506:
47:
514:
692:. The usage is deprecated but still prevails in the oil industry (often by capitalized "BarG" and "BarA"). As gauge pressure is relative to the current ambient pressure, which may vary in absolute terms by about 50 mBar, "BarG" and "BarA" are not interconvertible. Fuller descriptions such as "gauge pressure of 2 bars" or "2-bar gauge" are recommended.
552:(symbol hPa) which are numerically equivalent to millibar; for the same reason, the hectopascal is now the standard unit used to express barometric pressures in aviation in most countries. For example, the weather office of
578:
In scuba diving, bar is also the most widely used unit to express pressure, e.g. 200 bar being a full standard scuba tank, and depth increments of 10 metre of seawater being equivalent to 1 bar of pressure.
743:
1036:
548:
unit, meteorologists and weather reporters worldwide have long measured air pressure in millibar as the values are convenient. After the advent of SI units, some meteorologists began using
974:
567:. Specifically, an increase of 1 decibar occurs for every 1.019716 m increase in depth. In sea water with respect to the gravity variation, the latitude and the
582:
Many engineers worldwide use the bar as a unit of pressure because, in much of their work, using pascals would involve using very large numbers. In measurement of
1032:
571:
the pressure can be converted into metres' depth according to an empirical formula (UNESCO Tech. Paper 44, p. 25). As a result, decibar is commonly used in
620:
components are rated to the maximum system oil pressure, which is typically in hundreds of bar. For example, 300 bar is common for industrial fixed machinery.
747:
563:
In fresh water, there is an approximate numerical equivalence between the change in pressure in decibar and the change in depth from the water surface in
1033:"What do the letters 'g' and 'a' denote after a pressure unit? (FAQ - Pressure) : FAQs : Reference : National Physical Laboratory"
263:
556:
uses kilopascals and hectopascals on their weather maps. In contrast, Americans are familiar with the use of the millibar in US reports of
827:
994:
1094:
854:
911:
258:, despite previously mentioning the bar, now omits any mention of it. The bar has been legally recognised in countries of the
779:
689:
685:
865:
706:
674:), but they exist only for compatibility with legacy Asian encodings and are not intended to be used in new documents.
623:
In the maritime ship industries, pressures in piping systems, such as cooling water systems, is often measured in bar.
942:
721:
274:" and lists it as one of several units that "must not be introduced in fields where they are not presently used". The
701:
275:
66:
677:
The kilobar, equivalent to 100 MPa, is commonly used in geological systems, particularly in experimental
533:
214:
1542:
1087:
402:
O) (1 bar approximately corresponds to the gauge pressure of water (not absolute) at a depth of 10 meters).
55:
of 700 bar flattened this length of aluminium tubing of wall thickness 5 millimetres (0.20 in).
1537:
1119:
766:
1080:
613:
229:, 1 bar is roughly the atmospheric pressure on Earth at an altitude of 111 metres at 15 Β°C.
17:
1129:
522:
1060:
881:
International
Astronomical Union Style Manual. Comm. 5 in IAU Transactions XXB, 1989, Table 6
816:
595:
541:
387:
375:
170:
987:
1114:
711:
529:
218:
202:
180:
31:
8:
903:
617:
518:
237:
851:
739:
278:(IAU) also lists it under "Non-SI units and symbols whose continued use is deprecated".
587:
553:
226:
161:
775:
369:
189:
799:
233:
869:
858:
568:
381:
330:
1065:
963:
934:
259:
1531:
1104:
716:
537:
446:
429:
334:
210:
130:
71:
862:
1066:
US government atmospheric pressure map showing atmospheric pressure in mbar
890:
609:
602:
572:
549:
735:
497:
was used for a unit of weight in an early version of the metric system.
