Glossary - Cal/OSHA Compressed Gas Cylinder Safety Training

A gas that displaces oxygen in air and can cause oxygen deprivation, unconsciousness, or death. This entry refers to a simple asphyxiant.

A cryogenic liquid means a refrigerated liquefied gas having a boiling point colder than −90 °C (−130 °F) at 101.3 kPa (14.7 psia) absolute.

For DOT transportation purposes, a cylinder is a pressure vessel designed for pressures above 40 psia with a circular cross-section. It excludes portable tanks, multi-unit tank car tanks, cargo tanks, and tank cars.

DOT or Department means U.S. Department of Transportation.

A gas that, when packaged under pressure for transportation, is partially liquid at temperatures above −50 °C (−58 °F) is considered to be a liquefied compressed gas.

A gas that, when packaged under pressure for transportation, is entirely gaseous at −50 °C (−58 °F) and has a critical temperature less than or equal to −50 °C (−58 °F) is considered to be a non-liquefied compressed gas.

A gas that can support combustion more strongly than air, generally by supplying oxygen.

Psi means pounds per square inch. psig indicates gauge pressure relative to local atmospheric pressure; psia indicates absolute pressure relative to a vacuum.