FRM

Federal reference method (FRM) means a method of sampling and analyzing the ambient air for an air pollutant that is specified as a reference method in an appendix to part 50 of this chapter, or a method that has been designated as a reference method in accordance with this part; it does not include a method for which a reference method designation has been canceled in accordance with 53.11 or 53.16.

Source

40 CFR § 53.1

Scoping language

Terms used but not defined in this part shall have the meaning given them by the Act.