Everything you want to know about Commercial Retail Motor Fuel Dispensers (Gasoline Dispensers)

NIST Handbook 44 contains Specification paragraphs for how a device, that is used commercially, must be designed; Specification paragraphs are directed, particularly to manufacturers of devices, User requirement paragraphs that address how the device should be used that are directed particularly to the owner and operator of the device, and these and other paragraphs (General, Application, Notes, Tolerances, Definitions and Appendices) are used by manufacturers, users, owners, and by W&M Inspectors to inspect and test the commercial device.

NIST Handbook 44, Section 3.30, Liquid Measuring Devices, applies to devices used for the measurement of liquid and wholesale devices used for the measurement and delivery of agri-chemical liquids, such as fertilizers, feeds, herbicides, fungicides, defoliant, and are the requirements used to test and inspect retail motor fuel devices (gasoline dispensers).

Section 3.30, Liquid Measuring Devices, does not apply to liquid meters mounted on a vehicle tank, devices used for dispensing liquefied petroleum gas, liquids that do not remain liquid at atmospheric pressure and temperature, water meters, liquid meters used solely for dispensing product in connections with operations in which the amount dispensed does not affect customer charge and mass flow meters.

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Evaluation Procedures Outlines were created to provide a guide for field inspection, evaluation, and testing of various commercial devices.  EPOs include the code references in NIST Handbook 44 arranged in a format of Inspection, Pretest Determinations, Test Notes, Test, and Post-Test Tasks requirements.

Retail Motor Fuel Dispensers - Single, Dual, and Multi-Product (except blenders)

Retail Motor Fuel Dispensers – Blended Products

NCWM NTEP Publication 14 “Measuring Devices” contains the U.S. technical policies, checklist, and test procedures for type approval of commercial retail motor fuel devices (gasoline dispensers). A type valuation of a commercial retail motor fuel dispenser (gasoline dispenser) is required before it can be sold in most States in the U.S.

The OIML requirements for retail motor fuel dispensers (gasoline dispensers) are outlined in OIML R117:2019 Dynamic measuring systems for liquids other than water. Many countries require that a manufacturer’s device undergo an evaluation before it can be sold in their markets.

• Anti-Drain Requirements for Liquid Retail Motor Fuel Devices – April 2012
• Contract Sales Using Retail Motor-fuel Dispensers – March 2005 – (Article B-011)
• Printed Receipts at Retail Service Stations – September 2003 - (Article B-004)
• Remanufactured Device Guidelines Accepted/New Liquid Measuring Devices and Vehicle-Tank Meters Tolerances – August 2002 – (Article B-002)
• Upcoming Changes for Sealing Requirements for Measuring Devices with Remote Configuration Capability – August 2004 - (Article B-009)

• Petroleum Volume: Getting Calibrations in the Can – June 2012
• Draining Test Measures and Provers – March 2015
• Testing Blend Retail Motor Fuel Dispenser – December 2003 - (Article B-006)
• Fuel Tank Capacity and Gas Pump Accuracy – August 2005 – (Article B-014)

• Retail Motor Fuel Device Video – September 2013

Following testing, a state weights and measures jurisdiction places a sticker on gasoline dispensers that have passed the inspections and accuracy tests. These stickers include the date the dispenser was tested, with the name of the State weights and measures office. Each sticker will vary by State.

Contact your State or local jurisdictions' weights and measures office. A list of State weights and measures offices and contact information is maintained on the NIST OWM website at: State Weights and Measures Directors.

State Weights and Measures officials use certified field standard test measures, and provers that are calibrated by trained State Metrologists using traceable laboratory standards. The field standards used for testing gasoline dispensers must also comply with the design requirements outlined in NIST Handbook 105-3: Specifications and Tolerances for Graduated Neck Type Volumetric Field Standards.

State weights and measures officials follow NIST OWM Evaluation Procedure Outlines: EPO No. 21 – Retail Motor-Fuel Dispensers Single, Dual, and Multi-Product – Non-Blenders, EPO No. 22 – Retail Motor-Fuel Dispensers Blended Products

In addition, established procedures include proper pour and drain times and leveling the test measure and prover to ensure accurate readings.

A typical gasoline dispenser, in use, is given a maintenance tolerance of 1 cubic inch plus 1 cubic inch per indicated gallon. These devices are typically tested with a 5-gallon prover, so the tolerance per the 5-gallon test is ±6 cubic inches or ±98.32 milliliters. For newly installed devices, the acceptance tolerance is half the maintenance tolerance; for a 5-gallon test, it is ±3 cubic inches.

• Retail Motor-Fuel Dispenser
  • Short video clips from full video are provided here:
    • Wetting the Standard (1 min)
    • Selecting & Maintaining the Test Standard (2.5 min)
    • Normal & Slow Flow Test (2 min)
    • Leveling (1.5 min)
    • Reading the Meniscus (2 min)
    • Draining a Test Measure or Prover (2 min)
    • Anti-Drain Test (2 min)