Adopts With Amendments:

UMC 2021

Heads up: There are no amended sections in this chapter.
CALIFORNIA MECHANICAL CODE — MATRIX ADOPTION TABLE
CHAPTER 11 — REFRIGERATION
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency
BSC BSC-CG SFM HCD DSA OSHPD BSCC DPH AGR DWR CEC CA SL SLC
1
2
1-AC
AC
SS
SS/CC
1
1R
2
3
4
5
Adopt Entire Chapter
X
   
X
X
                     
X
           
Adopt Entire Chapter as
amended (amended
sections listed below)
   
X
       
X
X
X
X
X
X
X
X
               
Adopt only those sections
that are listed below
                                             
Chapter/Section                                              
1104.3, Exception                  
X
     
X
                 
1104.6, Exceptions 1 & 2    
X
                                       
1108.4    
X
       
X
X
                           
Table 1104.1                  
X
X
X
X
X
X
               
This state agency does not adopt sections identified with the following symbol:
The Office of the State Fire Marshal's adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
Part I governs the design, installation, and construction of refrigeration systems, equipment, refrigerant piping, pressure vessels, safety devices, replacement of parts, alterations, and substitution of different refrigerants. Part II governs the installation and construction of cooling towers.
Equipment for refrigerant recovery, recycling, or both shall comply with UL 1963.

Part I — Refrigeration Systems

Refrigeration systems using a refrigerant other than ammonia shall comply with this chapter and ASHRAE 15.
Refrigeration systems using ammonia as the refrigerant shall comply with IIAR 2, IIAR 3, IIAR 4, and IIAR 5 and shall not be required to comply with this chapter.
The refrigerant used shall be of a type listed in Table 1102.3 or in accordance with ASHRAE 34 where approved by the Authority Having Jurisdiction.

Exception: Lithium bromide absorption systems using water as the refrigerant.

