By Dwight Brunette, VT Agency of Agriculture, Food & Markets - January 2022
New homes benefit from newer construction techniques and materials that make them more efficient; however, for many Vermonters living in older less efficient homes, using more energy is the only way to maintain reasonable indoor temperatures in the winter. For many, this means relying on heating oil, and lots of it! Generating heat and hot water is especially tough on Vermont’s vulnerable citizens who may be living on a fixed income. For Vermonters, oil delivery trucks are a common sight on our roadways, especially during the winter months. Traveling between houses, businesses, and farms, these specialized fuel trucks distribute home heating oil, kerosene, gasoline and diesel, depending on the need of the consumer.
How can you, as a Vermont consumer, be sure that you are getting what you pay for even when you may not be present for your fuel delivery? The Agency of Agriculture’s Weights and Measures (W&M) specialists provide an essential service to Vermonters! We ensure, through yearly inspections and testing, that the oil delivery trucks, equipment and operators are delivering what the consumers are paying for. Vermont Law requires fuel businesses to deliver products accurately to consumers. Home heating fuel dealers ensure accuracy by utilizing metering systems similar to gas pumps used to fuel our vehicles. Home heating fuel delivery systems must be maintained and checked periodically to ensure accuracy. Vermont W&M specialists use a clever but simple device called a “prover” to test the accuracy of the delivery system.
A “prover” is a specially designed, calibrated, stainless steel container made for testing liquids. The standard prover used to test oil product delivery trucks has a 100-gallon test volume. To begin the test, the W&M specialist starts the meter at zero and then fills the prover to the volume to be tested. When testing oil delivery trucks, the standard is a 100-gallon draft. The specialist fills the prover until the display on the delivery truck meter reads 100 gallons, checks the volume delivered by reading markings on a glass tube called the ‘sight-glass’, and records the result. If you remember high school chemistry, the sight glass looks like a typical graduated cylinder and is read much the same way. The markings are in 5 cubic inch volume divisions.
After reading the prover, the specialist determines whether the results are within the tolerance for delivery for a Vehicle Tank Meter (VTM). The tolerance is the allowable amount a delivery can vary from the exact reading on the testing device (prover). The tolerance allowed for a VTM is adopted by The National Conference on Weights & Measures and published by the National Institute of Standards and Technology (NIST). Vermont adopts these regulations and tolerances for regulatory purposes. In the case of a 100-gallon fuel oil test, the tolerance is 69.3 cubic inches, plus or minus from 100 gallons delivered. There are 23099.93 cubic inches in 100 gallons (US). This allowable error is 0.3%, which is extremely small and imparts little economic impact on either the device owner or the consumer. It also indicates how incredibly accurate a meter can be!
Even though VTMs can be very accurate in design and in testing, other steps in the fuel delivery process can make a delivery inaccurate. Faulty hoses and nozzles, malalignment of display numbers, failure to start the delivery on zero and/or maintain the proper delivery volume and pressure, inadequate maintenance or mechanical problems, and other operator error can lead to inaccurate delivers. During an inspection, the W&M specialist monitors the operator using the delivery equipment to identify and troubleshoot issues. The specialist’s ability to identify problems and explain them to the operator helps to ensure deficiencies are remedied. If left uncorrected, these issues could lead to injury, spills, improper delivery, or loss to the business or consumer.
The VTM inspection is a process with many parts, some human and some mechanical, but this specialized inspection helps ensure operator safety and benefits the consumer by ensuring you get what you pay for!