| Contents Notes |
"This project was initiated to provide a scientific basis for choosing a reasonable standard of purity for recycled chloroflurocarbon (CFC) refrigerant in operating automobile air conditioners. It evaluated the quality of the refrigerant from air conditioners in automobiles of different makes, ages, and mileages, from different parts of the country, and with both failed and properly working air conditioners. The refrigerant, CFC-12, was tested for water content, acidity, residue quantity, refrigerant purity, residue purity, inorganic chloride, and inorganic fluoride. This work will be the basis for programs to reduce CFC emissions from the servicing of automotive air conditioners. Of the 227 cars sampled, neither the compressor oil nor the refrigerant showed any measurable levels of acid (to 1 ppm), inorganic chlorides (to 0.1 ppm), or inorganic fluorides (to 0.1 ppm). The gaseous refrigerant, in all but two samples was of higher purity than the specification for new CFC-12. The amount of residue measured in the CFC-12 was simply the compressor oil which was carried over into the sampling container by the refrigerant The amount of residue in each sample depended on the amount of refrigerant in the air conditioner, the rate at which the sample was removed (the sampling rate), and on how soon after the air conditioner was used the sample was taken. The residue (compressor oil) was also tested for purity. It was found to be very pure (>99% in all but one or two samples). That impurity was found to consist of very small amounts (<1 ppm) of a large number of different organic compounds. There was no statistically significant correlation between residue purity and car mileage, whether the car's compressor was functioning, or with the area of the U.S. where the sample was taken. Traces of water were found In the refrigerant The mean for all of the samples was found to be 56 ppm. No statistical correlation was found between the water content of the refrigerant and whether the compressor was working or failed nor with the area where the sample was taken; however, a statistically significant correlation was found between the odometer reading of the car and the water content The mean water content for odometers registering up to 18,000 mi (29,000 km) was 34 ppm. At higher mileage ranges, the mean moisture content of the refrigerant was In the 56- to 94-ppm range." |
