+---
+title: Facility Fuel-Oil Systems
+category: Mechanical / Piping & Pumps
+toc_depth: 3
+description: >
+ When to use: storage, transfer, conditioning, and distribution of No. 2 fuel
+ oil (distillate / ULSD) for stationary engine-generators, oil-fired boilers,
+ and burner equipment; aboveground and underground bulk tanks, sub-base and day
+ tanks, transfer pump sets, fuel polishing, leak detection, and supply/return
+ piping.
+ Not intended for: gaseous fuels (use natural-gas-piping), the generator set or
+ boiler equipment themselves (use generators / boilers / emergency-and-standby-
+ power), motor-vehicle dispensing/retail fueling, or aviation/marine fuels.
+---
+
+# Scope {toc}
+
+## This standard covers the complete fuel-oil system that stores, transfers, conditions, and delivers No. 2 distillate fuel oil to stationary prime movers and oil-fired heating equipment. The system boundary begins at the bulk storage tank fill connection and ends at the supply and return connections at the engine, generator day tank, or boiler burner train. Included work comprises bulk storage tanks, sub-base and day tanks, secondary containment, fuel transfer pump sets, fuel polishing and filtration, leak detection and overfill prevention, tank level monitoring, venting, and all interconnecting supply and return piping. {note}
+
+## The prime movers and heating appliances served by this system are specified elsewhere; this standard defines only the fuel supply infrastructure and its interfaces. {note}
+
+### The Contractor shall coordinate fuel supply and return pressures, flow rates, and connection locations with the generator set specified in [[syncs/generators]] and the oil-fired boiler specified in [[syncs/boilers]].
+
+### The Contractor shall coordinate emergency-power runtime and on-site fuel capacity requirements with [[syncs/emergency-and-standby-power]].
+
+## Fuel oil is a Class II combustible liquid; the entire system is governed by flammable and combustible liquids codes, and every clause in this standard is subordinate to the requirements of the authority having jurisdiction (AHJ). {note}
+
+# Referenced Standards {toc}
+
+## The publications listed below are referenced in this standard; the edition in force is the one adopted by the AHJ unless a specific edition is named. {note}
+
+| Standard | Title |
+|----------|-------|
+| NFPA 30 (2021) | Flammable and Combustible Liquids Code |
+| NFPA 31 (2024) | Standard for the Installation of Oil-Burning Equipment |
+| NFPA 110 (2022) | Standard for Emergency and Standby Power Systems |
+| NFPA 37 (2021) | Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines |
+| NFPA 70 (2023) | National Electrical Code (Article 501) |
+| UL 142 | Steel Aboveground Tanks for Flammable and Combustible Liquids |
+| UL 2085 | Protected Aboveground Tanks for Flammable and Combustible Liquids |
+| UL 58 | Steel Underground Tanks for Flammable and Combustible Liquids |
+| UL 1746 | External Corrosion Protection Systems for Steel Underground Storage Tanks |
+| UL 1316 | Glass-Fiber-Reinforced Plastic Underground Storage Tanks |
+| 40 CFR Part 112 | Oil Pollution Prevention (SPCC Rule) |
+| PEI RP200 (2024) | Recommended Practices for Installation of Aboveground Storage Systems |
+| API Standard 2000 | Venting Atmospheric and Low-Pressure Storage Tanks |
+| ASME B31.3 | Process Piping |
+| ASME B31.9 | Building Services Piping |
+| ASTM D975 | Standard Specification for Diesel Fuel |
+| ISO 4406 | Hydraulic Fluid Power — Fluids — Method for Coding the Level of Contamination by Solid Particles |
+| IBC (2021) / ASCE 7 | International Building Code and Minimum Design Loads for Buildings and Other Structures |
+| IFC (2021) | International Fire Code (Chapter 57) |
+
+# Definitions {toc}
+
+## The following terms are used throughout this standard: {note}
+
+- **Bulk (main) tank** is the primary fuel reservoir sized to satisfy the facility's full on-site fuel capacity requirement.
+- **Day tank** (also auxiliary or sub-base tank) is a small reservoir located at or near the prime mover that provides a short-duration fuel supply at the pressure and head the engine or burner requires.
+- **Sub-base (belly) tank** is a day tank built into the base rail of a packaged generator set and listed as part of the generator assembly.
+- **Fuel polishing** is continuous or periodic recirculation of stored fuel through multi-stage filtration and water separation to maintain fuel quality during extended storage.
+- **Interstitial space** is the annular cavity between the inner and outer walls of a double-wall tank or double-containment pipe, monitored for leaks.
+- **ULSD** (ultra-low-sulfur diesel) is ASTM D975 distillate with sulfur content ≤ 15 ppm; it is the de facto supply for both engine and heating applications in most jurisdictions.
