scope:

This standard covers the determination of the chemical composition of natural gas and similar gaseous mixtures within the ranges listed in Table 1, using a Gas Chromatograph (GC). The three columns represent the original Table 1, but separate the values to three distinct groups. The first group is concentrations lower than the data obtained from the round-robin project (RR-188). The second group is concentrations used in the round-robin project (RR-188). The equations listed in the precision statement in this standard cover the range listed in the middle column, after outliers were removed. The third group is concentrations higher than the data obtained from the round-robin project (RR-188).

The precision statement in this standard utilizes equations derived from a regression of the data in RR-188 and is detailed in GPA TP-31. The precision statement criterion applies only to values listed in Section 10, Table 6.

Components sometimes associated with natural gases, i.e., helium, hydrogen sulfide, water, carbon monoxide, hydrogen and other compounds are excluded from the main body of the method. These components may be determined and made a part of the complete compositional data. Refer to Appendix C.