Recently there has been a lot of news regarding "Gas Pump Testing" (a.k.a. Meter Calibration). Inaccuracies at the pumps are common, and exist for many reasons, primarily due to the use of a "Proving Can Test Measure". A Proving Can Test Measure is typically a 20L (5gal) container that you pour fuel into and then compare the readings on the side of the can vs. the gas pump. Exactly the same process invented 100 years ago, which was a great improvement over its predescessor, nothing. There are many variables contributing to inaccuracies with the Proving Can Test Measure, the biggest two would be Vapour Loss and Temperature. Vapour Loss is simply what happens to the fuel when exposed to the air, a small percentage of the fuel changes from a liquid to a vapour, hence, vapour loss to atmosphere. Newer technologies have partially compensated for Vapour Loss, but the "Open Neck" Proving Can Test Measure still in use today does nothing to compensate for vapour loss. Another significant variable is Temperature, there are no Proving Can Test Measures used in the field today that account for the variables associated to temperature. The influence of temperature on a Proving Can Test Measure made of stainless steel, mild steel or aluminium can be a dramatic variable. Impact of temperature on the fuel/product being tested can be significant as well, the greater the contrast in temperature between ambient (outside) temperature and the underground product temperature (storage tank), the more severe the effects will be on the test results. Due to the number of questions we have received on this "new" hot topic, we have assembled a few related articles and studies to help clarify the current discussion. First are the newspaper articles, Second we have posted a couple studies on the variables that affect "Gas Pump Testing", Third we have included our calibration video that illustrates why a Proving Can Test Measure is not accurate because it fails to isolate the variables affecting the process. * CLICK THE TITLE TO VIEW THE ORIGINAL ARTICLE Feds pump up fines for faulty gas measurements - CLICK HERE "Clement said that in about two-thirds of cases where pumps are inaccurate, customers are losing money <97> up to $2 per fill." "These measures would act as a strong deterrent to those who, through carelessness or indeed malicious intent, are selling inaccurately measured gasoline or other goods," said Industry Minister Tony Clement, who made the announcement in Port Coquitlam, B.C. Federal Inspectors to patrol the pumps nationwide - CLICK HERE "Under the new legislation, the gas cops can fine retailers anywhere from $10,000 to $25,000 all the way to $50,000 for repeat offenders." "Savage says the inaccurate measurements aren't a result of retailers going out with a pipe wrench and changing their pumps. She says over time, certain brands of pumps can wear out and there's a flawed pump-testing system that can be affected by cold temperatures." Colorado State Study - Summary of Results (Pump Testing) - CLICK HERE "Trade devices have to meet 40% of absolute tolerance (0.20 percent in the case of retail fuel dispensers) repeatability specification according to NIST Handbook 44 section, section T.3. and N.6.1.1. or Measurement Canada regulation 263 (b) 2/5 of the limit of error for non controlled conditions (0.20 percent for retail fuel dispensers)." Temperature vs. Accuracy you will notice in this study the dramatic impact temperature can play in calibration ("Gas Pump Testing") We have proven that Fuel Dispensers will cyclically repeat +/- 1 cu.in. Effects of Temperature - Nebraska Retail Fuel Dispenser Data - Submitted by Henry Oppermann - CLICK HERE "Three dispensers with Gilbarco meters and two dispensers with Tokheim meters were used to collect the data over a period of more than one year. Both the Gilbarco and Tokheim meters were positive displacement piston meters. Both the Gilbarco and Tokheim meters changed accuracy as the temperature of the product changed" The importance of this study illustrates the effects of temperature on the amount of fuel you will receive at the gas pump. Conclusions: The test results for a fuel dispenser can vary significantly if the temperature of the dispenser delivery system is not equalized before conducting the accuracy test. The accuracy of the dispenser meters varied slightly with the changes in the temperature of the product being measured. There was no detectable change in the accuracy of the meters at the same temperature during the period of data collection. The Measurement Canada Approved Cantest Electronic Proving System has eliminated the variables associated to the Proving Can Test Method outlined above. Cantest is the only company in North America with these capabilities; the video below will demonstrate how we identified and isolated all of these variables 10 YEARS AGO! Electronic Closed Loop Meter Calibration - Pump Testing Lab Quality Results in the Field, Where it Counts. Automatic Temperature Compensation and the Retail Sale of Gasoline and Diesel Fuel - CLICK HERE "An automatic temperature compensator is an electronic device which measures the temperature of petroleum products during delivery and automatically calculates the amount of product as though it had been delivered at 15°C. This practice is known as automatic temperature compensation (ATC).."" Discussion Paper on Establishing an Appropriate Level of Measurement Canada Intervention in the Downstream Petroleum Sector - CLICK HERE "The traceability of measurement standards is deemed to be critical to the industry and provisions should be maintained for this to continue. The accreditation of service organizations to perform water draws or calibrations may be possible, but industry would likely require that Measurement Canada have adequate provisions to ensure control within the accreditation program. Any potential for conflict of interest should be minimized. Similarly, assurance must be provided on an ongoing basis that an accreditation program or other alternate service delivery program is sustainable and audited. This should be the primary function of a regulatory body, to be an overseer of the process rather that doing the inspection themselves. Measurement Canada must be able to provide definitive answers and guidance to industry to resolve as necessary."