Q95. If a facility has a billing meter for natural gas distributed to the combustion units throughout the facility, and if these combustion units also have their own meters, is there an obligation under the rule to use the individual unit meters and with this the more stringent calibration requirements for each meter?

You would not be required to use the individual unit meters provided you qualify to report under either 40 CFR 98.36(c)(1) (i.e., aggregation of units) or 40 CFR 98.36(c)(3) (i.e., common pipe configuration). However, you must use the highest applicable Tier method to calculate emissions from all of the grouped combustion units.