Section 501.320  Gas Chromatograph

a)         A utility shall install all gas chromatographs according to the recommendations of the device's manufacturer.

b)         A utility shall set all in-service gas chromatographs to perform an automatic calibration at least once every 24 hours. If the utility is using the chromatograph to assist the measurement calculation at a utility-owned natural gas storage facility and the facility is not injecting or withdrawing natural gas, the utility may suspend the calibration of the chromatograph until the facility resumes injecting or withdrawing natural gas.

c)         A utility shall perform field verification of all in-service gas chromatographs at least every 3 months and verify that the un-normalized mole percent variance is within ± 1.5% of the gas contained within the calibrated gas cylinder.

d)         A utility shall certify or replace the calibrated gas cylinders at least every 36 months.