ADOPTS WITHOUT AMENDMENTS:

International Mechanical Code 2021 (IMC 2021)

Heads up: There are no amended sections in this chapter.

User note:

About this chapter: Chapter 11 provides for the protection of life and property from the potential fire and health hazards associated with refrigerant chemicals and the machinery that contains such chemicals. Some refrigerants are toxic, some are flammable and some are both. This chapter refers to the International Fire Code®, ASHRAE 15 and IIAR standards 2 through 5.

This chapter shall govern the design, installation, construction and repair of refrigeration systems that vaporize and liquefy a fluid during the refrigerating cycle. Permanently installed refrigerant storage systems and other components shall be considered as part of the refrigeration system to which they are attached.
Refrigerant piping design and installation for systems containing a refrigerant other than ammonia, including pressure vessels and pressure relief devices, 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.
Listed and labeled self-contained, factory-built equipment and appliances shall be tested in accordance with the applicable standards specified in Table 1101.2. Such equipment and appliances are deemed to meet the design, manufacture and factory test requirements of this code if installed in accordance with their listing and the manufacturer's instructions.

TABLE 1101.2

FACTORY-BUILT EQUIPMENT AND APPLIANCES

EQUIPMENT STANDARDS
Refrigeration fittings, including press-connect, flared and threaded UL 109 and UL 207
Air-conditioning equipment UL 1995 or UL/CSA 60335-2-40
Packaged terminal air conditioners and heat pumps UL 484 or UL/CSA 60335-2-40
Split-system air conditioners and heat pumps UL 1995 or UL/CSA 60335-2-40
Dehumidifiers UL 474 or UL/CSA 60335-2-40
Unit coolers UL 412 or UL/CSA 60335-2-89
Commercial refrigerators, freezers, beverage coolers and walk-in coolers UL 471 or UL/CSA 60335-2-89
Refrigerating units and walk-in coolers UL 427 or UL 60335-2-89
Refrigerant-containing components and accessories UL 207
Any portion of a refrigeration system that is subject to physical damage shall be protected in an approved manner.
Water supply and discharge connections associated with refrigeration systems shall be made in accordance with this code and the International Plumbing Code.
Fuel gas devices, equipment and appliances used with refrigeration systems shall be installed in accordance with the International Fuel Gas Code.
Mechanical refrigeration systems shall be maintained in proper operating condition, free from accumulations of oil, dirt, waste, excessive corrosion, other debris and leaks.
The type of refrigerant in refrigeration systems having a refrigerant circuit containing more than 220 pounds (99.8 kg) of Group A1 or 30 pounds (13.6 kg) of any other group refrigerant shall not be changed without prior notification to the code official and compliance with the applicable code provisions for the new refrigerant type.
Notification of refrigerant discharge shall be provided in accordance with the International Fire Code.
Refrigerant circuit access ports located outdoors shall be fitted with locking-type tamper-resistant caps or shall be otherwise secured to prevent unauthorized access.

Exception: This section shall not apply to refrigerant circuit access ports on equipment installed in controlled areas such as on roofs with locked access hatches or doors.

The system classification, allowable refrigerants, maximum quantity, enclosure requirements, location limitations, and field pressure test requirements shall be determined as follows:
  1. Determine the refrigeration system's classification, in accordance with Section 1103.3.
  2. Determine the refrigerant classification in accordance with Section 1103.1.
  3. Determine the maximum allowable quantity of refrigerant in accordance with Section 1104, based on type of refrigerant, system classification and occupancy.
  4. Determine the system enclosure requirements in accordance with Section 1104.
  5. Refrigeration equipment and appliance location and installation shall be subject to the limitations of Chapter 3.
  6. Nonfactory-tested, field-erected equipment and appliances shall be pressure tested in accordance with Section 1108.
The refrigerant shall be that which the equipment or appliance was designed to utilize or converted to utilize. Refrigerants not identified in Table 1103.1 shall be approved before use.
Refrigerants, including refrigerant blends, with different designations in ASHRAE 34 shall not be mixed in a system.

Exception: Addition of a second refrigerant is allowed where permitted by the equipment or appliance manufacturer to improve oil return at low temperatures. The refrigerant and amount added shall be in accordance with the manufacturer's instructions.

Refrigerants used in refrigeration systems shall be new, recovered or reclaimed refrigerants in accordance with Section 1102.2.2.1, 1102.2.2.2 or 1102.2.2.3. Where required by the equipment or appliance owner or the code official, the installer shall furnish a signed declaration that the refrigerant used meets the requirements of Section 1102.2.2.1, 1102.2.2.2 or 1102.2.2.3.

Exception: The refrigerant used shall meet the purity specifications set by the manufacturer of the equipment or appliance in which such refrigerant is used where such specifications are different from that specified in Sections 1102.2.2.1, 1102.2.2.2 and 1102.2.2.3.
Refrigerants shall be of a purity level specified by the equipment or appliance manufacturer.
Refrigerants that are recovered from refrigeration and air-conditioning systems shall not be reused in other than the system from which they were recovered and in other systems of the same owner. Recovered refrigerants shall be filtered and dried before reuse. Recovered refrigerants that show clear signs of contamination shall not be reused unless reclaimed in accordance with Section 1102.2.2.3.
Used refrigerants shall not be reused in a different owner's equipment or appliances unless tested and found to meet the purity requirements of AHRI 700. Contaminated refrigerants shall not be used unless reclaimed and found to meet the purity requirements of AHRI 700.
Refrigerant access ports shall be protected in accordance with Section 1101.9 whenever refrigerant is added to or recovered from refrigeration or air-conditioning systems.
Refrigerants shall be classified in accordance with ASHRAE 34 as listed in Table 1103.1.

