Chapter 1 Administration

Chapter 2 Definitions

Chapter 3 General Regulations

Chapter 4 Ventilation Air

Chapter 5 Exhaust Systems

Chapter 6 Duct Systems

Chapter 7 Combustion Air

Chapter 8 Chimneys and Vents

Chapter 9 Installation of Specific Appliances

Chapter 10 Boilers and Pressure Vessels

Chapter 11 Refrigeration

Chapter 12 Hydronics

Chapter 13 Fuel Gas Piping

Chapter 14 Process Piping

Chapter 15 Solar Energy Systems

Chapter 16 Stationary Power Plants

Chapter 17 Referenced Standards

Appendices [PDF]

Appendix A Residential Plan Examiner Review Form for HVAC System Design

Appendix B Procedures to be Followed to Place Gas Equipment in Operation

Appendix C Installation and Testing of Oil (Liquid) Fuel-Fired Equipment

Appendix D Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks

Appendix E Sustainable Practices

Appendix F Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design

Appendix G Example Calculation of Outdoor Air Rate

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.
Refrigeration systems shall comply with this chapter and ASHRAE 15.

Exception: Ammonia refrigeration systems shall comply with IIAR 2, IIAR 3, and IIAR 5.
The refrigerant used shall be of a type listed in Table 1102.2 or in accordance with ASHRAE 34 where approved by the Authority Having Jurisdiction.

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


TABLE 1102.2
REFRIGERANT GROUPS, PROPERTIES, AND ALLOWABLE QUANTITIES
[ASHRAE 34: TABLE 4-1, TABLE 4-2]
REFRIGERANT CHEMICAL FORMULA3 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-13 CClF3 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-32 CH2F2 Difluoromethane (methylene fluoride) A2L 1000 4.8
R-40 CH3Cl Chloromethane (methyl chloride) B2 - -
R-50 CH4 Methane A3 1000 -
R-113 CCl2FCClF2 1, 1, 2-trichloro-1, 2, 2 - trifluoro 
ethane
A1 1000 1.2
R-114 CClF2CClF2 1, 2-dichloro-1, 1, 2, 2 tetrafluoro 
ethane
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 CHClFCF3 2-chloro-1, 1, 2, 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 CH3CClF2 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-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 900 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
R429A zeotrope R-E170/152a/600a (60.0/10.0/30.0) A3 1000 0.81
R430A zeotrope R-152a/600a (76.0/24.0) A3 1000 1.3
R431A zeotrope R-290/152a (71.0/29.0) A3 1000 0.69
R432A zeotrope R-1270/E170 (80.0/20.0) A3 700 0.13
R433A zeotrope R-1270/290 (30.0/70.0) A3 880 0.34
R433B zeotrope R-1270/290 (5.0/95.0) A3 950 0.54
R433C zeotrope R-1270/290 (25.0/75.0) A3 790 0.41
R434A zeotrope R-125/141a/134a/600a 
(63.2/18.0/16.0/2.8)
A1 1000 20
R435A zeotrope R-E170/152a (80.0/20.0) A3 1000 1.1
R436A zeotrope R-290/600a (56.0/44.0) A3 1000 0.50
R436B 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-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-500 zeotrope R-12/152a (73.8/26.2)4 A1 1000 7.6
R-501 zeotrope R-22/12 (75.0/25.0) A1 1000 13
R-502 zeotrope R-22/115 (48.8/51.2) A1 1000 21
R-503 zeotrope R-23/13 (40.1/59.9) - 1000 -
R-504 zeotrope R-32/115 (48.2/51.8.) - 1000 28
R-507A5 zeotrope R-125/143a (50.0/50.0) A1 1000 32
R-508A5 zeotrope R-23/116 (39.0/61.0) A1 1000 14
R-508B zeotrope R-23/116 (46.0/54.0) A1 1000 13
R-509A5 zeotrope R-22/218 (44.0/56.0) A1 1000 24
R-510A zeotrope R-E170/600a (88.0/12.0) A3 1000 0.87
R-511A zeotrope R-290/E170 (95.0/5.0) A3 1000 0.59
R-512A zeotrope R-134a/152a (5.0/95.0) A2 1000 1.9
R-600 CH3CH2CH2CH3 Butane A3 1000 0.15
R-600a CH(CH3)2CH3 2-methylpropane (isobutane) A3 1000 0.59
R-601 CH3CH2CH2CH2
CH3
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-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-740 Ar Argon A1 - -
R-744 CO2 Carbon dioxide A1 5000 4.5
R-764 SO2 Sulfur dioxide B1 - -
R-1150 CH2=CH2 Ethene (ethylene) A3 200 -
R-1233zd(E) CF3CH=CHCl Trans- 1 -chloro- 3, 3, 3-trifluoro- 1 -
propane
A1 800 5.3
R-1234yf CF3CF=CH2 2, 3, 3, 3-tetrafluoro- 1 -propane 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
For SI units: 1 pound = 0.453 kg, 1 cubic foot = 0.0283 m3

