Overview
ISO 13331:1995 - "Road vehicles - Filler pipes and openings of motor vehicle fuel tanks - Vapour recovery system" - specifies dimensional and functional requirements to ensure compatibility between petrol‑powered vehicle filler pipes and refuelling vapour recovery nozzles (both active and passive systems). Developed primarily for passenger cars and commercial vehicles, the standard may also be applied to marine, industrial and other refuelling applications where vapour recovery is required. The dimensions are based on SAE J1140 and include requirements for sealing surfaces, locking lips, access zones and a nozzle test gauge.
Key topics and technical requirements
- Compatibility objective: Ensures vehicle filler pipe geometry accepts vapour recovery nozzles in intended orientations and supports vapour-tight seals where required.
- Definitions: Distinguishes active vapour recovery systems (powered extraction, e.g., vacuum pump) and passive systems (vapour displacement relying on sealing).
- Filler pipe sealing surface: Standardises the sealing interface and allowable diameters (referenced in the document figures) to mate with nozzle spouts.
- Internal locking lip: Must be present around at least 100° of the filler pipe circumference; minimum heights and depths are specified (measured from inside/outside walls and sealing plane) to interface with nozzle locking rings.
- Nozzle test gauge: A reference gauge (21 mm for unleaded-only vehicles; 24 mm when leaded fuel is acceptable) is defined to verify access and sealing. The test gauge establishes normal resting and insertion positions and angular limits (normal resting angle within +20° to −10° relative to filler pipe sealing surface).
- Filler pipe access zone: Composed of three parts - an oval sealing zone, a tapered rectangular handle zone, and a transition blend - and must permit nozzle insertion within ±90° of the upright position. Production tolerances to be considered.
- Orientation and spill prevention: Filler pipe orientation must ensure the nozzle in its normal resting position forms an angle of not less than 30° with the horizontal, with the fuel‑dispensing end pointing down.
- Vapour outlet ports: Located to permit vapour recovery for both active and passive systems.
- No‑lead restrictor: Placement specified so the test gauge penetrates it by at least 22.5 mm.
Applications and users
Who uses ISO 13331:1995:
- Vehicle and fuel‑system designers and OEMs - to design filler necks that are vapour‑recovery compatible.
- Refuelling nozzle and dispenser manufacturers - to ensure nozzle spouts mate correctly with vehicle filler openings.
- Test laboratories and compliance engineers - for verifying dimensional conformity using the nozzle test gauge.
- Regulatory bodies and environmental program managers - for specifying vehicle refuelling emission controls.
- Marine and industrial equipment designers - when vapour recovery during refuelling is required.
Related standards
- SAE J1140 (basis for dimensions)
- ISO 9158 / ISO 9159 (nozzle spouts)
- SAE J829 (fill cap and retainer)
- DIN 73 400 (bayonet closure dimensions)
Keywords: ISO 13331:1995, filler pipes, fuel tank openings, vapour recovery system, refuelling vapour recovery, nozzle test gauge, locking lip, vehicle fuel filler compatibility.