TABLE 1103.1

REFRIGERANT CLASSIFICATION, AMOUNT AND OEL

CHEMICAL REFRIGERANT FORMULA CHEMICAL NAME OF BLEND REFRIGERANT CLASSIFICATION AMOUNT OF REFRIGERANT PER OCCUPIED SPACE [F] DEGREES OF HAZARDa
Pounds per 1,000 cubic feet ppm g/m3 OELe
R-11d CCl3F trichlorofluoromethane A1 0.39 1,100 6.2 C1,000 2-0-0b
R-12d CCl2F2 dichlorodifluoromethane A1 5.6 18,000 90 1,000 2-0-0b
R-13d CClF3 chlorotrifluoromethane A1 1,000 2-0-0b
R-13B1d CBrF3 bromotrifluoromethane A1 1,000 2-0-0b
R-14 CF4 tetrafluoromethane (carbon tetrafluoride) A1 25 110,000 400 1,000 2-0-0b
R-22 CHClF2 chlorodifluoromethane A1 13 59,000 210 1,000 2-0-0b
R-23 CHF3 trifluoromethane (fluoroform) A1 7.3 41,000 120 1,000 2-0-0b
R-30 CH2Cl2 dichloromethane (methylene chloride) B1
R-32 CH2F2 difluoromethane (methylene fluoride) A2c 4.8 36,000 77 1,000 1-4-0
R-40 CH3Cl chloromethane (methyl chloride) B2
R-50 CH4 methane A3 1,000
R-113d CCl2FCClF2 1,1,2-trichloro-1,2,2-trifluoroethane A1 1.2 2,600 20 1,000 2-0-0b
R-114d CClF2CClF2 1,2-dichloro-1,1,2,2-tetrafluoroethane A1 8.7 20,000 140 1,000 2-0-0b
R-115 CClF2CF3 chloropentafluoroethane A1 47 120,000 760 1,000
R-116 CF3CF3 hexafluoroethane A1 34 97,000 550 1,000 1-0-0
R-123 CHCl2CF3 2,2-dichloro-1,1,1-trifluoroethane B1 3.5 9,100 57 50 2-0-0b
R-124 CHClFCF3 2-chloro-1,1,1,2-tetrafluoroethane A1 3.5 10,000 56 1,000 2-0-0b
R-125 CHF2CF3 pentafluoroethane A1 23 75,000 370 1,000 2-0-0b
R-134a CH2FCF3 1,1,1,2-tetrafluoroethane A1 13 50,000 210 1,000 2-0-0b
R-141b CH3CCl2F 1,1-dichloro-1-fluoroethane 0.78 2,600 12 500 2-1-0
R-142b CH3CClF2 1-chloro-1,1-difluoroethane A2 5.1 20,000 83 1,000 2-4-0
R-143a CH3CF3 1,1,1-trifluoroethane A2c 4.5 21,000 70 1,000 2-0-0b
R-152a CH3CHF2 1,1-difluoroethane A2 2.0 12,000 32 1,000 1-4-0
R-170 CH3CH3 ethane A3 0.54 7,000 8.7 1,000 2-4-0
R-E170 CH3OCH3 Methoxymethane (dimethyl ether) A3 1.0 8,500 16 1,000
R-218 CF3CF2CF3 octafluoropropane A1 43 90,000 690 1,000 2-0-0b
R-227ea CF3CHFCF3 1,1,1,2,3,3,3-heptafluoropropane A1 36 84,000 580 1,000
R-236fa CF3CH2CF3 1,1,1,3,3,3-hexafluoropropane A1 21 55,000 340 1,000 2-0-0b
R-245fa CHF2CH2CF3 1,1,1,3,3-pentafluoropropane B1 12 34,000 190 300 2-0-0b
R-290 CH3CH2CH3 propane A3 0.56 5,300 9.5 1,000 2-4-0
R-C318 -(CF2)4- octafluorocyclobutane A1 41 80,000 660 1,000
R-400d zeotrope R-12/114 (50.0/50.0) A1 10 28,000 160 1,000 2-0-0b
R-400d zeotrope R-12/114 (60.0/40.0) A1 11 30,000 170 1,000
R-401A zeotrope R-22/152a/124 (53.0/13.0/34.0) A1 6.6 27,000 110 1,000 2-0-0b
R-401B zeotrope R-22/152a/124 (61.0/11.0/28.0) A1 7.2 30,000 120 1,000 2-0-0b
R-401C zeotrope R-22/152a/124 (33.0/15.0/52.0) A1 5.2 20,000 84 1,000 2-0-0b
R-402A zeotrope R-125/290/22 (60.0/2.0/38.0) A1 17 66,000 270 1,000 2-0-0b
R-402B zeotrope R-125/290/22 (38.0/2.0/60.0) A1 15 63,000 240 1,000 2-0-0b
R-403A zeotrope R-290/22/218 (5.0/75.0/20.0) A2 7.6 33,000 120 1,000 2-0-0b
R-403B zeotrope R-290/22/218 (5.0/56.0/39.0) A1 18 70,000 290 1,000 2-0-0b
R-404A zeotrope R-125/143a/134a (44.0/52.0/4.0) A1 31 130,000 500 1,000 2-0-0b
R-405A zeotrope R-22/152a/142b/C318 (45.0/7.0/5.5/42.5) 16 57,000 260 1,000
R-406A zeotrope R-22/600a/142b (55.0/4.0/41.0) A2 4.7 21,000 25 1,000
R-407A zeotrope R-32/125/134a (20.0/40.0/40.0) A1 19 83,000 300 1,000 2-0-0b
R-407B zeotrope R-32/125/134a (10.0/70.0/20.0) A1 21 79,000 330 1,000 2-0-0b
R-407C zeotrope R-32/125/134a (23.0/25.0/52.0) A1 18 81,000 290 1,000 2-0-0b
R-407D zeotrope R-32/125/134a (15.0/15.0/70.0) A1 16 68,000 250 1,000 2-0-0b
R-407E zeotrope R-32/125/134a (25.0/15.0/60.0) A1 17 80,000 280 1,000 2-0-0b
R-407F zeotrope R-32/125/134a (30.0/30.0/40.0) A1 20 95,000 320 1,000
R-407G zeotrope R-32/125/134a (2.5/2.5/95.0) A1 13 52,000 210 1,000
R-407H zeotrope R-32/125/134a (32.5/15.0/52.5) A1 19 92,000 300 1,000
R-408A zeotrope R-125/143a/22 (7.0/46.0/47.0) A1 21 95,000 340 1,000 2-0-0b
R-409A zeotrope R-22/124/142b (60.0/25.0/15.0) A1 7.1 29,000 110 1,000 2-0-0b
R-409B zeotrope R-22/124/142b (65.0/25.0/10.0) A1 7.3 30,000 120 1,000 2-0-0b
R-410A zeotrope R-32/125 (50.0/50.0) A1 26 140,000 420 1,000 2-0-0b
R-410B zeotrope R-32/125 (45.0/55.0) A1 27 140,000 430 1,000 2-0-0b
R-411A zeotrope R-127/22/152a (1.5/87.5/11.0) A2 2.9 14,000 46 990
R-411B zeotrope R-1270/22/152a (3.0/94.0/3.0) A2 2.8 13,000 45 980
R-412A zeotrope R-22/218/142b (70.0/5.0/25.0) A2 5.1 22,000 82 1,000
R-413A zeotrope R-218/134a/600a (9.0/88.0/3.0) A2 5.8 22,000 94 1,000
R-414A zeotrope R-22/124/600a/142b (51.0/28.5/4.0/16.5) A1 6.4 26,000 100 1,000
R-414B zeotrope R-22/124/600a/142b (50.0/39.0/1.5/9.5) A1 6.0 23,000 95 1,000
R-415A zeotrope R-22/152a (82.0/18.0) A2 2.9 14,000 47 1,000
R-415B zeotrope R-22/152a (25.0/75.0) A2 2.1 12,000 34 1,000
R-416A zeotrope R-134a/124/600 (59.0/39.5/1.5) A1 3.9 14,000 62 1,000 2-0-0b
R-417A zeotrope R-125/134a/600 (46.6/50.0/3.4) A1 3.5 13,000 56 1,000 2-0-0b
R-417B zeotrope R-125/134a/600 (79.0/18.3/2.7) A1 4.3 15,000 70 1,000
R-417C zeotrope R-125/134a/600 (19.5/78.8/1.7) A1 5.4 21,000 87 1,000
R-418A zeotrope R-290/22/152a (1.5/96.0/2.5) A2 4.8 22,000 77 1,000
R-419A zeotrope R-125/134a/E170 (77.0/19.0/4.0) A2 4.2 15,000 67 1,000
R-419B zeotrope R-125/134a/E170 (48.5/48.0/3.5) A2 4.6 17,000 74 1,000
R-420A zeotrope R-134a/142b (88.0/12.0) A1 12 45,000 190 1,000 2-0-0b
R-421A zeotrope R-125/134a (58.0/42.0) A1 17 61,000 280 1,000 2-0-0b
R-421B zeotrope R-125/134a (85.0/15.0) A1 21 69,000 330 1,000 2-0-0b
R-422A zeotrope R-125/134a/600a (85.1/11.5/3.4) A1 18 63,000 290 1,000 2-0-0b
R-422B zeotrope R-125/134a/600a (55.0/42.0/3.0) A1 16 56,000 250 1,000 2-0-0b
R-422C zeotrope R-125/134a/600a (82.0/15.0/3.0) A1 18 62,000 290 1,000 2-0-0b
R-422D zeotrope R-125/134a/600a (65.1/31.5/3.4) A1 16 58,000 260 1,000 2-0-0b
R-422E zeotrope R-125/134a/600a (58.0/39.3/2.7) A1 16 57,000 260 1,000
R-423A zeotrope R-134a/227ea (52.5/47.5) A1 19 59,000 310 1,000 2-0-0b
R-424A zeotrope R-125/134a/600a/600/601a (50.5/47.0/0.9/1.0/0.6) A1 6.2 23,000 100 970 2-0-0b
R-425A zoetrope R-32/134a/227ea (18.5/69.5/12.0) A1 16 72,000 260 1,000 2-0-0b