478:
271:
255:
985:
817:"Nomenclature of the unit of absolute pressure, Charles F. Marvin, 1918"
774:(9th ed.), International Bureau of Weights and Measures, Dec 2022,
232:
The bar and the millibar were introduced by the
Norwegian meteorologist
1061:
Official SI website: Table 8. Non-SI units accepted for use with the SI
505:
267:
248:
684:
The abbreviations "bar(a)" and "bara" are sometimes used to indicate
678:
557:
513:
456:
357:
222:
140:
46:
217:(SI). A pressure of 1 bar is slightly less than the current average
206:
121:
81:
52:
988:"Algorithms for computation of fundamental properties of seawater"
626:
1019:
NFPA 68 Standard on
Explosion Protection by Deflagration Venting
590:, residual pressures are typically given in millibar, although
583:
462:
564:
450:
353:
241:
150:
744:
Creative
Commons Attribution-ShareAlike 3.0 Unported License
1124:
612:
boost is often described in bar outside the United States.
591:
393:
244:
493:) to denote the millibar. Between 1793 and 1795, the word
482:
707:
Conversion of units Β§ Pressure or mechanical stress
545:
904:"Canadian Weather at a Glance - Environment Canada"
986:Scientific Committee on Oceanic Research (1983).
473:is now deprecated and conflicts with the uses of
1529:
509:Map showing atmospheric pressure in mbar or hPa
656:
264:National Institute of Standards and Technology
236:, who was a founder of the modern practice of
1088:
485:, but it is still encountered, especially as
734:This article incorporates material from the
722:Orders of magnitude (pressure) Β§ 100kPa
324:
1095:
1081:
863:NIST Special Publication 811, 2008 edition
45:
536:is defined as 1013.25 mbar, 101.325
761:
759:
540:, 1.01325 bar, which is about 14.7
512:
504:
935:"Canadian Weather - Environment Canada"
281:Units derived from the bar include the
225:(approximately 1.013 bar). By the
213:(100 kPa), though not part of the
14:
1530:
964:US government atmospheric pressure map
932:
901:
605:are often expressed in units of bar.
795:
793:
791:
756:
544:. Despite the millibar not being an
364:and 1 bar is approximately equal to:
27:Unit of pressure equal to 100,000 Pa
945:from the original on 2 January 2018
914:from the original on 2 January 2018
270:its use except for "limited use in
24:
933:Canada, Environment (2013-04-16).
902:Canada, Environment (2013-04-16).
833:from the original on 29 April 2017
788:
398:1019.716 centimetres of water (cmH
25:
1554:
1054:
1039:from the original on 7 April 2016
768:The International System of Units
702:Centimetre or millimetre of water
598:(mmHg) were historically common.
1521:
1443:
1358:
1291:
1230:
1158:
465:. The unit's official symbol is
276:International Astronomical Union
1025:
1011:
1000:from the original on 2015-04-12
979:
968:
742:", which is licensed under the
957:
926:
895:
884:
875:
845:
809:
688:, and "bar(g)" and "barg" for
616:is often specified in bar. In
240:, with the bar defined as one
13:
1:
852:NIST Special Publication 1038
727:
534:standard atmospheric pressure
521:displaying bar (outside) and
418:) = 1 one-thousandth bar, or
329:The bar is defined using the
215:International System of Units
804:Conversion Factors for Units
457:
341:β‘ 100,000 Pa β‘ 100,000 N/m.
7:
695:
560:and other cyclonic storms.
10:
1559:
1017:
451:
411:
29:
1076:
657:
629:has characters for "mb" (
608:In the automotive field,
601:Pressures resulting from
436:
325:Definition and conversion
176:
157:
136:
117:
113:
95:
87:
77:
65:
60:
44:
39:
530:Atmospheric air pressure
500:
489:(rather than the proper
209:defined as 100,000
939:www.weatheroffice.gc.ca
908:www.weatheroffice.gc.ca
542:pounds per square inch
526:
523:pounds per square inch
510:
445:has its origin in the
1130:Pound per square inch
596:millimeter of mercury
516:
508:
469:; the earlier symbol
1115:Technical atmosphere
712:List of metric units
569:geopotential anomaly
219:atmospheric pressure
32:Bar (disambiguation)
30:For other uses, see
1543:Non-SI metric units
1120:Standard atmosphere
1073:
975:The Weather Channel
618:hydraulic machinery
519:tire-pressure gauge
262:since 2004. The US
238:weather forecasting
108:... is equal to ...
