A bar was a unit of pressure, nearly identical to the atmosphere. One bar was equal to 100 kilopascals.
Starfleet environmental suits measured oxygen pressure in millibars. (VOY: "Day of Honor")
This unit is used by meteorologists who find it easier to refer to atmospheric pressures without using decimals.
Comparative list of pressures
- 1,000 millibars = 1 bar
- The computer warned Tom Paris that his space suit was leaking, informing him that the oxygen level was dropping from 114 millibars to 93 millibars before B'Elanna Torres connected to his suit to share her oxygen. (VOY: "Day of Honor")
- While Paris and Torres shared their oxygen, the level dropped from 104 millibars, to 87 millibars, and finally to 71 millibars, before they were rescued by USS Voyager. (VOY: "Day of Honor")
- While traveling to orbit in an mag-lev carriage, Neelix noted that while at an altitude of eight hundred meters, the carriage was traveling at a velocity thirty kilometers per hour and the internal atmospheric pressure was at 700 millibars. (VOY: "Rise")
- The atmosphere at the surface of an unnamed planet which was home to a species of rock beasts was recorded at 800 millibars. (TAS: "Mudd's Passion")
- 1,000 bars = 1 kilobar
- A rod of parsteel William T. Riker gave Data and asked him to bend during his legal hearing had a tensile strength of 40 kilobars. (TNG: "The Measure Of A Man")