CRC · California Residential Code
Refrigerant piping, valves, detection and machinery room controls
If your HVAC/refrigeration system contains more than 6.6 pounds of refrigerant you must install stop valves at each compressor suction and discharge and at the liquid receiver outlet, support piping close to bends (first support within 6 ft, subsequent within 2 ft, supports every 15 ft), and equip any machinery room with properly sited detectors whose set points meet the code’s OEL/RCL limits and automatically trigger ventilation and shutdown when alarms reach the specified thresholds.
Last reviewed: July 6, 2026
What the code requires — plain English
The California requirements for refrigerant piping supports, mandatory stop valves for moderate refrigerant charges, and machinery-room refrigerant detectors are set in CMC Chapter 11 (Refrigeration). Key controlling sections are § 1109.6 (piping support), § 1110.1 (stop valves where the system charge is greater than 6.6 pounds), and § 1106.11.8 (refrigerant detectors and detector siting). These rules require mechanical support spacing and placement, stop valves at specified compressor/receiver locations for systems over 6.6 lb, and properly sited, set and tested detectors in refrigerating machinery rooms.
The most important practical rule: securely support refrigerant piping close to each bend and place stop valves and detectors required by charge thresholds so systems can be isolated and shut down quickly if a leak is detected.
Requirements in detail
Refrigerant piping supports (what to install and where)
- Piping and tubing must be securely fastened to permanent supports within 6 feet following the first bend from the compressor and within 2 feet of each subsequent bend or angle. Support spacing shall be at points not more than 15 feet apart. § 1109.6.
- If soft-annealed copper tubing conveys refrigerant and is exposed to potential mechanical injury, it must be enclosed in iron/steel piping or conduit (see § 1109.7).
- Visual inspection: refrigerant piping and joints erected on the premises shall be exposed for inspection prior to being covered (see § 1109.8).
Stop valves — when they are required and where
- Systems containing more than 6.6 pounds (2.99 kg) of refrigerant must have stop valves at all of these locations (minimum):
- the suction inlet of each compressor/compressor unit/condensing unit;
- the discharge of each compressor/compressor unit/condensing unit; and
- the outlet of each liquid receiver. § 1110.1.
- Exceptions (no stop valves required at those locations) include systems that have a pumpout function capable of storing the entire refrigerant charge, systems equipped with pumpout provisions, or self-contained systems. § 1110.1.
- Additional related requirements:
- Stop valves installed in copper refrigerant lines of 3/4 inch or less outside diameter shall be supported independently of the tubing/piping. § 1110.3.
- Required stop valves must be readily accessible from the machinery room floor or a level platform. § 1110.4.
- Stop valves must be tagged/identified, and a valve chart must be mounted under glass at an approved location near the principal machinery-room entrance. § 1110.5.
Refrigerant detectors in machinery rooms (siting, set points, testing)
- Each refrigerating machinery room per Section 1106.11 must contain one or more refrigerant detectors. The sensing element(s) must be located where refrigerant from a leak is expected to concentrate, with set points that trigger the alarm and ventilation responses required by §§ 1106.11.10 and 1106.11.11. Multiport-type detectors are prohibited. § 1106.11.8.
- Detector performance and settings (summary of § 1106.11.9 requirements):
- Detector must be capable of detecting each refrigerant used in the room.
- Detector must activate required responses within the time limits specified by the referenced sections.
- Detector set point must be not greater than the applicable Occupational Exposure Limit (OEL) value and not more than the applicable Refrigerant Concentration Limit (RCL) listed in Table 1102.3 (the lowest applicable value for any refrigerant present). If a refrigerant has no OEL/RCL in Table 1102.3, an ASHRAE 34–derived value may be used if approved by the AHJ.
- Detector must provide automatic self-testing and be tested at installation and annually (or per manufacturer instructions/Fire Code interval). § 1106.11.9.
