Common pressure units and conversions in process engineering (bar, Torr)

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The unit of pressure, bar, is used to measure pressure. In meteorology, millibars were commonly used in the past, but they were later replaced by the equivalent international unit of hectopascals. 1 Pa = 1 N/m2. In engineering, the unit of kilogram-force is still in use; 1 kilogram-force equals 9.80665 Newtons. From this, it follows that 1 kilogram-force per square centimeter equals 0.967841 atmospheres, or 98066.5 Pascals, which is equivalent to 1 engineering atmosphere. Millimeters of mercury is also a commonly used unit of pressure; the pressure generated by 1 millimeter of mercury is defined as a Torr. 1 Torr = 1/760 of an atm. At standard gravity at 0°C, the pressure corresponding to 1 mmHg is 1 Torr. 1 Torr ≈ 133.322 Pa = 1.333 mbar. 1 MPa = 10 bars. Additional units commonly used to express pressure include bars, kPa, MPa, and pSI. 1 Pa = 1 N/m2 = 1 (kg·m/s2)/m2 = 1 kg/(m·s2) = 0.01 mbar (millibar) = 0.00001 bar (bar) = one ten-thousandth of (kilogram-force per square centimeter). 1 bar = 0.1 MPa; therefore, 1 bar = 100 kPa = 10 Newtons per square centimeter (N/cm2) = 0.1 MPa. Reference source: Baidu Baike – bar (pressure unit)