Handling Contaminated Automotive Refrigerants
Motor vehicle air conditioner (MVAC) refrigerants can become contaminated in a number of ways, including from outside elements (air, dirt) or by other refrigerants from improper servicing. The information below can help technicians identify, recover, and dispose of contaminated refrigerants.
All vehicles should have a label identifying the refrigerant used in their MVACs. Additionally, each MVAC refrigerant has unique fittings attached to the high- and low-side service ports. However, MVACs could be retrofitted to another refrigerant and not properly relabeled or refitted, or could contain highly contaminated refrigerants.
Methods for identifying MVAC refrigerants:
- Check the refrigerant pressure. This does not guarantee that you will recognize a contaminated or alternative refrigerant; however, unusual head pressures may tip you off.
- Purchase a refrigerant identifier. EPA strongly recommends (but does not require) that technicians obtain this equipment. Basic identifiers simply confirm if a refrigerant is pure and uncontaminated. More advanced models can identify:
- The chemical composition of a refrigerant.
- The presence of flammable substances, which require special care and safe handling (see below).
- Whether the air purge cycle feature on your recycling equipment is functioning properly. Excess air in an MVAC system can lead to false readings in electronic low charge indicators, rapid clutch cycling and potential clutch failures, and noisy compressor operation.
Even the most sophisticated identifiers cannot properly identify all combinations of chemicals used in blend refrigerants. Most units identify potential chlorofluorocarbonchlorofluorocarbonA compound consisting of chlorine, fluorine, and carbon. CFCs are very stable in the troposphere. They move to the stratosphere and are broken down by strong ultraviolet (UV) light, where they release chlorine atoms that then deplete the ozone layer. CFCs are commonly used as refrigerants, solvents, and foam blowing agents. The most common CFCs are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115. The ozone depletion potential (ODP) for each CFC is, respectively, 1, 1, 0.8, 1, and 0.6. A table of all ozone-depleting substances (http://www.epa.gov/ozone/science/ods/index.html) shows their ODPs, global warming potentials (GWPs), and CAS numbers. CFCs are numbered according to a standard scheme (http://www.epa.gov/ozone/geninfo/numbers.html). (CFC)-12 and hydrofluorocarbonhydrofluorocarbonA compound consisting of hydrogen, fluorine, and carbon. The HFCs are a class of replacements for CFCs. Because they do not contain chlorine or bromine, they do not deplete the ozone layer. All HFCs have an ozone depletion potential of 0. Some HFCs have high GWPs. HFCs are numbered according to a standard scheme (http://www.epa.gov/ozone/geninfo/numbers.html). (HFC)-134a contaminants (such as air, hydrochlorofluorocarbonhydrochlorofluorocarbonA compound consisting of hydrogen, chlorine, fluorine, and carbon. The HCFCs are one class of chemicals being used to replace the CFCs. They contain chlorine and thus deplete stratospheric ozone, but to a much lesser extent than CFCs. HCFCs have ozone depletion potentials (ODPs) ranging from 0.01 to 0.1. Production of HCFCs with the highest ODPs are being phased out first, followed by other HCFCs. A table of ozone-depleting substances (http://www.epa.gov/ozone/science/ods/classtwo.html) shows their ODPs, GWPs, and CAS numbers. HCFCs are numbered according to a standard scheme (http://www.epa.gov/ozone/geninfo/numbers.html). [HCFC]-22, and hydrocarbons), but many were not designed to identify components in new substitutes.
Before you purchase a refrigerant identifier, check that the unit meets the Society of Automotive Engineers (SAE) J1771 standard. This indicates that the unit accurately identifies refrigerants. The identifier should also have a label stating its level of accuracy. If you are reluctant to invest in an identifier, consider borrowing or renting an identifier from a nearby service facility.
Recovering Contaminated Refrigerants
Technicians must recover any contaminated or unfamiliar refrigerant before repairing or recharging an MVAC. EPA prohibits venting all automotive refrigerants, with the exception of carbon dioxide (R-744). The best way to recover contaminated or unfamiliar refrigerants is to dedicate a recover-only unit to impure refrigerants. Some equipment manufacturers also offer recover-only units designed to remove these refrigerants.
Some refrigerants might be contaminated with flammable substances such as propane and butane. Learn your equipment’s safety features to guard against the risk of ignition.
Technicians should recover the refrigerant into standard U.S. Department of Transportation (DOT)-certified, gray-with-yellow-top recovery tanks. If the tank is not equipped with a float valve (which serves as overfill protection), make sure it is never filled beyond 60 percent of its gross-weighted capacity, as specified in the SAE J1989 and J2211 standards.
If MVAC service is not a large portion of your business, contact a nearby shop that may have the equipment necessary to recover contaminated refrigerants or unknown refrigerants.
Recycling Contaminated Refrigerants
Only recycle uncontaminated refrigerants using certified recovery and recycling equipment. Contaminated refrigerants could damage your equipment.
EPA regulations currently prohibit technicians from recycling blend substitute refrigerants (contaminated or not). If you have questions about disposing of specific blend refrigerants, call the refrigerant manufacturer. Most manufacturers have arrangements with specific reclaimers to handle their used refrigerants. Go to Choosing and Using Alternative Refrigerants for a list of manufacturer telephone numbers.
Storage and Disposition of Contaminated or Unfamiliar Refrigerants
Once recovered, there are several options for handling contaminated refrigerants.
If the refrigerant in your "junk" tank contains flammable substances, it may be considered hazardous. Follow any local ordinances that govern the storage of combustible mixtures.
If your shop generates over 100 kilograms (220 pounds) of hazardous wastes per month (including used coolant, paint, rust removers, solvents, degreasers, and battery acids), then your shop must meet storage and transportation requirements under the Resource Conservation and Recovery Act (RCRA). For more details, see the RCRA website. You may also wish to check out the website of the Coordinating Committee for Automotive Repair. Exit
Tanks of contaminated refrigerants should be reclaimed or destroyed. Investigate your options and pick the one that makes the most economic sense.
- If you have a contract with a waste hauler, see if it can handle the material. Waste haulers may require that the contents of your tank be identified, and they may charge for this identification. They typically send contaminated tanks to an incinerator for destruction.
- You may also want to contact one or more reclaimers who will send the refrigerant off site for either destruction or reclamation. Reclamation involves breaking up and purifying chemical components. Some reclaimers may not accept less than 500 or 1,000 pounds of contaminated or mixed refrigerants. In addition, some reclaimers cannot handle all contaminated or mixed refrigerants. You may need to contact multiple reclaimers, even ones outside of your area, to find one that can accept contaminated refrigerants. EPA maintains a list of reclaimers.
Before you enter into any agreement with either your waste hauler or a reclaimer, make sure you understand all of the costs involved; there could be separate charges for identifying, transporting, and destroying the material.
If you are responsible for shipping the tank, make sure that the hauler or reclaimer explains to you how to comply with any applicable DOT, state, and local shipping requirements.