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following action submittals for review before fabrication or installation:
+
+- Product data for tanks, pumps, filters, polishing equipment, gauges, valves, and leak-detection devices
+- Shop drawings showing tank dimensions, nozzle schedule, containment, and anchorage
+- Fuel system flow diagram showing tanks, pumps, piping, and instrumentation
+- Pump performance curves with the specified duty point identified
+- Tank vent sizing calculations per API 2000
+- Secondary containment volume calculations per 40 CFR 112
+- Seismic anchorage calculations stamped by a registered professional engineer where required
+- Fuel system control sequence of operation
+
+```datasheet
+label: Action submittals required
+type: checkbox
+options:
+ - Product data (tanks, pumps, filters, gauges, valves)
+ - Shop drawings (tank dimensions, nozzles, containment, anchorage)
+ - Fuel system flow diagram
+ - Pump performance curves with duty point
+ - Vent sizing calculations (API 2000)
+ - Secondary containment volume calculations (40 CFR 112)
+ - Seismic anchorage calculations (PE stamped)
+ - Control sequence of operation
+default:
+ - Product data (tanks, pumps, filters, gauges, valves)
+ - Shop drawings (tank dimensions, nozzles, containment, anchorage)
+ - Fuel system flow diagram
+ - Pump performance curves with duty point
+ - Vent sizing calculations (API 2000)
+ - Secondary containment volume calculations (40 CFR 112)
+ - Control sequence of operation
+```
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following informational submittals:
+
+- Tank listing labels (UL 142, UL 2085, UL 58, UL 1746, or UL 1316 as applicable)
+- Manufacturer welding and fabrication certifications for steel tanks
+- Material compatibility statement for elastomers in contact with ULSD
+- Field hydrostatic and pneumatic test reports for tanks and piping
+- Coordination confirmation with the generator and boiler specifications
+
+```datasheet
+label: Informational submittals required
+type: checkbox
+options:
+ - Tank listing labels
+ - Welding/fabrication certifications
+ - ULSD elastomer compatibility statement
+ - Field test reports (tanks and piping)
+ - Generator/boiler coordination confirmation
+default:
+ - Tank listing labels
+ - ULSD elastomer compatibility statement
+ - Field test reports (tanks and piping)
+ - Generator/boiler coordination confirmation
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following closeout submittals:
+
+- Operation and maintenance manuals for all equipment
+- As-built fuel system flow diagram and piping layout
+- Spill Prevention, Control, and Countermeasure (SPCC) Plan where applicable
+- State and local underground storage tank (UST) registration and permit documentation
+- Commissioning and leak-detection function test records
+- Warranty documents
+
+```datasheet
+label: Closeout submittals required
+type: checkbox
+options:
+ - Operation and maintenance manuals
+ - As-built flow diagram and piping layout
+ - SPCC Plan
+ - UST registration/permit documentation
+ - Commissioning and leak-detection test records
+ - Warranty documents
+default:
+ - Operation and maintenance manuals
+ - As-built flow diagram and piping layout
+ - Commissioning and leak-detection test records
+ - Warranty documents
+```
+
+# Quality Assurance {toc}
+
+## Regulatory Compliance {toc}
+
+### The fuel-oil system shall comply with NFPA 30, NFPA 31, and the International Fire Code as adopted by the AHJ.
+
+### Where the system serves emergency or standby power, it shall additionally comply with NFPA 110 and NFPA 37.
+
+### Aggregate aboveground storage exceeding 1,320 gallons, or aggregate underground storage exceeding 42,000 gallons, shall require a SPCC Plan under 40 CFR 112. {note}
+
+### The designer shall verify whether the cumulative capacity of all bulk, day, and sub-base tanks on the site exceeds the SPCC threshold; multiple generator sub-base tanks frequently exceed 1,320 gallons in aggregate without the threshold being recognized.
+
+### The Contractor shall obtain all state and local UST permits before underground tank installation. {note}
+
+### Underground storage tanks are regulated under state programs authorized by RCRA Subtitle I; the Contractor shall register the tank and provide proof of registration in the closeout submittals.
+
+## Qualifications {toc}
+
+### Tanks shall be fabricated by a manufacturer regularly engaged in producing listed fuel-oil storage tanks.
+
+### Field welding of steel piping shall be performed by welders qualified under ASME Section IX or the applicable piping code.
+
+### Fuel polishing and leak-detection equipment shall be commissioned by a technician certified by the equipment manufacturer.
+
+# Environmental and Service Conditions {toc}
+
+## Fuel Characteristics {toc}
+
+### The system shall be designed for No. 2 distillate fuel oil conforming to ASTM D975 Grade No. 2-D.
+
+### Where ultra-low-sulfur diesel (ULSD) is the supplied fuel, all wetted elastomers shall be compatible with ULSD. {note}
+
+### ULSD has lower lubricity and different solvency than legacy No. 2 fuel oil; seals, gaskets, and flexible connectors carried over from legacy details may swell, harden, or fail. Fluoroelastomer (FKM) seals are preferred for ULSD service.
