This practice should be used when and where a representative sample is required. A representative sample is necessary for accurate billing in custody transfer transactions.

This practice is not intended to preempt existing contract agreements.

Principles pertinent to this practice may be applied in most contractual agreements.

1.1 This practice covers the collection of natural gases and their synthetic equivalents using an automatic sampler.

1.2 This practice applies only to single-phase gas mixtures that vary in composition. A representative sample cannot be obtained from a two-phase stream.

1.3 This practice includes the selection, installation, and maintenance of automatic sampling systems.

1.4 This practice does not include the actual analysis of the acquired sample. Other applicable ASTM standards, such as Test Method D 1945, should be referenced to acquire that information.

1.5 The selection of the sampling system is dependent on several interrelated factors. These factors include source dynamics, operating conditions, cleanliness of the source gases, potential presence of moisture and hydrocarbon liquids, and trace hazardous components. For clean, dry gas sources, steady source dynamics, and normal operating conditions, the system can be very simple. As the source dynamics become more complex and the potential for liquids increases, or trace hazardous components become present, the complexity of the system selected and its controlling logic must be increased. Similarly, installation, operation, and maintenance procedures must take these dynamics into account.

1.6 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.