures in a Class I, Division 1 location where an explosion-proof enclosure is the means of protection shall be rated NEMA Type 7 in addition to the rating required for the environment.

12.2 Hazardous Locations at the Tank

12.2.1 The hazardous-location classification at each tank shall be as indicated on the electrical area classification drawings, and every electrical device on the tank shall be listed for the class, division, and group at its location.
NOTE A tank storing a Class II or Class III liquid below its flash point is not itself a classified location under NFPA 30, but the tank vent and the fill of a tank storing a heated oil, and every propane container under NFPA 58, sit in Class I locations whose extent the code tables define; the area classification drawing is where that determination is recorded, so the tank's devices are listed to it rather than to an assumption about the fuel. (12.2.2)
12.2.3 Sensors and probes that enter the tank or the interstitial space shall be intrinsically safe or shall be of a construction listed for the location, and intrinsically safe sensors shall be connected through the barrier the console or the sensor manufacturer specifies.
12.2.4 Metal tanks, fill connections, and vent devices shall be bonded to the grounding electrode system under Grounding And BondingGrounding and Bonding for Electrical SystemsResolves to the current adopted revision.sync/grounding-and-bonding, and the fill connection shall carry a bonding point for the delivery vehicle's bonding cable.

13 Anchorage and Flotation

13.1 Aboveground Tank Anchorage

13.1.1 Each aboveground tank shall be anchored to its foundation for the seismic and wind loads Adopted Building CodeAdopted Building CodeParameterEach project supplies its own value.adopted-building-code assigns to a nonbuilding structure of its weight and location, with the seismic demand determined under ASCE 7 for Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category.
13.1.2 The anchorage calculation for each aboveground tank shall be sealed by a professional engineer as indicated in the datasheet.
Sealed Anchorage Calculationradio
○ Sealed by a professional engineer licensed in the project jurisdiction
○ Prepared by the tank manufacturer without a seal
Derived — Seismic Design CategorySeismic Design CategoryParameterEach project supplies its own value.seismic-design-category and the operating weight of the tank (by default)
NOTE A tank in Seismic Design Category C or higher, or one whose operating weight makes it a nonbuilding structure the building code reviews, is anchored to a sealed calculation because the Authority Having Jurisdiction will ask for one at permit; a small tank in Seismic Design Category A or B is anchored to the manufacturer's standard detail. The requirement follows from the category and the weight, so the field points at them. (13.1.3)
13.1.4 Anchor bolts shall be of the type indicated in the datasheet.
Anchor Typeradio
○ Cast-in anchor rods
○ Post-installed anchors
NOTE Cast-in anchor rods are set to a template before the pad is poured and develop their full capacity in the concrete, which suits a new pad poured for the tank from the shop drawing's bolt pattern; post-installed anchors are drilled after the pad cures to the tank as it actually sits, which suits a tank set on an existing pad or one whose shop drawings arrive after the pad is poured, at a lower capacity per anchor and a qualification under ACI 318 Chapter 17 that the calculation has to carry. (13.1.5)
13.1.6 Cast-in anchor rods shall conform to Structural Steel Anchor BoltsAnchor Rods and Embedded SteelResolves to the current adopted revision.sync/structural-steel-anchor-bolts, and post-installed anchors shall conform to Post Installed AnchorsPost-Installed Concrete and Masonry AnchorsResolves to the current adopted revision.sync/post-installed-anchors, each of the grade, diameter, embedment, and pattern the anchorage calculation states.
13.1.7 Anchor clips, lugs, and saddle base plates shall be welded to the tank by the tank manufacturer and shall be sized for the reactions the anchorage calculation delivers to them.

13.2 Vehicle Impact Protection

13.2.1 An aboveground tank or propane container exposed to vehicle traffic shall be protected by bollards or barriers furnished under Site Furnishings And BollardsSite Furnishings and BollardsResolves to the current adopted revision.sync/site-furnishings-and-bollards at the locations indicated on the site plan, or shall be listed to UL 2085 where the datasheet selects that listing in place of barriers.

