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.
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.
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 for these refrigerant blends are approximated in the absence of adequate data for a component comprising less than 4 percent m/m of the blend and expected to have a small influence in an acute, accidental release.
7 Refrigerant flammability classification of Class 2L shall comply with the requirements for flammability classification or Class 2.
Exception: Lithium bromide absorption systems using water as the refrigerant.
| 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 |
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 for these refrigerant blends are approximated in the absence of adequate data for a component comprising less than 4 percent m/m of the blend and expected to have a small influence in an acute, accidental release.
7 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:
Exceptions:
- Laboratories with more than 100 square feet (9.29 m2) of space per person.
- Industrial occupancies.
- 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.
Notes:
| 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 |
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:
Exceptions:
- 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.
- 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:
Exceptions: The following closure devices shall not be considered:
- Smoke dampers, fire dampers, and combination smoke and fire dampers that close only in an emergency not associated with a refrigerant leak.
- 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:
- The space(s) containing the machinery is (are) separated 206 from other occupancies by tight construction with tight-fitting doors.
- Access is restricted to authorized personnel.
- 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. - Refrigerant detectors are installed with the sensing location and alarm level as required in refrigeration machinery rooms in accordance with Section 1106.4.
- 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.
- 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.
- 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]
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]
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:
Exceptions:
- Equipment containing Group A1 refrigerants shall be permitted to be supported by the same materials permitted for the building type.
- The use of approved vibration isolators specifically designed for the normal, wind, and seismic loads encountered, shall be permitted.
An unobstructed readily accessible opening
and passageway not less than 36 inches (914 mm) in width
and 80 inches (2032 mm) in height shall be provided and
maintained to the compressor, valves required by this chapter,
or other portions of the system requiring routine maintenance.
Exceptions:
Exceptions:
- Refrigerant evaporators, suspended overhead, shall be permitted to use portable means of access.
- 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.
- Cooling equipment, using Group A1 refrigerants or brine, located in an attic or furred space shall be permitted 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).
- 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:
Exceptions:
- Lighting fixtures shall be permitted to be omitted where the fixed lighting of the building will provide the required illumination.
- 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:
Exceptions:
- 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.
- A condensing unit in a room or space that has permanent gravity ventilation having an area of 2 square feet (0.2 m2) or more to other rooms or openings exceeding 1000 ft3/hp (37.95 m3/kW).
Refrigeration systems or
portions thereof shall not be located within a required exit enclosure. Refrigeration compressors exceeding 5 horsepowers (3.7 kW) rating shall be located not less than 10 feet
(3048 mm) from an exit opening in a Group A; Group B;
Group E; Group F; Group I; Group R, Division 1; or Group
S Occupancy, unless separated by a one-hour fire-resistive
occupancy separation.
Condensate from air-cooling coils shall
be collected and drained to an approved location. Drain pans
and coils shall be arranged to allow thorough drainage and
access for cleaning. Where temperatures drop below freezing,
heat tracing and insulation of condensate drains shall be
installed.
Where defrost cycles are required for
portions of the system, provisions shall be made for collection
and disposal of the defrost liquid in a safe and sanitary
manner.
Where condensate or defrost liquids are
generated in an attic or furred space and structural damage will result from overflow, provisions for overflow shall be
provided.
Disposal of condensate, defrost, or overflow discharges shall
comply with Section 310.0.
Air conditioning
refrigerant circuit access ports located outdoors shall be
protected from unauthorized access with locking-type tamper-resistant
caps or in a manner approved by the Authority
Having Jurisdiction.
Exception: Refrigerant ports in secure locations protected by walls or fencing and requiring key-access.
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.
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.
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:
Exceptions:
- Lithium bromide absorption systems using water as the refrigerant.
- Ammonia-water absorption unit systems installed outdoors, provided that the quantity of refrigerant in a single system does not exceed Table 1102.2 amounts and the discharge is shielded and dispersed.
- Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location.
- Systems containing less than 35 pounds (15.9 kg) of refrigerant R-717 and located in an approved exterior location.
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:
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.
- Alarm 1: 25 percent of the LFL, 50 percent of the IDLH, or the OEL, whichever is less.
