StacksVerified U.S. regulatory reference

40 CFR §60.4405

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
If you elect to install and certify a NOX-diluent CEMS under § 60.4345, then the initial performance test required under § 60.8 may be performed in the following alternative manner:
  1. (a)Perform a minimum of nine RATA reference method runs, with a minimum time per run of 21 minutes, at a single load level, within plus or minus 25 percent of 100 percent of peak load, while the source is combusting the fuel that is a normal primary fuel for that source. The ambient temperature must be greater than 0 °F during the RATA runs.
  2. (b)For each RATA run, concurrently measure the heat input to the unit using a fuel flow meter (or flow meters) and measure the electrical and thermal output from the unit.
  3. (c)Use the test data both to demonstrate compliance with the applicable NOX emission limit under § 60.4320 and to provide the required reference method data for the RATA of the CEMS described under § 60.4335.
  4. (d)Compliance with the applicable emission limit in § 60.4320 is achieved if the arithmetic average of all of the NOX emission rates for the RATA runs, expressed in units of ppm or lb/MWh, does not exceed the emission limit.