METHOD OF CALCULATING THE TOTAL GWP OF A MIXTURE

The GWP of a mixture is calculated as a weighted average, derived from the sum of the weight fractions of the individual substances multiplied by their GWP, unless otherwise specified, including substances that are not fluorinated greenhouse gases. Σ (Substance X % GWP) (Substance Y % GWP) … (Substance N % GWP), where % is the contribution by weight with a weight tolerance of +/– 1 %. For example: applying the formula to a blend of gases consisting of 60 % dimethyl ether, 10 % HFC-152a and 30 % isobutane: Σ (60 % 1) (10 % 124) (30 % 3) → Total GWP = 13,9 The GWP of the following non-fluorinated substances are used to calculate the GWP of mixtures. For other substances not listed in this annex a default value of 0 applies. Based on the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, unless otherwise indicated. Substance not listed in the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change, default value on the basis of the GWPs of other hydrocarbons. Substance GWP Common name Industrial designation Chemical Formula methane CH_(4) 25 nitrous oxide N_(2)O 298 dimethyl ether CH_(3)OCH_(3) 1 methylene chloride CH_(2)Cl_(2) 9 methyl chloride CH_(3)Cl 13 chloroform CHCl_(3) 31 ethane R-170 CH_(3)CH_(3) 6 propane R-290 CH_(3)CH_(2)CH_(3) 3 butane R-600 CH_(3)CH_(2)CH_(2)CH_(3) 4 isobutane R-600a CH(CH_(3))_(2)CH_(3) 3 pentane R-601 CH_(3)CH_(2)CH_(2)CH_(2)CH_(3) 5 isopentane R-601a (CH_(3))_(2)CHCH_(2)CH_(3) 5 ethoxyethane (diethyl ether) R-610 CH_(3)CH_(2)OCH_(2)CH_(3) 4 methyl formate R-611 HCOOCH_(3) 25 hydrogen R-702 H_(2) 6 ammonia R-717 NH_(3) 0 ethylene R-1150 C_(2)H_(4) 4 propylene R-1270 C_(3)H_(6) 2 cyclopentane C_(5)H_(10) 5

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Source: EUR-Lex (Cellar) · retrieved 2026-11-04 · Text as adopted (Official Journal); later amendments are not incorporated in this text.