R-426A zeotrope R-125/134a/600a/601a (5.1/93.0/1.3/0.6) A1 5.2 20,000 83 990
R-427A zeotrope R-32/125/143a/134a (15.0/25.0/10.0/50.0) A1 18 79,000 290 1,000 2-1-0
R-428A zeotrope R-125/143a/290/600a (77.5/20.0/0.6/1.9) A1 23 83,000 370 1,000
R-429A zeotrope R-E170/152a/600a (60.0/10.0/30.0) A3 0.81 6,300 13 1,000
R-430A zeotrope R-152a/600a (76.0/24.0) A3 1.3 8,000 21 1,000
R-431A zeotrope R-290/152a (71.0/29.0) A3 0.69 5,500 11 1,000
R-432A zeotrope R-1270/E170 (80.0/20.0) A3 0.13 1,200 2.1 700
R-433A zeotrope R-1270/290 (30.0/70.0) A3 0.34 3,100 5.5 880
R-433B zeotrope R-1270/290 (5.0-95.0) A3 0.51 4,500 8.1 950
R-433C zeotrope R-1270/290 (25.0-75.0) A3 0.41 3,600 6.6 790
R-434A zeotrope R-125/143a/600a (63.2/18.0/16.0/2.8) A1 20 73,000 320 1,000
R-435A zeotrope R-E170/152a (80.0/20.0) A3 1.1 8,500 17 1,000
R-436A zeotrope R-290/600a (56.0/44.0) A3 0.50 4,000 8.1 1,000
R-436B zeotrope R-290/600a (52.0/48.0) A3 0.51 4,000 8.1 1,000
R-437A zeotrope R-125/134a/600/601 (19.5/78.5/1.4/0.6) A1 5.0 19,000 82 990
R-438A zeotrope R-32/125/134a/600/601a (8.5/45.0/44.2/1.7/0.6) A1 4.9 20,000 79 990
R-439A zeotrope R-32/125/600a (50.0/47.0/3.0) A2 4.7 26,000 76 990
R-440A zeotrope R-290/134a/152a (0.6/1.6/97.8) A2 1.9 12,000 31 1,000
R-441A zeotrope R-170/290/600a/600 (3.1/54.8/6.0/36.1) A3 0.39 3,200 6.3 1,000
R-442A zeotrope R-32/125/134a/152a/227ea (31.0/31.0/30.0/3.0/5.0) A1 21 100,000 330 1,000
R-443A zeotrope R-1270/290/600a (55.0/40.0/5.0) A3 0.19 1,700 3.1 580
R-444A zeotrope R-32/152a/1234ze(E) (12.0/5.0/83.0) A2c 5.1 21,000 81 850
R-444B zeotrope R-32/152a/1234ze(E) (41.5/10.0/48.5) A2c 4.3 23,000 69 890
R-445A zeotrope R-744/134a/1234ze(E) (6.0/9.0/85.0) A2c 4.2 16,000 67 930
R-446A zeotrope R-32/1234ze(E)/600 (68.0/29.0/3.0) A2c 2.5 16,000 39 960
R-447A zeotrope R-32/125/1234ze(E) (68.0/3.5/28.5) A2c 2.6 16,000 42 900
R-447B zeotrope R-32/125/1234ze(E) (68.0/8.0/24.0) A2c 23 30,000 360 970
R-448A zeotrope R-32/125/1234yf/134a/1234ze(E) (26.0/26.0/20.0/21.0/7.0) A1 24 110,000 390 890
R-449A zeotrope R-32/125/1234yf/134a (24.3/24.7/25.3/25.7) A1 23 100,000 370 830
R-449B zeotrope R-32/125/1234yf/134a (25.2/24.3/23.2/27.3) A1 23 100,000 370 850
R-449C zeotrope R-32/125/1234yf/134a (20.0/20.0/31.0/29.0) A1 23 98,000 360 800
R-450A zeotrope R-134a/1234ze(E) (42.0/58.0) A1 20 72,000 320 880
R-451A zeotrope R-1234yf/134a (89.8/10.2) A2c 5.3 18,000 81 520
R-451B zeotrope R-1234yf/134a (88.8/11.2) A2c 5.3 18,000 81 530
R-452A zeotrope R-32/125/1234yf (11.0/59.0/30.0) A1 27 10,000 440 780
R-452B zeotrope R-32/125/1234yf (67.0/7.0/26.0) A2c 23 30,000 360 870
R-452C zeotrope R-32/125/1234yf (12.5/61.0/26.5) A1 27 100,000 430 800
R-453A zeotrope R-32/125/134a/227ea/600/601a (20.0/20.0/53.8/5.0/0.6/0.6) A1 7.8 34,000 120 1,000
R-454A zeotrope R-32/1234yf (35.0/65.0) A2c 28 16,000 450 690
R-454B zeotrope R-32/1234yf (68.9/31.1) A2c 22 19,000 360 850
R-454C zeotrope R-32/1234yf (21.5/78.5) A2c 29 19,000 460 620
R-455A zeotrope R-744/32/1234yf (3.0/21.5/75.5) A2c 23 30,000 380 650
R-456A zeotrope R-32/134a/1234ze(E) (6.0/45.0/49.0) A1 20 77,000 320 900
R-457A zeotrope R-32/1234yf/152a (18.0/70.0/12.0) A2c 25 15,000 400 650
R-458A zeotrope R-32/125/134a/227ea/236fa (20.5/4.0/61.4/13.5/0.6) A1 18 76,000 280 1,000
R-459A zeotrope R-32/1234yf/1234ze(E) (68.0/26.0/6.0) A2c 23 27,000 360 870
R-459B zeotrope R-32/1234yf/1234ze(E) (21.0/69.0/10.0) A2c 30 16,000 470 640
R-460A zeotrope R-32/125/134a/1234ze(E) (12.0/52.0/14.0/22.0) A1 24 92,000 380 650
R-460B zeotrope R-32/125/134a/1234ze(E) (28.0/25.0/20.0/27.0) A1 25 120,000 400 950
R-461A zeotrope R-125/143a/134a/227ea/600a (55.0/5.0/32.0/5.0/3.0) A1 17 61,000 270 1,000
R-462A zeotrope R-32/125/143a/134a/600 (9.0/42.0/2.0/44.0/3.0) A2 3.9 16,000 62 1,000
R-463A zeotrope R-744/32/125/1234yf/134a (6.0/36.0/30.0/14.0/14.0) A1 19 98,000 300 990
R-500e azeotrope R-12/152a (73.8/26.2) A1 7.6 30,000 120 1,000 2-0-0b
R-501d azeotrope R-22/12 (75.0/25.0) A1 13 54,000 210 1,000
R-502e azeotrope R-22/115 (48.8/51.2) A1 21 73,000 330 1,000 2-0-0b
R-503e azeotrope R-23/13 (40.1/59.9) 1,000 2-0-0b
R-504d azeotrope R-32/115 (48.2/51.8) 28 140,000 450 1,000
R-507A azeotrope R-125/143a (50.0/50.0) A1 32 130,000 520 1,000 2-0-0b
R-508A azeotrope R-23/116 (39.0/61.0) A1 14 55,000 220 1,000 2-0-0b
R-508B azeotrope R-23/116 (46.0/54.0) A1 13 52,000 200 1,000 2-0-0b
R-509A azeotrope R-22/218 (44.0/56.0) A1 24 75,000 390 1,000 2-0-0b
R-510A azeotrope R-E170/600a (88.0/12.0) A3 0.87 7,300 14 1,000
R-511A azeotrope R-290/E170 (95.0/5.0) A3 0.59 5,300 9.5 1,000
R-512A azeotrope R-134a/152a (5.0/95.0) A2 1.9 11,000 31 1,000
R-513A azeotrope R-1234yf/134a (56.0/44.0) A1 20 72,000 320 650
R-513B azeotrope R-1234yf/134a (58.5/41.5) A1 21 74,000 330 640
R-514A azeotrope R-1336mzz(S)/1130(E) (74.7/25.3) B1 0.86 2,400 14 320
R-515A azeotrope R-1234ze(E)/227ea (88.0/12.0) A1 19 62,000 300 810
R-516A azeotrope R-1234yf/134a/152a (77.5/8.5/14.0) A2 7.0 27,000 110 590
R-600 CH3CH2CH2CH3 butane A3 0.15 1,000 2.4 1,000 1-4-0
R-600a CH(CH3)2CH3 2-methylpropane (isobutane) A3 0.59 4,000 9.6 1,000 2-4-0
R-601 CH3CH2CH2 CH2CH3 pentane A3 0.18 1,000 2.9 600
R-601a (CH3)2CHCH2CH3 2-methylbutane (isopentane) A3 0.18 1,000 2.9 600
R-610 CH3CH2OCH2CH3 ethoxyethane (ethyl ether) 400
R-611 HCOOCH3 methyl formate B2 100
R-718 H2O water A1 0-0-0
R-744 CO2 carbon dioxide A1 4.5 40,000 72 5,000 2-0-0b
R-1130(E) CHCl=CHCl trans-1,2-dichloroethene B1 0.25 1,000 4 200
R-1132a CF2=CH2 1,1-difluoroethylene A2 2.0 13,000 33 500
R-1150 CH2=CH2 ethene (ethylene) A3 200 1-4-2
R-1224yd(Z) CF3CF=CHCl (Z)-1-chloro-2,3,3,3-tetrafluoroethylene A1 23 60,000 360 1,000
R-1233zd(E) CF3CH=CHCl trans-1-chloro-3,3,3-trifluoro-1-propene A1 5.3 16,000 85 800
R-1234yf CF3CF=CH2 2,3,3,3-tetrafluoro-1-propene A2c 4.7 16,000 75 500
R-1234ze(E) CF3CH=CHF trans-1,3,3,3-tetrafluoro-1-propene A2c 4.7 16,000 75 800
R-1270 CH3CH=CH2 Propene (propylene) A3 0.1 1,000 1.7 500 1-4-1
R-1336mzz(Z) CF3CHCHCF3 cis-1,1,1,4,4,4-hexaflouro-2-butene A1 5.4 13,000 87 500