61:General information
1071:
868:2016-06-03 at the
857:2016-03-19 at the
746:but not under the
686:absolute pressures
588:vacuum engineering
554:Environment Canada
527:
511:
477:denoting the unit
227:barometric formula
186:
178:
167:
162:US customary units
159:
146:
138:
127:
119:
1538:Units of pressure
1526:
1525:
781:978-92-822-2272-0
432:(1 hPa = 100 Pa).
195:
194:
96:Conversions
16:(Redirected from
1550:
1519:
1518:
1515:
1508:
1507:
1504:
1497:
1496:
1493:
1486:
1485:
1482:
1475:
1474:
1471:
1467:
1455:
1454:
1451:
1441:
1440:
1437:
1431:
1429:
1428:
1425:
1422:
1414:
1413:
1410:
1403:
1402:
1399:
1392:
1391:
1388:
1376:
1375:
1372:
1369:
1356:
1351:
1350:
1342:
1341:
1328:
1327:
1324:
1321:
1314:
1313:
1306:
1305:
1302:
1299:
1289:
1288:
1281:
1279:
1267:
1266:
1263:
1260:
1252:
1246:
1245:
1237:
1228:
1217:
1216:
1213:
1210:
1207:
1198:
1196:
1187:
1185:
1176:
1174:
1165:
1097:
1090:
1083:
1074:
1070:
1049:
1048:
1046:
1044:
1029:
1023:
1022:
1021:(2023 ed.).
1015:
1009:
1008:
1006:
1005:
999:
992:
983:
977:
972:
966:
961:
955:
954:
952:
950:
930:
924:
923:
921:
919:
899:
893:
888:
882:
879:
873:
849:
843:
842:
840:
838:
832:
821:
813:
807:
800:British Standard
797:
786:
784:
773:
763:
673:
672:SQUARE MIRIBAARU
670:
667:
665:
660:
659:
654:
651:
648:
646:
641:
638:
635:
633:
460:
454:
453:
425:
423:
368:0.98692327
347:
340:
234:Vilhelm Bjerknes
187:
179:
168:
160:
153:
147:
139:
128:
120:
49:
37:
36:
21:
1558:
1557:
1553:
1552:
1551:
1549:
1548:
1547:
1528:
1527:
1516:
1513:
1511:
1505:
1502:
1500:
1494:
1491:
1489:
1483:
1480:
1478:
1472:
1469:
1465:
1463:
1452:
1449:
1447:
1438:
1435:
1433:
1426:
1423:
1420:
1419:
1417:
1411:
1408:
1406:
1400:
1397:
1395:
1389:
1386:
1384:
1373:
1370:
1367:
1365:
1354:
1348:
1346:
1339:
1337:
1325:
1322:
1319:
1317:
1311:
1309:
1303:
1300:
1297:
1295:
1286:
1284:
1277:
1275:
1264:
1261:
1258:
1256:
1250:
1243:
1241:
1235:
1226:
1214:
1211:
1208:
1205:
1203:
1194:
1192:
1183:
1181:
1172:
1170:
1163:
1101:
1072:Pressure units
1057:
1052:
1042:
1040:
1031:
1030:
1026:
1016:
1012:
1003:
1001:
997:
990:
984:
980:
973:
969:
962:
958:
948:
946:
931:
927:
917:
915:
900:
896:
889:
885:
880:
876:
870:Wayback Machine
859:Wayback Machine
850:
846:
836:
834:
830:
819:
815:
814:
810:
798:
789:
782:
771:
765:
764:
757:
730:
698:
690:gauge pressures
671:
668:
663:
662:
652:
649:
644:
643:
640:SQUARE MB SMALL
639:
636:
631:
630:
503:
439:
428:1 millibar = 1
421:
419:
401:
392:750.06168
386:750.06158
380:29.529983
374:14.503774
345:
