What does vacuum (bara / barg) mean?

In technology, the term "vacuum" is always used when, under normal conditions, there is significantly less pressure than atmospheric pressure in a predefined vessel / room / tank. By removing the internal pressure, a mechanical, inwardly directed load builds up in a vessel / room / tank due to the external pressure. The technical vacuum can be divided into several qualities / categories. The vacuum created is defined according to the remaining amount of matter in the vessel / tank / room. In industry, the rough vacuum is mostly used, whereas in medical / chemical technology, fine vacuum and below is often used. Pascal (Pa), millibar (mbar) or Torr (torr / mmHg) is normally used as the unit of measurement.

Diagram comparing vacuum at bar(g) and bar(a)


Pressure range vacuum Pressure in mbar
Normal pressure 1013,5
Rough pressure (low to medium) 300 ... 1
Fine vacuum 1 ... 10-3
High vacuum (HV) 10-3 ... 10-7
Ultra high vacuum (UHV) 10-7 ... 10-12
Extrem high vacuum (XHV) < 10-12
Perfect vacuum (IV) 0
+49 (0) 2461 91634 00