is the measure of the oxidation stability of greases and lubricating oils in separate tests: ASTM-D-942 (grease), ASTM-D-2272 (oil) and ASTM-D-2112 (electrical insulating oils). In all tests, the sample is placed in a container, or bomb, which is then charged with oxygen and pressurized; a constant elevated temperature is maintained. ASTM-D-2272 utilizes a rotating bomb, which is placed in a heated bath; the test therefore is commonly called the rotary bomb oxidation test. Oxidation stability is expressed in terms of pressure drop in a given time period (D-942) or in terms of the time required to achieve a specified pressure drop (D-2272, D-2112).