- 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.
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:
- 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.
- 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.
- Machinery rooms where carbon dioxide (R-744) or water (R-718) is the refrigerant.
- 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:
Exceptions:
- Momentary temperature excursions such as electrical contacts in A1 and B1 systems.
- 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:
For SI units: 1 cubic foot per minute = 0.00047 m3/s, 1 pound = 0.453 kg
(Equation 1107.2)
| Q | = | Air flow rate, cubic feet per minute. |
| G | = | Refrigerant mass in largest system, pounds. |
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:
- 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.
Where:
(Equation 1107.3)
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 - 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 mechanical
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.
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:
Exceptions:
- Penetrations connecting the basement and the first floor.
- Penetrations connecting the top floor and a machinery penthouse or roof installation.
- Penetrations connecting adjacent floors served by the refrigeration system.
- 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.
- 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:
- Enclosed by an approved gastight, fire-resistive duct or shaft with openings to those floors served by the refrigerating system.
- Located on the exterior wall of a building where vented to the outdoors or to the space served by the system and not used as an air shaft, closed court, or similar space. [ASHRAE 15:8.10.3]
Refrigerant piping
crossing an open space that affords passageway in a building
shall be not less than 7.25 feet (2210 mm) above the floor
unless the piping is located against the ceiling of such space
and is permitted by the Authority Having Jurisdiction.
[ASHRAE 15:8.10.1]
Passages shall not be obstructed by refrigerant piping.
Refrigerant piping shall not be located in an elevator,
dumbwaiter, or other shaft containing a moving object, or
in a shaft that has openings to living quarters, or to means
of egress. Refrigerant piping shall not be installed in an
enclosed public stairway, stair landing, or means of
egress. [ASHRAE 15:8.10.2]
Refrigerant piping placed
underground shall be protected against corrosion.
Refrigerant piping
installed in concrete floors shall be encased in a pipe
duct. Refrigerant piping shall be isolated and supported
to prevent damaging vibration, stress, or corrosion.
[ASHRAE 15:8.10.4]
In addition to the requirements of Section
1105.2, piping and tubing shall be securely fastened to a
permanent support within 6 feet (1829 mm) following the first
bend in such tubing from the compressor and within 2 feet
(610 mm) of each subsequent bend or angle. Piping and
tubing shall be supported at points not more than 15 feet
(4572 mm) apart.
Refrigerant piping and tubing shall
be installed so that it is not subject to damage from an external
source. Soft annealed copper tubing shall not exceed 13/8
inches (35 mm) nominal size. Mechanical joints shall not be
made on tubing exceeding 3/4 of an inch (20 mm) nominal size.
Soft annealed copper tubing conveying refrigerant shall be
enclosed in iron or steel piping and fittings, or in conduit,
molding, or raceway that will protect the tubing against
mechanical injury from an exterior source.
Exceptions:
Exceptions:
- 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.
- 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.
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:
- The suction inlet of a compressor, compressor unit, or condensing unit.
- The discharge of a compressor, compressor unit, or condensing unit.
- The outlet of a liquid receiver.
- Systems that have a refrigerant pumpout function capable of storing the refrigerant charge, or are equipped with the provisions for pumpout of the refrigerant.
- 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:
- The suction inlet of a compressor, compressor unit, or condensing unit.
- The discharge outlet of a compressor, compressor unit, or condensing unit.
- 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.
- The outlet of a liquid receiver.
- The inlets and outlets of condensers where more than one condenser is used in parallel in the systems.
Stop valves installed in copper refrigerant lines of 3⁄4 of an inch (20 mm) or less outside diameter shall
be supported independently of the tubing or piping.
Stop valves required by Section 1110.0 shall
be readily accessible from the refrigeration machinery room
floor or a level platform.
Stop valves shall be identified by
tagging in accordance with the reference standard for identification.
A valve chart shall be mounted under glass at an
approved location near the principal entrance to a refrigeration
machinery room.
Pressure-limiting devices 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]
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]
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:
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:
- 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.
- 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.
- 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.
- The compressor is equipped with capacity regulation.