For SI: 1 pound = 0.454 kg, 1 cubic foot = 0.0283m3

  1. Degrees of hazard are for health, fire, and reactivity, respectively, in accordance with NFPA 704.
  2. Reduction to 1-0-0 is allowed if analysis satisfactory to the code official shows that the maximum concentration for a rupture or full loss of refrigerant charge would not exceed the IDLH, considering both the refrigerant quantity and room volume.
  3. The ASHRAE Standard 34 flammability classification for this refrigerant is 2L, which is a subclass of Class 2.
  4. Class I ozone depleting substance; prohibited for new installations.
  5. Occupational Exposure Limit based on the OSHA PEL, ACGIH TLV-TWA, the TERA WEEL or consistent value on a time-weighed average (TWA) basis (unless noted C for ceiling) for an 8 hr/d and 40 hr/wk.
Locations of refrigerating systems are described by occupancy classifications that consider the ability of people to respond to potential exposure to refrigerants. Where equipment or appliances, other than piping, are located outside a building and within 20 feet (6096 mm) of any building opening, such equipment or appliances shall be governed by the occupancy classification of the building. Occupancy classifications shall be defined as follows:
  1. Institutional occupancy is that portion of premises from which occupants cannot readily leave without the assistance of others because they are disabled, debilitated or confined. Institutional occupancies include, among others, hospitals, nursing homes, asylums and spaces containing locked cells.
  2. Public assembly occupancy is that portion of premises where large numbers of people congregate and from which occupants cannot quickly vacate the space. Public assembly occupancies include, among others, auditoriums, ballrooms, classrooms, passenger depots, restaurants and theaters.
  3. Residential occupancy is that portion of premises that provides the occupants with complete independent living facilities, including permanent provisions for living, sleeping, eating, cooking and sanitation. Residential occupancies include, among others, dormitories, hotels, multiunit apartments and private residences.
  4. Commercial occupancy is that portion of premises where people transact business, receive personal service or purchase food and other goods. Commercial occupancies include, among others, office and professional buildings, markets (but not large mercantile occupancies) and work or storage areas that do not qualify as industrial occupancies.
  5. Large mercantile occupancy is that portion of premises where more than 100 persons congregate on levels above or below street level to purchase personal merchandise.
  6. Industrial occupancy is that portion of premises that is not open to the public, where access by authorized persons is controlled, and that is used to manufacture, process or store goods such as chemicals, food, ice, meat or petroleum.
  7. Mixed occupancy occurs where two or more occupancies are located within the same building. Where each occupancy is isolated from the rest of the building by tight walls, floors and ceilings and by self-closing doors, the requirements for each occupancy shall apply to its portion of the building. Where the various occupancies are not so isolated, the occupancy having the most stringent requirements shall be the governing occupancy.
Refrigeration systems shall be classified according to the degree of probability that refrigerant leaked from a failed connection, seal or component could enter an occupied area. The distinction is based on the basic design or location of the components.
Double-indirect open-spray systems, indirect closed systems and indirect-vented closed systems shall be classified as low-probability systems, provided that all refrigerant-containing piping and fittings are isolated where the quantities in Table 1103.1 are exceeded.

Direct systems and indirect open-spray systems shall be classified as high-probability systems.

Exception: An indirect open-spray system shall not be required to be classified as a high-probability system if the pressure of the secondary coolant is at all times (operating and standby) greater than the pressure of the refrigerant.
The refrigerant, occupancy and system classification cited in this section shall be determined in accordance with Sections 1103.1, 1103.2 and 1103.3, respectively.
Except as provided in Sections 1104.2.1 and 1104.2.2, all components containing the refrigerant shall be located either outdoors or in a machinery room where the quantity of refrigerant in an independent circuit of a system exceeds the amounts shown in Table 1103.1. For refrigerant blends not listed in Table 1103.1, the same requirement shall apply where the amount for any blend component exceeds that indicated in Table 1103.1 for that component. This requirement shall also apply where the combined amount of the blend components exceeds a limit of 69,100 parts per million (ppm) by volume. Machinery rooms required by this section shall be constructed and maintained in accordance with Section 1105 for Group A1 and B1 refrigerants and in accordance with Sections 1105 and 1106 for Group A2, B2, A3 and B3 refrigerants.

