scope:

The density data recommended in Table 1 were compiled by the Compressed Gas Association, Inc. (CGA), to provide uniform values for liquid and gas densities of atmospheric gases and hydrogen for users and suppliers of these commodities.

Density data are shown to four significant figures; however, it may be difficult to verify data experimentally to this level of accuracy. The fourth-place figure as recommended by CGA is shown since large quantity shipments can be affected by the omission of the fourth significant figure.

It should be noted that the data published here are for pure product made under laboratory conditions and might not be appropriate for certain grades of commercially available gases without some adjustment for the known impurities.

References are cited for all values to provide a permanent record and as an aid to those having an interest in further details. As additional research is published, CGA may revise these recommended data. CGA is grateful to The National Institute of Standards and Technology (NIST), an agency of the U.S. Department of Commerce, for its cooperation in the development of these data, as well as to the gas producing companies who actively participated in this project.¹

The conversion equivalents listed in Table 2 should be used to convert volumetric units other than standard gas volumes.

¹ National Institute of Standards and Technology,