Nonmethane cutter.

(a) Application. You may use a nonmethane cutter to measure CH 4 with a FID analyzer. A nonmethane cutter oxidizes all nonmethane hydrocarbons to CO 2 and H 2 O. You may use a nonmethane cutter for raw or diluted exhaust for batch or continuous sampling. (b) System performance. Determine nonmethane-cutter performance as described in § 1065.365 and use the results to calculate CH 4 or NMHC emissions in § 1065.660. (c) Configuration. Configure the nonmethane cutter with a bypass line if it is needed for the verification described in § 1065.365. (d) Optimization. You may optimize a nonmethane cutter to maximize the penetration of CH 4 and the oxidation of all other hydrocarbons. You may humidify a sample and you may dilute a sample with purified air or oxygen (O 2 ) upstream of the nonmethane cutter to optimize its performance. You must account for any sample humidification and dilution in emission calculations. [70 FR 40516, July 13, 2005, as amended at 73 FR 37300, June 30, 2008; 76 FR 57442, Sept. 15, 2011]