Bar (Russian designation: bar ; international: bar ; from Greek. Βάρος - gravity) - an off-system unit of pressure measurement , approximately equal to one atmosphere . One bar is 10 5 Pa [1] or 10 6 dyne / cm² (in the GHS system).
| Bar | |
|---|---|
| bar | |
| Value | pressure |
| System | off-system |
| Type of | derivative |
In the Russian Federation, the bar is approved for use as an off-system unit with no time limit with the scope of application " industry " [2] . The International Organization of Legal Metrology (OIML), in its recommendations, refers the bar to units of measurement “that can be temporarily applied until the date established by national regulations, but which should not be entered if they are not used” [3] .
Previously, the unit of pressure of the GHS system was equal to 1 dyn / cm 2 . This unit was also called barium or barium . At present, barium continues to be a unit of pressure in the GHS system; it is equal to 1 dyne / cm² = 10 −6 bar = 0.1 Pa [4] [5] .
| Pascal (Pa, Pa) | Bar (bar, bar) | Technical atmosphere (at, at) | Physical atmosphere (atm) | Millimeter of mercury (mmHg, mm Hg, Torr, torr) | Meter of water (m water, mH 2 O) | Pound-force per square inch (psi) | |
|---|---|---|---|---|---|---|---|
| 1 Pa | 1 N / m² | 10 −5 | 10,197⋅10 −6 | 9.8692⋅10 −6 | 7,5006⋅10 −3 | 1.0197⋅10 −4 | 145.04⋅10 −6 |
| 1 bar | 10 5 | 1⋅10 6 dyne / cm² | 1,0197 | 0.98692 | 750.06 | 10,197 | 14,504 |
| 1 at | 98,066.5 | 0.980665 | 1 kgf / cm² | 0.96784 | 735.56 | ten | 14,223 |
| 1 atm | 101325 | 1.01325 | 1,033 | 1 atm | 760 | 10.33 | 14,696 |
| 1 mmHg Art. | 133,322 | 1.3332⋅10 −3 | 1.3595⋅10 −3 | 1.3158⋅10 −3 | 1 mmHg Art. | 13,595⋅10 −3 | 19,337⋅10 −3 |
| 1 m water Art. | 9806.65 | 9.80665⋅10 −2 | 0.1 | 0.096784 | 73,556 | 1 m water Art. | 1.4223 |
| 1 psi | 6894.76 | 68,948⋅10 −3 | 70,307⋅10 −3 | 68,046⋅10 −3 | 51,715 | 0.70307 | 1 lbf / in² |
- In meteorology, a unit of millibars (mbar) of 0.001 bar, or 10³ dyne / cm² (exactly), or 0.986923⋅10 −3 atm (physical atmospheres) is often used to measure atmospheric pressure.
- To measure atmospheric pressure on planets with a very rarefied atmosphere, a microbar (μbar) of 10 −6 bar is used.
- 1 technical atmosphere = 1 kgf / cm² ( kilogram-force per centimeter square)
- Approximately: 1 bar ≈ 1 atm ≈ 1 at ≈ 1 kgf / cm² ≈ 14.5 psi
Notes
- ↑ GOST 8.417-2002 . State system for ensuring uniformity of measurements. Units of quantities.
- ↑ Regulation on units allowed for use in the Russian Federation Archived copy of November 2, 2013 on the Wayback Machine Approved by the Government of the Russian Federation of October 31, 2009 N 879.
- ↑ OIML International Document D2. Legalized (officially approved for use) units. Appendix A (inaccessible link) . Date of treatment October 10, 2013. Archived October 14, 2013.
- ↑ Dengub V.M. , Smirnov V.G. Units of quantities. Dictionary dictionary. - M .: Publishing house of standards, 1990. - S. 23. - 240 p. - ISBN 5-7050-0118-5 .
- ↑ Vlasov A.D. , Murin B.P. Units of physical quantities in science and technology: a Handbook. - M .: Energoatomizdat, 1990 .-- S. 101. - 176 p. - ISBN 5-283-03966-8 .