An Explanation of the Refrigerant Designation Numbering System

by
Robert P. Scaringe, Ph.D., P.E.
and
Lawrence R. Grzyll

Because the chemical names of typical refrigerants are long and complex a method of referring to refrigerants by number was developed by DuPont. The numbering system was released for general use in 1956 and has become an industry standard. A complete discussion, of the number designation and safety classification of the refrigerants, is presented in ASHRAE Standard 34-1989.

Briefly, the method of designating a refrigerant by number is as follows.

(Note that the numbering system begins on the right.)

First digit on the right	=	Number of fluorine atoms
Second digit from the right	=	Number of hydrogen atoms plus one
Third digit from the right	=	Number of carbon atoms minus one (not used when equal to zero)
Fourth digit from the right	=	Number of unsaturated carbon-carbon bonds in the compound (not used when equal to zero)

When bromine is present in place of all or part of the chlorine, the same rules apply except that the capital letter "B" after the designation for the parent compound shows the presence of the bromine (Br). The number following the letter "B" shows the number of Bromine atoms present.

The lower-case letter that follows the refrigeration designation refers to the form of the molecule when different forms (isomers) are possible, with the most symmetrical form indicated by the number alone. As the form becomes increasingly unsymmetrical, the letters a, b, and c (lower case) are appended (For example, HFC-134a).

If not all of the carbon bonds are occupied by fluorine or hydrogen atoms, the remainder are attached to chlorine.

Because the structure of a refrigerant, whether CFC, HCFC, or HFC, has become so important, they are often referred to in this way. For example, R-12 is CFC-12; R-22 is HCFC-22; R-134a is HFC-134a. This is simply a way of pointing out their chemical structure and therefore their relative ozone-depletion potential. Table 1 contains a complete list of refrigerants and their chemical formulation. Some examples are presented below.

Example 1. CHClF2
Number of F atoms	= 2
Number of H atoms + 1	= 2
Number of C atoms – 1	= 0

The refrigerant in Example 1 is designated HCFC-22. Because carbon has four bonds and the total of F and H = 3, there is one Cl atom.

Example 2. CCl2FCClF2
Number of F atoms	= 3
Number of H atoms + 1	= 1
Number of C atoms – 1	= 1

The refrigerant in Example 2 is designated CFC-113. Because two carbon atoms connected together have six bonds remaining and the total of F and H = 3, there are three Cl atoms present.

Example 3. The Designation of Refrigeration Isomers

Isomer	Formula
CFC-216	CF3CCl2CF3
CFC-216a	CF2ClCF2CF2Cl
CFC-216b	CF2ClCFClCF3
CFC-216c	CFCl2CF2CF3

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Table 1. Refrigerant Numbering System

