This SAE Recommended Practice describes instrumentation for determining the amount of methane in air and exhaust gas.

Purpose—This document provides a means for a batch measurement of the methane concentration in light-duty vehicle exhaust samples. Nonmethane hydrocarbon concentration can be obtained by subtracting the methane concentration from the total hydrocarbon concentration obtained by a separate measurement made in accordance with accepted practices such as SAE J1094, J254, or a current Federal Test Procedure.¹

¹ See Code of Federal Regulations, Title 40 Protection of Environment, Part 86, Subpart B, Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks; Test Procedures (40 CFR 86.101 et seq.) (as possibly amended by the Federal Register).