A professional who tests ability of gas metres to accurately measure specified volume of gas at maximum and average cubic-feet-per-hour capacity and adjusts metres to correct excessive registration error. Responsibilities include:

• Connects hoses from prover to metre inlet and outlet and raises prover bell until prover gauge registers zero.
• Turns valve to allow measured amount of air or gas to pass through metre at specified flow-rate.
• Closes valve and compares registration on metre gauge.
• Screws fitting into metre outlet to retard flow of gas and repeats test.
• Turns setscrews to adjust metre and repeats test until metre registration is within specified limits according to prover and metre gas readings.
• analyses test results to determine cause of persistent registration errors.
• Segregates metres requiring repair.
• Records test results and date on metre card.
• May maintain temperature of oil used as gas seal in prover within specified limits to ensure accurate and uniform test readings.
• May test ability of flowmeters to accurately measure gas and liquid and be designated flowmeter test and certification technician.