14 Propane Containers

14.1 Propane Container Scope

14.1.1 Requirements in this article apply where a tank under this standard stores liquefied petroleum gas for an engine-generator, a boiler, or other on-site equipment.
NOTE A propane container is a pressure vessel rather than an atmospheric tank, so none of the listing, containment, venting, or overfill articles for liquid fuel tanks apply to it; NFPA 58 governs its construction, its valves, its siting, and its filling, and this article carries the vessel-side selections. The container's vapor withdrawal rate at the site's low temperature is checked under GeneratorsEngine GeneratorsResolves to the current adopted revision.sync/generators for a generator and under BoilersBoilersResolves to the current adopted revision.sync/boilers for a boiler, and the first-stage regulator at the service valve begins the piping under Fuel Gas PipingFacility Liquefied-Petroleum and Fuel Gas PipingResolves to the current adopted revision.sync/fuel-gas-piping. (14.1.2)
14.1.3 The propane container shall be procured as indicated in the datasheet.
Propane Container Procurementradio
○ Container purchased and furnished under this standard
○ Container leased from the propane supplier and set under the supplier's agreement
NOTE A purchased container is the Owner's, is specified, submitted, and tested like any other vessel under this standard, and is filled by any supplier; a leased container is the supplier's, arrives with the supplier's valves and gauge, is set by the supplier to NFPA 58, and ties the Owner to that supplier's fuel for the lease term, at no capital cost. Which the Owner wants is a commercial decision, so the field carries no default. (14.1.4)
14.1.5 Where the datasheet selects a leased container, the Contractor shall furnish the foundation, the anchorage, the protection from vehicles, and the area classification coordination under this standard, and shall obtain from the supplier the container data and the siting plan the Action Submittals require.

14.2 Propane Container Construction and Placement

14.2.1 The propane container shall be designed, fabricated, tested, and stamped to ASME BPVC Section VIII, Division 1 for a design pressure not less than NFPA 58 requires for propane, shall be registered with the National Board, and shall carry the nameplate data NFPA 58 requires.
14.2.2 The propane container shall be placed as indicated in the datasheet.
Propane Container Placementradio
● Aboveground on saddles or legs
○ Underground
○ Mounded
NOTE An aboveground container is set on a pad, inspected by sight, and is the placement of most containers serving a generator or a boiler, which is why it is the default; an underground container disappears from the site, is permitted at shorter separation distances under NFPA 58, and brings a coating, cathodic protection, and a dome over its valves that NFPA 58 requires of a buried container; a mounded container is an aboveground container covered with earth, which gives the fire protection of burial without an excavation, at the cost of the mound and the same coating and cathodic protection. (14.2.3)
14.2.4 The propane container shall have the water capacity indicated in the datasheet.
Propane Container Water Capacityrange
gal
1202503255001000145019902500390050006000120001800030000
Derived — the runtime or delivery interval established under the served equipment standard, the full-load propane consumption of the served equipment, the maximum filling limit NFPA 58 imposes for the container's placement, and the vapor withdrawal rate the container surface delivers at Site Ambient Temperature MinimumSite Ambient Temperature MinimumParameterEach project supplies its own value.site-ambient-temperature-minimum (by default)
NOTE A propane container is filled only to the limit NFPA 58 sets for its placement, about 80 percent of its water capacity for an aboveground container, and the vapor the engine or burner draws is boiled off the surface of the liquid by the heat the container takes from the air, so a container can hold enough fuel by volume and still starve the load on a cold night when the liquid is low; the capacity follows from the runtime and the consumption like a diesel tank's, with the vaporization check added, and the sizes offered are the catalog sizes the ASME shops build. (14.2.5)
14.2.6 The propane container shall be furnished with the filler valve, the pressure relief valve of the capacity NFPA 58 requires for the container, the fixed maximum liquid level gauge, the float gauge, the vapor service valve with an excess-flow or back-check function, the liquid withdrawal valve where one is required, and the pressure gauge that NFPA 58 requires for a container of its capacity, each listed for propane.
14.2.7 The container's pressure relief valve shall discharge upward and away from the container, and on an underground or mounded container shall vent through the dome to the height above grade NFPA 58 requires.
14.2.8 The propane container shall be located as indicated on the site utility plan and shall satisfy the separation distances NFPA 58 requires from buildings, property lines, sources of ignition, and other containers for its water capacity and placement.
14.2.9 An aboveground propane container shall be set on a concrete foundation constructed under Concrete PadsConcrete Equipment PadsResolves to the current adopted revision.sync/concrete-pads or Shallow FoundationsShallow Foundations (Spread and Strip Footings)Resolves to the current adopted revision.sync/shallow-foundations and anchored for the wind and seismic loads Adopted Building CodeAdopted Building CodeParameterEach project supplies its own value.adopted-building-code assigns, with the anchorage calculation sealed as the Sealed Anchorage Calculation selection above requires.
14.2.10 An underground or mounded propane container shall be coated and cathodically protected as NFPA 58 requires of a buried container, shall be restrained against flotation with groundwater at Seasonal High Groundwater ElevationSeasonal High Groundwater ElevationParameterEach project supplies its own value.seasonal-high-groundwater-elevation, and shall be furnished with a dome over its valves that keeps the valves above the surrounding grade and out of standing water.
14.2.11 An aboveground propane container shall be painted a heat-reflective light color, and every container shall be marked as NFPA 58 requires with the product name and the hazard identification.

