Q618. For estimating compressor rod-packing venting, the Transmission Compression Tool units are "number of compressor cylinders" while the Underground NG Storage Tool units are "number of compressors". What is the difference and which should be used?

A618. EPA has developed the applicability tool spreadsheets using best available data to help industry determine whether or not a facility may exceed the reporting threshold and be subject to reporting to the GHGRP. Based on the data available, EPA has developed factors on a per cylinder level and per compressor level for the transmission compression and underground storage industry segments, respectively. The transmission compression applicability tool may be used for the natural gas transmission compression industry segment and the underground natural gas storage tool for underground natural gas storage industry segment. Please note that the applicability tools are only intended to assist reporting facilities/owners in understanding key provisions of the rule. They are not intended to be a substitute for the rule nor are they intended to be used for reporting.