For metering systems having diaphragm pumps, the normal leak-check procedure will not detect leakages within the pump. For these cases, the following leak-check procedure is suggested: make a 10-minute calibration run at 0.00035 cubic meters per minute (0.02 cubic feet per minute); at the end of the run, take the difference between the measured wet test meter and the dry gas meter volumes; divide the difference by 10, to get the leak rate. The leak rate should not exceed 0.00057 cubic meters per minute (0.02 cubic feet per minute). [Section No. 3.4.2, Page 5 of 22, Quality Assurance Handbook by EPA, 1980 Version]