scope:

The purpose of this publication is to recommend procedures for obtaining samples from flowing natural gas streams that represent the composition of the vapor phase portion of the system being analyzed. These representative samples are subsequently transported to a laboratory and analyzed for composition and/or trace contaminants or analyzed onsite by portable or on-line chromatographs.

The methods outlined in this publication are designed for sampling natural gas from systems that are at or above the Hydrocarbon Dew Point temperature. As the temperature of the flowing stream decreases or the pressure increases to impinge upon the Hydrocarbon Dew Point, it becomes increasingly difficult to obtain a representative sample of the flowing stream. This standard does not address accounting for the liquid hydrocarbon portion of two-phase systems.

The scope of this standard does not include composite gas sampling (samples taken in increments over relatively long time periods) systems. For information on composite sampling, the reader is referred to API 14.1 and ASTM D5287.

Due to lake of supporting research data, the scope of this standard does not include sampling from vacuum sources.