Notes:
1   The preferred name is followed by the popular name in parenthesis.
2   The OEL are 8-hour TWA; a C designation denotes a ceiling limit.
3   Azeotropic refrigerants exhibit some segregation of components at conditions of temperature and pressure other than those at which they where formulated. The extent of segregation depends on the particular azeotrope and hardware system configuration.
4   The exact composition of this azeotrope is in question and additional experimental studies are needed.
5   R-507, R-508, and R-509 shall be permitted as 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   The amount of refrigerant per occupied space values tor these refrigerant blends are approximated in the absence of adequate data tor a component comprising less tban 4 percent m/m of the blend and expected to have a small influence in an acute, accidental release.
7   Refrigerant flammability classification of Class 2L shall comply with the requirements for flammability classification or Class 2.
Refrigerants shall be classified in accordance with Table 1102.2.
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 portable-unit 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
MACHINE 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, 2, 3 & 4] 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   See Section 1104.0.
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   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 1102.2, 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, 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 shall not be considered:
  1. Smoke dampers, fire dampers, and combination smoke and 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 refrigerant quantity limit in the system 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 where calculating the refrigerant quantity limit in the system. [ASHRAE 15:7.3.2.3]
The amounts shown in Table 1102.2 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. [ASHRAE 15:7.2.1]
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 206 from other occupancies by tight construction with tightfitting doors.
  2. Access is restricted to authorized personnel.
  3. The floor area per occupant is not less than 100 square feet (9.29 m2).

    Exception: The minimum floor area shall not apply where the space is provided with egress directly to the outdoors or into approved building exits.
  4. Refrigerant detectors are installed with the sensing location and alarm level as required in refrigeration machinery rooms in accordancc with Section 1106.4.
  5. Open flames and surfaces exceeding 800°F (427°C) shall not be permitted where a Group A2, B2, A3, or B3 refrigerant, other than R-717 (ammonia), is used.
  6. 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 other than R-717 (ammonia) 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.
  7. 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, 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 R-717 (ammonia), shall not exceed 1100 pounds (498.9 kg) without approval by the Authority Having Jurisdiction. [ASHRAE 15:7.5.1.1]
In nonindustrial occupancies, Group A2, A3, B1, B2, and B3 refrigerants shall not be used in high probability systems for human comfort.
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 a 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. Where contamination is evident by discoloration, odor, acid test results, or system history, recovered refrigerants shall be reclaimed in accordance with Section 1104.7.3. [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 1102.2 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 904.7 and Section 904.8. Cooling equipment used for human comfort in dwelling units shall be selected to satisfy the calculated loads determined in accordance with the reference standards in Chapter 17 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 unobstmcted 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 by 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 pern1itted to be provided an 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 lighting fixtures shall be installed for equipment required by this code to be accessible or readily accessible. Such fixtures 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. Lighting fixtures 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 1107.0.
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 tamperresistant 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 amount of refrigerant stored in a machinery room in 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 1102.2.
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. Ammonia-water absorption unit systems installed outdoors, provided that the quantity of refrigerant in a single system docs not exceed Table 1102.2 amounts and the discharge is shielded and dispersed.
  3. Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location.
  4. Systems containing less than 35 pounds (15.9 kg) of refrigerant R-717 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.
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.
Exits shall comply with the building code for special hazards.
Machinery rooms shall be provided with one or more approved refrigerant-vapor detectors sensing where refrigerant from a leak is likely to concentrate. The detector(s) shall be configured to activate two separate alarms at concentrations not greater than the following:
  1. Alarm 1: 25 percent of the LFL, 50 percent of the IDLH, or the OEL, whichever is less.
  2. Alarm 2: 25 percent of the LFL or the vapor detector's upper detection limit, whichever is less. This alarm shall not be required for Group A1 and B1 refrigerants.
    Alarm 1 shall activate visual and audible alarms inside the refrigerating machinery room and outside each entrance to the refrigerating machinery room, and shall activate mechanical ventilation in accordance with Section 1107.6 and emergency shutoff in accordance with Section 1108.3. The alarms shall be of the manual reset type with the reset located inside the refrigerating machinery room. Alarms shall provide a sound pressure level of not less than 15 decibels (dB) above the operating ambient noise sound pressure level of the space in which they are installed and provide an approved visual alarm.