- Detection responses and ventilation: detection of refrigerant concentration that exceeds 25% of the lower flammable limit (LFL) or the detector’s upper detection limit, whichever is lower, shall automatically de-energize refrigerant compressors, refrigerant pumps, and normally-closed automatic refrigerant valves, and may trigger ventilation or other safety actions as described in § 1106.11.6.2 and related provisions. § 1106.11.6.2 / § 1106.11.8.
- Machinery-room ventilation must either run continuously (and alarm on failure) or be activated by refrigerant detectors; detectors can be used to start ventilation per § 1106.11.6.1. § 1106.11.6.1.
- Emergency shutdown controls: an emergency shutoff switch (break-glass or tamper-resistant cover) shall be installed immediately outside the principal machinery-room entrance to provide off-only control of compressors, pumps, and normally-closed automatic refrigerant valves; for refrigerants other than A1 and B1, Alarm 2 shall automatically activate emergency shutoff per § 1108.3. § 1108.3.
Quick reference table
| Parameter / decision point | Value / requirement (bold = key) | Code reference |
|---|---|---|
| Support after first bend | Secure support within 6 feet of the first bend from the compressor | § 1109.6 |
| Support near subsequent bends | Support within 2 feet of each subsequent bend/angle | § 1109.6 |
| Maximum support spacing | Supports at points not more than 15 feet apart | § 1109.6 |
| Stop-valve threshold | Stop valves required when system charge > 6.6 pounds | § 1110.1 |
| Stop-valve locations (min.) | Suction inlet, discharge, outlet of liquid receiver | § 1110.1 |
| Stop-valve exceptions | Pumpout-capable systems; self-contained systems | § 1110.1 |
| Detector siting | Detector sensing element located where refrigerant will concentrate; no multiport devices | § 1106.11.8 |
| Detector set points | ≤ applicable OEL and ≤ applicable RCL (Table 1102.3) | § 1106.11.9 — Table 1102.3 not retrieved in excerpts |
| Detector response threshold for shutdown | 25% of LFL or detector upper limit, whichever is lower, to de-energize compressors/pumps/valves | § 1106.11.6.2 |
| Detector testing interval | Installation test and annual testing (or per manufacturer/Fire Code) | § 1106.11.9 |
Note: Table 1102.3 (OEL and RCL numeric values) was referenced by the code but its numerical values were not included in the retrieved excerpts; consult Table 1102.3 in CMC Chapter 11 or the adopted CRC edition for the specific numeric OEL/RCL values.
Exceptions & special cases
- Support exceptions: tubing entirely within or within 5 feet of a refrigerant compressor that is not subject to external injury is excepted from the support/enclosure requirement; copper tubing serving a dwelling unit that contains Group A1 refrigerant and is placed in locations not subject to damage is also excepted. § 1109.6 / § 1109.7.
- Stop-valve exceptions: systems with pumpout capability to store the entire refrigerant charge, and self-contained systems, are exempt from the § 1110.1 stop-valve locations. § 1110.1.
- Detector selection: when refrigerants in the room have no OEL/RCL listed in Table 1102.3, the code permits using ASHRAE 34–derived values when approved by the Authority Having Jurisdiction (AHJ). § 1106.11.9.
- Multiport detectors are prohibited — use single-port or single-sensor detectors sited where leaks will concentrate. § 1106.11.8.
Common mistakes
- Installing supports too far from bends: failing to place the first support within 6 ft of the first bend or 2 ft of subsequent bends — this is a direct § 1109.6 violation.
- Omitting stop valves when system charge exceeds 6.6 lb — installers sometimes assume residential scales are exempt; they are not unless the system matches an explicit exception (pumpout/self-contained). § 1110.1.
- Concealing piping before inspection: covering joints or concealed fittings without prior visual inspection is prohibited unless the code exception applies. § 1109.8.
- Using multiport/sampling devices in place of required single-sensor detectors for machinery rooms — the code prohibits multiport devices. § 1106.11.8.