- Capacity regulation actuates to a flow at not less than 90 percent of the pressure-relief device setting.
- 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:
Exceptions:
- 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.
- 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]
Exception: Where fusible plugs are used on the highside, they shall be located above or below the liquid refrigerant level. [ASHRAE 15:9.4.8]
The seats and discs of pressure-relief
devices shall be constructed of compatible material to resist
refrigerant corrosion or other chemical action caused by the
refrigerant. Seats or discs of cast iron shall not be used. Seats
and discs shall be limited in distortion, by pressure or other
cause, to a set pressure change of not more than 5 percent in
a span of five years. [ASHRAE 15:9.4.9]
Pressure-relief valves shall start to function at a pressure not exceeding the
design pressure of the parts of the system protected.
Exception: Relief valves that discharge into other parts of the
system shall comply with Section 1112.10.1. [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:
- The system contains less than 110 pounds (49.9 kg) of a Group A1 refrigerant.
- The system contains less than 6.6 pounds (2.99 kg) of a Group A2, B1 or B2 refrigerant.
- The system does not contain any quantity of a Group A3 or B3 refrigerant.
- The system is not required to be installed in a machinery room in accordance with Section 1106.0.
- 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:
- 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. - 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.
- For heavier-than-air refrigerants, the point of vent discharge shall be located not less than 20 feet (6096 mm) horizontally from below-grade walkways, entrances, pits or ramps where a release of the entire system charge into such a space would yield a concentration of refrigerant in excess of the RCL. The direct discharge of a relief vent into enclosed outdoor spaces, such as a courtyard with walls on all sides, shall not be permitted where a release of the entire system charge into such a space would yield a concentration of refrigerant in excess of the RCL. The volume for the refrigerant concentration calculation shall be determined using the gross area of the space and a height of 8.2 feet (2499 mm), regardless of the actual height of the enclosed space.
- 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.
- The termination point of vent discharge line shall be made in a manner that prevents foreign material or debris from entering the discharge piping.
- 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:
- The pressure-relief valve that protects the higher-pressure vessel shall be selected to deliver capacity in accordance with Section 1113.5 without exceeding the maximum allowable working pressure of the higher-pressure vessel accounting for the change in mass flow capacity due to the elevated backpressure.
- 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.
- 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:
- The pressure-relief device set pressure shall not exceed 15 psig (103 kPa).
- The floor drain shall be sized to handle the flow rate from a single broken tube in a refrigerant-containing heat exchanger.
- 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]
For SI units: 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa
| 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 |
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:
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 1112.11.3):
For conventional relief valves: 15 percent of set pressure:
For balanced relief valves: 25 percent of set pressure:
For rupture disks alone: fusible plugs, and pilot operated relief devices, 50 percent of set pressure:
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]
[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). |
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 1112.11.3):
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:
[Equation 1112.13(2)]
Where:
For rupture members:
For fusible plugs:
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
C = 0.64P1d2
[Equation 1112.13(1)]
[Equation 1112.13(2)]
| 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:
Where:
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]
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]
| 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:
- The relief valves are located on the lowside of the system.
- The vessel is provided with shutoff valves designed to allow pump down of the refrigerant charge of the pressure vessel.
- 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:
Exceptions:
- Ammonia absorption systems serving a single dwelling unit.
- 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.
- 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:
- Name of contractor installing the equipment.
- Name and number designation of refrigerant in system.
- 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]
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:
Exceptions:
- Mixtures of dry nitrogen, inert gases, nonflammable refrigerants permitted for factory tests.
- 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.
- 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:
For SI units: 1 pound-force per square inch gauge = 6.8947 kPa
* Special design required; test pressures typically exceed 1000 psig (6895 kPa).
Exceptions:
- Compressors, condensers, evaporators, coded pressure vessels, safety devices, pressure gauges, control mechanisms, and systems that are factory tested.
- 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.
| 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* | - | - | - |
* 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:
Exceptions:
- 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.
- 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.
- 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.
- 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:
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]
- Be listed individually or as part of an assembly.
- Marked directly on the vessel or on a nameplate attached to the vessel in accordance with ASME BPVC Section VIII.
- 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.
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.