+
+### Wetted elastomeric seals, gaskets, and flexible connectors shall be fluoroelastomer (FKM) or another material certified compatible with ULSD.
+
+```datasheet
+label: Fuel grade
+type: select
+options:
+ - No. 2-D distillate (ASTM D975)
+ - Ultra-low-sulfur diesel (ULSD, ≤ 15 ppm sulfur)
+ - No. 2-D dyed (off-road)
+default: Ultra-low-sulfur diesel (ULSD, ≤ 15 ppm sulfur)
+```
+
+```datasheet
+label: Wetted seal/elastomer material
+type: select
+options:
+ - Fluoroelastomer (FKM)
+ - Nitrile (NBR)
+ - Fluorosilicone
+default: Fluoroelastomer (FKM)
+```
+
+## Climate {toc}
+
+### No. 2 fuel oil begins to precipitate wax near its cloud point, approximately -7 °C (20 °F); systems in cold climates shall include freeze and gel protection. {note}
+
+### Where the design ambient temperature can approach or fall below the fuel cloud point, the system shall include tank heating or pipe trace heating to keep fuel above its gel point.
+
+```datasheet
+label: Cold-weather fuel conditioning
+type: select
+options:
+ - None
+ - Electric immersion tank heater
+ - Hot-water/steam tank heat exchanger
+ - Electric pipe trace heating
+default: None
+```
+
+```datasheet
+label: Fuel heater thermostat setpoint
+type: range
+unit: °C
+min: 5
+max: 30
+step: 1
+default: 10
+```
+
+## Seismic {toc}
+
+### Tanks and fuel system components in Seismic Design Categories C through F shall be anchored per IBC Chapter 16 and ASCE 7. {note}
+
+### Seismic anchorage is frequently omitted for tanks and for sub-base tanks integral to a generator skid; the skid anchorage shall be designed by the structural engineer of record.
+
+### Tank and piping seismic restraints shall be designed and stamped by a registered professional engineer where the seismic design category requires it.
+
+```datasheet
+label: Seismic design category
+type: select
+options:
+ - A
+ - B
+ - C
+ - D
+ - E
+ - F
+default: D
+```
+
+# System Architecture {toc}
+
+## The fuel-oil system is configured around the relationship between a large bulk tank that holds the required on-site capacity and a small day tank that feeds the prime mover at the head it needs. {note}
+
+## A bulk tank located more than a short distance from the engine, or below the engine fuel pump's lift capability, cannot reliably feed the engine directly; a day tank with a transfer pump is then required. {note}
+
+### Where the bulk tank cannot satisfy the engine fuel-supply pressure and lift limits directly, the system shall include a day tank fed by a fuel transfer pump set.
+
+### The day tank proximity, capacity, and fill controls shall comply with the day-tank provisions of NFPA 110 for emergency and standby applications.
+
+## Selecting the tank arrangement is the first architectural decision and drives containment strategy, fire-code setbacks, and the transfer pump scope. {note}
+
+```datasheet
+label: System architecture
+type: select
+options:
+ - Bulk tank with gravity feed to day tank
+ - Bulk tank with transfer pump to day tank
+ - Bulk tank with transfer pump to sub-base tank
+ - Sub-base tank only (no separate bulk tank)
+ - Day tank with direct supplier fill (no bulk tank)
+default: Bulk tank with transfer pump to sub-base tank
+```
+
+## Tank Location {toc}
+
+### Tank location is determined by site constraints, fire-code setbacks, and architectural coordination, and shall be shown on the drawings. [[drawing: tank location plan]]
+
+### Aboveground tank setback distances from buildings, property lines, and ignition sources shall comply with NFPA 30 and the IFC.
+
+### Where required setbacks cannot be met, the tank shall be a UL 2085 fire-rated protected tank or shall be otherwise protected as permitted by the AHJ.
+
+# Storage Tanks {toc}
+
+## Tank Type {toc}
+
+### The tank type, aboveground or underground, shall be selected based on site constraints, regulatory burden, and fire-code setbacks. {note}
+
+### Aboveground tanks are easier to inspect and monitor but consume site area and are subject to fire-code setbacks; underground tanks free the site but add corrosion-protection, leak-monitoring, and permitting obligations.
+
+```datasheet
+label: Tank installation type
+type: select
+options:
+ - Aboveground (AST)
+ - Underground (UST)
+default: Aboveground (AST)
+```
+
+## Tank Construction {toc}
+
+### Tanks shall be double-wall construction with continuous interstitial monitoring unless the AHJ accepts single-wall construction within an external secondary containment structure. {note}
+
+### Double-wall tanks satisfy SPCC secondary containment without a separate dike and provide a monitored interstitial space; single-wall tanks require an external containment structure and are prohibited by many jurisdictions.