15 Testing

15.1 Factory Testing

15.1.1 Each liquid fuel tank shall be tightness tested at the factory at the pressure and for the duration its listing standard requires, for the primary tank and for the interstitial space, and the certificate shall be submitted under Informational Submittals.
15.1.2 Each propane container shall be hydrostatically tested at the factory as ASME BPVC Section VIII, Division 1 requires, and the manufacturer's data report shall be submitted under Action Submittals.

15.2 Field Tightness Testing

15.2.1 After the tank is set and before it is connected or backfilled, the Contractor shall tightness test the primary tank and the interstitial space by the method indicated in the datasheet, at the pressure or vacuum and for the duration the tank manufacturer and NFPA 30 require, and shall record the result.
Field Tightness Test Methodradio
● Pneumatic test of the primary with soap solution on every weld and fitting
○ Hydrostatic test of the primary
○ Vacuum test of the interstitial space with the primary tested pneumatically
NOTE An air test at the few pounds the listing allows, with soap solution on every seam and plug, finds a pinhole the eye cannot and is the test every tank manufacturer's instructions call for, which is why it is the default; a hydrostatic test puts no stored energy in the shell but leaves water in a fuel tank that then has to be dried, and it is the test an Authority Having Jurisdiction sometimes requires of a large tank; a vacuum test of the interstice proves the secondary tight by pulling a vacuum and watching it hold, and some manufacturers ship a tank under factory vacuum so that the gauge at delivery is the test. (15.2.2)
15.2.3 A tank shall not be pressurized above the test pressure the manufacturer states, and a fiberglass tank shall not be pressure tested with liquid.
15.2.4 A tank or interstitial space that fails a field tightness test shall be repaired by the manufacturer or replaced, and the test repeated at the Contractor's expense.
15.2.5 Where the state underground tank program or the Authority Having Jurisdiction requires a precision tightness test of an underground tank after installation, the Contractor shall perform it by a method the program accepts, before the tank is placed in service, at the Contractor's expense.

15.3 Functional Testing of Appurtenances

15.3.1 After installation and before the tank is placed in service, the Contractor shall exercise each leak detection sensor, each level alarm contact, and the overfill alarm by simulating the condition at the sensor, and shall confirm that each alarm is received at the console, the generator controller, or the plant monitoring system the datasheet sends it to.
15.3.2 The automatic shutoff valve, where furnished, shall be tested in place by the method its manufacturer specifies, and the test recorded on the functional test record.
15.3.3 The cathodic protection of a steel underground tank shall be commissioned under STI R051 after backfill, and the structure-to-soil potentials recorded with the test station location on the commissioning record.
15.3.4 The leak detection functional test, the overfill alarm test, and the cathodic protection commissioning shall be witnessed by the Owner's representative, who shall be notified in writing not less than five working days before each test.

16 Installation

16.1 Setting Aboveground Tanks

16.1.1 Aboveground tanks shall be installed in accordance with the manufacturer's instructions, NFPA 30, the adopted fire code, NFPA 37 where the tank serves an engine, NFPA 31 where it serves a burner, and PEI RP200 for the installation practices it covers.
16.1.2 Aboveground tanks shall be set at the separation distances from buildings, property lines, public ways, and sources of ignition that NFPA 30 and the adopted fire code require for the tank's listing and capacity.
16.1.3 Tanks shall be lifted only at the manufacturer's lifting lugs, with the spreader bar the manufacturer specifies where one is specified, and never by the nozzles, the vents, or a sling around a coated shell.
16.1.4 Tanks shall be set level on the pad within the manufacturer's tolerance, with the drain or water draw-off at the low point, and shimmed only with the full-bearing shims the manufacturer permits.
16.1.5 Tank fill, vent, supply, return, and gauge nozzles shall be protected with caps or plugs until the fuel-oil system connects to them under Fuel Oil SystemsFacility Fuel-Oil SystemsResolves to the current adopted revision.sync/fuel-oil-systems, and the Contractor shall make no connection to a nozzle that puts load on the shell.
16.1.6 Grading around an aboveground tank shall direct a release away from building openings and storm inlets, coordinated with Site Rough GradingSite Grading and Subgrade PreparationResolves to the current adopted revision.sync/site-rough-grading, and a tank shall not be set where surface water ponds against the shell or the supports.