- Incorrect detector set points: setting detectors above the applicable OEL/RCL or failing to use the lowest applicable value for multiple refrigerants — the code requires detector set points to be ≤ the lowest OEL/RCL for the refrigerants present. § 1106.11.9.
Worked example — concrete scenario
Scenario: A multi-family building has a remote condensing unit that contains 8.5 pounds of an A2L refrigerant and a liquid receiver. The compressor and receiver are located inside a small machinery room.
What the code requires:
- Because the system charge is > 6.6 pounds, install stop valves at the suction inlet, at the discharge, and at the outlet of the liquid receiver (unless the system is self-contained or has a pumpout function) per § 1110.1.
- Ensure those stop valves are readily accessible from the machinery-room floor or a level platform and tagged, and mount a valve chart under glass near the principal entrance per § 1110.4 / § 1110.5.
- Run refrigerant piping supports so the first support is within 6 feet after the first bend from the compressor, subsequent bends are supported within 2 feet, and supports are spaced no more than 15 feet apart, per § 1109.6.
- Install one or more refrigerant detectors in the machinery room sited where A2L refrigerant would concentrate; set detector set points to be no greater than the applicable OEL and RCL (lowest applicable values) and to trigger the required ventilation/shutdown actions (e.g., de-energize compressors/pumps/valves at 25% of LFL or detector upper limit, whichever is lower) as required by § 1106.11.8 / § 1106.11.9 / § 1106.11.6.2. If Table 1102.3 values are needed, consult that table for numeric OEL/RCLs.
Related provisions (quick list)
- § 1109.7 — Pipe enclosure (soft-annealed copper protection).
- § 1109.8 — Visual inspection prior to concealment.
- § 1106.11.6.1 — Machinery-room mechanical ventilation operation and activation.
- § 1106.11.9 — Refrigerant detector performance, set points and testing requirements.
- § 1108.3 — Emergency shutoff switch location and Alarm 2 activation for non-A1/B1 refrigerants.
- § 1110.3 — Independent support of small-diameter stop valves.
- § 1110.4 — Access to stop valves (readily accessible).
- § 1110.5 — Identification and valve chart requirements.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 8.10.4 High relevance — show source text
[ASHRAE 15:8.10.4] 1109.6 Support. 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. 1109.7 Pipe Enclosure. 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 1 [3] ⁄ 8 inches (35 mm) nominal size. Mechanical joints, other than approved press-connect joints, shall not be made on tubing exceeding [3] ⁄ 4 of an inch (20 mm) nominal size. Soft annealed copper tubing conveying refrigerant shall be enclosed in iron or steel piping and fittings, or in conduit, molding, or raceway that will protect the tubing against mechanical injury from an exterior source.
2025 CALIFORNIA MECHANICAL CODE 239
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REFRIGERATION
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. 1109.8 Visual Inspection. 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. 1109.9 Condensation. 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. 1109.10 Identification. Piping shall be in accordance with the reference standard for identification. The type of refrigerant, function and pressure shall be indicated.
1110.0 Valves.
1110.1 More than 6.6 Pounds of Refrigerant. 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 each compressor, compressor unit, or condensing unit. (2) The discharge of each compressor, compressor unit, or condensing unit. (3) The outlet of each liquid receiver. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing the entire refrigerant charge. (2) Systems that are equipped with the provisions for pumpout of the refrigerant. (3) Self-contained systems. [ASHRAE 15:9.12.4] **1110.2 More than 110 Pounds of Refrigerant.
CRC § 608.9.1 High relevance — show source text
608.9.1 Refrigerants other than ammonia. A detector, or a sampling tube that draws air to a detector, shall be provided at an approved location where refrigerant from a leak is expected to accumulate. The system shall be designed to initiate audible and visible alarms inside of and outside each entrance to the refrigerating machinery room and transmit a signal to an approved location where the concentration of refrigerant detected exceeds the lesser of the following:
- The corresponding TLV-TWA values shown in the California Mechanical Code for the refrigerant classification.
- Twenty-five percent of the lower flammable limit (LFL).