TABLE 1102.3
REFRIGERANT GROUPS, PROPERTIES, AND ALLOWABLE QUANTITIES8
[ASHRAE 34:TABLE 4-1, TABLE 4-2]
REFRIGERANT CHEMICAL FORMULA CHEMICAL NAME1
(COMPOSITION FOR BLENDS)
SAFETY GROUP7 OEL2 (ppm) POUNDS PER 1000 CUBIC FEET OF SPACE
R-11
CCl3F
Trichlorofluoromethane
A1
C1000
0.39
R-12
CCl2F2
Dichlorodifluoromethane
A1
1000
5.6
R-12B1
CBrCIF2
Bromochlorodifluoromethane
R-13
CCIF3
Chlorotrifluoromethane
A1
1000
R-13B1
CBrF3
Bromotrifluoromethane
A1
1000
R-14
CF4
Tetrafluoromethane (carbon tetrafluoride)
A1
1000
25
R-21
CHCl2F
Dichlorofluoromethane
B1
R-22
CHClF2
Chlorodifluoromethane
A1
1000
13
R-23
CHF3
Trifluoromethane
A1
1000
7.3
R-30
CH2Cl2
Dichloromethane (methylene chloride)
B1
R-31
CH2ClF
Chlorofluoromethane
R-32
CH2F2
Difluoromethane (methylene fluoride)
A2L
1000
4.8
R-40
CH3Cl
Chloromethane (methyl chloride)
B2
R-41
CH3F
Fluoromethane (methyl fluoride)
R-50
CH4
Methane
A3
1000
R-113
CCl2FCCIF2
1, 1, 2-trichloro-1, 2, 2 — trifluoroethane
A1
1000
1.2
R-114
CClF2CCIF2
1, 2-dichloro-1, 1, 2, 2 tetrafluoroethane
A1
1000
8.7
R-115
CClF2CF3
Chloropentafluoroethane
A1
1000
47
R-116
CF3CF3
Hexafluoroethane
A1
1000
34
R-123
CHCl2CF3
2, 2-dichloro-1, 1, 1, - trifluoroethane
B1
50
3.5
R-124
CHCIFCF3
2-chloro-1, 1, 1, 2 - tetrafluoroethane
A1
1000
3.5
R-125
CHF2CF3
Pentafluoroethane
A1
1000
23
R-134a
CH2FCF3
1, 1, 1, 2-tetrafluoroethane
A1
1000
13
R-141b
CH3CCl2F
1, 1-dichloro-1-fluoroethane
500
0.78
R-142b
CH3CCIF2
1-chloro-1, 1-difluoroethane
A2
1000
5.1
R-143a
CH3CF3
1, 1, 1-trifluoroethane
A2L
1000
4.5
R-152a
CH3CHF2
1, 1-difluoroethane
A2
1000
2.0
R-170
CH3CH3
Ethane
A3
1000
0.54
R-E170
CH3OCH3
Methoxymethane (Dimethyl ether)
A3
1000
1.0
R-218
CF3CF2CF3
Octafluoropropane
A1
1000
43
R-227ea
CF3CHFCF3
1, 1, 1, 2, 3, 3, 3-heptafluoropropane
A1
1000
36
R-236fa
CF3CH2CF3
1, 1, 1, 3, 3, 3-hexafluoropropane
A1
1000
21
R-245fa
CHF2CH2CF3
1, 1, 1, 3, 3-pentafluoropropane
B1
300
12
R-290
CH3CH2CH3
Propane
A3
1000
0.56
R-C318
-(CF2)4-
Octafluorocyclobutane
A1
1000
41
R-400
zeotrope
R-12/114 (50.0/50.0)
A1
1000
10
R-400
zeotrope
R-12/114 (60.0/40.0)
A1
1000
11
R-401A
zeotrope
R-22/152a/124 (53.0/13.0/34.0)
A1
1000
6.6
R-401B
zeotrope
R-22/152a/124 (61.0/11.0/28.0)
A1
1000
7.2
R-401C
zeotrope
R-22/152a/124 (33.0/15.0/52.0)
A1
1000
5.2
R-402A
zeotrope
R-125/290/22 (60.0/2.0/38.0)
A1
1000
17
R-402B
zeotrope
R-125/290/22 (38.0/2.0/60.0)
A1
1000
15
R-403A
zeotrope
R-290/22/218 (5.0/75.0/20.0)
A2
1000
7.6
R-403B
zeotrope
R-290/22/218 (5.0/56.0/39.0)
A1
1000
18
R-404A
zeotrope
R-125/143a/134a (44.0/52.0/4.0)
A1
1000
31
R-405A
zeotrope
R-22/152a/142b/C318 (45.0/7.0/5.5/42.5)
1000
16
R-406A
zeotrope
R-22/600a/142b (55.0/4.0/41.0)
A2
1000
4.7
R-407A
zeotrope
R-32/125/134a (20.0/40.0/40.0)
A1
1000
19
R-407B
zeotrope
R-32/125/134a (10.0/70.0/20.0)
A1
1000
21
R-407C
zeotrope
R-32/125/134a (23.0/25.0/52.0)
A1
1000
18
R-407D
zeotrope
R-32/125/134a (15.0/15.0/70.0)
A1
1000
16
R-407E
zeotrope
R-32/125/134a (25.0/15.0/60.0)
A1
1000
17
R-407F
zeotrope
R-32/125/134a (30.0/30.0/40.0)
A1
1000
20
R-407G
zeotrope
R-32/125/134a (2.5/2.5/95.0)
A1
1000
13
R-407H
zeotrope
R-32/125/134a (32.5/15.0/52.5)
A1
1000
19
R-407I
zeotrope
R-32/125/124a (19.5/8.5/72.0)
A1
1000
16.0
R-408A
zeotrope
R-125/143a/22 (7.0/46.0/47.0)
A1
1000
21
R-409A
zeotrope
R-22/124/142b (60.0/25.0/15.0)
A1
1000
7.1
R-409B
zeotrope
R-22/124/142b (65.0/25.0/10.0)
A1
1000
7.3
R-410A
zeotrope
R-32/125 (50.0/50.0)
A1
1000
26
R-410B
zeotrope
R-32/125 (45.0/55.0)
A1
27
R-411A6
zeotrope
R-1270/22/152a (1.5/87.5/11.0)
A2
990
2.9
R-411B6
zeotrope
R-1270/22/152a (3.0/94.0/3.0)
A2
980
2.8
R-412A
zeotrope
R-22/218/142b (70.0/5.0/25.0)
A2
1000
5.1
R-413A
zeotrope
R-218/134a/600a (9.0/88.0/3.0)
A2
1000
5.8
R-414A
zeotrope
R-22/124/600a/142b (51.0/28.5/4.0/16.5)
A1
1000
6.4
R-414B
zeotrope
R-22/124/600a/142b (50.0/39.0/1.5/9.5)
A1
1000
6.0
R-415A
zeotrope
R-22/152a (82.0/18.0)
A2
1000
2.9
R-415B
zeotrope
R-22/152a (25.0/75.0)
A2
1000
2.1
R-416A6
zeotrope
R-134a/124/600 (59.0/39.5/1.5)
A1
1000
3.9
R-417A6
zeotrope
R-125/134a/600 (46.6/50.0/3.4)
A1
1000
3.5
R-417B
zeotrope
R-125/134a/600 (79.0/18.3/2.7)
A1
1000
4.3
R-417C
zeotrope
R-125/134a/600 (19.5/78.8/1.7)
A1
1000
5.4
R-418A
zeotrope
R-290/22/152a (1.5/96.0/2.5)
A2
1000
4.8
R-419A
zeotrope
R-125/134a/E170 (77.0/19.0/4.0)
A2
1000
4.2
R-419B
zeotrope
R-125/134a/E170 (48.5/48.0/3.5)
A2
1000
4.6
R-420A
zeotrope
R-134a/142b (88.0/12.0)
A1
1000
12
R-421A
zeotrope
R-125/134a (58.0/42.0)
A1
1000
17
R-421B
zeotrope
R-125/134a (85.0/15.0)
A1
1000
21
R-422A
zeotrope
R-125/134a/600a (85.1/11.5/3.4)
A1
1000
18
R-422B
zeotrope
R-125/134a/600a (55.0/42.0/3.0)
A1
1000
16
R-422C
zeotrope
R-125/134a/600a (82.0/15.0/3.0)
A1
1000
18
R-422D
zeotrope
R-125/134a/600a (65.1/31.5/3.4)
A1
1000
16
R-422E
zeotrope
R-125/134a/600a (58.0/39.3/2.7)
A1
1000
16
R-423A
zeotrope
R-134a/227ea (52.5/47.5)
A1
1000
19
R-424A6
zeotrope
R-125/134a/600a/600/601a
(50.5/47.0/0.9/1.0/0.6)
A1
970
6.2
R-425A
zeotrope
R-32/134a/227ea (18.5/69.5/12.0)
A1
1000
16
R-426A6
zeotrope
R-125/134a/600/601a (5.1/93.0/1.3/0.6)
A1
990
5.2
R427A
zeotrope
R-32/125/143a/134a (15.0/25.0/10.0/50.0)
A1
1000
18
R428A
zeotrope
R-125/143a/290/600a (77.5/20.0/0.6/1.9)
A1
1000
23
R-429A
zeotrope
R-E170/152a/600a (60.0/10.0/30.0)
A3
1000
0.81
R-430A
zeotrope
R-152a/600a (76.0/24.0)
A3
1000
1.3
R-431A
zeotrope
R-290/152a (71.0/29.0)
A3
1000
0.69
R-432A
zeotrope
R-1270/E170 (80.0/20.0)
A3
700
0.13
R-433A
zeotrope
R-1270/290 (30.0/70.0)
A3
880
0.34
R-433B
zeotrope
R-1270/290 (5.0/95.0)
A3
950
0.51
R-433C
zeotrope
R-1270/290 (25.0/75.0)
A3
790
0.41
R-434A
zeotrope
R-125/143a/134a/600a
(63.2/18.0/16.0/2.8)
A1
1000
20
R-435A
zeotrope
R-E170/152a (80.0/20.0)
A3
1000
1.1
R-436A
zeotrope
R-290/600a (56.0/44.0)
A3
1000
0.50
R-436B
zeotrope
R-290/600a (52.0/48.0)
A3
1000
0.51
R-437A
zeotrope
R-125/134a/600/601 (19.5/78.5/1.4/0.6)
A1
990
5.0
R-438A
zeotrope
R-32/125/134a/600/601a
(8.5/45.0/44.2/1.7/0.6)
A1
990
4.9
R-439A
zeotrope
R-32/125/600a (50.0/47.0/3.0)
A2
990
4.7
R-440A
zeotrope
R-290/134a/152a (0.6/1.6/97.8)
A2
1000
1.9
R-441A
zeotrope
R-170/290/600a/600 (3.1/54.8/6.0/36.1)
A3
1000
0.39
R-442A
zeotrope
R-32/125/134a/152a/227ea
(31.0/31.0/30.0/3.0/5.0)
A1
1000
21
R-443A
zeotrope
R-1270/290/600a (55.0/40.0/5.0)
A3
580
0.19
R-444A
zeotrope
R-32/152a/1234ze(E) (12.0/5.0/83.0)
A2L
850
5.1
R-444B
zeotrope
R-32/152a/1234ze(E) (41.5/10.0/48.5)
A2L
890
4.3
R-445A
zeotrope
R-744/134a/1234ze (E) (6.0/9.0/85.0)
A2L
930
4.2
R-446A
zeotrope
R-32/1234ze(E)/600 (68.0/29.0/3.0)
A2L
960
2.5
R-447A
zeotrope
R-32/125/1234ze(E) (68.0/3.5/28.5)
A2L
900
2.6
R-447B
zeotrope
R-32/125/1234ze(E) (68.0/8.0/24.0)
A2L
970
23
R-448A
zeotrope
R-32/125/1234yf/134a/1234ze(E)
(26.0/26.0/20.0/21.0/7.0)
A1
890
24
R-449A
zeotrope
R-32/125/1234yf/134a
(24.3/24.7/25.3/25.7)
A1
830
23
R-449B
zeotrope
R-32/125/1234yf/134a
(25.2/24.3/23.2/27.3)
A1
850
23
R-449C
zeotrope
R-32/125/1234yf/134a
(20.0/20.0/31.0/29.0)
A1
800
23
R-450A
zeotrope
R-134a/1234ze(E) (42.0/58.0)
A1
880
20
R-451A
zeotrope
R-1234yf/134a (89.8/10.2)
A2L
520
5.3
R-451B
zeotrope
R-1234yf/134a (88.8/11.2)
A2L
530
5.3
R-452A
zeotrope
R-32/125/1234yf (11.0/59.0/30.0)
A1
780
27
R-452B
zeotrope
R-32/125/1234yf (67.0/7.0/26.0)
A2L
870
23
R-452C
zeotrope
R-32/125/1234yf (12.5/61.0/26.5)
A1
800
27
R-453A
zeotrope
R-32/125/134a/227ea/600/601a
(20.0/20.0/53.8/5.0/0.6/0.6)
A1
1000
7.8
R-454A
zeotrope
R-32/1234yf (35.0/65.0)
A2L
690
28
R-454B
zeotrope
R-32/1234yf (68.9/31.1)
A2L
850
22
R-454C
zeotrope
R-32/1234yf (21.5/78.5)
A2L
620
29
R-455A
zeotrope
R-744/32/1234yf (3.0/21.5/75.5)
A2L
650
23
R-456A
zeotrope
R-32/134a/1234ze(E) (6.0/45.0/49.0)
A1
900
20
R-457A
zeotrope
R-32/1234yf/152a (18.0/70.0/12.0)
A2L
650
25
R-458A
zeotrope
R-32/125/134a/227ea/236fa
(20.5/4.0/61.4/13.5/0.6)
A1
1000
18
R-459A
zeotrope
R-32/1234yf/1234ze(E)
  (68.0/26.0/6.0)
A2L
870
23
R-459B
zeotrope
R-32/1234yf/1234ze(E)
 (21.0/69.0/10.0)
A2L
640
30
R-460A
zeotrope
R-32/125/134a/1234ze(E)
(12.0/52.0/14.0/22.0)
A1
650
24
R-460B
zeotrope
R-32/125/134a/1234ze(E)
(28.0/25.0/20.0/27.0)
A1
950
25
R-460C
zeotrope
R-32/125/134a/1234ze(E)
(2.5/2.5/46.0/49.0)
A1
900
20.0
R-461A
zeotrope
R-125/143a/134a/227ea/600a
(55.0/5.0/32.0/5.0/3.0)
A1
1000
17
R-462A
zeotrope
R-32/125/143a/134a/600
(9.0/42.0/2.0/44.0/3.0)
A2
1000
3.9
R-463A
zeotrope
R-744/32/125/1234yf/134a
(6.0/36.0/30.0/14.0/14.0)
A1
990
19
R-464A
zeotrope
R-32/125/1234ze(E)/227ea
(27.0/27.0/40.0/6.0)
A1
930
27.0
R-465A
zeotrope
R-32/290/1234yf
(21.0/7.9/71.1)
A2
660
2.5
R-500
R-12/152a (73.8/26.2)
A1
1000
7.6
R-501
R-22/12 (75.0/25.0)4
A1
1000
13
R-502
R-22/115 (48.8/51.2)
A1
1000
21
R-503
R-23/13 (40.1/59.9)
1000
R-504
R-32/115 (48.2/51.8)
1000
28
R-505
R-12/31 (78.0/22.0)4
R-506
R-31/114 (55.1/44.9)
R-507A5
R-125/143a (50.0/50.0)
A1
1000
32
R-508A5
R-23/116 (39.0/61.0)
A1
1000
14
R-508B
R-23/116 (46.0/54.0)
A1
1000
13
R-509A5
azeotrope3
R-22/218 (44.0/56.0)
A1
1000
24
R-510A
azeotrope3
R-E170/600a (88.0/12.0)
A3
1000
0.87
R-511A
R-290/E170 (95.0/5.0)
A3
1000
0.59
R-512A
R-134a/152a (5.0/95.0)
A2
1000
1.9
R-513A
R-1234yf/134a (56.0/44.0)
A1
650
20
R-513B
R-1234yf/134a (58.5/41.5)
A1
640
21
R-514A
R-1336mzz(Z)/1130 (E) (74.7/25.3)
B1
320
0.86
R-515A
R-1234ze(E)/227ea (88.0/12.0)
A1
810
19
R-516A
R-1234yf/134a/152a (77.5/8.5/14.0)
A2L
590
7.0
R-600
CH3CH2CH2CH3
Butane
A3
1000
0.15
R-600a
CH(CH3)2CH3
2-methylpropane (isobutene)
A3
1000
0.59
R-601
CH3CH2CH2CH2CH3
Pentane
A3
600
0.18
R-601a
(CH3)2CHCH2CH3
2-methylbutane (isopentane)
A3
600
0.18
R-610
CH3CH2OCH2CH3
Ethoxyethane (ethyl ether)
400
R-611
HCOOCH3
Methyl formate
B2
100
R-620
(Reserved for future assignment)
R-630
CH3NH2
Methanamine (methyl amine)
R-631
CH3CH2(NH2)
Ethanamine (ethyl amine)
R-702
H2
Hydrogen
A3
R-704
He
Helium
A1
R-717
NH3
Ammonia
B2L
25
0.014
R-718
H2O
Water
A1
R-720
Ne
Neon
A1
R-728
N2
Nitrogen
A1
R-732
O2
Oxygen
R-740
Ar
Argon
A1
R-744
CO2
Carbon dioxide
A1
5000
3.4
R-744A
N2O
Nitrous oxide
R-764
SO2
Sulfur dioxide
B1
R-1130(E)
CHCl=CHCl
Trans-1,2-dichloroethene
B1
200
0.25
R-1132a
CF2 = CH2
1, 1-difluoroethylene
A2
500
2.0
R-1150
CH2=CH2
Ethene (ethylene)
A3
200
R-1224yd(Z)
CF3CF=CHCl
(Z)-1-chloro-2,3,3,3-tetrafluoropropen
A1
1000
23
R-1233zd(E)
CF3CH=CHCl
Trans-1-chloro-3, 3,3 -trifluoro-1- propene
A1
800
5.3
R-1234yf
CF3CF=CH2
2, 3, 3, 3-tetrafluoro-1-propene
A2L
500
4.7
R-1234ze(E)
CF3CH=CHF
Trans-1,3,3,3- tetrafluoro-1-propene
A2L
800
4.7
R-1270
CH3CH=CH2
Propene (propylene)
A3
500
0.11
R-1336mzz(Z)
CF3CHCHCF3
Cis-1,1,1,4,4,4-hexaflouro-2-butene
A1
500
5.4
For SI units: 1 pound = 0.453 kg, 1 cubic foot = 0.0283 m3
Notes:
  1. 1 The preferred chemical name is followed by the popular name in parenthesis.
  2. 2 The OELs are 8-hour TWAs; a "C" designation denotes a ceiling limit.
  3. 3 Azeotropic refrigerants exhibit some segregation of components at conditions of temperature and pressure other than those at which they were formulated. The extent of segregation depends on the particular azeotrope and hardware system configuration.
  4. 4 The exact composition of this azeotrope is in question and additional experimental studies are needed.
  5. 5 R-507, R-508, and R-509 are allowed alternative designations for R-507A, R-508A, and R-509A due to a change in designations after assignment of R-500 through R-509. Corresponding changes were not made for R-500 through R-506.
  6. 6 The RCL values for these refrigerant blends are approximated in the absence of adequate data for a component comprising less than 4 percent m/m of the blend and expected to have a small influence in an acute, accidental release.
  7. 7 Refrigerant flammability classification of Class 2L shall comply with the requirements for flammability classification of Class 2.
  8. 8 In accordance with Section 1102.2, ammonia refrigeration systems are not regulated by this chapter. R-717 (ammonia) is included in this table because the table is extracted from ASHRAE 34 and is not capable of being modified.
Refrigerants shall be classified in accordance with Table 1102.3 or in accordance with ASHRAE 34 where approved by the Authority Having Jurisdiction.
Table 1102.3 classifies refrigerants by toxicity and flammability, and assigns safety groups using combinations of toxicity class and flammability class. For the purposes of this chapter, the refrigerant Groups A1, A2L, A2, A3, B1, B2L, B2, and B3 shall be considered to be individual and distinct safety groups. Each refrigerant is assigned into not more than one group.
Refrigeration systems shall be classified according to the degree of probability that a leakage of refrigerant will enter an occupancy-classified area in accordance with Section 1103.2.1 and Section 1103.2.2. [ASHRAE 15:5.2]
Systems in which the basic design, or the location of components, is such that a leakage of refrigerant from a failed connection, seal, or component will enter the occupied space shall be classified as high-probability systems. A high-probability system shall be a direct system or an indirect open spray system in which the refrigerant is capable of producing pressure that is more than the secondary coolant. [ASHRAE 15:5.2.1]
Systems in which the basic design, or the location of the components, is such that a leakage of refrigerant from a failed connection, seal, or component is not capable of entering the occupied space shall be classified as low-probability systems. A low-probability system shall be an indirect closed system, double indirect system, or an indirect open spray system. In a low-probability indirect open spray system, the secondary coolant pressure remains more than the refrigerant pressure in operating and standby conditions. [ASHRAE 15:5.2.2]
Group A3 and B3 refrigerants shall not be used except where approved by the Authority Having Jurisdiction.

