Chlorofluorocarbons (CFCs) were originally seen as wonder chemicals. Developed in the 1920s by Thomas Midgeley, they soon became very popular as refrigerants, for making plastic foam and as aerosol propellants.
CFCs have a useful combination of physical properties. They are very stable, non-toxic and non-flammable. Unfortunately their chemical stability also means that they destroy stratospheric ozone, although this was not known when they were developed.
Halons, which contain bromine, are very effective in putting fires out. Their most useful characteristic is that they can be used where both people and machinery are present, without doing any damage to either. They have become widely used in computer rooms, museums, on ships and aircraft, for general office fire-protection and for industrial applications. The two main halons are 1301, used in fixed systems, and 1211, used in portable fire extinguishers.
Hydrochlorofluororcarbons (HCFCs) were developed as an interim replacement for CFCs. They break down more readily in the lower atmosphere, so that little of the chlorine they contain reaches the stratosphere.
HCFCs are considered necessary in some applications in the short to medium term, to help users to move rapidly away from the use of CFCs; they have some ozone depleting potential, but damage done by HCFCs is between one-fiftieth and one-tenth of that done by the same amount of the major CFCs.
Other ODS materials include: Carbon Tetrachloride, 1,1,1 Trichloroethane and Methyl Bromide.
Recovery and recycling have had an important role to play in the move away from ozone depleting substances. This was recognised by EC Regulation 2037/2000. Article 16, which became effective on 1st January 2001, obliging users to recover controlled substances from commercial and industrial refrigeration and air conditioning equipment, equipment containing solvents and fire fighting equipment.
All ODS used in refrigeration and air conditioning equipment must be recovered during servicing and maintenance of equipment or prior to dismantling or disposal of equipment.
Since 1st January 2001 recovered CFCs have been destroyed by licensed contractors. Recovered HCFCs however, can either be destroyed or can be re-used until 2015.
Virgin Halons cannot be used for refilling existing fire protection systems. Recovered, recycled or reclaimed halons may only be used in a limited number of “critical uses”, for example, in certain military and aerospace applications. The critical uses are listed in Annex VII of the EC regulation.
Butterworth Laboratories Ltd have been providing analysis of ODS materials since the early 1990’s. This initially started with the analysis of Halons 1211 and 1301 being recycled from fire extinguisher systems.
The same technology has also been applied to the analysis of ODS materials from Refrigeration and Air Conditioning systems as well as Blowing Agents used in Foam, and Aerosol Propellants.
The laboratory have developed and validated a number of specific methods to meet ISO17025 Accreditation requirements using GC-Headspace. They have routinely tested Halons, for Fire Fighting extinguishers, to BSEN27201-1:1994, it’s equivalent ISO 7201-1:1989 and ASTM D5632, as detailed in the United States Department of Defence Mil-Std-12218C. Testing has also been performed to the Air-conditioning and Refrigeration Industry (ARI) Standard 700 as well as its European equivalent.
For more information on ODS Analysis please contact: Frank Judge