+
+### Aboveground steel tanks shall be listed to UL 142.
+
+### Fire-rated aboveground tanks shall be listed to UL 2085 with two-hour fire resistance, integral secondary containment, and impact protection.
+
+### Underground steel tanks shall be listed to UL 58, with external corrosion protection listed to UL 1746 where the tank is bare steel.
+
+### Underground fiberglass tanks shall be listed to UL 1316.
+
+### Specifying single-wall tanks where the AHJ, fire code, or SPCC plan requires double-wall or fire-rated construction is a common error; the designer shall confirm local requirements and setback distances before selecting the tank construction.
+
+```datasheet
+label: Tank wall construction
+type: select
+options:
+ - Double-wall with interstitial monitoring
+ - Single-wall within external containment
+default: Double-wall with interstitial monitoring
+```
+
+```datasheet
+label: Aboveground tank listing
+type: select
+options:
+ - UL 142 standard
+ - UL 2085 fire-rated/protected
+default: UL 142 standard
+```
+
+```datasheet
+label: Underground tank material/listing
+type: select
+options:
+ - Steel, UL 58 with UL 1746 corrosion protection
+ - Fiberglass, UL 1316
+default: Steel, UL 58 with UL 1746 corrosion protection
+```
+
+```datasheet
+label: Underground steel corrosion protection type (UL 1746)
+type: select
+options:
+ - Sacrificial anode cathodic protection
+ - Impressed-current cathodic protection
+ - Composite (FRP-clad)
+ - Jacketed
+default: Jacketed
+```
+
+## Tank Capacity {toc}
+
+### The bulk tank capacity shall be sized to provide the facility's required on-site fuel runtime at full rated load. {note}
+
+### For NFPA 110 emergency and standby systems, the runtime requirement is set by the system Class; Class 96 requires 96 hours of fuel at full rated load and is the most demanding common case.
+
+### The bulk tank shall be sized to hold not less than 133 percent of the fuel required for the full-rated-load runtime period. {note}
+
+### NFPA 110 requires the main tank to hold 133 percent of the fuel needed for the rated runtime; sizing the tank to only the bare runtime volume leaves no usable design margin and no allowance for unpumpable bottoms.
+
+### The day tank shall be sized for not less than the engine or burner supply duration required by the prime mover, commonly an 8-hour supply at full load. {note}
+
+```datasheet
+label: NFPA 110 system Level
+type: select
+options:
+ - Level 1 (life safety)
+ - Level 2 (non-life-safety)
+ - Not applicable (heating only)
+default: Level 1 (life safety)
+```
+
+```datasheet
+label: On-site fuel runtime (NFPA 110 Class)
+type: select
+options:
+ - Class 8 (8 hours)
+ - Class 24 (24 hours)
+ - Class 48 (48 hours)
+ - Class 72 (72 hours)
+ - Class 96 (96 hours)
+default: Class 96 (96 hours)
+```
+
+```datasheet
+label: Bulk tank usable capacity
+type: range
+unit: gal
+min: 500
+max: 30000
+step: 100
+default: 4000
+drawing_ref: true
+```
+
+```datasheet
+label: Bulk tank sizing margin over rated runtime
+type: range
+unit: '%'
+min: 100
+max: 150
+step: 1
+default: 133
+```
+
+```datasheet
+label: Day/sub-base tank capacity
+type: range
+unit: gal
+min: 50
+max: 1000
+step: 10
+default: 150
+```
+
+## Tank Configuration {toc}
+
+### The bulk tank geometry shall suit the available footprint; horizontal cylindrical, vertical cylindrical, and rectangular configurations are all acceptable for listed tanks. {note}
+
+### A sub-base tank shall be dimensionally compatible with the generator base rail, and its fill, supply, and return port locations shall match the generator set. {note}
+
+### Sub-base tank dimensions and port locations are sized to the generator frame; the generator specification and this fuel system specification shall cross-reference each other to confirm compatibility before fabrication.
+
+```datasheet
+label: Bulk tank geometry
+type: select
+options:
+ - Horizontal cylindrical
+ - Vertical cylindrical
+ - Rectangular
+default: Horizontal cylindrical
+```
+
+```datasheet
+label: Day tank mounting
+type: select
+options:
+ - Floor-mounted free-standing
+ - Wall-mounted
+ - Integral to generator base rail (sub-base)
+default: Floor-mounted free-standing
+```
+
+# Secondary Containment {toc}
+
+## Secondary containment confines a tank or piping leak to a defined, impervious volume so that released fuel is recovered rather than reaching soil, groundwater, or storm drains. It may be provided by the tank's integral double wall, by an external dike or berm, or by a lined concrete basin. {note}
+
+### Secondary containment shall be sized for not less than 100 percent of the capacity of the largest single tank served, plus freeboard for precipitation where the containment is exposed to weather. {note}
+
+### A common rule of thumb of 110 percent of tank volume does not satisfy 40 CFR 112 in high-rainfall regions; the containment shall be sized for the full largest-tank volume plus calculated precipitation freeboard.