Exceptions:
  1. Laboratories with more than 100 square feet (9.29 m2) of space per person.
  2. Industrial occupancies.
  3. Listed self-contained systems containing not more than 0.331 pounds (0.150 kg) of Group A3 refrigerant, provided that the equipment is installed in accordance with the listing and the manufacturer's installation instructions. [ASHRAE 15:7.5.3]
Refrigeration systems shall be limited in application in accordance with Table 1104.1, and the requirements of Section 1104.0.

TABLE 1104.1
PERMISSIBLE REFRIGERATION SYSTEMS1
  OCCUPANCY GROUP3 HIGH-PROBABILITY SYSTEM LOW PROBABILITY SYSTEM MACHINERY ROOM
 
A-1
Group A1 only
Any
Any
 
A-2
Group A1 only
Any
Any
 
A-3
Group A1 only
Any
Any
 
A-4
Group A1 only
Any
Any
 
B
Group A12 only
Any
Any
 
E
Group A1 only
Any
Any
 
F-1
Group A12 only
Any
Any
 
F-2
Any2
Any
Any
 
H-1
Any
Any
Any
 
H-2
Any
Any
Any
 
H-3
Any
Any
Any
 
H-4
Group A1 only
Any
Any
 
H-5
Group A1 only
Any
Any
 
I-1
None
Any
Any
 
I-2
Group A1 only
Any
Any
[OSHPD 1, 1R, 2, 3, 4 & 5]
I-2.1
Group A1 only
Any
Any
 
I-3
None
Any
Any
 
I-4
Group A1 only
Any
Any
 
M
Group A12 only
Any
Any
 
R-1
Group A1 only
Any
Any
 
R-2
Group A1 only
Any
Any
 
R-3
Group A1 only
Any
Any
 
R-4
Group A1 only
Any
Any
 
S-1
Group A12 only
Any
Any
 
S-2
Any2
Any
Any
 
U
Any
Any
Any
Notes:
  1. 1 See Section 1104.0.
  2. 2 A refrigerant shall be permitted to be used within a high-probability system where the room or space is in accordance with Section 1104.4.
  3. 3 Occupancy classifications are defined in the building code.
The concentration of refrigerant in a complete discharge of an independent circuit of high-probability systems shall not exceed the amounts shown in Table 1102.3, except as provided in Section 1104.3 and Section 1104.4. The volume of occupied space shall be determined in accordance with Section 1104.2.1 through Section 1104.2.3.

Exceptions:
  1. Listed equipment containing not more than 6.6 pounds (2.99 kg) of refrigerant, regardless of the refrigerant safety classification, provided the equipment is installed in accordance with the listing and with the manufacturer's installation instructions.
  2. Listed equipment for use in laboratories with more than 100 square feet (9.29 m2) of space per person, regardless of the refrigerant safety classification, provided that the equipment is installed in accordance with the listing and the manufacturer's installation instructions. [ASHRAE 15:7.2]
The volume used to convert from refrigerant concentration limits to refrigerating system quantity limits for refrigerants in Section 1104.2 shall be based on the volume of space to which refrigerant disperses in the event of a refrigerant leak. [ASHRAE 15:7.3]
Where a refrigerating system or part thereof is located in one or more enclosed occupied spaces that do not connect through permanent openings or HVAC ducts, the volume of the smallest occupied space shall be used to determine the refrigerant quantity limit in the system. Where different stories and floor levels connect through an open atrium or mezzanine arrangement, the volume to be used in calculating the refrigerant quantity limit shall be determined by multiplying the floor area of the lowest space by 8.2 feet (2499 mm). [ASHRAE 15:7.3.1]
Where a refrigerating system or a part thereof is located within an air handler, in an air distribution duct system, or in an occupied space served by a mechanical ventilation system, the entire air distribution system shall be analyzed to determine the worst-case distribution of leaked refrigerant. The worst case or the smallest volume in which the leaked refrigerant disperses shall be used to determine the refrigerant quantity limit in the system, subject to the criteria in accordance with Section 1104.2.3.1 through Section 1104.2.3.3. [ASHRAE 15:7.3.2]
Closures in the air distribution system shall be considered. Where one or more spaces of several arranged in parallel are capable of being closed off from the source of the refrigerant leak, their volume(s) shall not be used in the calculation.

Exceptions: The following closure devices are not considered:
  1. Smoke dampers, fire dampers, and combination smoke/fire dampers that close only in an emergency not associated with a refrigerant leak.
  2. Dampers, such as variable-air-volume (VAV) boxes, that provide limited closure where airflow is not reduced below 10 percent of its maximum (with the fan running). [ASHRAE 15:7.3.2.1]
The space above a suspended ceiling shall not be included in calculating the refrigerating system quantity limits unless such space is part of the air supply or return system. [ASHRAE 15:7.3.2.2]
The volume of the supply and return ducts and plenums shall be included when calculating the refrigerating system quantity limits. [ASHRAE 15:7.3.2.3]
The RCL value required in Section 1104.2 shall be reduced by 50 percent for the areas of institutional occupancies. The total of Group A2, B2, A3, and B3 refrigerants shall not exceed 550 pounds (249.5 kg) in the occupied areas and machinery rooms of institutional occupancies.

Exception: The total of all Group A2L refrigerants shall not be limited in machinery rooms of institutional occupancies.
[OSHPD 1 & 4] Exception: For technology equipment centers not attached to a patient care area the amounts shown in Table 1102.3 may be calculated at 100 percent.
Section 1104.2 shall not apply in industrial occupancies and refrigerated rooms where in accordance with the following:
  1. The space(s) containing the machinery is (are) separated from other occupancies by tight construction with tight-fitting doors.
  2. Access is restricted to authorized personnel.
  3. Refrigerant detectors are installed with the sensing location and alarm level as required in refrigeration machinery rooms in accordance with Section 1106.2.2.2.
  4. Open flames and surfaces exceeding 800°F (427°C) shall not be permitted where a Group A2, B2, A3, or B3 refrigerant, is used.
  5. Electrical equipment that is in accordance with Class 1, Division 2, of NFPA 70 where the quantity of a Group A2, B2, A3, or B3 refrigerant in an independent circuit is capable of exceeding 25 percent of the lower flammability limit (LFL) upon release to the space based on the volume determined in accordance with Section 1104.2.1 through Section 1104.2.3.
  6. Refrigerant containing parts in systems exceeding 100 horsepower (74.6 kW) compressor drive power, except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure-relief valves for either, low-probability pumps, and connecting piping, are located in a machinery room or outdoors. [ASHRAE 15:7.2.2]
The total of Group A2, B2, A3, and B3 refrigerants, other than Group A2L and B2L refrigerants shall not exceed 1100 pounds (498.9 kg) without approval by the Authority Having Jurisdiction. Institutional Occupancies shall comply with Section 1104.3.
In nonindustrial occupancies, Group A2, A2L, A3, B1, B2L, B2, and B3 refrigerants shall not be used in high-probability systems for human comfort.
Exceptions:
  1. Listed equipment, units having a factory-sealed refrigerating system, containing no more than 2.2 lbs. (1kg) of A2L refrigerant installed in accordance with the listing and the manufacturer's installation instructions.
  2. Listed equipment for non-residential applications, having a factory-sealed refrigerating system and containing no more than 4 lbs. (1.8 kg) of A2L refrigerant installed in accordance with the listing and the manufacturer's installation instructions.
Refrigerants shall be of a type specified by the equipment manufacturer. Unless otherwise specified by the equipment manufacturer, refrigerants used in new equipment shall be of purity in accordance with AHRI 700.
Recovered refrigerants shall not be reused except in the system from which they were removed or as provided in Section 1104.7.2 or Section 1104.7.3. When contamination is evident by discoloration, odor, acid test results, or system history, recovered refrigerants shall be reclaimed in accordance with Section 1104.7.3 before reuse. [ASHRAE 15:7.5.1.4]
Recycled refrigerants shall not be reused except in systems using the same refrigerant and lubricant designation and belonging to the same owner as the systems from which they were removed. Where contamination is evident by discoloration, odor, acid test results, or system history, recycled refrigerants shall be reclaimed in accordance with Section 1104.7.3.

Exception: Drying shall not be required in order to use recycled refrigerants where water is the refrigerant, is used as an absorbent or is a deliberate additive. [ASHRAE 15:7.5.1.5]
Used refrigerants shall not be reused in a different owner's equipment unless tested and found to be in accordance with the requirements of AHRI 700. Contaminated refrigerants shall not be used unless reclaimed and is in accordance with AHRI 700. [ASHRAE 15:7.5.1.6]
Refrigerants, including refrigerant blends, with different designations as in accordance with Table 1102.3 shall not be mixed in a system.

Exception: Addition of a second refrigerant shall be permitted where specified by the equipment manufacturer to improve oil return at low temperatures. The refrigerant and amount added shall be in accordance with the manufacturer's instructions. [ASHRAE 15:7.5.1.7]
A change in the type of refrigerant in a system shall not be made without notifying the Authority Having Jurisdiction, the user, and due observance of safety requirements. The refrigerant being considered shall be evaluated for suitability. [ASHRAE 15:5.3]
Cooling systems used for human comfort shall be in accordance with the return-air and outside- air provisions for furnaces in Section 604.1 and Section 904.7. Cooling equipment used for human comfort in residential buildings shall be selected in accordance with ACCA Manual S to satisfy the calculated loads determined in accordance with ACCA Manual J or other approved methods. Refrigerants used for human comfort shall be in accordance with Section 1104.6.
Supports and anchorage for refrigeration equipment and piping shall be designed in accordance with the building code as Occupancy Category H (hazardous facilities). Supports shall be made of noncombustible materials.

Exceptions:
  1. Equipment containing Group A1 refrigerants shall be permitted to be supported by the same materials permitted for the building type.
  2. The use of approved vibration isolators specifically designed for the normal, wind, and seismic loads encountered, shall be permitted.
     A compressor or portion of a condensing unit supported from the ground shall rest on a concrete or other approved base extending not less than 3 inches (76 mm) above the adjoining ground level.
An unobstructed readily accessible opening and passageway not less than 36 inches (914 mm) in width and 80 inches (2032 mm) in height shall be provided and maintained to the compressor, valves required by this chapter, or other portions of the system requiring routine maintenance.