Detection of a refrigerant concentration exceeding the upper detection limit or 25 percent of the lower flammable limit (LFL), whichever is lower, shall stop refrigerant equipment in the machinery room in accordance with Section 608.10.1.
608.10 Remote controls. Where flammable refrigerants are used and compliance with Section 1106 of the California Mechanical Code is required, remote control of the mechanical equipment and appliances located in the machinery room as required by Sections 608.10.1 and 608.10.2 shall be provided at an approved location immediately outside the machinery room and adjacent to its principal entrance.
608.10.1 Refrigeration system emergency shutoff. A clearly identified switch of the break-glass type or with an approved tamperresistant cover shall provide off-only control of refrigerant compressors, refrigerant pumps and normally closed automatic refrigerant valves located in the machinery room. Additionally, this equipment shall be automatically shut off when the refrigerant vapor concentration in the machinery room exceeds the vapor detector’s upper detection limit or 25 percent of the LEL, whichever is lower.
608.10.2 Ventilation system. A clearly identified switch of the break-glass type or with an approved tamper-resistant cover shall provide on-only control of the machinery room ventilation fans.
608.11 Emergency pressure control system. Permanently installed refrigeration systems in machinery rooms containing more than 6.6 pounds (3 kg) of flammable, toxic or highly toxic refrigerant or ammonia shall be provided with an emergency pressure control system in accordance with Sections 608.11.1 and 608.11.2.
608.11.1 Automatic crossover valves. Each high- and intermediate-pressure zone in a refrigeration system shall be provided with a single automatic valve providing a crossover connection to a lower pressure zone. Automatic crossover valves shall comply with Sections 608.11.1.1 through 608.11.1.3.
608.11.1.1 Overpressure limit set point. Automatic crossover valves shall be arranged to automatically relieve excess system pressure to a lower pressure zone if the pressure in a high- or intermediate-pressure zone rises to within 90 percent of the set point for emergency pressure relief devices.
608.11.1.2 Manual operation. Where required by the fire code official, automatic crossover valves shall be capable of manual operation.
608.11.1.3 System design pressure. Refrigeration system zones that are connected to a higher pressure zone by an automatic crossover valve shall be designed to safely contain the maximum pressure that can be achieved by interconnection of the two zones.
608.11.2 Automatic emergency stop. An automatic emergency stop feature shall be provided in accordance with Sections 608.11.2.1 and 608.11.2.2.
CRC § 1109.8 High relevance — show source text
1109.8 Visual Inspection. 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. 1109.9 Condensation. 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. 1109.10 Identification. Piping shall be in accordance with the reference standard for identification. The type of refrigerant, function and pressure shall be indicated.
1110.0 Valves.
1110.1 More than 6.6 Pounds of Refrigerant. 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 each compressor, compressor unit, or condensing unit. (2) The discharge of each compressor, compressor unit, or condensing unit. (3) The outlet of each liquid receiver. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing the entire refrigerant charge. (2) Systems that are equipped with the provisions for pumpout of the refrigerant. (3) Self-contained systems. [ASHRAE 15:9.12.4] 1110.2 More than 110 Pounds of Refrigerant. 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 each compressor, compressor unit, or condensing unit. (2) The discharge outlet of each compressor, compressor unit, or condensing unit. (3) The inlet of each 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 each liquid receiver. (5) The inlets and outlets of condensers when more than one condenser is used in parallel in the system. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing entire the refrigerant charge.
(2) Systems that are equipped with the provisions for pumpout of the refrigerant.
(3) Self-contained systems. [ASHRAE 15:9.12.5] 1110.3 Support. 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.
1110.4 Access. Stop valves required by Section 1110.0 shall be readily accessible from the refrigeration machinery room floor or a level platform.
1110.5 Identification. 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.
1111.0 Pressure-Limiting Devices.
1111.1 Where Required. Pressure-limiting devices complying with Section 1111.2 through Section 1111.4 shall be provided for compressors on all systems operating above atmospheric pressure.