+
+### Containment liners, coatings, and berm materials shall be compatible with fuel oil and impervious for the design service life.
+
+### Containment areas exposed to weather shall include a means to drain and inspect accumulated rainwater without releasing fuel.
+
+```datasheet
+label: Secondary containment method
+type: select
+options:
+ - Integral double-wall tank
+ - Lined concrete basin
+ - Concrete berm
+ - Earthen dike with liner
+default: Integral double-wall tank
+```
+
+```datasheet
+label: Containment capacity basis
+type: select
+options:
+ - 100% of largest tank
+ - 100% of largest tank plus precipitation freeboard
+ - 110% of largest tank
+default: 100% of largest tank plus precipitation freeboard
+```
+
+```datasheet
+label: Precipitation freeboard design event
+type: range
+unit: in
+min: 0
+max: 12
+step: 0.5
+default: 6
+```
+
+# Fuel Transfer Pumps {toc}
+
+## The transfer pump set moves fuel from the bulk tank to the day or sub-base tank on demand from the day-tank level controls. {note}
+
+## Pump redundancy is the central reliability decision: a simplex set is a single point of failure, while a duplex lead-lag set continues to deliver fuel if one pump fails. {note}
+
+### Fuel transfer pumps serving an NFPA 110 Level 1 system shall be duplex (lead-lag) with automatic alternation and failure changeover. {note}
+
+### For Level 1 emergency systems a single transfer pump is a single point of failure between the bulk tank and the engine; a redundant pump preserves fuel delivery under a pump fault.
+
+### Each pump shall be sized to deliver the full day-tank refill rate independently.
+
+### Pumps shall be positive-displacement gear or vane type, or centrifugal, matched to the fuel viscosity and the required day-tank refill rate.
+
+### Each pump shall be protected by a strainer on its suction and a pressure-relief or return path on its discharge.
+
+```datasheet
+label: Transfer pump arrangement
+type: select
+options:
+ - Simplex
+ - Duplex (lead-lag) with automatic alternation
+default: Duplex (lead-lag) with automatic alternation
+```
+
+```datasheet
+label: Pump type
+type: select
+options:
+ - Gear (positive displacement)
+ - Vane (positive displacement)
+ - Centrifugal
+default: Gear (positive displacement)
+```
+
+```datasheet
+label: Transfer pump flow rate
+type: range
+unit: gpm
+min: 1
+max: 50
+step: 1
+default: 10
+```
+
+```datasheet
+label: Transfer pump discharge pressure
+type: range
+unit: psi
+min: 10
+max: 75
+step: 5
+default: 25
+```
+
+# Fuel Conditioning {toc}
+
+## Filtration and Water Separation {toc}
+
+### Fuel shall pass through filtration and water separation between the bulk tank and the prime mover. {note}
+
+### Modern high-pressure injection equipment is intolerant of particulate and water; filtration protects the injectors and the day-tank fuel quality.
+
+### A duplex filter/separator arrangement shall be provided so an element can be changed without interrupting fuel flow.
+
+### Filter elements shall be sized to the prime mover's cleanliness requirement, typically 10-micron nominal, or 2-micron for modern common-rail injection.
+
+### Each filter housing shall include a differential-pressure indicator to signal element loading.
+
+```datasheet
+label: Filter arrangement
+type: select
+options:
+ - Simplex
+ - Duplex (change without interruption)
+default: Duplex (change without interruption)
+```
+
+```datasheet
+label: Filter rating
+type: select
+options:
+ - 30-micron nominal
+ - 10-micron nominal
+ - 2-micron nominal
+default: 10-micron nominal
+```
+
+```datasheet
+label: Water removal method
+type: select
+options:
+ - Water-absorbing element
+ - Coalescing separator
+ - Both (separator plus absorbing element)
+default: Coalescing separator
+```
+
+```datasheet
+label: Differential-pressure indicator
+type: select
+options:
+ - Visual gauge
+ - Gauge with alarm contact
+default: Gauge with alarm contact
+```
+
+## Fuel Polishing {toc}
+
+### Fuel stored for extended periods shall be maintained by a fuel polishing system. {note}
+
+### Fuel sized for a 96-hour runtime at a low daily consumption rate may sit in the tank for months; ULSD absorbs more water and supports microbial growth faster than legacy diesel, so static long-term storage degrades fuel quality if it is not maintained.
+
+### Where the design fuel turnover exceeds approximately 30 days, the system shall include a dedicated fuel polishing skid with multi-stage filtration, water separation, and continuous or scheduled recirculation. {note}
+
+### NFPA 110 does not name fuel polishing directly, but its fuel-quality maintenance requirement implies it for extended-storage generator fuel; omitting polishing, biocide dosing, and water-bottom monitoring is a common reliability defect.