16.2 Setting Underground Tanks

16.2.1 Underground tanks shall be installed in accordance with the manufacturer's instructions, NFPA 30, the adopted fire code, 40 CFR Part 280 and the state program, and PEI RP100.
16.2.2 An underground tank shall be inspected for shipping damage, holidays in its coating, and interstitial vacuum on arrival and again immediately before it is lowered into the excavation, and a damaged tank shall not be set until the manufacturer has approved the repair in writing.
16.2.3 The excavation shall be free of standing water, debris, and sharp objects before bedding is placed, and the tank shall be set on the bedding without dropping and without dragging across the excavation.
16.2.4 Where an underground tank is set and cannot be backfilled the same day, the Contractor shall ballast the tank with the liquid and to the level the manufacturer specifies against a rise of groundwater, and shall not use fuel as ballast.
16.2.5 Hold-down straps shall be tensioned, the backfill placed and compacted in lifts around the tank, and the deflection of a fiberglass tank measured, in the sequence the manufacturer's instructions state, before any load is placed over the tank.
16.2.6 Risers for the fill, the vents, the gauge, and the monitoring openings shall terminate in a liquid-tight containment sump or a spill container at grade, and the containment sumps shall be of a construction that can be tested or monitored as 40 CFR Part 280 requires.

16.3 Protection Pending Connection

16.3.1 Until the tank is connected and placed in service, the Contractor shall keep the interstitial space dry, the spill containers lidded, the fill and vent openings capped, and the monitoring openings plugged, and shall remove any water that enters the interstice before the functional tests.

17 Delivery, Storage, and Handling

17.1 Tanks shall be delivered with every nozzle capped or plugged, with the lifting lugs protected, and with the listing label, the nameplate, and the fuel marking legible and undamaged.
17.2 Tanks shall be stored on level supports that bear on the saddles, skid, or the manufacturer's blocking, and never on the shell, and a coated tank shall be stored on supports that do not cut its coating.
17.3 A fiberglass tank and a jacketed steel tank shall be stored on the dunnage they ship on, chocked against rolling, and protected from sunlight where the manufacturer requires it.
17.4 A tank stored at the site for more than 30 days shall be inspected monthly for standing water in the interstitial space and in the spill containers, and the water removed.

18 Warranty

18.1 The tank manufacturer shall warrant each tank against defects in materials and workmanship, including leakage of the primary tank and the secondary containment, for the period indicated in the datasheet, measured from the date of substantial completion.
Tank Warranty Periodrange
Not less than
years
125102030
NOTE A steel aboveground tank carries a one- or two-year workmanship warranty from most manufacturers, a composite or jacketed steel underground tank carries a thirty-year warranty against corrosion and structural failure, and a fiberglass underground tank a thirty-year warranty on the same terms; the long warranties are conditioned on an installation inspected to the manufacturer's checklist, which is why the installation instructions and the warranty conditions are submitted together. The period follows the construction selected, so the field carries no default. (18.2)
18.3 The warranty shall cover the repair or replacement of the tank, its removal and reinstallation where it cannot be repaired in place, and the retesting of the tank after the repair.
18.4 Where a tank is repaired or replaced under warranty, the repaired or replaced tank shall carry a new warranty of the same term from the date of the repair, or the remainder of the original term, whichever ends later.

19 Spare Parts

19.1 The Contractor shall deliver the spare parts indicated in the datasheet at substantial completion.
Spare Parts Delivered at Substantial Completioncheckbox
☑ Leak detection sensor of each type installed
☐ Level alarm float or probe of each type installed
☑ Fill cap and spill container gaskets of each size installed
☐ Normal vent cap of each size installed
☐ Emergency vent gasket of each size installed
☐ Manway gasket of each size installed
19.2 Spare parts shall be furnished in the quantity of one of each selected class for every five tanks installed, with not fewer than one of each, shall match the installed parts in model and material, and shall be turned over against a written inventory signed by the Owner's representative.

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