CRC § 1106.3 High relevance — show source text
1106.3 Normal Operation . . . . . . . . . . . . . 233
1106.4 Natural Ventilation . . . . . . . . . . . . 234
1106.5 Combustion Air . . . . . . . . . . . . . . . 234
1106.6 Ventilation Intake . . . . . . . . . . . . . 234
1106.7 Maximum Temperature . . . . . . . . 234
1106.8 Refrigerant Parts in Air Duct. . . . . 234
1106.9 Dimensions. . . . . . . . . . . . . . . . . . 234
1106.10 Exits . . . . . . . . . . . . . . . . . . . . . . . 234
1106.11 Machinery Room, A2L and B2L . . 234
Table 1106.11.10.2 Refrigerant Detector Set Points, Response Times, Alarms, and Ventilation Levels . . . . . . . . . . . . . 235
Table 1106.11.11.2 Level 1 Ventilation Rate for
Class 2L Refrigerants . . . . . . . . . . . 236
1107.0 Machinery Room, Special Requirements . . . . . . . . . . . . . . . . 236
1107.1 General. . . . . . . . . . . . . . . . . . . . . 236
1108.0 Refrigeration Machinery Room Equipment and Controls . . . . . . . . 237
1108.1 General. . . . . . . . . . . . . . . . . . . . . 237
1108.2 Electrical . . . . . . . . . . . . . . . . . . . . 237
1108.3 Emergency Shutoff . . . . . . . . . . . . 237
2025 CALIFORNIA MECHANICAL CODE
1108.4 Installation, Maintenance, and Testing . . . . . . . . . . . . . . . . . . . . . 237
1108.5 Emergency Pressure Control System . . . . . . . . . . . . . . . . . . . . . 237
1109.0 Refrigeration Piping, Containers, and Valves . . . . . . . . . . . . . . . . . . 237
1109.1 Materials . . . . . . . . . . . . . . . . . . . . 237
Table 1109.1 Materials for Refrigerant Piping, Tubing, and Fittings . . . . . . . . . . . 239
1109.2 Joints . . . . . . . . . . . . . . . . . . . . . . 239
1109.3 Penetration of Piping . . . . . . . . . . 239
1109.4 Location of Refrigeration Piping . . 239
1109.5 Underground Piping . . . . . . . . . . . 239
1109.6 Support . . . . . . . . . . . . . . . . . . . . . 239
1109.7 Pipe Enclosure . . . . . . . . . . . . . . . 239
1109.8 Visual Inspection . . . . . . . . . . . . . 240
CRC § 1108.2 High relevance — show source text
1108.2 Electrical . . . . . . . . . . . . . . . . . . . . 237
1108.3 Emergency Shutoff . . . . . . . . . . . . 237
2025 CALIFORNIA MECHANICAL CODE
1108.4 Installation, Maintenance, and Testing . . . . . . . . . . . . . . . . . . . . . 237
1108.5 Emergency Pressure Control System . . . . . . . . . . . . . . . . . . . . . 237
1109.0 Refrigeration Piping, Containers, and Valves . . . . . . . . . . . . . . . . . . 237
1109.1 Materials . . . . . . . . . . . . . . . . . . . . 237
Table 1109.1 Materials for Refrigerant Piping, Tubing, and Fittings . . . . . . . . . . . 239
1109.2 Joints . . . . . . . . . . . . . . . . . . . . . . 239
1109.3 Penetration of Piping . . . . . . . . . . 239
1109.4 Location of Refrigeration Piping . . 239
1109.5 Underground Piping . . . . . . . . . . . 239
1109.6 Support . . . . . . . . . . . . . . . . . . . . . 239
1109.7 Pipe Enclosure . . . . . . . . . . . . . . . 239
1109.8 Visual Inspection . . . . . . . . . . . . . 240
1109.9 Condensation . . . . . . . . . . . . . . . . 240
1109.10 Identification . . . . . . . . . . . . . . . . . 240
1110.0 Valves. . . . . . . . . . . . . . . . . . . . . . 240
1110.1 More than 6.6 Pounds of
Refrigerant . . . . . . . . . . . . . . . . . . 240
1110.2 More than 110 Pounds of
Refrigerant . . . . . . . . . . . . . . . . . . 240
1110.3 Support . . . . . . . . . . . . . . . . . . . . . 240
1110.4 Access . . . . . . . . . . . . . . . . . . . . . 240
1110.5 Identification . . . . . . . . . . . . . . . . . 240
1111.0 Pressure-Limiting Devices . . . . . . 240
1111.1 Where Required . . . . . . . . . . . . . . 240
1111.2 Setting . . . . . . . . . . . . . . . . . . . . . 240
