# Commission Regulation (EC) No 761/2009 of 23 July 2009 amending, for the purpose of its adaptation to technical progress, Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) (Text with EEA relevance), Division 1.2: DEFINITIONS AND UNITS

Extent: E+W+S+N.I.

The vapour pressure of a substance is defined as the saturation pressure above a solid or liquid substance.
The SI unit of pressure, which is the pascal (Pa), should be used. Other units which have been employed historically are given hereafter, together with their conversion factors:
1 Torr
=
1 mm Hg
=
1,333 × 102 Pa
1 atmosphere
=
1,013 × 105 Pa
1 bar
=
105 Pa
The SI unit of temperature is the kelvin (K). The conversion of degrees Celsius to kelvin is according to the formula:
T = t + 273,15
where, T is the kelvin or thermodynamic temperature and t is the Celsius temperature.
Table 1
When using a capacitance manometer
Measuring method
Substances
Estimated repeatability
Estimated reproducibility
Recommended range
Solid
Liquid
Dynamic method
Low melting
Yes
up to 25 %
1 to 5 %
up to 25 %
1 to 5 %
103 Pa to 2 × 103 Pa
2 × 103 Pa to 105 Pa
Static method
Yes
Yes
5 to 10 %
5 to 10 %
10 Pa to 105 Pa
10–2 Pa to 105 Pa
Isoteniscope method
Yes
Yes
5 to 10 %
5 to 10 %
102 Pa to 105 Pa
Effusion method: vapour pressure balance
Yes
Yes
5 to 20 %
up to 50 %
10–3 to 1 Pa
Effusion method: Knudsen cell
Yes
Yes
10 to 30 %
—
10–10 to 1 P
Effusion method: isothermal thermogravimetry
Yes
Yes
5 to 30 %
up to 50 %
10–10 to 1 Pa
Gas saturation method
Yes
Yes
10 to 30 %
up to 50 %
10–10 to 103 Pa
Spinning rotor method
Yes
Yes
10 to 20 %
—
10–4 to 0,5 Pa

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Source: https://www.legislation.gov.uk/eur/2009/761/annex/I/division/1/division/1.2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-761/annex-I/division-1/division-1.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.