【国外标准】 Standard Practice for Automatic Sampling of Gaseous Fuels

4.1 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, accurate compositional analysis of the flowing stream, gravity determination for flow calculations and other desired information concerning the properties of the stream contents.4.2 This practice is not intended to preempt existing contract agreements or regulatory requirements.4.3 Principles pertinent to this practice may be applied in most contractual agreements.4.4 Warning—Many gages are extremely flammable and can contain toxic substances. Caution should be taken in all aspects of sample collection and handling. Sample vessels should only be handled in well ventilated locations away from sparks and flames. Improper handling can result in an explosion or injury, or both.1.1 This practice covers the collection of gaseous fuels and their synthetic equivalents using an automatic sampler.1.2 This practice applies only to single-phase gas mixtures. This practice does not address 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 D1945, should be used 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 standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.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.