Q618. There are differences in the applicability tool calculation spreadsheets for the estimation of vented emission from reciprocating compressor rod-packing venting. In the Transmission Compression Tool the units are "number of compressor cylinders" while in the Underground NG Storage Tool the units are "number of compressors". What is the difference and which do you think should be used?

A618. EPA has developed the calculation spreadsheets using best available data to help industry determine applicability. Based on the data available, EPA has developed factors on a per cylinder level and compressor level for transmission and underground storage segments, respectively. The transmission compression tool may be used for the transmission segment and the underground storage tool for underground storage segment. Please note that the applicability tool is intended to assist reporting facilities/owners in understanding key provisions of the rule. They are not intended to be a substitute for the rule.