Conversion Factors for Pressure Units

As pressure is an important parameter in any CVD system, it is useful to know the pressure conversion from one representation system to another. This appendix lists commonly used conversions of a pressure represented in different unit systems, e.g ISO unit, imperical units and so forth. 

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Various units are used for expressing pressures (see Chapter 1, Footnote 8). A pressure of one standard atmosphere, or 0.1013 MPa, can support a column of mercury 760 mm high or a column of water 10.35 m high. As indicated in Chapter 1, the SI unit for pressure is the pascal (Pa), which is 1 N m-2 an SI quantity of convenient size for hydrostatic pressures in plants is often the MPa (1 MPa = 10 bar = 9.87 atm). (An extensive list of conversion factors for pressure units is given in Appendix II, which also includes values for related quantities such as RT.) Pressure is force per unit area and so is dimensionally the same as energy per unit volume (e.g., 1 Pa = 1 N m-2 = 1J m-3). Vw has the units of m3 mol-1, so VWP and hence /aw can be expressed in J mol-1. 

This table gives the appropriate value of R for use in the ideal gas equation, PV = nRT, when the variables are expressed in other units. The following conversion factors for pressure units were used in generating the table ... 

Conversion Factors for Pressure Units, 1-40 Conversion Factors for Thermal... 

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