Numerical Designation Of Refrigerants

Standard 34–92 of the American Society of Heating, Refrigerating and Airconditioning Engineers has categorized and numbered all refrigerants, including air and water. The industrial refrigerants, including those in current as well as future possible use, fall into one of five chemical groups:

• Halocarbons
• Azeotropes
• Zeotropes
• Organic compounds
• Inorganic compounds

Examples of acceptable usage of number designations are R 22, R-22, Refrigerant 22, or (Trade name) 22. The convenience of a numbering system is especially apparent for the halocarbons that have complex chemical names. Some popular industrial refrigerants are listed in Table 12.2

fig 1 302 - Numerical Designation Of Refrigerants

The halocarbon family consists of halogenated hydrocarbons that contain one or more of the halides—chlorine, bromine, fluorine, or iodine. Hydrogen may or may not be present. The numbering system applicable to the halocarbons and some hydrocarbons is as follows:

• The first digit on the right is the number of fluorine atoms
• The second digit from the right is one more than the number of hydrogen atoms
• The third digit from the right is one less than the number of carbon atoms

When the third digit from the right is zero, it is omitted from the number. The 600 series has been assigned to miscellaneous organic compounds and the 700 series to inorganic compounds. Azeotropes that have been commercialized are assigned identifying numbers in the 500 series in order of their commercial appearance.