PART 2Method of calculating the total global warming potential (GWP) for a preparation
The total GWP for a preparation is a weighted average, derived from the sum of the weight fractions of the individual substances multiplied by their GWPs.
Σ (Substance X % x GWP) + (Substance Y % x GWP) + … (Substance N % x GWP)
where % is the contribution by weight with a weight tolerance of +/- 1 %.
For example: applying the formula to a theoretical blend of gases consisting of 23 % HFC-32; 25 % HFC-125 and 52 % HFC-134a;
Σ (23 % x 550) + (25 % x 3 400) + (52 % x 1 300)
→ Total GWP = 1 652,5