+
+### Stored fuel cleanliness shall be maintained to a target consistent with ASTM D975 limits and the prime mover's ISO 4406 particulate requirement.
+
+### Provisions for fuel stabilizer and biocide dosing shall be included for systems whose fuel turnover exceeds 30 days.
+
+```datasheet
+label: Fuel polishing system
+type: select
+options:
+ - None (short turnover, < 30 days)
+ - Periodic polishing skid
+ - Continuous recirculation polishing skid
+default: Continuous recirculation polishing skid
+```
+
+```datasheet
+label: Polishing final filtration rating
+type: select
+options:
+ - 5-micron
+ - 2-micron
+ - 1-micron
+default: 2-micron
+```
+
+```datasheet
+label: Stored fuel cleanliness target (ISO 4406)
+type: select
+options:
+ - 18/16/13
+ - 16/14/11
+ - 14/12/9
+default: 16/14/11
+```
+
+```datasheet
+label: Fuel stabilizer / biocide dosing provision
+type: checkbox
+options:
+ - Stabilizer dosing port
+ - Biocide dosing port
+ - Water-bottom sampling provision
+default:
+ - Stabilizer dosing port
+ - Water-bottom sampling provision
+```
+
+# Leak Detection and Overfill Prevention {toc}
+
+## Leak detection identifies a release into the interstitial space or containment before fuel escapes the system; overfill prevention stops a fill before the tank is overtopped. {note}
+
+### The interstitial space of every double-wall tank and double-containment pipe shall be continuously monitored for leaks. {note}
+
+### EPA UST regulations and many state AST regulations require continuous interstitial monitoring; treating leak detection as an optional add-on creates code non-compliance and inspection failures.
+
+### Secondary containment areas shall include a means to detect liquid accumulation.
+
+### Each tank fill shall include overfill prevention by an overfill prevention valve, a high-level alarm, or an automatic fill shutoff, per NFPA 30 and 40 CFR 112. {note}
+
+### A high-level alarm shall annunciate at a normally attended location.
+
+### An automatic shutoff shall stop the transfer pump or close the fill on a high-high level signal.
+
+```datasheet
+label: Interstitial leak detection
+type: select
+options:
+ - Continuous electronic (interstitial sensor)
+ - Continuous (vacuum/pressure monitored interstice)
+ - Periodic manual
+default: Continuous electronic (interstitial sensor)
+```
+
+```datasheet
+label: Overfill prevention method
+type: select
+options:
+ - Overfill prevention valve
+ - High-level alarm
+ - Automatic fill shutoff
+ - High-level alarm with automatic shutoff
+default: High-level alarm with automatic shutoff
+```
+
+```datasheet
+label: High-level alarm setpoint (% of tank capacity)
+type: range
+unit: '%'
+min: 80
+max: 95
+step: 1
+default: 90
+```
+
+# Tank Level Monitoring {toc}
+
+## Tank level monitoring provides the operating level for fill scheduling, fuel inventory, and the low-level alarms that protect the prime mover. {note}
+
+### Underground storage tanks shall be equipped with an automatic tank gauge (ATG) with continuous electronic level monitoring. {note}
+
+### State and EPA UST regulations require continuous electronic inventory and leak monitoring on underground tanks; a mechanical float gauge alone does not satisfy these programs.
+
+### Aboveground bulk tanks shall be equipped with a continuous level gauge; an ATG should be provided on large aboveground systems.
+
+### Day tanks shall include level switches for pump start, pump stop, high-level, and low-level alarm functions.
+
+```datasheet
+label: Bulk tank level monitoring
+type: select
+options:
+ - Mechanical float gauge
+ - Automatic tank gauge (ATG, continuous electronic)
+ - ATG with remote monitoring
+default: Automatic tank gauge (ATG, continuous electronic)
+```
+
+```datasheet
+label: Day tank level controls
+type: checkbox
+options:
+ - Pump start (low) switch
+ - Pump stop (high) switch
+ - High-level alarm switch
+ - Low-level alarm switch
+default:
+ - Pump start (low) switch
+ - Pump stop (high) switch
+ - High-level alarm switch
+ - Low-level alarm switch
+```
+
+# Venting {toc}
+
+## Normal vents relieve the pressure and vacuum produced by filling, emptying, and thermal breathing; emergency vents relieve the overpressure produced by fire exposure. {note}
+
+### Normal vents shall be sized per API 2000 for the tank's maximum fill and withdrawal rates. {note}
+
+### Sub-base tanks up to 10,000-gallon capacity are commonly served by a 2-inch NPT normal vent sized per API 2000, but the vent shall be confirmed against the actual fill rate.
+
+### Aboveground tanks shall be provided with emergency relief venting for fire exposure per NFPA 30.