Exceptions:

  1. Machinery rooms are not required for listed equipment and appliances containing not more than 6.6 pounds (3 kg) of refrigerant, regardless of the refrigerant's safety classification, where installed in accordance with the equipment's or appliance's listing and the equipment or appliance manufacturer's installation instructions.
  2. Piping in compliance with Section 1107 is allowed in other locations to connect components installed in a machinery room with those installed outdoors.
The amounts shown in Table 1103.1 shall be reduced by 50 percent for all areas of institutional occupancies except kitchens, laboratories and mortuaries. The total of all Group A2, B2, A3 and B3 refrigerants shall not exceed 550 pounds (250 kg) in occupied areas or machinery rooms.
This section applies only to rooms and spaces that: are within industrial occupancies; contain a refrigerant evaporator; are maintained at temperatures below 68°F (20°C); and are used for manufacturing, food and beverage preparation, meat cutting, other processes and storage. Where a machinery room would otherwise be required by Section 1104.2, a machinery room shall not be required where all of the following conditions are met:
  1. The space containing the machinery is separated from other occupancies by tight construction with tight-fitting doors.
  2. Access is restricted to authorized personnel.
  3. Refrigerant detectors are installed as required for machinery rooms in accordance with Section 1105.3.

    Exception: Refrigerant detectors are not required in unoccupied areas that contain only continuous piping that does not include valves, valve assemblies, equipment or equipment connections.

  4. Surfaces having temperatures exceeding 800°F (427°C) and open flames are not present where any Group A2, B2, A3 or B3 refrigerant is used (see Section 1104.3.4).
  5. All electrical equipment and appliances conform to Class I, Division 2, hazardous location classification requirements of NFPA 70 where the quantity of any Group A2, B2, A3 or B3 refrigerant in a single independent circuit would exceed 25 percent of the lower flammability limit (LFL) upon release to the space.
  6. All refrigerant-containing parts in systems with a total connected compressor power exceeding 100 horsepower (hp) (74.6 kW)—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 either outdoors or in a machinery room.
Refrigerant applications, maximum quantities and use shall be restricted in accordance with Sections 1104.3.1 through 1104.3.4.
In other than industrial occupancies where the quantity in a single independent circuit does not exceed the amount in Table 1103.1, Group B1, B2 and B3 refrigerants shall not be used in high-probability systems for air conditioning for human comfort.

Group A2 and B2 refrigerants shall not be used in high-probability systems where the quantity of refrigerant in any independent refrigerant circuit exceeds the amount shown in Table 1104.3.2. Group A3 and B3 refrigerants shall not be used except where approved.

Exception: This section does not apply to laboratories where the floor area per occupant is not less than 100 square feet (9.3 m2).

TABLE 1104.3.2

MAXIMUM PERMISSIBLE QUANTITIES OF REFRIGERANTS

TYPE OF REFRIGERATION SYSTEM MAXIMUM POUNDS FOR VARIOUS OCCUPANCIES
Institutional Public assembly Residential All other occupancies
Sealed absorption system        
In exit access
0 0 3.3 3.3
In adjacent outdoor locations
0 0 22 22
In other than exit access
0 6.6 6.6 6.6
Unit systems        
In other than exit access
0 0 6.6 6.6

For SI: 1 pound = 0.454 kg.

The total of all Group A2, B2, A3 and B3 refrigerants shall not exceed 1,100 pounds (499 kg) except where approved.
Where any device having an open flame or surface temperature greater than 800°F (427°C) is used in a room containing more than 6.6 pounds (3 kg) of refrigerant in a single independent circuit, a hood and exhaust system shall be provided in accordance with Section 510. Such exhaust system shall exhaust combustion products to the outdoors.

Exception: A hood and exhaust system shall not be required where any of the following apply:

  1. The refrigerant is R-718 (water) or R-744 (carbon dioxide).
  2. The combustion air is ducted from the outdoors in a manner that prevents leaked refrigerant from being combusted.
  3. A refrigerant detector is used to stop the combustion in the event of a refrigerant leak (see Sections 1105.3 and 1105.5).
Volume calculations shall be in accordance with Sections 1104.4.1 through 1104.4.3.
Where the refrigerant-containing parts of a system are located in one or more spaces that do not communicate through permanent openings or HVAC ducts, the volume of the smallest, enclosed occupied space shall be used to determine the permissible quantity of refrigerant in the system.

Where an evaporator or condenser is located in an air duct system, the volume of the smallest, enclosed occupied space served by the duct system shall be used to determine the maximum allowable quantity of refrigerant in the system.

Exception: If airflow to any enclosed space cannot be reduced below one-quarter of its maximum, the entire space served by the air duct system shall be used to determine the maximum allowable quantity of refrigerant in the system.
Where the space above a suspended ceiling is continuous and part of the supply or return air plenum system, this space shall be included in calculating the volume of the enclosed space.
Machinery rooms shall be designed and constructed in accordance with the International Building Code and this section.
Ducts and air handlers in the machinery room that operate at a lower pressure than the room shall be sealed to prevent any refrigerant leakage from entering the airstream.
Refrigerant detectors in machinery rooms shall be provided as required by Sections 608.9 and 608.18 of the International Fire Code.
Periodic tests of the mechanical ventilating system shall be performed in accordance with manufacturer's specifications and as required by the code official.
Fuel-burning appliances and equipment having open flames and that use combustion air from the machinery room shall not be installed in a machinery room.

Exceptions:

  1. Where the refrigerant is water (R-718) or carbon dioxide (R-744).
  2. Fuel-burning appliances shall not be prohibited in the same machinery room with refrigerant-containing equipment or appliances where combustion air is ducted from outside the machinery room and sealed in such a manner as to prevent any refrigerant leakage from entering the combustion chamber, or where a refrigerant vapor detector is employed to automatically shut off the combustion process in the event of refrigerant leakage.
Machinery rooms shall be mechanically ventilated to the outdoors.

Exception: Where a refrigerating system is located outdoors more than 20 feet (6096 mm) from any building opening and is enclosed by a penthouse, lean-to or other open structure, natural or mechanical ventilation shall be provided. Location of the openings shall be based on the relative density of the refrigerant to air. The free-aperture cross section for the ventilation of the machinery room shall be not less than:

(Equation 11-1)

For SI:

where:

= The free opening area in square feet (m2).

G = The mass of refrigerant in pounds (kg) in the largest system, any part of which is located in the machinery room.

The discharge of the air shall be to the outdoors in accordance with Chapter 5. Exhaust from mechanical ventilation systems shall be discharged not less than 20 feet (6096 mm) from a property line or openings into buildings.
Indoor mechanical exhaust intake openings shall be located where refrigerant leakage is likely to concentrate based on the refrigerant's relative density to air, and the locations of the air current paths and refrigerating machinery.
Provisions shall be made for makeup air to replace that being exhausted. Openings for makeup air shall be located to avoid intake of exhaust air. Supply and exhaust ducts to the machinery room shall not serve any other area, shall be constructed in accordance with Chapter 5 and shall be covered with corrosion-resistant screen of not less than 1/4-inch (6.4 mm) mesh.
Mechanical ventilation systems shall be capable of exhausting the minimum quantity of air both at normal operating and emergency conditions, as required by Sections 1105.6.3.1 and 1105.6.3.2. Multiple fans or multispeed fans shall be allowed to produce the emergency ventilation rate and to obtain a reduced airflow for normal ventilation.

During occupied conditions, the mechanical ventilation system shall exhaust the larger of the following:

  1. Not less than 0.5 cfm per square foot (0.0025 m3/s • m2) of machinery room area or 20 cfm (0.009 m3/s) per person.
  2. A volume required to limit the room temperature rise to 18°F (10°C) taking into account the ambient heating effect of all machinery in the room.
Upon actuation of the refrigerant detector required in Section 1105.3, the mechanical ventilation system shall exhaust air from the machinery room in the following quantity:
(Equation 11-2)

For SI:

where:

= The airflow in cubic feet per minute (m3/s).

G = The design mass of refrigerant in pounds (kg) in the largest system, any part of which is located in the machinery room.