1111.3 Location . . . . . . . . . . . . . . . . . . . . 240
1111.4 Emergency Stop . . . . . . . . . . . . . . 240
1112.0 Pressure-Relief Devices . . . . . . . . 241
CRC § 608.7 High relevance — show source text
608.7 Testing of equipment. Refrigeration equipment and systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant shall be subject to periodic testing in accordance with Section 608.7.1. Records of tests shall be maintained. Tests of emergency devices or systems required by this chapter shall be conducted by persons trained and qualified in refrigeration systems.
6-10 2025 CALIFORNIA FIRE CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
BUILDING SERVICES AND SYSTEMS
608.7.1 Periodic testing. The following emergency devices or systems shall be periodically tested in accordance with the manufacturer’s instructions and as required by the fire code official.
- Treatment and flaring systems.
- Valves and appurtenances necessary to the operation of emergency refrigeration control boxes.
- Fans and associated equipment intended to operate emergency ventilation systems.
- Detection and alarm systems.
608.8 Emergency signs. Refrigeration units or systems having a refrigerant circuit containing more than 220 pounds (100 kg) of Group A1 or 30 pounds (14 kg) of any other group refrigerant shall be provided with approved emergency signs, charts and labels in accordance with NFPA 704. Hazard signs shall be in accordance with the California Mechanical Code for the classification of refrigerants listed therein.
608.9 Refrigerant detection. Machinery rooms shall be provided with a refrigerant detector with an audible and visible alarm. Where ammonia is used as the refrigerant, detection shall comply with IIAR 2. For refrigerants other than ammonia, refrigerant detection shall comply with Section 608.9.1.
608.9.1 Refrigerants other than ammonia. A detector, or a sampling tube that draws air to a detector, shall be provided at an approved location where refrigerant from a leak is expected to accumulate. The system shall be designed to initiate audible and visible alarms inside of and outside each entrance to the refrigerating machinery room and transmit a signal to an approved location where the concentration of refrigerant detected exceeds the lesser of the following:
- The corresponding TLV-TWA values shown in the California Mechanical Code for the refrigerant classification.
- Twenty-five percent of the lower flammable limit (LFL).
Detection of a refrigerant concentration exceeding the upper detection limit or 25 percent of the lower flammable limit (LFL), whichever is lower, shall stop refrigerant equipment in the machinery room in accordance with Section 608.10.1.
608.10 Remote controls. Where flammable refrigerants are used and compliance with Section 1106 of the California Mechanical Code is required, remote control of the mechanical equipment and appliances located in the machinery room as required by Sections 608.10.1 and 608.10.2 shall be provided at an approved location immediately outside the machinery room and adjacent to its principal entrance.
608.10.1 Refrigeration system emergency shutoff. A clearly identified switch of the break-glass type or with an approved tamperresistant cover shall provide off-only control of refrigerant compressors, refrigerant pumps and normally closed automatic refrigerant valves located in the machinery room. Additionally, this equipment shall be automatically shut off when the refrigerant vapor concentration in the machinery room exceeds the vapor detector’s upper detection limit or 25 percent of the LEL, whichever is lower.
