GWP values of various refrigerants are important for a number of reasons, not least as a means of comparing their relative effect when they are released to atmosphere.
As science progresses and reviews take place the GWP values of some refrigerants have altered slightly, which has led to a number of different values being quoted. For instance the F-Gas Regulation (EC) 842/2006 referred to the 3rd IPCC assessment. The new F-Gas Regulation (EC) 517/2014 which will come into effect on 1st January 2015 will use the 4th IPCC assessment values.
New F-Gas Regulation
One of the requirements of the new regulation relates to leak check requirements which are based upon the GWP CO2 equivalent Tonnes. This means that the threshold level for leak checking different refrigerants varies dependent upon the GWP of the refrigerant that is used. The new regulation uses the 4th assessment values which are listed in annex 1 for the single component F-Gases. Annex 2 covers other fluorinated greenhouse gases. Whilst annex 4 states the method for calculating the total GWP of a mixture or blend. It also lists the GWP value to be used for non-fluorinated substances that are used in mixtures or blends.
The GWP values of relevance from Annex 1 are given in Table 1 below;
The GWP of relevant refrigerant mixtures and blends are shown in table 2.
Leak Checking Requirements
The new F-Gas regulation sets leak checking requirements based upon 5, 50 and 500 CO2 Equivalent Tonnes. With the most significant changes affecting high GWP refrigerants for the 500 CO2 Equivalent Tonnes as fixed leak detection is required for this threshold. The different requirements are shown in table 2 for current refrigerants. The new requirements will take effect from 1st January 2015, except for systems with a charge below 3kg (6kg for hermetic systems) where it will apply from 1st January 2017.
F-Gas Regulation (EC) 517/2014 - http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2014.150.01.0195.01.ENG
4th IPCC assessment values - http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-2.html
ACRIB is an umbrella organisation for the UK RACHP industry comprising trade associations and professional institutes: AMDEA, ARC, B&ES, BFFF, CIBSE, CRT, FETA, FSDF, IOR. It provides the ACRIB Skillcard scheme for the recognition of individual operative qualifications in working with the full range of refrigerants. For more information see www.acrib.org.uk