Pressure relief devices, fusible plugs and purge systems located within the machinery room shall terminate outside of the structure at a location not less than 15 feet (4572 mm) above the adjoining grade level and not less than 20 feet (6096 mm) from any window, ventilation opening or exit.
Emergency pressure control systems shall be provided in accordance with Section 608.11 of the International Fire Code.
Machinery rooms larger than 1,000 square feet (93 m2) shall have not less than two exits or exit access doorways. Where two exit access doorways are required, one such doorway is permitted to be served by a fixed ladder or an alternating tread device. Exit access doorways shall be separated by a horizontal distance equal to one-half the maximum horizontal dimension of the room. All portions of machinery rooms shall be within 150 feet (45 720 mm) of an exit or exit access doorway. An increase in exit access travel distance is permitted in accordance with Section 1017.1 of the International Building Code. Exit and exit access doorways shall swing in the direction of egress travel and shall be equipped with panic hardware, regardless of the occupant load served. Exit and exit access doorways shall be tight fitting and self-closing.
Where required by Section 1104.2, the machinery room shall meet the requirements of this section in addition to the requirements of Section 1105.
There shall not be an open flame-producing device or continuously operating hot surface over 800°F (427°C) permanently installed in the room.
Where refrigerants of Groups A2, A3, B2 and B3 are used, the machinery room shall conform to the Class I, Division 2, hazardous location classification requirements of NFPA 70.

Exception: Machinery rooms for systems containing Group A2L refrigerants that are provided with ventilation in accordance with Section 1106.4.

Machinery rooms with systems containing Group A2L refrigerants that do not conform to the Class I, Division 2, hazardous location electrical requirements of NFPA 70, as permitted by the exception to Section 1106.3, shall comply with Sections 1106.4.1 through 1106.4.3.
Exception: Machinery rooms conforming to the Class I, Division 2, hazardous location classification requirements of NFPA 70 are not required to comply with Sections 1106.4.1 and 1106.4.2.
Ventilation shall be activated by the refrigerant detection system in the machinery room. Refrigerant detection systems shall be in accordance with Section 608.9 of the International Fire Code and all of the following:
  1. The detectors shall activate at or below a refrigerant concentration of 25 percent of the LFL.
  2. Upon activation, the detection system shall activate the emergency ventilation system required by Section 1106.4.2.
  3. The detection, signaling and control circuits shall be supervised.
An emergency ventilation system shall be provided at the minimum exhaust rate specified in ASHRAE 15 or Table 1106.4.2. Shutdown of the emergency ventilation system shall be by manual means.

TABLE 1106.4.2

MINIMUM EXHAUST RATES

REFRIGERANT Q(m/sec) Q(cfm)
R32 15.4 32,600
R143 13.6 28,700
R444A 6.46 13,700
R444B 10.6 22,400
R445A 7.83 16,600
R446A 23.9 50,700
R447A 23.8 50,400
R451A 7.04 15,000
R451B 7.05 15,000
R1234yf 7.80 16,600
R1234ze(E) 5.92 12,600
The emergency ventilation system point of discharge to the atmosphere shall be located outside of the structure at not less than 15 feet (4572 mm) above the adjoining grade level and not less than 20 feet (6096 mm) from any window, ventilation opening or exit.
Remote control of the mechanical equipment and appliances located in the machinery room shall comply with Sections 1106.5.1 and 1106.5.2.
A clearly identified switch of the break-glass type or with an approved tamper-resistant cover shall provide off-only control of refrigerant compressors, refrigerant pumps, and normally closed, automatic refrigerant valves located in the machinery room. Additionally, this equipment shall be automatically shut off whenever the refrigerant vapor concentration in the machinery room exceeds the vapor detector's upper detection limit or 25 percent of the LEL, whichever is lower.
A clearly identified switch of the break-glass type or with an approved tamper-resistant cover shall provide on-only control of the machinery room ventilation fans.
Refrigeration units and systems shall be provided with approved emergency signs, charts, and labels in accordance with the International Fire Code.
Refrigerant piping material for other than R-717 (ammonia) systems shall conform to the requirements in this section. Piping material and installations for R-717 (ammonia) refrigeration systems shall comply with IIAR 2.
Used pipe, fittings, valves and other materials that are to be reused shall be clean and free from foreign materials and shall be approved for reuse.
Materials, joints and connections shall be rated for the operating temperature and pressure of the refrigerant system. Materials shall be suitable for the type of refrigerant and type of lubricant in the refrigerant system. Magnesium alloys shall not be used in contact with any halogenated refrigerants. Aluminum, zinc, magnesium and their alloys shall not be used in contact with R-40 (methyl chloride).
Refrigerant pipe shall conform to one or more of the standards listed in Table 1107.4. The exterior of the pipe shall be protected from corrosion and degradation.

TABLE 1107.4

REFRIGERANT PIPE

PIPING MATERIAL STANDARD
Aluminum tube ASTM B210/ASTM B210M, ASTM B491/B491M
Brass (copper alloy) pipe ASTM B43
Copper linesets ASTM B280, ASTM B1003
Copper pipe ASTM B42, ASTM B302
Copper tubea ASTM B68, ASTM B75, ASTM B88, ASTM B280, ASTM B819
Steel pipeb ASTM A53, ASTM A106
Steel tube ASTM A254, ASTM A334
  1. Soft annealed copper tubing larger than 13/8 inch (35 mm) O.D. shall not be used for field-assembled refrigerant piping unless it is protected from mechanical damage.
  2. ASTM A53, Type F steel pipe shall not be used for refrigerant lines having an operating temperature less than -20°F (-29°C).
The minimum weight of steel pipe for Group A2, A3, B2 and B3 refrigerants shall be Schedule 80 for sizes 11/2 inches or less in diameter.
Refrigerant pipe fittings shall be approved for installation with the piping materials to be installed, and shall conform to one of more of the standards listed in Table 1107.5 or shall be listed and labeled as complying with UL 207.

TABLE 1107.5

REFRIGERANT PIPE FITTINGS

FITTING MATERIAL STANDARD
Aluminum ASTM B361
Brass (copper alloy) ASME B16.15, ASME B16.24
Copper ASME B16.15, ASME B16.18, ASME B16.22, ASME B16.24, ASME B16.26, ASME B16.50
Steel ASTM A105, ASTM A181, ASTM A193, ASTM A234, ASTM A420, ASTM A707
The minimum and maximum cup depth of field-fabricated copper brazed swaged fitting connections shall comply with Table 1107.5.1.