338:
331:SI derived unit
327:
185:
177:
166:
158:
148:
145:
137:
126:
118:
56:
35:
28:
23:
22:
15:
12:
11:
5:
1556:
1546:
1545:
1540:
1524:
1523:
1520:
1509:
1498:
1487:
1476:
1461:
1460:1 lbf/in
1457:
1456:
1445:
1442:
1415:
1404:
1393:
1382:
1378:
1377:
1363:
1360:
1357:
1352:
1343:
1334:
1330:
1329:
1315:
1307:
1293:
1290:
1282:
1273:
1269:
1268:
1253:
1247:
1238:
1232:
1229:
1224:
1220:
1219:
1200:
1189:
1178:
1167:
1160:
1157:
1153:
1152:
1149:
1146:
1143:
1140:
1137:
1133:
1132:
1127:
1122:
1117:
1112:
1107:
1102:
1100:
1099:
1092:
1085:
1077:
1069:
1068:
1063:
1056:
1055:External links
1053:
1051:
1050:
1024:
1010:
978:
967:
956:
925:
894:
883:
874:
861:, Sec. 4.3.2;
844:
808:
787:
780:
754:
753:
752:
729:
726:
725:
724:
719:
714:
709:
704:
697:
694:
502:
499:
438:
435:
434:
433:
426:
404:
403:
399:
396:
390:
384:
378:
372:
362:
361:
352:1,000,000 Ba (
326:
323:
260:European Union
193:
192:
188:0.986923
183:
174:
173:
169:14.50377
164:
155:
154:
143:
134:
133:
124:
115:
114:
111:
110:
105:
98:
97:
93:
92:
89:
85:
84:
79:
75:
74:
69:
63:
62:
58:
57:
50:
42:
41:
26:
9:
6:
4:
3:
2:
1555:
1544:
1541:
1539:
1536:
1535:
1533:
1510:
1499:
1488:
1477:
1462:
1459:
1458:
1446:
1416:
1405:
1394:
1383:
1380:
1379:
1364:
1361:
1353:
1344:
1335:
1332:
1331:
1316:
1308:
1294:
1283:
1274:
1271:
1270:
1254:
1248:
1239:
1233:
1225:
1222:
1221:
1201:
1190:
1179:
1168:
1161:
1155:
1154:
1150:
1147:
1144:
1141:
1138:
1135:
1134:
1131:
1128:
1126:
1123:
1121:
1118:
1116:
1113:
1111:
1108:
1106:
1103:
1098:
1093:
1091:
1086:
1084:
1079:
1078:
1075:
1067:
1064:
1062:
1059:
1058:
1038:
1034:
1028:
1020:
1014:
996:
989:
982:
976:
971:
965:
960:
944:
940:
936:
929:
913:
909:
905:
898:
892:
887:
878:
871:
867:
864:
860:
856:
853:
848:
829:
825:
818:
812:
805:
801:
796:
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792:
783:
777:
770:
769:
762:
760:
755:
751:
749:
745:
741:
737:
732:
731:
723:
720:
718:
717:Metric prefix
715:
713:
710:
708:
705:
703:
700:
699:
693:
691:
687:
682:
680:
675:
628:
624:
621:
619:
615:
614:Tire pressure
611:
606:
604:
603:deflagrations
599:
597:
593:
589:
585:
580:
576:
574:
570:
566:
561:
559:
555:
551:
547:
543:
539:
535:
531:
524:
520:
515:
507:
498:
496:
492:
488:
484:
480:
476:
472:
468:
464:
459:
448:
447:Ancient Greek
444:
431:
427:
417:
413:
409:
408:
407:
397:
395:
391:
389:
385:
383:
379:
377:
373:
371:
367:
366:
365:
359:
355:
351:
350:
349:
348:is equal to:
342:
336:
332:
322:
320:
316:
312:
308:
304:
300:
296:
292:
288:
284:
279:
