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