Exceptions:
  1. Refrigerant evaporators, suspended overhead, shall be permitted to use portable means of access.
  2. Air filters, brine control or stop valves, fan motors or drives, and remotely de-energized electrical connections shall be permitted to be provided access to an unobstructed space not less than 30 inches (762 mm) in depth, width, and height. Where an access opening is immediately adjacent to these items and the equipment is capable of being serviced, repaired, and replaced from this opening, the dimensions shall be permitted to be reduced to 22 inches (559 mm) by 30 inches (762 mm) provided the largest piece of equipment is removed through the opening.
  3. Cooling equipment, using Group A1 refrigerants or brine, located in an attic or furred space shall be permitted to be provided access by a minimum opening and passageway thereto of not less than 22 inches (559 mm) by 30 inches (762 mm).
  4. Cooling or refrigeration equipment, using Group A1 or B1 refrigerants or brine, located on a roof or on an exterior wall of a building, shall be permitted to be provided access as for furnaces in Section 304.3.
In addition to the requirements of Section 301.4, permanent luminaires shall be installed for equipment required by this code to be accessible or readily accessible. Such luminaires shall provide illumination to perform the required tasks for which access is provided. Control of the illumination source shall be provided at the access entrance.

Exceptions:
  1. Luminaires shall be permitted to be omitted where the fixed lighting of the building will provide the required illumination.
  2. Equipment located on the roof or on the exterior walls of a building.
Where not in a refrigerant machinery room, rooms or spaces in which a refrigerant-containing portion of a condensing unit is installed shall be provided with ventilation in accordance with Section 1105.5.1 or Section 1105.5.2. Ventilation for machinery rooms shall comply with Section 1106.0.
Permanent gravity ventilation openings of not less than 2 square feet (0.2 m2) net free area opening shall be terminated directly to the outside of the building or extend to the outside of the building by continuous ducts.
A mechanical exhaust system shall be designed to provide a complete change of air not less than every 20 minutes in such room or space and shall discharge to the outside of the building.

Exceptions:
  1. A condensing unit in a room or space where the cubical content exceeds 1000 cubic feet per horsepower (ft3/hp) (37.95 m3/kW) of the unit.
  2. A condensing unit in a room or space that has permanent gravity ventilation having an area of 2 square feet (0.2 m2) or more to other rooms or openings exceeding 1000 ft3/hp (37.95 m3/kW).
Refrigeration systems or portions thereof shall not be located within a required exit enclosure. Refrigeration compressors exceeding 5 horsepowers (3.7 kW) rating shall be located not less than 10 feet (3048 mm) from an exit opening in a Group A; Group B; Group E; Group F; Group I; Group R, Division 1; or Group S Occupancy, unless separated by a one-hour fire-resistive occupancy separation.
Condensate from air-cooling coils shall be collected and drained to an approved location. Drain pans and coils shall be arranged to allow thorough drainage and access for cleaning. Where temperatures drop below freezing, heat tracing and insulation of condensate drains shall be installed.
Where defrost cycles are required for portions of the system, provisions shall be made for collection and disposal of the defrost liquid in a safe and sanitary manner.
Where condensate or defrost liquids are generated in an attic or furred space, and structural damage will result from overflow, provisions for overflow shall be provided.
Disposal of condensate, defrost, or overflow discharges shall comply with Section 310.0.
Air conditioning refrigerant circuit access ports located outdoors shall be protected from unauthorized access with locking-type tamper-resistant caps or in a manner approved by the Authority Having Jurisdiction.

Exception: Refrigerant ports in secure locations protected by walls or fencing and requiring key access.
Refrigerants and refrigerant oils not charged within the refrigeration system shall be stored in accordance with Section 1105.12.1 and the fire code. Storage of materials in a refrigeration machinery room shall comply with the fire code.
The total amount of refrigerant stored in a machinery room in all containers not provided with relief valves and piping in accordance with Section 1113.0 shall not exceed 330 pounds (149.7 kg). Refrigerant shall be stored in approved storage containers. Additional quantities of refrigerant shall be stored in an approved storage facility. [ASHRAE 15:11.5]
Refrigeration systems shall be provided with a refrigeration machinery room where the conditions as outlined in Section 1106.1.1 through Section 1106.1.4 exist.

Exception: Refrigeration equipment shall be permitted to be located outdoors in accordance with ASHRAE 15.
The quantity of refrigerant in a single, independent refrigerant circuit of a system exceeds the amounts of Table 1102.3.
Direct- and indirect-fired absorption equipment is used.

Exception: Direct and indirect-fired lithium bromide absorption systems using water as the refrigerant.
An A1 system having an aggregate combined compressor horsepower of 100 (74.6 kW) or more is used.
The system contains other than a Group A1 refrigerant.

Exceptions:
  1. Lithium bromide absorption systems using water as the refrigerant.
  2. Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location.
     Refrigeration machinery rooms shall house refrigerant-containing portions of the system other than the piping and evaporators permitted by Section 1104.4, discharge piping required of this chapter, and cooling towers regulated by Part II of this chapter, and their essential piping.
Where a refrigeration system is located indoors and a machinery room is required in accordance with Section 1106.1, the machinery room shall be in accordance with Section 1106.2.1 through Section 1106.2.5.2.
Machinery rooms shall not be prohibited from housing other mechanical equipment unless specifically prohibited elsewhere in this chapter. A machinery room shall be so dimensioned that parts are accessible with space for service, maintenance, and operations. There shall be clear head room of not less than 7.25 feet (2210 mm) below equipment situated over passageways. [ASHRAE 15:8.11.1]
Each refrigeration machinery room shall have a tight-fitting door or doors opening outward, self-closing where they open into the building and adequate in number to ensure freedom for persons to escape in an emergency. With the exception of access doors and panels in air ducts and air-handling units in accordance with Section 1106.6, there shall be no openings that will permit passage of escaping refrigerant to other parts of the building. [ASHRAE 15:8.11.2]
Each refrigeration machinery room shall contain one or more refrigerant detectors in accordance with Section 1106.2.2.2, located in areas where refrigerant from a leak will concentrate, that actuate an alarm and mechanical ventilation in accordance with Section 1106.2.4 at a set point not more than the corresponding Occupational Exposure Limit, OEL, in accordance with Table 1102.3, a set point determined in accordance with the OEL as defined in Chapter 2 shall be approved by the Authority Having Jurisdiction. The alarm shall annunciate visual and audible alarms inside the refrigeration machinery room and outside each entrance to the refrigeration machinery room. The alarms required in this section shall be of the manual reset type with the reset located inside the refrigeration machinery room. Alarms set at other levels, such as IDLH, and automatic reset alarms shall be permitted in addition to those required in accordance with this section. The meaning of each alarm shall be clearly marked by signage near the annunciator.

Exception: Refrigerant detectors are not required where only systems using R-718 (water) are located in the refrigeration machinery room.
Refrigerant detectors required in accordance with Section 1106.2.2.1 or Section 1107.1.7 shall meet all of the following conditions:
  1. The refrigerant detector shall perform automatic self-testing of sensors. Where a failure is detected, a trouble signal shall be activated.
  2. The refrigerant detector shall have one or more set points to activate responses in accordance with Section 1106.2.2.1 or Section 1107.1.7.
  3. The refrigerant detector as installed, including any sampling tubes, shall activate responses within a time not to exceed 30 seconds after exposure to refrigerant concentration exceeding the set point value specified in Section 1106.2.2.1 or Section 1107.1.7.
Machinery rooms shall be vented to the outdoors, utilizing mechanical ventilation in accordance with Section 1106.2.4 and Section 1106.2.5.
Mechanical ventilation referred to in Section 1106.2.3 shall be by one or more power-driven fans capable of exhausting air from the machinery room at not less than the amount shown in accordance with Section 1106.2.5.

     To obtain a reduced airflow for normal ventilation, multiple fans or multispeed fans shall be used. Provision shall be made to supply makeup air to replace that being exhausted. Ducts for supply and exhaust to the machinery room shall serve no other area. The makeup air supply locations shall be positioned relative to the exhaust air locations to avoid short-circuiting. Inlets to the exhaust ducts shall be located in an area where refrigerant from a leak will concentrate, in consideration of the location of the replacement supply air paths, refrigerating machines, and the density of the refrigerant relative to air.

     Inlets to exhaust ducts shall be within 1 foot (305 mm) of the lowest point of the machinery room for refrigerants that are heavier than air, and shall be within 1 foot (305 mm) of the highest point for refrigerants that are lighter than air. The discharge of the exhaust air shall be to the outdoors in such a manner as not to cause a nuisance or danger.
An emergency ventilation system shall be required to exhaust an accumulation of refrigerant due to leaks or a rupture of the system. The emergency ventilation required shall be capable of removing air from the machinery room in not less than the airflow quantity in Section 1106.2.5.1 or Section 1106.2.5.2. Where multiple refrigerants are present, then the highest airflow quantity shall apply.
The emergency ventilation for A1, A2, A3, B1, B2L, B2 and B3 refrigerants shall have the capacity to provide mechanical exhaust at a rate as determined in accordance with Equation 1106.2.5.1.

(Equation 1106.2.5.1)


Where:

Q = Air flow rate, cubic feet per minute.
G = Refrigerant mass in largest system, pounds.
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 pound = 0.453 kg
The emergency ventilation for A2L refrigerants shall have the capacity to provide mechanical exhaust at a rate determined in accordance with Table 1106.2.5.2.

TABLE 1106.2.5.2
REQUIRED AIRFLOW FOR GROUP A2L REFRIGERANTS
REFRIGERANT MINIMUM AIR FLOW*
(CFM)
R-32
32 500
R-143a
28 600
R-444A
13 700
R-444B
22 400
R-445A
16 400
R-446A
50 500
R-447A
50 200
R-447B
29 600
R-451A
14 900
R-451B
14 900
R-452B
31 500
R-454A
4290
R-454B
6650
R-454C
32 800
R-455A
4770
R-457A
31 400
R-1234yf
16 500
R-1234zeE
12 600
For SI units: 1 cubic foot per minute = 0.00047 m3/s
* The values were tabulated from the following equation:

(Equation 1106.2.5.2)

Where:

p = Refrigerant density, pounds per cubic feet (kg/m3).
v = Refrigerant velocity equal to the refrigerant acoustic velocity (speed of sound), feet per second (m/s).
A = Cross-section flow area of refrigerant leak, square feet (m2), A = 0.00136 ft2 (0.000126 m2).
LFL = Lower Flammability Limit, or ETFL60 where no LFL exist, published value in accordance with ASHRAE 34.
QA2L = Minimum required airflow rate, conversion to other units of measures is permitted, cubic feet per second (m3/s).
For exact ventilation rates and for refrigerants not listed, the ventilation rate shall be calculated using this equation.
A part of the refrigeration machinery room mechanical ventilation shall be in accordance with the following:
  1. Operated, where occupied, to supply not less than 0.5 CFM/ft2 (2.54 L/s/m2) of machinery room area or 20 cubic feet per minute (9.44 L/s) per person.
  2. Operable, where occupied at a volume required to not exceed the higher of a temperature rise of 18°F (10°C) above inlet air temperature or a maximum temperature of 122°F (50°C).
Where a refrigerating system is located outdoors more than 20 feet (6096 mm) from buildings opening and is enclosed by a penthouse, lean-to, or other open structure, natural or mechanical ventilation shall be provided. The requirements for such natural ventilation shall be in accordance with the following:
  1. The free-aperture cross section for the ventilation of a machinery room shall be not less than as determined in accordance with Equation 1106.4.

