Page 441 - Mechanical Engineers' Handbook (Volume 4)

430 Refrigeration

Table 1 Refrigerant Numbering System (ANSI/ASHRAE 34-2001) a
Normal
Refrigerant Boiling
Number Chemical Molecular Point, Safety
Designation Chemical Name Formula Mass C Group
Methane Series
10 Tetrachloramethane CC1 4 153.8 77 B1
11 Trichlorofluoromethane CC1 3 F 137.4 24 A1
12 Dichlorodifluoromethane CC1 2 F 2 120.9 30 A1
13 Chlorotrifluoromethane CCIF 3 104.5 81 A1
22 Chlorodifluoromethane CHCIF 2 86.5 41 A1
32 Difluoromethane CH 2 F 2 52.0 52 A2
50 Methane CH 4 16.0 161 A3
Ethane Series
113 1,1,2-Trichlorotrifluoro-ethane CC1 2 FCCIF 2 187.4 48 A1
114 1,2-Dichlorotetrafluoro-ethane CCIF 2 CCIF 2 170.9 4 A1
123 2,2-Dichloro-1,1,1-trifluoroethane CHCL2CF3 152.9 27 B1
125 Pentafluoroethane CHF 2 CF 3 120.0 49 A1
134a 1,1,1,2-Tetrafluoroethane CH 2 FCF 3 102.0 26 A1
170 Ethane CH 3 CH 3 30.0 89 A3
Propane Series
290 Propane CH 3 CH 2 CH 3 44.0 42 A3
Zeotropes Composition
407C R-32/R-125/R-134a (23/25/52 wt %) 95.0 44 A1
410A R-32/R-125 (50/50 wt%) 72.6 53 A1
Azeotropes Composition
500 R-12/152a (73.8/26.2 wt %) 99.31 33 A1
502 R-22/115 (48.8/51.2 wt %) 112.0 45 A1
Hydrocarbons
600 Butane CH 3 CH 2 CH 2 CH 3 58.1
600a Isobutane CH(CH 3 ) 3 58.1 12 A3
Inorganic Compounds
717 Ammonia NH 3 17.0 33 B2
728 Nitrogen N 2 28.0 196 A1
744 Carbon dioxide CO 2 44.0 78 A1
764 Sulfur dioxide SO 2 64.1 10 B1
Unsaturated Organic Compounds
1140 Vinyl chloride CH 2 —CHCI 62.5 14 B3
1150 Ethylene CH 2 —CH 2 28.1 104 A3
1270 Propylene CH 3 CH—CH 2 42.1 48 A3

a Reference 9, reprinted by permission from ASHRAE Standard 34-2001. American Society of Heating, Refrigerating and Air-Conditioning
Engineers, Inc., www.ashrae.org.

upper safety limit for airborne exposure to the refrigerant. If the refrigerant is nontoxic in
quantities less than 400 parts per million, then it is a class A refrigerant. If exposure to less
than 400 parts per million is toxic, then the substance is given the class B designation. The
numerical designation refers to the flammability of the refrigerant. The last column of Table
1 shows the toxicity and flammability rating of many of the common refrigerants.
The A1 group of refrigerants generally fulfills the basic requirements for an ideal re-
frigerant, with considerable flexibility as to refrigeration capacity. Many are used for comfort
air conditioning since they are nontoxic and nonflammable. These refrigerants are also used