+
+### Vent piping shall terminate outdoors at the height and location required by NFPA 30 and NFPA 31, away from building openings and air intakes. [[drawing: vent termination location]]
+
+### Vent terminations shall be fitted with a weatherproof cap and, where required, a flame arrester.
+
+### Undersized or poorly located vents are a frequent source of requests for information; the vent routing shall be coordinated with the structural and architectural drawings before installation.
+
+```datasheet
+label: Normal vent sizing basis
+type: select
+options:
+ - API 2000
+ - Tank manufacturer's listed vent
+default: API 2000
+```
+
+```datasheet
+label: Emergency relief venting
+type: select
+options:
+ - Weighted emergency vent (form integral to tank)
+ - Spring-loaded emergency relief valve
+ - Long-bolt manhole cover (emergency relief)
+default: Weighted emergency vent (form integral to tank)
+```
+
+```datasheet
+label: Vent flame arrester
+type: select
+options:
+ - Required
+ - Not required
+default: Required
+```
+
+# Piping {toc}
+
+## Supply and return piping carries fuel from the bulk tank through the transfer and conditioning equipment to the prime mover and back. {note}
+
+## Piping Material {toc}
+
+### Fuel oil supply and return piping shall be black steel, Schedule 40, with welded, threaded, or flanged joints, unless another material is specifically permitted below. {note}
+
+### Black steel Schedule 40 with 150-pound fittings is the standard fuel oil piping; copper and double-containment piping are alternatives for specific conditions.
+
+### Copper tubing may be used for heating-oil supply lines up to 2 inches only where permitted by the AHJ; the designer shall verify the AHJ accepts copper for the fuel in service before specifying it. {note}
+
+### NFPA 31 permits copper for heating oil up to 2 inches, but some AHJs prohibit copper for diesel; copper shall not be specified without confirming local acceptance.
+
+### Where SPCC or the AHJ requires secondary containment of piping, double-containment piping with an inner carrier pipe inside an outer containment pipe shall be provided.
+
+```datasheet
+label: Primary piping material
+type: select
+options:
+ - Black steel Schedule 40
+ - Copper (heating oil ≤ 2 in., where AHJ permits)
+ - Double-containment (carrier within outer jacket)
+default: Black steel Schedule 40
+```
+
+```datasheet
+label: Piping joints
+type: select
+options:
+ - Welded
+ - Threaded
+ - Flanged
+ - Welded and flanged
+default: Welded and flanged
+```
+
+```datasheet
+label: Pipe design code
+type: select
+options:
+ - ASME B31.9 (building services)
+ - ASME B31.3 (process piping)
+default: ASME B31.9 (building services)
+```
+
+## Piping Arrangement {toc}
+
+### Return piping shall terminate below the minimum operating fuel level in the tank. {note}
+
+### A return line that discharges above the fuel surface foams and aerates the fuel and entrains air into the transfer pumps; the return shall be extended below the minimum fuel level.
+
+### Piping routing, slopes, and equipment connection points shall be shown on the drawings. [[drawing: fuel piping layout]]
+
+### Supply and return connections to the prime mover shall be made with listed flexible connectors compatible with the fuel in service.
+
+# Electrical and Hazardous Locations {toc}
+
+## Tank vents, fill openings, and pump rooms create classified hazardous locations in which only suitable electrical equipment may be installed. {note}
+
+### Electrical equipment and wiring within the classified distances of tank vents and fill openings, and within fuel pump rooms, shall comply with NEC Article 501. {note}
+
+### Pump rooms and the zones within defined distances of vents and fills are NEC Class I, Division 1 or 2 locations; standard non-classified electrical equipment in these zones is a code violation typically caught only at inspection.
+
+### Level sensors, leak-detection devices, and pump controls within classified areas shall be listed for the area classification.
+
+### The extent of each classified area shall be determined per NEC Article 501 and NFPA 30 and shown on the drawings. [[drawing: hazardous area classification plan]]
+
+```datasheet
+label: Pump room area classification
+type: select
+options:
+ - Class I, Division 1
+ - Class I, Division 2
+ - Unclassified (equipment outside classified distances)
+default: Class I, Division 2
+```
+
+# Boiler and Burner Interface {toc}
+
+## Oil-fired burners require a specific fuel pressure and flow at the burner inlet; the transfer pump and regulating valve must deliver exactly that. {note}
+
+### The fuel supply pressure and flow at the burner inlet shall match the burner manufacturer's requirements. {note}
+
+### Burner fuel pressure requirements are frequently left to the burner contractor without a clear responsibility assignment; the transfer pump curve and the pressure-regulating valve shall be matched to the burner specification, and this responsibility shall be assigned in the contract documents.
+
+### A fuel oil pressure-regulating valve shall be provided where the transfer pump discharge pressure exceeds the burner's rated inlet pressure.