    (Equation 1106.4)

    Where:

    F = The free opening area, square feet.
    G = The mass of refrigerant in the largest system, any part of which is located in the machinery room, pounds.
    For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 pound = 0.453 kg
  2. The location of the gravity ventilation openings shall be based on the relative density of the refrigerant to air. [ASHRAE 15:8.11.5(a), (b)]
No open flames that use combustion air from the machinery room shall be installed where refrigerant is used. Combustion equipment shall not be installed in the same machinery room with refrigerant-containing equipment except under one of the following conditions:
  1. Combustion air shall be ducted from outside the machinery room and sealed in such a manner as to prevent refrigerant leakage from entering the combustion chamber.
  2. A refrigerant detector, that is in accordance with Section 1106.2.2.1, shall be installed to automatically shut down the combustion process in the event of refrigerant leakage.
Exception: Machinery rooms where carbon dioxide (R-744) or water (R-718) is the refrigerant.
There shall be no airflow to or from an occupied space through a machinery room unless the air is ducted and sealed in such a manner as to prevent a refrigerant leakage from entering the airstream. Access doors and panels in ductwork and air-handling units shall be gasketed and tight fitting. [ASHRAE 15:8.11.7]
Makeup air intakes to replace the exhaust air shall be provided to the refrigeration machinery room directly from outside the building. Intakes shall be located as required by other sections of the code and fitted with backdraft dampers or other approved flow-control means to prevent reverse flow. Distribution of makeup air shall be arranged to provide thorough mixing within the refrigeration machinery room to prevent short circuiting of the makeup air directly to the exhaust.
Ventilation or mechanical cooling systems shall be provided to maintain a temperature of not more than 104°F (40°C) in the refrigerant machinery room under design load and weather conditions.
Joints and refrigerant-containing parts of a refrigerating system located in an air duct carrying conditioned air to and from an occupied space shall be constructed to withstand a temperature of 700°F (371°C) without leakage into the airstream. [ASHRAE 15:8.8]
Refrigeration machinery rooms shall be of such dimensions that system parts are readily accessible with approved space for maintenance and operations. An unobstructed walking space not less than 36 inches (914 mm) in width and 80 inches (2032 mm) in height shall be maintained throughout, allowing free access to not less than two sides of moving machinery and approaching each stop valve. Access to refrigeration machinery rooms shall be restricted to authorized personnel and posted with a permanent sign.
Access to the refrigeration machinery room shall be restricted to authorized personnel. Doors shall be clearly marked or permanent signs shall be posted at each entrance to indicate this restriction. [ASHRAE 15:8.11.8]
Exits shall comply with the building code for special hazards.
In cases specified in the rules of Section 1106.1, a refrigeration machinery room shall comply with the special requirements in accordance with Section 1107.1.1 through Section 1107.1.10, in addition to Section 1106.2.
There shall be no flame-producing device or continuously operating hot surface over 800°F (427°C) permanently installed in the room.
Doors communicating with the building shall be approved, self-closing, tight-fitting fire doors.
Walls, floor, and ceiling shall be tight and of noncombustible construction. Walls, floor, and ceiling separating the refrigeration machinery room from other occupied spaces shall be not less than one-hour fire-resistive construction.
The refrigeration machinery room shall have a door that opens directly to the outdoors or through a vestibule equipped with self-closing, tight-fitting doors.
Exterior openings, where present, shall not be under a fire escape or an open stairway.
All pipes piercing the interior walls, ceiling, or floor of such rooms shall be tightly sealed to the walls, ceiling, or floor through which they pass.
Where refrigerant of Groups A2L or B2L are used, the requirements of Class 1, Division 2, of the California Electrical Code, shall not apply to the machinery room provided that the conditions in Section 1107.1.7.1 through Section 1107.1.7.3 are met.
The mechanical ventilation system in the machinery room is run continuously in accordance with Section 1106.2.5 and failure of the mechanical ventilation system actuates an alarm, or the mechanical ventilation system in the machinery room is activated by one or more refrigerant detectors, in accordance with the requirements of Section 1106.2.2.1 and Section 1106.2.2.2.
For the refrigerant detection required in Section 1106.2.2.1, detection of refrigerant concentration that exceeds 25 percent of the LFL or the upper detection limit of the refrigerant detector, whichever is lower, shall automatically de-energize the following equipment in the machinery room:
  1. refrigerant compressors
  2. refrigerant pumps
  3. normally-closed automatic refrigerant valves
Where any refrigerant of Groups A2, A3, B2, or B3 are used, the machinery room shall comply with Class 1, Division 2, of the California Electrical Code.
As part of the mechanical ventilation system in accordance with Section 1106.2.4, refrigeration systems that contain more than 110 pounds (50 kg) of any Group A2L, A2, A3, B2L, B2, or B3, refrigerant shall have not less than one exhaust air inlet located adjacent to each system not more than 9 feet (3 m) away.
Remote control of the mechanical equipment in the refrigeration machinery room shall be provided immediately outside the machinery room door solely for the purpose of shutting down the equipment in an emergency. Ventilation fans shall be on a separate electrical circuit and have a control switch located immediately outside the machinery room door.
Equipment, piping, ducts, vents, or similar devices that are not essential for the refrigeration process, maintenance of the equipment, or for the illumination, ventilation, or fire protection of the room shall not be placed in or pass through a refrigeration machinery room.
Electrical equipment and installations shall comply with the electrical code. The refrigeration machinery room shall not be classified as a hazardous location except as provided in Section 1107.1.7 or Section 1107.1.8.
A clearly identified emergency shut-off switch of the break-glass type or with an approved tamper-resistant cover shall be provided immediately adjacent to and outside of the principal refrigeration machinery room entrance. The switch shall provide off-only control of refrigerant compressors, refrigerant pumps, and normally-closed automatic refrigerant valves located in the machinery room. For other than A1 and B1 refrigerants, emergency shutoff shall be automatically activated by refrigerant Alarm 2 in accordance with Section 1106.2.2.1.
Detection and alarm systems in accordance with Section 1106.2.2.1 shall be installed, maintained, and tested in accordance with the fire code and with the equipment manufacturer's specification.
Where required by the fire code, an emergency pressure control system shall be installed in accordance with applicable fire code requirements.
Materials used in the construction and installation of refrigerating systems shall be suitable for conveying the refrigerant used. Materials shall not be used that will deteriorate because of the refrigerant, lubricant, or their combination in presence of air or moisture to a degree that poses a safety hazard. [ASHRAE 15:9.1.1] Refrigerant piping shall be metallic.
Copper and copper alloy refrigeration piping, valves, fittings, and related parts used in the construction and installation of refrigeration systems shall be approved for the intended use. Refrigeration piping shall comply with ASME B31.5.
Copper linesets shall comply with ASTM B280 or ASTM B1003.
Iron and steel refrigeration piping, valves, fittings, and related parts shall be approved for the intended use. Pipe exceeding 2 inches (50 mm) iron pipe size shall be electric-resistance welded or seamless pipe. Refrigeration piping shall comply with ASME B31.5.
Aluminum, zinc, magnesium, or their alloys shall not be used in contact with methyl chloride. Magnesium alloys shall not be used where in contact with halogenated refrigerants. [ASHRAE 15:9.1.2]
Iron or steel pipe joints shall be of approved threaded, flanged, or welded types. Exposed threads shall be tinned or coated with an approved corrosion inhibitor. Copper or copper alloy pipe joints of iron pipe size shall be of approved threaded, flanged, press-connect or brazed types. Copper tubing joints and connections shall be connected by approved flared, lapped, swaged, or brazed joints, soldered joints, or mechanical joints that comply with UL 207 either individually or as part of an assembly or a system by an approved nationally recognized laboratory. Piping and tubing shall be installed so as to prevent vibration and strains at joints and connections.
Refrigerant piping shall not penetrate floors, ceilings, or roofs.

Exceptions:
  1. Penetrations connecting the basement and the first floor.
  2. Penetrations connecting the top floor and a machinery penthouse or roof installation.
  3. Penetrations connecting adjacent floors served by the refrigeration system.
  4. Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1102.3 for the smallest occupied space through which the refrigerant piping passes.
  5. In other than industrial occupancies and where the refrigerant concentration exceeds that listed in Table 1102.3 for the smallest occupied space, penetrations that connect separate pieces of equipment that are in accordance with one of the following:
    1. Enclosed by an approved gastight, fire-resistive duct or shaft with openings to those floors served by the refrigerating system.
    2. Located on the exterior wall of a building where vented to the outdoors or to the space served by the system and not used as an air shaft, closed court, or similar space. [ASHRAE 15:8.10.3]
Refrigerant piping crossing an open space that affords passageway in a building shall be not less than 7.25 feet (2210 mm) above the floor unless the piping is located against the ceiling of such space and is permitted by the Authority Having Jurisdiction. [ASHRAE 15:8.10.1]
Passages shall not be obstructed by refrigerant piping. Refrigerant piping shall not be located in an elevator, dumbwaiter, or other shaft containing a moving object, or in a shaft that has openings to living quarters, or to means of egress. Refrigerant piping shall not be installed in an enclosed public stairway, stair landing, or means of egress. [ASHRAE 15:8.10.2]
Refrigerant piping placed underground shall be protected against corrosion.
Refrigerant piping installed in concrete floors shall be encased in a pipe duct. Refrigerant piping shall be isolated and supported to prevent damaging vibration, stress, or corrosion. [ASHRAE 15:8.10.4]
In addition to the requirements of Section 1105.2, piping and tubing shall be securely fastened to a permanent support within 6 feet (1829 mm) following the first bend in such tubing from the compressor and within 2 feet (610 mm) of each subsequent bend or angle. Piping and tubing shall be supported at points not more than 15 feet (4572 mm) apart.
Refrigerant piping and tubing shall be installed so that it is not subject to damage from an external source. Soft annealed copper tubing shall not exceed 13/8 inches (35 mm) nominal size. Mechanical joints, other than approved press-connect joints, shall not be made on tubing exceeding 3/4 of an inch (20 mm) nominal size. Soft annealed copper tubing conveying refrigerant shall be enclosed in iron or steel piping and fittings, or in conduit, molding, or raceway that will protect the tubing against mechanical injury from an exterior source.

Exceptions:
  1. Tubing entirely within or tubing within 5 feet (1524 mm) of a refrigerant compressor where so located that it is not subject to external injury.
  2. Copper tubing serving a dwelling unit, where such tubing contains Group A1 refrigerant and is placed in locations not subject to damage from an external source.
Refrigerant piping and joints erected on the premises shall be exposed to view for visual inspection prior to being covered or enclosed.