TABLE 1107.5.1

COPPER BRAZED SWAGED CUP DEPTHS

FITTING SIZE (inch) MINIMUM DEPTH (inch) MAXIMUM DEPTH (inch)
1/8 0.15 0.23
3/16 0.16 0.24
1/4 0.17 0.26
3/8 0.20 0.30
1/2 0.22 0.33
5/8 0.24 0.36
3/4 0.25 0.38
1 0.28 0.42
11/4 0.31 0.47
11/2 0.34 0.51
2 0.40 0.60
21/2 0.47 0.71
3 0.53 0.80
31/2 0.59 0.89
4 0.64 0.96
For SI: 1 inch = 25.4 mm.
Valves shall be of materials that are compatible with the type of piping material, refrigerants and oils in the system. Valves shall be listed and labeled and rated for the temperatures and pressures of the refrigerant systems in which the valves are installed.
Flexible connectors and expansion and vibration control devices shall be listed and labeled for use in refrigerant systems.
Joints and connections shall be of an approved type. Joints and connections shall be tight for the pressure of the refrigerant system when tested in accordance with Section 1110.
Joints between different piping materials shall be made with approved adapter fittings. Joints between dissimilar metallic piping materials shall be made with a dielectric fitting or a dielectric union conforming to dielectric tests of ASSE 1079. Adapter fittings with threaded ends between different materials shall be joined with thread lubricant in accordance with Section 1108.3.4.
Pipe shall be cut square, reamed and chamfered, and shall be free from burrs and obstructions. Pipe ends shall have full-bore openings and shall not be undercut.
Where required by Sections 1108.4 through 1108.9, the preparation and installation of brazed, flared, mechanical, press-connect, soldered, threaded and welded joints shall comply with Sections 1108.3.1 through 1108.3.5.
Joint surfaces shall be cleaned. An approved flux shall be applied where required by the braze filler metal manufacturer. The piping being brazed shall be purged of air to remove the oxygen and filled with one of the following inert gases: oxygen-free nitrogen, helium or argon. The piping system shall be pre-purged with an inert gas for a minimum time corresponding to five volume changes through the piping system prior to brazing. The pre-purge rate shall be at a minimum velocity of 100 feet per minute (0.508 m/s). The inert gas shall be directly connected to the tube system being brazed to prevent the entrainment of ambient air. After the pre-purge, the inert gas supply shall be maintained through the piping during the brazing operation at a minimum pressure of 1.0 psi (6.89 kPa) and a maximum pressure of 3.0 psi (20.67 kPa). The joint shall be brazed with a filler metal conforming to AWS A5.8.
Mechanical joints shall be installed in accordance with the manufacturer's instructions.
Flared fittings shall be installed in accordance with the manufacturer's instructions. The flared fitting shall be used with the tube material specified by the fitting manufacturer. The flared tube end shall be made by a tool designed for that operation.
Press-connect joints shall be installed in accordance with the manufacturer's instructions.
Joint surfaces to be soldered shall be cleaned and a flux conforming to ASTM B813 shall be applied. The joint shall be soldered with a solder conforming to ASTM B32. Solder joints shall be limited to refrigerant systems using Group A1 refrigerant and having a pressure of less than or equal to 200 psi (1378 kPa).
Threads shall conform to ASME B1.1, ASME B1.13M, ASME B1.20.1 or ASME B1.20.3. Thread lubricant, pipe-joint compound or thread tape shall be applied on the external threads only and shall be approved for application on the piping material.
Joint surfaces to be welded shall be cleaned by an approved procedure. Joints shall be welded with an approved filler metal.
Joints between aluminum tubing or fittings shall be brazed, mechanical, press-connect or welded joints conforming to Section 1108.3.
Joints between brass pipe or fittings shall be brazed, mechanical, press-connect, threaded or welded joints conforming to Section 1108.3.
Joints between copper or copper-alloy pipe or fittings shall be brazed, mechanical, press-connect, soldered, threaded or welded joints conforming to Section 1108.3.
Joints between copper or copper-alloy tubing or fittings shall be brazed, flared, mechanical, press-connect or soldered joints.
Joints between steel pipe or fittings shall be mechanical joints, threaded, press-connect or welded joints conforming to Section 1108.3.
Joints between steel tubing or fittings shall be flared, mechanical, press-connect or welded joints conforming to Section 1108.3.
Refrigerant piping installations, other than R-717 (ammonia) refrigeration systems, shall comply with the requirements of this section. The design of refrigerant piping shall be in accordance with ASME B31.5.
Refrigerant piping shall comply with the installation location requirements of Sections 1109.2.1 through 1109.2.7. Refrigerant piping for Groups A2L and B2L shall also comply with the requirements of Section 1109.3. Refrigerant piping for Groups A2, A3, B2 and B3 shall also comply with the requirements of Section 1109.4.
Exposed refrigerant piping installed in open spaces that afford passage shall be not less than 7 feet 3 inches (2210 mm) above the finished floor.
Refrigerant piping shall be protected by locating it within the building elements or within protective enclosures.

Exception: Piping protection within the building elements or protective enclosure shall not be required in any of the following locations:

  1. Where installed without ready access or located more than 7 feet 3 inches (2210 mm) above the finished floor.
  2. Where located within 6 feet (1829 mm) of the refrigerant unit or appliance.
  3. Where located in a machinery room complying with Section 1105.
Refrigerant piping shall not be installed in any of the following locations:
  1. Exposed within a fire-resistance-rated exit access corridor.
  2. Within an interior exit stairway.
  3. Within an interior exit ramp.
  4. Within an exit passageway.
  5. Within an elevator, dumbwaiter or other shaft containing a moving object.
Refrigerant piping installed in concrete floors shall be encased in pipe, conduit or ducts. The piping shall be protected to prevent damage from vibration, stress and corrosion.
Refrigerant piping that penetrates two or more floor/ceiling assemblies shall be enclosed in a fire-resistance-rated shaft enclosure. The fire-resistance-rated shaft enclosure shall comply with Section 713 of the International Building Code.

Exceptions:

  1. Systems using R-718 refrigerant (water).
  2. Piping in a direct system using Group A1 refrigerant where the refrigerant quantity does not exceed the limits of Table 1103.1 for the smallest occupied space through which the piping passes.
  3. Piping located on the exterior of the building where vented to the outdoors.
Exposed piping with ready access having surface temperatures greater than 120°F (49°C) or less than 5°F (-15°C) shall be protected from contact or shall have thermal insulation that limits the exposed insulation surface temperature to a range of 5°F (-15°C) to 120°F (49°C).
Refrigerant pipe located in areas other than the room or space where the refrigerating equipment is located shall be identified. The pipe identification shall be located at intervals not exceeding 20 feet (6096 mm) on the refrigerant piping or pipe insulation. The minimum height of lettering of the identification label shall be 1/2 inch (12.7 mm). The identification shall indicate the refrigerant designation and safety group classification of refrigerant used in the piping system. For Group A2, A3, B2 and B3 refrigerants, the identification shall also include the following statement: "DANGER—Risk of Fire or Explosion. Flammable Refrigerant." For any Group B refrigerant, the identification shall also include the following statement: "DANGER—Toxic Refrigerant."
Piping systems using Group A2L or B2L refrigerant shall comply with the requirements of Sections 1109.3.1 and 1109.3.2.
In addition to the requirements of Section 305.5, aluminum, copper and steel tube used for Group A2L and B2L refrigerants and located in concealed locations where tubing is installed in studs, joists, rafters or similar member spaces, and located less than 11/2 inches (38 mm) from the nearest edge of the member, shall be continuously protected by shield plates. Protective steel shield plates having a minimum thickness of 0.0575 inch (1.46 mm) (No. 16 gage) shall cover the area of the tube plus the area extending not less than 2 inches (51 mm) beyond both sides of the tube.
Refrigerant pipe shafts with systems using Group A2L or B2L refrigerant shall be naturally or mechanically ventilated. The shaft ventilation exhaust outlet shall comply with Section 501.3.1. Naturally ventilated shafts shall have a pipe, duct or conduit not less than 4 inches (102 mm) in diameter that connects to the lowest point of the shaft and extends to the outdoors. The pipe, duct or conduit shall be level or pitched downward to the outdoors. Mechanically ventilated shafts shall have a minimum airflow velocity in accordance with Table 1109.3.2. The mechanical ventilation shall be continuously operated or activated by a refrigerant detector. Systems utilizing a refrigerant detector shall activate the mechanical ventilation at a maximum refrigerant concentration of 25 percent of the lower flammable limit of the refrigerant. The detector, or a sampling tube that draws air to the detector, shall be located in an area where refrigerant from a leak will concentrate. The shaft shall not be required to be ventilated for double-wall refrigerant pipe where the interstitial space of the double-wall pipe is vented to the outdoors.