    Alarms set at other refrigerant concentration levels shall be permitted in addition to those required by this section provided the meaning of each alarm is marked by signage or displays near the annunciators.
Refrigeration machinery rooms shall be separated from other portions of the building, as required in the special hazards provisions of the building code. Penetrations shall be sealed to inhibit the passage of refrigerant vapor.
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 1106.4, shall be installed to automatically shut down the combustion process in the event of refrigerant leakage.
Exceptions:
  1. Machinery rooms where carbon dioxide (R-744) or water (R-718) is the refrigerant.
  2. Machinery rooms where ammonia (R-717) is the refrigerant and internal combustion engines are used as the prime mover for the compressors. [ASHRAE 15:8.11.6]
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]
Open flames or devices having an exposed surface exceeding 800°F (427°C) shall be prohibited in refrigeration machinery rooms.

Exceptions:
  1. Momentary temperature excursions such as electrical contacts in A1 and B1 systems.
  2. Refrigeration machinery rooms used exclusively for direct-fired absorption equipment.
Refrigeration machinery rooms shall be provided with a source of outside air for ventilation and removal of rejected heat.
Refrigeration machinery rooms shall be provided with dedicated mechanical exhaust systems. The exhaust systems shall have the capacity to provide emergency purge of escaping refrigerant at a rate of 30 air changes per hour (ACH) for ammonia, or for other refrigerants as determined in accordance with Equation 1107.2:
(Equation 1107.2)
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
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 1107.3.
    (Equation 1107.3)
    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 15:5.11.5(a), (b)]
Exhaust inlets or permanent openings shall be located to provide ventilation throughout the entire refrigeration machinery room.
Fans providing refrigeration machinery room refrigerant exhaust in accordance with Section 1107.2 shall be permitted to be automatically or manually controlled to provide intermittent ventilation where the machinery room is occupied or in accordance with Section 1107.10.
Fans required by Section 1107.2 to provide emergency purge ventilation shall be activated by refrigerant Alarm 1 in accordance with Section 1106.4 and by a clearly identified switch of the break-glass type, or protected by an approved tamper resistant cover located immediately adjacent to and outside of the principal refrigerant machinery room entrance. Two colored and labeled indicator lamps responding to the differential pressure across the purge fan or current through the fan motor shall be provided for each switch. One lamp shall indicate flow; the other shall indicate no flow.
Exhaust from mcchanical ventilation systems shall comply with Section 502.2.2.
Fans and associated equipment intended to operate the emergency purge of other than Group A1 or Group B1 refrigerants shall be in accordance with the requirements for a Class I, Division 1 hazardous location as specified in the electrical code.
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]
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 1107.8.
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 1106.4.
Detection and alarm systems in accordance with Section 1106.4 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 compatible with the conveying refrigerant used. Materials shall not be used that will deteriorate due to the chemical action of the refrigerant, lubricant, or combination of both where exposed to air or moisture to a degree that poses a safety hazard. [ASHRAE 15:9.1.1]
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.
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, or brazed types. Copper tubing joints and connections shall be approved flared, lapped, swaged, or brazed joints. 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 connccting thc basement and the first floor.
  2. Penetrations connecting the top floor and a machinery penthouse or roof installation.
  3. Penetrations connccting adjacent floors served by the refrigeration system.
  4. Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1102.2 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 1102.2 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 Pis inches (35 mm) nominal size. Mechanical joints shall not be made on tubing exceeding 34 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 34 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 shall be provided on systems operating above atmospheric pressure.