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METHANE SERIES
NAME	FORMULA	SAFETY GROUP^a
		1988	1993
R-10	CCl4	2	B1
R-11	CCl3F	1	A1
R-12	CCl3F2	1	A1
R-12B1	CBrCIF2
R-12B2	CBr2F2
R-13	CClF3	1	A1
R-13B1	CBrF3	1	A1
R-14	CF4	1	A1
R-20	CHCl3
R-21	CHCl2F	2	B1
R-22	CHClF2	1	A1
R-22B1	CHBrF2
R-23	CHF3
R-30	CH2Cl2	2	B2
R-30B1	CH2BrCl
R-31	CH2ClF
R-32	CH2F2
R-40	CH3Cl	2	B2
R-41	CH3F
R-50	CH4	3a	A3
ETHANE SERIES
110	CCl3CCl3
111	CCl3CCl2F
112	CCl2FCCl2F
112a	CCl3CClF2
113	CCl2FCClF2	1	A1
113a	CCl3CF3
114	CClF2CClF2	1	A1
114a	CCl2FCF3
114B2	CBrF2CBrF2
115	CClF2CF3	1	A1
116	CF3CF3
120	CHCl2CCl3
121	CHCl2CFCl2
121a	CHFClCCl3
122	CHCl2CClF2
122a	CHClFCCl2F
122b	CHF2CCl3
123	CHCl2CF3		B1
123a	CHClFCClF2
123b	CHF2CCl2F
124	CHClFCF3		A1b
124a	CHF2CClF2
125	CHF2CF3		A1b
130	CHCl2CHCl2
130a	CCl3CH2Cl
131	CHClFCHCl2
131a	CH2ClCFCl2
131b	CH2FCCl3
132	CHClFCHClF
132a	CHCl2CHF2
132b	CH2ClCClF2
132c	CH2FCCl2F
133	CHFClCHF2
133a	CH2ClCF3
133b	CH2FCClF2
134	CHF2CHF2
134a	CH2FCFF3		A1
140	CH2ClCHCl2
140a	CH3CCl3
141	CH2ClCHClF
141a	CH2FCHCl2
141b	CH3CCl2F
142	CH2ClCHF2	3b
142a	CH2FCHClF
142b	CH3CClF2	3b	A2
143	CH2FCHF2
143a	CH3CF3
150	CH2ClCH2Cl
150a	CH3CHCl2
151	CH2ClCH2F
151a	CH3CHClF
152	CH2FCH2F
152a	CH3CHF2	3b	A2
160	CH3CH2Cl
161	CH3CH2F
170	CH3CH3	3a	A3
PROPANE SERIES
216	CF3CCl2CF3
216a	CCIF2CF2CClF2
216b	CF2ClCFClCF3
216c	CFCl2CF2CF3
218	CF3CF2CF3		A1
290	CH3CH2CH3	3a	A3
C316	C4Cl2F6
C317	C4ClF7
C318	C4F8	1	A1
600	CH3CH2CH2CH3	3a	A3
600a	CH(CH3)3	3a	A3
610	C2H5OC2H5
611	HCOOCH3	2	B2
630	CH3NH2
631	C2H5NH2
702	H2		A3
704	He		A1
717	NH3	2	B2
718	H20		A1
720	Ne		A1
728	N2		A1
729	Air
732	02
740	A		A1
744	C02	1	A1
744A	N20
764	SO2	2	B1
1112a	CCl2=CF2
1113	CClF=CF2
1114	CF2=CF2
1120	CHCl=CCl2
1130	CHCI=CHCI
1132A	CH2=CF2
1140	CH2=CHCl		B3
1141	CH2=CHF
1150	CH2=CH2	3a	A3
1270	CH3CH=CH2	3a	A3
ZEOTROPES SERIES
400	R-12/114			A1
401	R-22/152a/124	A1
402	R-125/290/22		A1
AZEOTROPES^c
500	R-12/152a(73.8/26.2)	1	A1
501d	R-22/12(75/25)		A1
502	R-22/115(48.8/51.2)	2	A1
503	R-23/13(40.1/59.9)
504	R-32/115(48.2/51.8)
505d	R-12/31(78.0/22.0)
506	R-31/114 (55.1/44.9)

a Both 1988 and 1993 ASHRAE 34 safety group classifications are listed. The new ASHRAE 34a-1993 standard includes two alphanumeric characters. The capital letter indicates the toxicity where A signifies non-toxic and B signifies toxic. The numeral denotes flammability where Class 1 indicates no flame propagation. Class 2 signifies refrigerants having moderate flammability (a lower flammability limit of more that 0.10 kg/m3 at 21°C and 101 kPa and a heat of combustion of less than 19,000 kJ/kg). Class 3 signifies refrigerants having high flammability (an LFL of less than or equal to 0.10 kg/m3 at 21°C and 101 kPa or a heat of combustion greater than or equal to 19,000 kJ/kg).

b Toxicity classification is based on recommended exposure limits provided by chemical suppliers. This rating is provisional and will be reviewed when toxicological testing is completed.

c All azeotropic refrigerants, by their nature, exhibit some segregation of components at conditions of temperature and pressure other than those at which they were formulated. The exact extent of this segregation depends on the particular azeotrope and hardware system configuration.

d The exact composition of this azeotrope is in question and additional experimental studies are needed.

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