Exception: Copper tubing enclosed in iron or steel piping conduit, molding, or raceway, provided there are no fittings or joints concealed therein.
Piping and fittings that convey brine, refrigerant, or coolants that during normal operation are capable of reaching a surface temperature below the dew point of the surrounding air and that are located in spaces or areas where condensation will cause a hazard to the building occupants or damage to the structure, electrical or other equipment shall be protected to prevent such damage.
Piping shall be in accordance with the reference standard for identification. The type of refrigerant, function and pressure shall be indicated.
Systems containing more than 6.6 pounds (2.99 kg) of refrigerant shall have stop valves installed at the following locations:
  1. The suction inlet of a compressor, compressor unit, or condensing unit.
  2. The discharge of a compressor, compressor unit, or condensing unit.
  3. The outlet of a liquid receiver.
Exceptions:
  1. Systems that have a refrigerant pumpout function capable of storing the refrigerant charge, or are equipped with the provisions for pumpout of the refrigerant.
  2. Self-contained systems. [ASHRAE 15:9.12.4]
Systems containing more than 110 pounds (49.9 kg) of refrigerant shall have stop valves installed at the following locations:
  1. The suction inlet of a compressor, compressor unit, or condensing unit.
  2. The discharge outlet of a compressor, compressor unit, or condensing unit.
  3. The inlet of a liquid receiver, except for self-contained systems or where the receiver is an integral part of the condenser or condensing unit.
  4. The outlet of a liquid receiver.
  5. The inlets and outlets of condensers where more than one condenser is used in parallel in the systems.
Exception: Systems that have a refrigerant pumpout function capable of storing the refrigerant charge, or are equipped with the provisions for pumpout of the refrigerant or self-contained systems. [ASHRAE 15:9.12.5]
Stop valves installed in copper refrigerant lines of 3/4 of an inch (20 mm) or less outside diameter shall be supported independently of the tubing or piping.
Stop valves required by Section 1110.0 shall be readily accessible from the refrigeration machinery room floor or a level platform.
Stop valves shall be identified by tagging in accordance with the reference standard for identification. A valve chart shall be mounted under glass at an approved location near the principal entrance to a refrigeration machinery room.
Pressure-limiting devices complying with Section 1111.2 through Section 1111.4 shall be provided for compressors on all systems operating above atmospheric pressure.

Exception: Pressure limiting devices are not required for listed factory-sealed systems containing less than 22 pounds (9.9 kg) of Group A1 refrigerant. [ASHRAE 15:9.9.1]
Pressure limiting devices shall be set in accordance with one the following:
  1. For positive displacement compressors:
    1. When systems are protected by a highside pressure relief device, the compressor's pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
    2. When systems are not protected by a highside pressure relief device, the compressor's pressure limiting device shall be set not more than the system's highside design pressure.
  2. For nonpositive displacement compressors:
    1. When systems are protected by a highside pressure relief device, the compressor's pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
    2. When systems are protected by a lowside pressure relief device that is only subject to lowside pressure, and is provided with a permanent relief path between the systems' highside and lowside, without intervening valves, the compressor's pressure limiting device shall be set not more than the systems' highside design pressure. [ASHRAE 15:9.9.2]
Stop valves shall not be installed between the pressure imposing element and pressure limiting devices serving compressors. [ASHRAE 15:9.9.3]
Activation of a pressure-limiting device shall stop the action of the pressure-imposing element. [ASHRAE 15:9.9.4]
Refrigeration systems shall be protected by a pressure-relief device or other approved means to safely relieve pressure due to fire or abnormal conditions. [ASHRAE 15:9.4.1]
A positive displacement compressor with a stop valve in the discharge connection shall be equipped with a pressure-relief device that is sized, and with a pressure setting, in accordance with the compressor manufacturer to prevent rupture of the compressor or to prevent the pressure from increasing to more than 10 percent above the maximum allowable working pressure of components located in the discharge line between the compressor and the stop valve or in accordance with Section 1113.5, whichever is larger. The pressure-relief device shall discharge into the low-pressure side of the system or in accordance with Section 1112.11.

Exception: Hermetic refrigerant motor-compressors that are listed and have a displacement not more than 50 cubic feet per minute (1.42 m3/min).

The relief device(s) shall be sized based on compressor flow at the following conditions:
  1. For compressors in single-stage systems and high-stage compressors of other systems, the flow shall be calculated based on 50°F (10°C) saturated suction temperature at the compressor suction.
  2. For low-stage or booster compressors in compound systems, the compressors that are capable of running only where discharging to the suction of a high-stage compressor, the flow shall be calculated based on the saturated suction temperature equal to the design operating intermediate temperature.
  3. For low-stage compressors in cascade systems, the compressors that are located in the lower-temperature stage(s) of cascade systems, the flow shall be calculated based on the suction pressure being equal to the pressure setpoint of the pressure-relieving devices that protect the lowside of the stage against overpressure.
Exceptions: For Section 1112.2(1), Section 1112.2(2), and Section 1112.2(3), the discharge capacity of the relief device shall be permitted to be the minimum regulated flow rate of the compressor where the following conditions are met:
  1. The compressor is equipped with capacity regulation.
  2. Capacity regulation actuates to a flow at not less than 90 percent of the pressure-relief device setting.
  3. A pressure-limiting device is installed and set in accordance with the requirements of Section 1111.0. [ASHRAE 15:9.8]
Liquid-containing portions of systems, including piping, that is isolated from pressure-relief devices required elsewhere, and that develops pressures exceeding their working design pressures due to temperature rise, shall be protected by the installation of pressure-relief devices.
Heat exchanger coils located downstream, or upstream within 18 inches (457 mm), of a heating source and capable of being isolated shall be fitted with a pressure-relief device that discharges to another part of the system in accordance with Section 1112.5 through Section 1112.5.2 or outside any enclosed space in accordance with Section 1112.11. The pressure relief device shall be connected at the highest possible location of the heat exchanger or piping between the heat exchanger and its manual isolation valves.

Exceptions:
  1. Relief valves shall not be required on heat exchanger coils that have a design pressure more than 110 percent of refrigerant saturation pressure when exposed to the maximum heating source temperature.
  2. A relief valve shall not be required on self-contained or unit systems where the volume of the lowside of the system, which is shut off by valves, is more than the specific volume of the refrigerant at critical conditions of temperature and pressure, as determined in accordance with Equation 1112.4.
V1/[W1 - (V2 - V1)/ Vgt]
Shall be more than Vgc (Equation 1112.4)

Where:

V1 = Lowside volume, cubic foot (m3).
V2 = Total volume of system, cubic foot (m3).
W1 = Total weight of refrigerant in system, pounds (kg).
Vgt = Specific volume of refrigerant vapor at 110°F (43°C), cubic feet per pound (m3/kg).
Vgc = Specific volume at critical temperature and pressure, cubic feet per pound (m3/kg). [ASHRAE 15:9.4.4]
Pressure rise resulting from hydrostatic expansion due to temperature rise of liquid refrigerant trapped in or between closed valves shall be addressed in accordance with Section 1112.5.1 and Section 1112.5.2. [ASHRAE 15:9.4.3]
Where trapping of liquid with subsequent hydrostatic expansion is capable of occurring automatically during normal operation or during standby, shipping, or power failure, engineering controls shall be used that are capable of preventing the pressure from exceeding the design pressure. Acceptable engineering controls include but are not limited to the following:
  1. Pressure relief device to relieve hydrostatic pressure to another part of the system.
  2. Reseating pressure relief valve to relieve the hydrostatic pressure to an approved treatment system. [ASHRAE 15:9.4.3.1]
Where trapping of liquid with subsequent hydrostatic expansion is capable of occurring only during maintenance—i.e., when personnel are performing maintenance tasks—either engineering or administrative controls shall be used to relieve or prevent the hydrostatic overpressure. [ASHRAE 15:9.4.3.2]
Pressure-relief devices shall be direct-pressure actuated or pilot operated. Pilot-operated pressure-relief valves shall be self-actuated, and the main valve shall open automatically at the set pressure and, where an essential part of the pilot fails, shall discharge its full rated capacity. [ASHRAE 15:9.4.5]
Stop valves shall not be located between a pressure-relief device and parts of the system protected thereby. A three-way valve, used in conjunction with the dual relief valve in accordance with Section 1113.6, shall not be considered a stop valve. [ASHRAE 15:9.4.6]
Pressure-relief devices shall be connected directly to the pressure vessel or other parts of the system protected thereby. These devices shall be connected above the liquid refrigerant level and installed so that they are accessible for inspection and repair, and so that they are not capable of being readily rendered inoperative.

Exception: Where fusible plugs are used on the highside, they shall be located above or below the liquid refrigerant level. [ASHRAE 15:9.4.8]
The seats and discs of pressure-relief devices shall be constructed of compatible material to resist refrigerant corrosion or other chemical action caused by the refrigerant. Seats or discs of cast iron shall not be used. Seats and discs shall be limited in distortion, by pressure or other cause, to a set pressure change of not more than 5 percent in a span of five years. [ASHRAE 15:9.4.9]
Pressure-relief valves shall start to function at a pressure not exceeding the design pressure of the parts of the system protected.

Exception: Relief valves that discharge into other parts of the system shall comply with Section 1112.11.3. [ASHRAE 15:9.5.1]
Rupture members used in lieu of, or in series with, a relief valve shall have a nominal rated rupture pressure not exceeding the design pressure of the parts of the system protected. The conditions of application shall comply with ASME BPVC Section VIII. The size of rupture members installed ahead of relief valves shall not be less than the relief-valve inlet. [ASHRAE 15:9.5.2]
Pressure-relief systems designed for vapor shall comply with Section 1112.11.1 through Section 1112.11.4.1.
Pressure-relief devices, including fusible plugs, serving refrigeration systems shall be permitted to discharge to the interior of a building where in accordance with the following:
  1. The system contains less than 110 pounds (49.9 kg) of a Group A1 refrigerant.
  2. The system contains less than 6.6 pounds (2.99 kg) of a Group A2, B1 or B2 refrigerant.
  3. The system does not contain any quantity of a Group A3 or B3 refrigerant.
  4. The system is not required to be installed in a machinery room in accordance with Section 1106.0.
  5. The refrigerant concentration limits in Section 1104.2 are not exceeded. Refrigeration systems that do not comply with the above requirements shall comply with the requirements of Section 1112.11.2 through Section 1112.11.4. [ASHRAE 15:9.7.8.1]
Pressure-relief devices designed to discharge external to the refrigeration system shall be arranged to discharge outside of a building and shall be in accordance with the following:
  1. The point of vent discharge shall be located not less than 15 feet (4572 mm) above the adjoining ground level.

