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320 Applied Process Design for Chemical and Petrochemical Plants

Table 11-4 Table 11-5
Comparison of Safety Group Classifications in ASHRAE Underwriters’ Laboratories Classification of Comparative
Standard 34-1989 and ASHRAE Standard 34-1992 Hazard to Life of Gases and Vapors

Refrigerant Chemical Safety Group Group Definition Examples
Number Formula Old New
1 Gases or vapors that Sulfur dioxide
10 CCl 4 2 B1 in concentrations of
11 CCl 3 F 1 A1 1
about / 2 —1% for
12 CCl 2 F 2 1 A1 durations of exposure
13 CClF 3 1 A1
of about 5 min are
13B1 CBrF 3 1 A1
lethal or produce
14 CF 4 1 A1
serious injury.
21 CHCl 2 F 2 B1
22 CHClF 2 1 A1 2 Gases or vapors that Ammonia
23 CHF 3 A1 in concentrations of Methyl bromide
1
30 CH 2 Cl 2 2 B2 about / 2 —1% for
32 CH 2 F 2 A2 durations of exposure
1
40 CH 3 Cl 2 B2 of about / 2 hr are
50 CH 4 3a A3 lethal or produce
113 CCl 2 FCClF 2 1 A1 serious injury.
114 CClF 2 CClF 2 1 A1 3 Gases or vapors that Carbon
115 CClF 2 CF 3 1 A1 in concentrations of tetrachloride
116 CF 3 CF 3 A1 1
about 2—2 / 2 % for Chloroform
123 CHCl 2 CF 3 B1
durations of exposure Methyl formate
124 CHClFCF 3 A1 of about 1 hr are
125 CHF 2 CF 3 A1
lethal or produce
134a CF 3 CH 2 F A1
serious injury.
142b CClF 2 CH 3 3b A2
143a CF 3 CH 3 A2 4 Gases or vapors that Dichloroethylene
152a CHF 2 CH 3 3b A2 in concentrations of Methyl chloride
1
170 CH 3 CH 3 3a A3 about 2—2 / 2 % for Ethyl bromide
218 CF 3 CF 2 CF 3 A1 durations of exposure
290 CH 3 CH 2 CH 3 3a A3 of about 2 hr are
C318 C 4 F 8 1 A1 lethal or produce
400 R12/114 (must be specified) 1 A1/A1 serious injury.
500 R12/152a (73.8/26.2) 1 A1 Between 4 and 5 Appear to classify as Methylene
501 R22/12 (75.0/25.0)* 1 A1 somewhat less toxic chloride
502 R22/115 (48.8/51.2) 1 A1
than Group 4. Ethyl chloride
507A R125/143a (50/50) A1
Much less toxic than Refrigerant 113
508A R23/116 (39/61) A1
Group 4 but somewhat
508B R23/116 (46/54) A1/A1
509A R22/218 (44/56) A1 more toxic than
Group 5.
600 CH 3 CH 2 CH 2 CH 3 3a A3
600a CH(CH 3 ) 3 3a A3 5a Gases or vapors much Refrigerant 11
611 HCOOCH 3 2 B2 less toxic than Group Refrigerant 22
702 H 2 A3 4 but more toxic than Carbon dioxide
704 He A1 Group 6.
717 NH 3 2 B2 5b Gases or vapors that Ethane
718 H 2 O A1 available data indicate Propane
720 Ne A1 would classify as either Butane
728 N 2 A1 Group 5a or Group 6.
740 Ar A1
6 Gases or vapors that Refrigerant 12
744 CO 2 1 A1 in concentrations up Refrigerant 114
764 SO 2 2 B1
to at least 20% by Refrigerant 13B1
1140 CHCl CH 2 B3
volume for durations
1150 CH 2 CH 2 3a A3
of exposure of about
1270 CH 3 CH CH 2 3a A3
2 hr do not appear to
*The exact composition of this azeotrope is in question. produce injury.
Used by permission: ANSI/ASHRAE Standard 34-92 ©1992—1994; 1997
ASHRAE Handbook Fundamentals, I-P Ed. Table 9, p. 18.9, ©1997. American Used by permission: ASHRAE 1977 Fundamentals Handbook, Table 12, p.
Society of Heating, Refrigerating, and Air Conditioning Engineers, Inc. 15.9, ©1977, 2 nd printing (1978). American Society of Heating,
All rights reserved. Refrigerating, and Air Conditioning Engineers, Inc. All rights reserved.