# Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery, Division 3.3.2.3: Relative humidity

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

If humidity is measured as a relative humidity RH %, the amount of water of an ideal gas x H2O [mol/mol] is calculated by means of equation (7-80):
x H2O = RH % 100 × RH % 100 × P H2O P abs
(7-80)
Where:
RH % relative humidity [%]
p H2O water vapour pressure at 100 % relative humidity at the location of relative humidity measurement, T sat=T amb [kPa]
p abs wet static absolute pressure at the location of relative humidity measurement [kPa]

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Source: https://www.legislation.gov.uk/eur/2017/654/annex/VII/division/3/division/3.3/division/3.3.2/division/3.3.2.3 (the official version)
Page: https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-3/division-3.3/division-3.3.2/division-3.3.2.3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.