    Exception: Outdoor systems containing Group A1 refrigerant shall be permitted to discharge at any elevation where the point of discharge is located in an access-controlled area accessible to authorized personnel only.
  2. The point of vent discharge shall be located not less than 20 feet (6096 mm) from windows, building ventilation openings, pedestrian walkways, or building exits.
  3. For heavier-than-air refrigerants, the point of vent discharge shall be located not less than 20 feet (6096 mm) horizontally from below-grade walkways, entrances, pits or ramps where a release of the entire system charge into such a space would yield a concentration of refrigerant in excess of the RCL. The direct discharge of a relief vent into enclosed outdoor spaces, such as a courtyard with walls on all sides, shall not be permitted where a release of the entire system charge into such a space would yield a concentration of refrigerant in excess of the RCL. The volume for the refrigerant concentration calculation shall be determined using the gross area of the space and a height of 8.2 feet (2499 mm), regardless of the actual height of the enclosed space.
  4. The termination point of a vent discharge line shall be made in a manner that prevents discharged refrigerant from spraying directly onto personnel that are capable of being in the vicinity.
  5. The termination point of vent discharge line shall be made in a manner that prevents foreign material or debris from entering the discharge piping.
  6. Relief vent lines that terminate vertically upward and are subject to moisture entry shall be provided with a drip pocket having a length of not less than 24 inches (610 mm) and having the size of the vent discharge pipe. The drip pocket shall be installed to extend below the first change in vent pipe direction and shall be fitted with a valve or drain plug to permit removal of accumulated moisture. [ASHRAE 15:9.7.8.2]
Pressure-relief valves designed to discharge from a higher-pressure vessel into a lower pressure vessel internal to the system shall comply with the following:
  1. The pressure-relief valve that protects the higher-pressure vessel shall be selected to deliver capacity in accordance with Section 1113.5 without exceeding the maximum allowable working pressure of the higher-pressure vessel accounting for the change in mass flow capacity due to the elevated backpressure.
  2. The capacity of the pressure-relief valve protecting the part of the system receiving a discharge from a pressure-relief valve protecting a higher-pressure vessel shall be not less than the sum of the capacity required in Section 1113.5 plus the mass flow capacity of the pressure-relief valve discharging into that part of the system.
  3. The design pressure of the body of the relief valve used on the higher-pressure vessel shall be rated for operation at the design pressure of the higher-pressure vessel in both pressure-containing areas of the valve. [ASHRAE 15:9.7.8.3]
Additional requirements for relief device discharge location and allowances shall apply for specific refrigerants in accordance with Section 1112.11.4.1. [ASHRAE 15:9.7.8.4]
Where water is the refrigerant, discharge to a floor drain shall be permitted where the following conditions are met:
  1. The pressure-relief device set pressure shall not exceed 15 psig (103 kPa).
  2. The floor drain shall be sized to handle the flow rate from a single broken tube in a refrigerant-containing heat exchanger.
  3. The Authority Having Jurisdiction finds it acceptable that the working fluid, corrosion inhibitor, and other additives used in this type of refrigeration system are permitted to infrequently be discharged to the sewer system, or a catch tank that is sized to handle the expected discharge shall be installed and equipped with a normally closed drain valve and an overflow line to drain. [ASHRAE 15:9.7.8.4.1]
The piping used for pressure-relief device discharge shall be in accordance with Section 1112.12.1 through Section 1112.12.5. [ASHRAE 15:9.7.9]
Piping connected to the discharge side of a fusible plug or rupture member shall have provisions to prevent plugging of the pipe upon operation of a fusible plug or rupture member. [ASHRAE 15:9.7.9.1]
The size of the discharge pipe from the pressure-relief device or fusible plug shall be not less than the outlet size of the pressure-relief device or fusible plug. [ASHRAE 15:9.7.9.2]
The maximum length of the discharge piping installed on the outlet of pressure-relief devices and fusible plugs discharging to the atmosphere shall be determined in accordance with Section 1112.12.4 and Section 1112.12.5. See Table 1112.12.3 for the allowable flow capacity of various equivalent lengths of single discharge piping vents for conventional pressure-relief valves. [ASHRAE 15:9.7.9.3]

TABLE 1112.12.3
ATMOSPHERIC PRESSURE AT NOMINAL INSTALLATION ELEVATION (Pa)
[ASHRAE 15:TABLE 9.7.9.3.2]
ELEVATION ABOVE SEA LEVEL, FEET POUNDS PER SQUARE INCH, ABSOLUTE (Pa)
0
14.7
500
14.4
1000
14.2
1500
13.9
2000
13.7
2500
13.4
3000
13.2
3500
12.9
4000
12.7
4500
12.5
5000
12.2
6000
11.8
7000
11.3
8000
10.9
9000
10.5
1000
10.1
For SI units: 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa
The design back pressure due to flow in the discharge piping at the outlet of pressure-relief devices and fusible plugs, discharging to atmosphere, shall be limited by the allowable equivalent length of piping determined in accordance with Equation 1112.12.4(1).

[Equation 1112.12.4(1)]

Where:

L = Equivalent length of discharge piping, feet.
Cr = Rated capacity as stamped on the relief device in pounds per minute (lb/min), or in SCFM multiplied by 0.0764, or as calculated in Section 1112.14 for a rupture member or fusible plug, or as adjusted for reduced capacity due to piping in accordance with the manufacturer of the device, or as adjusted for reduced capacity due to piping as estimated by an approved method.
f = Moody friction factor in fully turbulent flow.
d = Inside diameter of pipe or tube, inches.
ln = Natural logarithm.
P2 = Absolute pressure at outlet of discharge piping, psia.
P0 = Allowed back pressure (absolute) at the outlet of pressure relief device, (psia).
For SI units: 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa, 1 pound per minute = 0.00756 kg/s

     Unless the maximum allowable back pressure (P0) is specified by the relief valve manufacturer, the following maximum allowable back pressure values shall be used for P0, where P is the set pressure and Pa is atmospheric pressure at the nominal elevation of the installation (see Table 1112.12.3):

For conventional relief valves: 15 percent of set pressure:

[Equation 1112.12.4(2)]

For balanced relief valves: 25 percent of set pressure:

[Equation 1112.12.4(3)]

For rupture disks alone: fusible plugs, and pilot operated relief devices, 50 percent of set pressure:

[Equation 1112.12.4(4)]

     For fusible plugs, P shall be the saturated absolute pressure for the stamped temperature melting point of the fusible plug or the critical pressure of the refrigerant used, whichever is smaller. [ASHRAE 15:9.7.9.3.1, 9.7.9.3.2]
When outlets of two or more relief devices or fusible plugs, which are expected to operate simultaneously, connect to a common discharge pipe, the common pipe shall be sized large enough to prevent the back pressure at each relief device from exceeding the maximum allowable back pressure in accordance with Section 1112.12.4. [ASHRAE 15:9.7.9.3.3]
The rated discharge capacity of a pressure-relief device expressed in pounds of air per minute (kg/s), shall be determined in accordance with ASME BPVC Section VIII. Pipe and fittings between the pressure-relief valve and the parts of the system it protects shall have not less than the area of the pressure-relief valve inlet area. [ASHRAE 15:9.7.6]
The rated discharge capacity of a rupture member or fusible plug discharging to atmosphere under critical flow conditions, in pounds of air per minute (kg/s), shall be determined in accordance with the following formulas:

[Equation 1112.14(1)]

  [Equation 1112.14(2)]

Where:
C = Rated discharge capacity of air, pounds per minute.
d = Smallest internal diameter of the inlet pipe, retaining flanges, fusible plug, or rupture member; inches.


For rupture members:

[Equation 1112.14(3)]

For fusible plugs:

P1 = Absolute saturation pressure, corresponding to the stamped temperature melting point of the fusible plug or the critical pressure of the refrigerant used, whichever is smaller, pound-force per square inch atmosphere, psia. [ASHRAE 15:9.7.7]
For SI units: 1 inch = 25.4 mm, 1 pound-force per square inch = 6.8947 kPa, 1 pound per minute = 0.00756 kg/s
Pressure vessels shall be provided with overpressure protection in accordance with ASME BPVC Section VIII. Pressure vessels containing liquid refrigerant that are capable of being isolated by stop valves from other parts of a refrigerating system shall be provided with overpressure protection. Pressure relief devices or fusible plugs shall be sized in accordance with Section 1113.5. [ASHRAE 15:9.7.1, 9.7.2]
Pressure vessels with an internal gross volume of 3 cubic feet (0.1 m3) or less shall use one or more pressure relief devices or a fusible plug. Pressure vessels of more than 3 cubic feet (0.1 m3) but less than 10 cubic feet (0.28 m3) internal gross volume shall use one or more pressure relief devices. Fusible plugs shall not be used. [ASHRAE 15:9.7.2.1, 9.7.2.2]
For pressure-relief valves discharging into the lowside of the system, a single relief valve (not rupture member) of the required relieving capacity shall not be used on vessels of 10 cubic feet (0.28 m3) or more internal gross volume except under the conditions permitted in Section 1112.11.3. [ASHRAE 15:9.7.3]
Two or more pressure-relief devices in parallel to obtain the required capacity shall be considered as one pressure-relief device. The discharge capacity shall be the sum of the capacities required for each pressure vessel being protected.
The minimum required discharge capacity of the pressure-relief device or fusible plug for a pressure vessel shall be determined in accordance with Equation 1113.5:

(Equation 1113.5)

Where:
C = Minimum required discharge capacity of the relief device expressed as mass flow of air, pounds per minute (kg/s).
D = Outside diameter of vessel, feet (m).
L = Length of vessel, feet (m).
f = Factor dependent upon type of refrigerant from Table 1113.5.


     Where combustible materials are used within 20 ft (6096 mm) of a pressure vessel, the value of f shall be multiply by 2.5. Equation 1113.5 is based on fire conditions, other heat sources shall be calculated separately. Where one pressure-relief device or fusible plug is used to protect more than one pressure vessel, the required capacity shall be the sum of the capacity required for every pressure vessel. [ASHRAE 15:9.7.5]

TABLE 1113.5
RELIEF DEVICES CAPACITY FACTOR*
[ASHRAE 15:TABLE 9.7.5]
REFRIGERANT VALUE OF f
Where used on the lowside of a limited-charge cascade system:
R-23, R-170, R-744, R-1150, R-508A, R-508B
1
R-13, R-13B1, R-503
2
R-14
2.5
Other applications:
R-718
0.2
R-717
0.5
R-11, R-32, R-113, R-123, R-142b, R-152a, R-290, R-600, R-600a, R-764
1
R-12, R-22, R-114, R-124, R-134a, R-401A, R-401B, R-401C, R-405A, R-406A, R-407C, R-407D, R-407E, R-409A, R-409B, R-411A, R-411B, R-411C, R-412A, R-414A, R-414B, R-500, R-1270
1.6
R-143a, R-402B, R-403A, R-407A, R-408A, R-413A
2
R-115, R-402A, R-403B, R-404A, R-407B, R-410A, R-410B, R-502, R-507A, R-509A
2.5
*  In accordance with Section 1102.2, ammonia refrigeration systems are not regulated by this chapter. R-717 (ammonia) is included in this table because the table is extracted from ASHRAE 15 and is not capable of being modified.
Pressure vessels of 10 cubic feet (0.28 m3) or more internal gross volume shall use one or more rupture member(s) or dual pressure-relief valves where discharging to the atmosphere. Dual pressure-relief valves shall be installed with a three-way valve to allow testing or repair. Where dual relief valves are used, the valve shall comply with Section 1113.5.

