These test methods provide accurate and reliable methods to measure the relative density of gaseous fuels on an intermittent or continuous basis. These measurements are frequently used for regulatory or contract compliance custody transfer and process control.

1.1 These test methods cover the determination of relative density of gaseous fuels, including liquefied petroleum gases, in the gaseous state at normal temperatures and pressures. The test methods specified are sufficiently varied in nature so that one or more may be used for laboratory, control, reference, gas measurement, or in fact, for any purpose in which it is desired to know the relative density of gas or gases as compared to the density of dry air at the same temperature and pressure.

1.2 The procedures appear in the following sections:

Note 1—The test methods and apparatus described herein are representative of methods and apparatus used broadly in industry. Manufacturer's instructions for specific models should be consulted for further details and as supplements to the information presented here. In addition to instrumentation described below additional equally accurate and satisfactory instruments may be available.

1.3 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.