API RECOMMENDED PRACTICE 1004 & EPA STAGE I RECOVERY

Rack Bottom Loading & Vapor Recovery Manual

Standard operating procedures for bulk petroleum rack loading: 4-inch API dry-break valves, vapor recovery hookup, internal emergency air bars, and rack permissive interlocks.

01 API RP 1004 Hookup Sequence Checklist RACK PERMISSIVE: GREEN

Step 1: Electrostatic Grounding Cable Attached

Heavy-duty ground clamp bonded to trailer brass grounding stud (< 10 ohms resistance to earth).

Step 2: Scully Optic Overfill Plug Connected

Optical socket mated with rack umbilical. Confirms all compartment high-level liquid sensors dry and pulsing.

Step 3: Vapor Recovery Arm Locked (Stage I EPA)

4-inch vapor elbow latched to trailer vapor return poppet valve. Displaced hydrocarbon vapors routed to terminal vapor recovery unit (VRU).

Step 4: Pneumatic Emergency Internal Valve Bar Opened

Pneumatic air bar charged to open bottom tank shear valves. Guard interlock bar rotated clear of loading heads.

Step 5: 4-Inch API Loading Arm Coupler Clamped

Dry-break loading head latched onto API adapter valve. Cam levers locked into secondary safety detents.

02 Rack Permissive Interlock Status

Terminal Rack Meter Permissive

FLOW AUTHORIZED (600 GPM)

All five safety interlocks verified. Preset batch ready to pump.

Safety Interlock Live Circuit Telemetry:

Ground Resistance: 4.2 Ω (Pass < 10 Ω)

Scully Optic Sensor Array: 5 of 5 Sensors Pulsing Dry

Vapor Header Pressure: +0.8 In. H2O (VRU Draw Active)

Connect Fuel Terminal Rack APIs with Exspeedite

API RP 1004 Safety Philosophy for Bottom Loading Petroleum Tankers

Prior to the widespread adoption of bottom loading, petroleum tankers were top-loaded through open manholes—a hazardous practice that generated massive static electricity charges and vented volatile organic compounds (VOCs) directly into the atmosphere. The API Recommended Practice 1004 standard established a sealed, closed-loop loading system operating from ground level.

Stage I Vapor Recovery Closed Loop

As liquid fuel enters the bottom of each compartment at up to 600 gallons per minute, the rising liquid piston displaces air saturated with explosive hydrocarbon vapors. The vapor return header routes these fumes through a flame arrestor directly to the terminal's vapor recovery unit (VRU), capturing 99%+ of volatile emissions.

Pneumatic Emergency Shear Valves

DOT-406 trailers carry internal emergency valves positioned inside the tank shell. The external discharge piping incorporates a sacrificial shear groove. In the event of a pull-away or external collision at the loading rack, the pipe shears off cleanly while the internal spring-loaded poppet valve remains locked shut, preventing major environmental spills.

Enterprise Wholesale Terminal Automation with Exspeedite

Exspeedite TMS connects directly with wholesale petroleum terminal automation systems (TAS) such as DTN, Toptech Systems, and Dearman. Driver card credentials, compartment gallon allocations, and supplier customer account numbers are automatically synced, eliminating terminal lockout delays.

Direct TAS Rack Automation Sync Driver Terminal Card Expiration Tracking Automated Electronic Rack BOL Ingestion Instant Wholesale Fuel Margin Auditing