Exception: A single relief valve shall be permitted on pressure vessels of 10 cubic feet (0.28 m3) or more internal gross volume where in accordance with the following conditions:
  1. The relief valves are located on the lowside of the system.
  2. The vessel is provided with shutoff valves designed to allow pumpdown of the refrigerant charge of the pressure vessel.
  3. Other pressure vessels in the system are separately protected in accordance with Section 1113.1. [ASHRAE 15:9.7.2.3]
Systems containing other than Group A1 or B1 refrigerants shall discharge to atmosphere through an approved flaring device.

Exceptions:
  1. Where the Authority Having Jurisdiction determines upon review of a rational engineering analysis that fire, health, or environmental hazards will not result from the proposed atmospheric release.
  2. Lithium bromide absorption system using water as the refrigerant.
Flaring devices shall be designed to incinerate the entire discharge. The products of refrigerant incineration shall not pose health or environmental hazards. Incineration shall be automatic upon initiation of discharge, shall be designed to prevent blow-back, and shall not expose structures or materials to the threat of fire. Standby fuel, such as LP-Gas, and standby power shall have the capacity to operate for one and a half times the required time for complete incineration of the charge.
Flaring systems shall be tested to demonstrate their safety and effectiveness. A report from an approved agency shall be submitted detailing the emission products from the system as installed.
In addition to labels required elsewhere in this chapter, a refrigeration system shall be provided with identification labels in accordance with Section 1115.2 and Section 1115.3.
A condenser, receiver, absorber, accumulator and similar equipment having an internal volume of more than 3 cubic feet (0.1 m3) and containing refrigerant shall be equipped with a permanent label setting forth the type of refrigerant in such vessel.
In a refrigeration machinery room and for a direct refrigerating system of more than 10 horsepower (7.5 kW), there shall be a permanent sign at an approved location giving the following information:
  1. Name of contractor installing the equipment.
  2. Name and number designation of refrigerant in system.
  3. Pounds of refrigerant in system.
Pressure-relief valves for refrigerant containing components shall be set and sealed by the manufacturer or an assembler as defined in ASME BPVC Section VIII. Each pressure relief valve shall be marked by the manufacturer or assembler with the data required in ASME BPVC Section VIII.

Exception: Relief valves for systems with design pressures of 15 pounds-force per square inch gauge (psig) (103 kPa) or less shall be marked. [ASHRAE 15:9.6.1]
Rupture members for refrigerant pressure vessels shall be marked with the data required in accordance with ASME BPVC Section VIII. [ASHRAE 15:9.6.2]
Fusible plugs shall be marked with the melting temperatures in °F (°C). [ASHRAE 15:9.6.3]
Refrigerant-containing parts of unit systems shall be tested and proved tight by the manufacturer at not less than the design pressure for which they are rated. Pressure vessels shall be tested in accordance with Section 1117.0. [ASHRAE 15:9.14.1]
Tests shall be performed with dry nitrogen or another nonflammable, nonreactive, dried gas. Oxygen, air, or mixtures containing them shall not be used. The means used to build up the test pressure shall have a pressure-limiting device or a pressure-reducing device and a gage on the outlet side. The pressure-relief device shall be set above the test pressure but low enough to prevent permanent deformation of the system's components.

Exceptions:
  1. Mixtures of dry nitrogen, inert gases, nonflammable refrigerants permitted for factory tests.
  2. Mixtures of dry nitrogen, inert gases, or a combination of them with flammable refrigerants in concentrations not exceeding the lesser of a refrigerant weight fraction (mass fraction) of 5 percent or 25 percent of the LFL shall be permitted for factory tests.
  3. Compressed air without added refrigerant shall be permitted for factory tests provided the system is subsequently evacuated to less than 0.039 inch of mercury (0.132 kPa) before charging with refrigerant. The required evacuation level is atmospheric pressure for systems using R-718 (water) or R-744 (carbon dioxide) as the refrigerant. [ASHRAE 15:9.14.1.1]
The test pressure applied to the highside of each factory-assembled refrigerating system shall be not less than the design pressure of the highside. The test pressure applied to the lowside of a factory assembled refrigerating system shall be not less than the design pressure of the lowside.
Units with a design pressure of 15 psig (103 kPa) or less shall be tested at a pressure not less than 1.33 times the design pressure, and shall be proved leak-tight at not less than the lowside design pressure. [ASHRAE 15:9.14.3]
Refrigerant-containing parts of a system that is field-erected shall be tested and proved tight after complete installation and before the operation. The high and low sides of each system shall be tested and proved tight at not less than the lower of the pressure in Table 1116.2 or the setting of the pressure-relief device.

Exceptions:
  1. Compressors, condensers, evaporators, coded pressure vessels, safety devices, pressure gauges, control mechanisms, and systems that are factory tested.
  2. Refrigeration systems containing Group R-22, not exceeding 5 tons of refrigeration capacity (18 kW), and field-piped using approved, factory-charged line sets shall be permitted to be proved tight by observing retention of pressure on a set of charging gauges and soaping connections while the system is operating.
TABLE 1116.2
FIELD LEAK TEST PRESSURES (psig)*
REFRIGERANT NUMBER HIGHSIDE WATER COOLED HIGHSIDE AIR COOLED LOWSIDE
11
15
35
15
12
140
220
140
22
230
360
230
113
15
15
15
114
40
80
40
115
275
340
275
123
15
30
15
134a
150
250
150
152a
130
220
130
500
165
265
165
502
250
385
250
744*
For SI units: 1 pound-force per square inch gauge = 6.8947 kPa
* Special design required; test pressures typically exceed 1000 psig (6895 kPa).
Tests shall be performed with dry nitrogen or other nonflammable, nonreactive, dried gas. Oxygen, air, or mixtures containing them shall not be used. The means used to build up the test pressure shall have either a pressure-limiting device or a pressure-reducing device and a gauge on the outlet side. The pressure-relief device shall be set above the test pressure but low enough to prevent permanent deformation of the system's components.

Exceptions:
  1. Mixtures of dry nitrogen, inert gases, or a combination of them with nonflammable refrigerant in concentrations of a refrigerant weight fraction (mass fraction) not exceeding 5 percent shall be permitted for tests.
  2. Mixtures of dry nitrogen, inert gases, or a combination of them with flammable refrigerants in concentrations not exceeding the lower of a refrigerant weight fraction (mass fraction) of 5 percent or 25 percent of the LFL shall be permitted for tests.
  3. Compressed air without added refrigerants shall be permitted for tests, provided the system is subsequently evacuated to less than 1000 microns (0.1333 kPa) before charging with refrigerant. The required evacuation level is atmospheric pressure for systems using R-718 (water) or R-744 (carbon dioxide) as the refrigerant.
  4. Systems erected on the premises using Group A1 refrigerant and with copper tubing not exceeding 0.62 of an inch (15.7 mm) outside diameter shall be tested by means of the refrigerant charged into the system at the saturated vapor pressure of the refrigerant at not less than 68°F (20°C). [ASHRAE 15:10.1.2]
A dated declaration of test shall be provided for systems containing more than 55 pounds (24.9 kg) of refrigerant. The declaration shall give the name of the refrigerant and the field test pressure applied to the highside and the lowside of the system. The declaration of test shall be signed by the installer and, where an inspector is present at the tests, the inspector shall also sign the declaration. Where requested, copies of this declaration shall be furnished to the Authority Having Jurisdiction. [ASHRAE 15:10.2]
Brine-containing portions of a system shall be tested at one and a half times the design pressure of the system using brine as the test fluid.
Pressure vessels having inside dimensions of 6 inches (152 mm) or less shall be:
  1. Listed either individually or as part of an assembly by an approved, nationally recognized testing laboratory, or
  2. Marked directly on the vessel or on a nameplate attached to the vessel with a "U" or "UM" symbol signifying compliance with ASME BPVC Section VIII, or
  3. When requested by the Authority Having Jurisdiction, the manufacturer shall provide documentation to confirm that the vessel meets the design, fabrication, and testing requirements of ASME BPVC Section VIII.
Exception: Vessels having an internal or external design pressure of 15 psig (103 kPa) or less.

     Pressure vessels having inside dimensions of 6 inches (152 mm) or less shall be protected by either a pressure-relief device or a fusible plug. [ASHRAE 15:9.3.1.1]
Where a pressure-relief device is used to protect a pressure vessel having an inside dimension of 6 inches (152 mm) or less, the ultimate strength of the pressure vessel so protected shall withstand a pressure of not less than 3.0 times the design pressure. [ASHRAE 15:9.3.1.2]
Where a fusible plug is used to protect a pressure vessel having an inside diameter of 6 inches (152 mm) or less, the ultimate strength of the pressure vessel so protected shall withstand a pressure 2.5 times the saturation pressure of the refrigerant used at the temperature stamped on the fusible plug or 2.5 times the critical pressure of the refrigerant used, whichever is less. [ASHRAE 15:9.3.1.3]
Pressure vessels having an inside diameter exceeding 6 inches (152 mm) and having an internal or external design pressure greater than 15 psig (103 kPa) shall be directly marked, or marked on a nameplate, with a "U" or "UM" symbol signifying compliance with the rules of ASME BPVC Section VIII. [ASHRAE 15:9.3.2]
Pressure vessels having an internal or external design pressure of 15 psig (103 kPa) or less shall have an ultimate strength to withstand not less than 3.0 times the design pressure and shall be tested with a pneumatic test pressure of not less than 1.25 times the design pressure or a hydrostatic test pressure of not less than 1.5 times the design pressure. [ASHRAE 15:9.3.3]
Refrigeration systems shall be operated and maintained as required by the fire code.

Part II — Cooling Towers

Cooling towers, evaporative condensers, and fluid coolers shall be readily accessible. Where located on roofs, such equipment having combustible exterior surfaces shall be protected with an approved automatic fire-extinguishing system.
Cooling towers, evaporative condensers, and fluid coolers shall be supported on noncombustible grillage designed in accordance with the building code. Seismic restraints shall be as required by the building code.
Drains, overflows, and blow-down provisions shall have an indirect connection to an approved disposal location. Discharge of chemical waste shall be as approved by the regulatory authority.
Chemical treatment systems shall comply with the fire code. Where chemicals used present a contact hazard to personnel, approved emergency eye-wash and shower facilities shall be installed.
Cooling towers, evaporative condensers, and fluid coolers shall include controls that automate system bleed based on conductivity, fraction of metered makeup volume, metered bleed volume, recirculating pump run time, or bleed time.
Cooling towers, evaporative condensers, and fluid coolers shall be located such that their plumes cannot enter occupied spaces. Plume discharges shall be not less than 25 feet (7620 mm) away from a ventilation inlet to a building. Location on the property shall be as required for buildings by the building code.
Electrical systems shall be in accordance with the electrical code. Equipment shall be provided with a vibration switch to shut off fans operating with excessive vibration. In climates commonly subject to electrical storms, lightning protection shall be provided on roof-mounted equipment.
Equipment containing refrigerants as a part of a closed-cycle refrigeration system shall comply with Part I of this chapter. Equipment containing other fluids that are flammable, combustible, or hazardous shall be in accordance with this code and the fire code.
Cooling towers, evaporative condensers, and fluid coolers shall be equipped with drift eliminators that have a drift rate of not more than 0.005 percent of the circulated water flow rate in accordance with the equipment manufacturer's instructions.
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