277:
273:
269:
265:
261:
257:
252:
250:
246:
243:
239:
235:
230:
228:
224:
220:
216:
212:
208:
204:
200:
191:
184:
182:
175:
172:
165:
163:
156:
152:
144:
142:
135:
132:
125:
123:
116:
112:
109:
106:
104:
100:
99:
94:
90:
86:
83:
80:
76:
73:
72:Metric system
70:
68:
64:
59:
54:
48:
43:
38:
33:
19:
1381:1 Torr
1109:
1041:. Retrieved
1027:
1018:
1013:
1002:. Retrieved
981:
970:
959:
947:. Retrieved
938:
928:
916:. Retrieved
907:
897:
891:Grave (unit)
886:
877:
847:
835:. Retrieved
823:
811:
803:
802:BS 350:2004
767:
733:
683:
676:
625:
622:
610:turbocharger
607:
600:
581:
577:
573:oceanography
562:
550:hectopascals
528:
494:
490:
486:
474:
470:
466:
442:
440:
415:
405:
363:
343:
328:
318:
314:
310:
306:
302:
298:
294:
290:
286:
282:
280:
253:
231:
221:on Earth at
198:
196:
107:
102:
78:Unit of
1333:1 atm
1223:1 bar
736:Citizendium
461:), meaning
430:hectopascal
424:10 bar
272:meteorology
256:SI brochure
247:per square
203:metric unit
181:Atmospheres
101:1 bar
67:Unit system
1532:Categories
1272:1 at
1156:1 Pa
1043:7 February
1004:2014-05-11
872:, Sec. 5.2
740:Bar (unit)
728:References
653:SQUARE BAR
642:), "bar" (
558:hurricanes
346:1 bar
339:1 bar
268:deprecates
249:centimeter
1151:(lbf/in)
738:article "
679:petrology
441:The word
358:cgs units
317:(symbol:
309:(symbol:
301:(symbol:
293:(symbol:
285:(symbol:
223:sea level
141:CGS units
129:100
1037:Archived
995:Archived
943:Archived
912:Archived
866:Archived
855:Archived
828:Archived
824:noaa.gov
696:See also
669:㍊
650:㍴
637:㏔
525:(inside)
412:millibar
406:Notes:
315:millibar
307:centibar
207:pressure
149:10
122:SI units
82:pressure
53:pressure
1430:
1418:
1385:133.322
1310:735.559
1218:lbf/in
1202:1 Pa =
1191:1 Pa =
1180:1 Pa =
1169:1 Pa =
1162:1 Pa =
1148:(Torr)
627:Unicode
586:and in
313:), and
299:decibar
291:kilobar
283:megabar
266:(NIST)
18:Kilobar
1512:51.714
1366:14.695
1355:1.0332
1318:14.223
1257:14.503
1251:750.06
1236:1.0197
1193:7.5006
1182:9.8692
1171:1.0197
1145:(atm)
1139:(bar)
1105:Pascal
778:
666:
664:U+334A
655:) and
647:
645:U+3374
634:
632:U+33D4
584:vacuum
565:metres
532:where
463:weight
437:Origin
356:) (in
344:Thus,
335:pascal
103:in ...
88:Symbol
1501:0.068
1490:0.070
1479:0.068
1448:0.019
1434:0.001
1407:0.001
1396:0.001
1347:1.013
1296:0.967
1285:0.980
1242:0.986
1204:0.000
1199:Torr
1142:(at)
1136:(Pa)
998:(PDF)
991:(PDF)
949:6 May
918:6 May
837:6 May
831:(PDF)
820:(PDF)
772:(PDF)
658:γγͺγγΌγ«
501:Usage
458:baros
452:Ξ²Ξ¬ΟΞΏΟ
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