CRC § 1107.1.7.1 High relevance — show source text
1107.1.7.1 Mechanical Ventilation. The mechanical ventilation system in the machinery room is run continuously in accordance with Section 1106.11.6.1 and failure of the mechanical ventilation system actuates an alarm, or the mechanical ventilation system in the machinery room is activated by one or more refrigerant detectors, in accordance with the requirements of Section 1106.11.11.
1107.1.7.2 Refrigeration Detectors. For the refrigerant detection required in Section 1106.2.5, detection of refrigerant concentration that exceeds 25 percent of the LFL or the upper detection limit of the refrigerant detector, whichever is lower, shall automatically de-energize the following equipment in the machinery room:
(1) refrigerant compressors
(2) refrigerant pumps
(3) normally-closed automatic refrigerant valves
1107.1.7.3 Machinery Rooms. The machinery room shall comply with Section 1106.11. 1107.1.8 Group A2, A3, B2, or B3 Refrigerants. Where any refrigerant of Groups A2, A3, B2, or B3 are used, the machinery room shall comply with Class 1, Division 2, of of the California Electrical Code .
1107.1.9 Refrigeration Systems. As part of the mechanical ventilation system in accordance with Section 1106.2.8, refrigeration systems that contain more
than 110 pounds (50 kg) of any Group A2L, A2, A3, B2L, B2, or B3, refrigerant shall have not less than one exhaust air inlet located adjacent to each system not more than 9 feet (3 m) away.
1107.1.10 Remote Control. Remote control of the
mechanical equipment in the refrigeration machinery room shall be provided immediately outside the machinery room door solely for the purpose of shutting down the equipment in an emergency. Ventilation fans shall be on a separate electrical circuit and have a control switch located immediately outside the machinery room door.
1108.0 Refrigeration Machinery Room Equipment and Controls.
1108.1 General. 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.
1108.2 Electrical. Electrical equipment and installations shall comply with California Electrical Code . The refrigeration machinery room shall not be classified as a hazardous location except as provided in Section 1107.1.7 or Section 1107.1.8.
1108.3 Emergency Shutoff. A clearly identified emergency shutoff switch of the break-glass type or with an approved tamper-resistant cover shall be provided immediately adjacent to and outside of the principal refrigeration machinery room entrance. The switch shall provide off-only control of refrigerant compressors, refrigerant pumps, and normally-closed automatic refrigerant valves located in the machinery room. For other than A1 and B1 refrigerants, emergency shutoff shall be automatically activated by refrigerant Alarm 2 in accordance with Section 1106.2.5.
CRC § 1106.1.2 High relevance — show source text
1106.1.2 Equipment. Direct- and indirect-fired absorption equipment is used.
Exception: Direct and indirect-fired lithium bromide absorption systems using water as the refrigerant.
1106.1.3 A1 System. An A1 system having an aggregate combined compressor horsepower of 100 (74.6 kW) or more is used.
1106.1.4 A1 Refrigerant. The system contains other than a Group A1 refrigerant.
Exceptions:
(1) Lithium bromide absorption systems using water as the refrigerant.
(2) Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location.
Refrigeration machinery rooms shall house refrigerant-containing portions of the system other than the piping and evaporators permitted by Section 1104.4, discharge piping required of this chapter, and cooling towers regulated by Part II of this chapter, and their essential piping.
1106.2 Refrigeration Machinery Room, General Requirements. Where a refrigeration system is located indoors and a machinery room is required in accordance with Section 1106.1, the machinery room shall be in accordance with Section 1106.2.1 through Section 1106.2.9.1.