Exception: Factory-sealed systems containing less than 22 pounds (9.9 kg) of Group A1 refrigerant listed by an approved agency. [ASHRAE 15:9.9.1]
Where required in Section 1111.1, the maximum setting to which a pressure-limiting device is capable of being readily set by use of the adjusting means provided shall not exceed the design pressure of the highside of a system that is not protected by a pressure-relief device or 90 percent of the setting of the pressure-relief device installed on the highside of a system. The pressure-limiting device shall stop the action of the pressure-imposing element at a pressure not more than the maximum setting.

Exception: On systems using nonpositive displacement compressors, the maximum setting of the pressure-limiting device shall not be required to be less than the design pressure of the highside of the system provided the pressure-relief device is located in the lowside, subject to lowside pressure, and there is a permanent (unvalved) relief path between the highside and the lowside of the system. [ASHRAE 15:9.9.2]
Pressure-limiting devices shall be connected between the pressure-imposing element and the stop valve on the discharge side. There shall be no intervening stop valves in the line leading to the pressure-limiting device. [ASHRAE 15:9.9.3]
Where the system is protected by a pressure-relief device, the pressure-limiting device shall stop the action of the pressure-imposing element at a pressure not exceeding 90 percent of the setting of the pressure relief device.
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 1112.10.

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.
Evaporators located downstream, or upstream within 18 inches (457 mm), of a heating coil shall be fitted with a pressure-relief device discharging outside the building in accordance with the requirements of Section 1112.10.

Exceptions:
  1. Relief valves shall not be required on heating coils that are designed to produce a temperature that will result in the saturation pressure of the refrigerant being less than the design pressure.
  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 ] > 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-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: Reliefvalves that discharge into other parts of the system shall comply with Section 1112.10.1. [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 1112.10.1 through Section 1112.10.4.1.
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 1104.0 are not exceeded. Refrigeration systems that do not comply with the above requirements shall comply with the requirements of Section 1112.10.2 through Section 1112.10.4. [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 oflhe 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 higherpressure 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 How 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 1112.10.4.1. [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 Hoor 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 1112.11.1 through Section 1112.11.5. [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 1112.11.4 and Section 1112.11.5. See Table 1112.11.3 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 1112.11.3
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 1112.11.4(1).

[Equation 1112.11.4(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
1112.13 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 1112.1l.3):

For conventional relief valves: 15 percent of set pressure:

P0 = (0.15•P)+Pa [Equation 1112.11.4(2)]

For balanced relief valves: 25 percent of set pressure:

P0 = (0.25•P)+Pa [Equation 1112.11.4(3)]

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

P0 = (0.50•P)+Pa [Equation 1112.11.4(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]
Where 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 outlet pressure at each relief device from exceeding the maximum allowable outlet pressure in accordance with Section 1112.11.4. [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:

   C = 0.64P1d2                        [Equation 1112.13(1)]

[Equation 1112.13(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:

P1 = (rated pressure in psig x 1.1) + 14.7 [Equation 1112.13(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 the refrigerating system shall be provided with overpressure protection. Pressure-relief devices or fuse 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 1112.10.1. [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:

C = fDL (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 off 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, R408A, 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
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 pump down of the retrigcrant 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. Ammonia absorption systems serving a single dwelling unit.
  2. 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.
  3. 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 threat of fire. Standby fuel, such as LP-Gas, and standby power shall have the capacity to operate for one and a halftimes 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 in accordance with ASME BPVC Section VIII. Pressure-relief valves shall be marked by the manufacturer or assembler with the data required in accordance with 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 by the manufacturer with the pressure-setting capacity. [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 beset 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 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
502 250 386 250
717 235 390 235
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 comply with the following:
  1. Be listed individually or as part of an assembly.
  2. Marked directly on the vessel or on a nameplate attached to the vessel in accordance with ASME BPVC Section VIII.
  3. Where requested by the Authority Having Jurisdiction, the manufacturer shall provide documentation to confirm that the vessel design, fabrication, and testing requirements are in accordance with 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 of more than 15 psig (103 kPa) shall be directly marked, or marked on a nameplate in accordance with 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.
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 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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