+
+### Fuel supply and return interface points, pressures, and flows shall be coordinated with [[syncs/boilers]].
+
+```datasheet
+label: Burner fuel pressure regulation
+type: select
+options:
+ - Direct (pump matched to burner)
+ - Pressure-regulating valve at burner
+ - Pressure-regulating valve at pump skid
+default: Pressure-regulating valve at burner
+```
+
+# Testing {toc}
+
+## Field testing confirms that tanks and piping are leak-free and that the control, alarm, and leak-detection functions operate as designed. {note}
+
+### Steel storage tanks shall be tested for tightness per the tank manufacturer's instructions and NFPA 31 before being placed in service. {note}
+
+### Fuel oil piping shall be pressure tested per the applicable piping code and NFPA 31, and shall hold the test pressure without loss for the required duration.
+
+### Interstitial spaces of double-wall tanks and double-containment piping shall be tested for integrity before backfill or concealment.
+
+### Leak-detection, overfill-prevention, high-level, and low-level alarm functions shall be function tested and the results recorded.
+
+### The fuel transfer and day-tank fill control sequence shall be commissioned and demonstrated under load.
+
+```datasheet
+label: Piping test method
+type: select
+options:
+ - Hydrostatic
+ - Pneumatic
+ - Hydrostatic then in-service
+default: Hydrostatic
+```
+
+```datasheet
+label: Piping test pressure
+type: range
+unit: psi
+min: 50
+max: 150
+step: 5
+default: 75
+```
+
+```datasheet
+label: Piping test hold duration
+type: range
+unit: hr
+min: 1
+max: 24
+step: 1
+default: 4
+```
+
+# Installation {toc}
+
+## Aboveground tanks shall be installed on foundations and supports designed for the full tank weight per PEI RP200 and the structural drawings. {note}
+
+### Underground tanks shall be installed with the bedding, backfill, anchoring, and deflection control required by the tank manufacturer and UL listing. {note}
+
+### Buoyancy anchoring shall be provided for underground tanks where the design groundwater level can reach the tank.
+
+### Tanks and components shall be installed plumb, level, and accessible for inspection, maintenance, and element replacement.
+
+### Sub-base tanks integral to a generator skid shall be anchored to the structural slab through the generator skid anchorage.
+
+### Identification labels and spill-control signage shall be installed at fills, vents, and tanks as required by NFPA 30 and the AHJ.
+
+```datasheet
+label: Aboveground tank foundation
+type: select
+options:
+ - Reinforced concrete slab
+ - Concrete piers/saddles
+ - Steel support stand
+default: Reinforced concrete slab
+```
+
+```datasheet
+label: Underground tank anchorage
+type: select
+options:
+ - None (above groundwater)
+ - Deadman anchors with straps
+ - Concrete hold-down pad with straps
+default: Deadman anchors with straps
+```
+
+# Delivery, Storage, and Handling {toc}
+
+## Tanks, pumps, and conditioning equipment shall be protected from damage and contamination from delivery through installation. {note}
+
+### Tank openings shall be kept capped and sealed until piping connections are made.
+
+### Equipment shall be stored off the ground, protected from weather, and handled with rigging suited to its weight and listed lifting points.
+
+### Internal surfaces of tanks and piping shall be kept clean and dry to prevent water and debris from contaminating the fuel system.
+
+# Warranty {toc}
+
+## The warranty assures the owner that tanks and equipment will perform for a defined period and assigns repair responsibility. {note}
+
+### The Contractor shall warrant the fuel-oil system against defects in materials and workmanship for the project warranty period.
+
+### Tank manufacturers' standard tank and corrosion-protection warranties shall be transferred to the owner.
+
+```datasheet
+label: System warranty period
+type: range
+unit: yr
+min: 1
+max: 5
+step: 1
+default: 1
+```
+
+```datasheet
+label: Tank manufacturer warranty
+type: select
+options:
+ - Standard (1 year)
+ - Extended (10 year, steel)
+ - Extended (30 year, fiberglass/corrosion)
+default: Extended (30 year, fiberglass/corrosion)
+```
+
+# Spare Parts {toc}
+
+## Spare consumables allow routine maintenance to proceed without procurement delay and keep the conditioning equipment effective. {note}
+
+### The Contractor shall furnish spare filter and water-separator elements for each filter and polishing stage.
+
+### The Contractor shall furnish spare gaskets and seals compatible with the fuel in service.
+
+```datasheet
+label: Spare parts to be furnished
+type: checkbox
+options:
+ - Spare filter elements (one set per stage)
+ - Spare water-separator elements
+ - Spare polishing-skid elements
+ - Spare gaskets and FKM seals
+ - Differential-pressure indicator spares
+default:
+ - Spare filter elements (one set per stage)
+ - Spare water-separator elements
+ - Spare gaskets and FKM seals
+```