TABLE 1109.3.2

SHAFT VENTILATION VELOCITY

CROSS-SECTIONAL AREA OF SHAFT (square inches) MINIMUM VENTILATION VELOCITY (feet per minute)
≤ 20 100
> 20 ≤ 250 200
> 250 ≤ 1,250 300
> 1,250 400
For SI: 1 square inch = 645 mm2; 1 foot per minute = 0.0058 m/s.
Piping systems using Group A2, A3, B2 or B3 refrigerant shall comply with the requirements of Sections 1109.4.1 and 1109.4.2.
Piping material for Group A2, A3, B2 or B3 refrigerant located inside the building, except for machinery rooms, shall be copper pipe, brass pipe or steel pipe. Pipe joints located in areas other than the machinery room shall be welded. Self-contained listed and labeled equipment or appliances shall have piping material based on the listing requirements.
Refrigerant pipe shafts with systems using Group A2, A3, B2 or B3 refrigerant shall be continuously mechanically ventilated. The shaft ventilation exhaust outlet shall comply with Section 501.3.1. Mechanically ventilated shafts shall have a minimum airflow velocity as specified in Table 1109.3.2. The shaft shall not be required to be ventilated for double-wall refrigerant pipe where the interstitial space of the double-wall pipe is vented to the outdoors.
The annular space between the outside of a refrigerant pipe and the inside of a pipe sleeve or opening in a building envelope wall, floor or ceiling assembly penetrated by a refrigerant pipe shall be sealed in an approved manner with caulking material or foam sealant or closed with a gasketing system. The caulking material, foam sealant or gasketing system shall be designed for the conditions at the penetration location and shall be compatible with the pipe, sleeve and building materials in contact with the sealing materials. Refrigerant pipes penetrating fire-resistance-rated assemblies or membranes of fire-resistance-rated assemblies shall be sealed or closed in accordance with Section 714 of the International Building Code.
Refrigerant piping shall be installed so as to prevent strains and stresses that exceed the structural strength of the pipe. Where necessary, provisions shall be made to protect piping from damage resulting from vibration, expansion, contraction and structural settlement.
Refrigerating piping and fittings that, during normal operation, will reach a surface temperature below the dew point of the surrounding air, and are located in spaces or areas where condensation has the potential to cause a safety hazard to the building occupants, structure, electrical equipment or any other equipment or appliances, shall be insulated or protected in an approved manner to prevent damage from condensation.
Stop valves shall be installed in specified locations in accordance with Sections 1109.8.1 and 1109.8.2. Stop valves shall be supported in accordance with  Section 1109.8.3 and identified in accordance with Section 1109.8.4.

Exceptions:

  1. Systems that have a refrigerant pumpout function capable of storing the entire refrigerant charge in a receiver or heat exchanger.
  2. Systems that are equipped with provisions for pumping out the refrigerant using either portable or permanently installed refrigerant recovery equipment.
  3. Self-contained listed and labeled systems.
Stop valves shall be installed in the following locations on refrigerating systems containing more than 6.6 pounds (3.0 kg) of refrigerant:
  1. The suction inlet of each compressor, compressor unit or condensing unit.
  2. The discharge outlet of each compressor, compressor unit or condensing unit.
  3. The outlet of each liquid receiver.
In addition to stop valves required by Section 1109.8.1, systems containing more than 100 pounds (45 kg) of refrigerant shall have stop valves installed in the following locations:
  1. Each inlet of each liquid receiver.
  2. Each inlet and each outlet of each condenser where more than one condenser is used in parallel.

Exceptions:

  1. Stop valves shall not be required at the inlet of a receiver in a condensing unit nor at the inlet of a receiver that is an integral part of the condenser.
  2. Systems utilizing nonpositive displacement compressors.
Stop valves shall be supported to prevent detrimental stress and strain on the refrigerant piping system. The piping system shall not be utilized to support stop valves on copper tubing or aluminum tubing 1 inch (25.4 mm) outside diameter or larger.
Stop valves shall be identified where their intended purpose is not obvious. Where valves are identified by a numbering or lettering system, legend(s) or key(s) for the valve identification shall be located in the room containing the indoor refrigeration equipment. The minimum height of lettering of the identification label shall be 1/2 inch (12.7 mm).
Refrigerant piping systems, other than R-717 (ammonia) refrigeration systems, that are erected in the field shall be pressure tested for strength and leak tested for tightness, in accordance with the requirements of this section, after installation and before being placed in operation. Tests shall include both the high- and low-pressure sides of each system.

Exception: Listed and labeled equipment, including compressors, condensers, vessels, evaporators, gas bulk storage tanks, safety devices, pressure gauges and control mechanisms, shall not be required to be tested.

Refrigerant pipe and joints installed in the field shall be exposed for visual inspection and testing prior to being covered or enclosed.
The medium used for pressure testing the refrigerant system shall be one of the following inert gases: oxygen-free nitrogen, helium or argon. For R-744 refrigerant systems, carbon dioxide shall be allowed as the test medium. For R-718 refrigerant systems, water shall be allowed as the test medium. Oxygen, air, combustible gases and mixtures containing such gases shall not be used as a test medium. Systems erected on the premises with tubing not exceeding 5/8 inch (15.9 mm) outside diameter shall be allowed to use the refrigerant identified on the nameplate label or marking as the test medium.
The means used to pressurize the refrigerant piping system shall have on its outlet side a test pressure measuring device and either a pressure-limiting device or a pressure-reducing device. The test pressure measuring device shall have an accuracy of ±3 percent or less of the test pressure and shall have a resolution of 5 percent or less of the test pressure.
The refrigerant piping system shall be tested as a whole or separate tests shall be conducted for the low-pressure side and high-pressure side of the piping system. The refrigerant piping system shall be tested in accordance with both of the following methods:
  1. The system shall be pressurized for a period of not less than 60 minutes to not less than the lower of the design pressures or the setting of the pressure relief device(s). The design pressures for testing shall be the pressure listed on the label nameplate of the condensing unit, compressor, compressor unit, pressure vessel or other system component with a nameplate. Additional test gas shall not be added to the system after the start of the pressure test. The system shall not show loss of pressure on the test pressure measuring device during the pressure test. Where using refrigerant as a test medium in accordance with Section 1110.3, the test pressure shall be not less than the saturation dew point pressure at 77°F (25°C).
  2. A vacuum of 500 microns shall be achieved. After achieving a vacuum, the system shall be isolated from the vacuum pump. The system pressure shall not rise above 1,500 microns for a period of not less than 10 minutes.
Joints and all refrigerant-containing parts of a refrigerating system located in an air duct of an air-conditioning system that conveys conditioned air to and from human-occupied spaces shall be tested at a pressure of 150 percent of the higher of the design pressure or pressure relief device setting.
Limited charge systems with a pressure relief device, erected on the premises, shall be tested at a pressure not less than one and one-half times the pressure setting of the relief device. Listed and labeled limited charge systems shall be tested at the equipment or appliance design pressure.
Where a compressor protected by a pressure relief device is used as a booster to obtain an intermediate pressure, and such compressor discharges into the suction side of another compressor, the booster compressor shall be considered to be a part of the low-pressure side of the system.
Where testing systems using centrifugal or other nonpositive displacement compressors, the entire system shall be considered to be the low-pressure side for test purposes.
The installing contractor or registered design professional of record shall issue a certificate of test to the code official for all systems containing 55 pounds (25 kg) or more of refrigerant. The certificate shall give the test date, name of the refrigerant, test medium and the field test pressure applied to the high-pressure side and the low-pressure side of the system. The certification of test shall be signed by the installing contractor or registered design professional and shall be made part of the public record.

The following emergency devices and systems shall be periodically tested in accordance with the manufacturer's instructions and as required by the code official:

  1. Treatment and flaring systems.
  2. Valves and appurtenances necessary to the operation of emergency refrigeration control boxes.
  3. Fans and associated equipment intended to operate emergency ventilation systems.
  4. Detection and alarm systems.
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