1106.2.1 Access. Machinery rooms shall not be prohibited from housing other mechanical equipment unless specifically prohibited elsewhere in this chapter. A machinery room shall be so dimensioned that parts are accessible with space for service, maintenance, and operations. There shall be clear head room of not less than
7.25 feet (2210 mm) below equipment situated over passageways. [ASHRAE 15:8.11.1]
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1106.2.2 Openings. Each refrigeration machinery room shall have a tight-fitting door or doors opening outward, self-closing where they open into the building and adequate in number to ensure freedom for persons to escape in an emergency. With the exception of access doors and panels in air ducts and air-handling units in accordance with Section 1106.2.3, there shall be no openings that will permit passage of escaping refrigerant to other parts of the building. [ASHRAE 15:8.11.2]
1106.2.3 Airflow. 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 any refrigerant leakage from entering the airstream. Access doors and panels in ductwork and air-handling units shall be gasketed and tight fitting. [ASHRAE 15:8.11.3]
1106.2.4 Restricted Access. Access to the refrigeration machinery room shall be restricted to authorized personnel. Doors shall be clearly marked, or permanent signs shall be posted at each entrance to indicate this restriction. [ASHRAE 15:8.11.4]
**1106.2.5 Detectors and Alarms.
CRC § 1109.3 High relevance — show source text
1109.3 Penetration of Piping. Refrigerant piping shall not penetrate floors, ceilings, or roofs.
Exceptions:
(1) Penetrations connecting the basement and the first floor.
(2) Penetrations connecting the top floor and a machinery penthouse or roof installation. (3) Penetrations connecting adjacent floors served by the refrigeration system. (4) Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1102.3 for the smallest occupied space through which the refrigerant piping passes. (5) In other than industrial occupancies and where the refrigerant concentration exceeds that listed in Table 1102.3 for the smallest occupied space, penetrations that connect separate pieces of equipment that are in accordance with one of the following: (a) Enclosed by an approved gastight, fire-resistive duct or shaft with openings to those floors served by the refrigerating system. (b) 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] 1109.4 Location of Refrigeration Piping. Refrigerant piping crossing an open space that affords passageway in any 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] 1109.4.1 Protection from Mechanical Damage. Passages shall not be obstructed by refrigerant piping. Refrigerant piping shall not be placed in any elevator, dumbwaiter, or other shaft containing a moving object or in any 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] 1109.5 Underground Piping. Refrigerant piping placed underground shall be protected against corrosion. 1109.5.1 Piping in Concrete Floors. Refrigerant piping installed in concrete floors shall be encased in pipe duct. Refrigerant piping shall be isolated and supported to prevent damaging vibration, stress, or corrosion.
[ASHRAE 15:8.10.4] 1109.6 Support. 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. 1109.7 Pipe Enclosure. 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 1 [3] ⁄ 8 inches (35 mm) nominal size. Mechanical joints, other than approved press-connect joints, shall not be made on tubing exceeding [3] ⁄ 4 of an inch (20 mm) nominal size. Soft annealed copper tubing conveying refrigerant shall be enclosed in iron or steel piping and fittings, or in conduit, molding, or raceway that will protect the tubing against mechanical injury from an exterior source.
CRC § 49.9 High relevance — show source text
** 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 each compressor, compressor unit, or condensing unit. (2) The discharge outlet of each compressor, compressor unit, or condensing unit. (3) The inlet of each 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 each liquid receiver. (5) The inlets and outlets of condensers when more than one condenser is used in parallel in the system. Exceptions: (1) Systems that have a refrigerant pumpout function capable of storing entire the refrigerant charge.
(2) Systems that are equipped with the provisions for pumpout of the refrigerant.
(3) Self-contained systems. [ASHRAE 15:9.12.5] 1110.3 Support. 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.
1110.4 Access. Stop valves required by Section 1110.0 shall be readily accessible from the refrigeration machinery room floor or a level platform.
1110.5 Identification. 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.
1111.0 Pressure-Limiting Devices.
1111.1 Where Required. Pressure-limiting devices complying with Section 1111.2 through Section 1111.4 shall be provided for compressors on all systems operating above atmospheric pressure.
Exception: Pressure limiting devices are not required for listed factory-sealed systems containing less than 22 pounds (9.9 kg) of Group A1 refrigerant. [ASHRAE 15:9.9.1] 1111.2 Setting. Pressure limiting devices shall be set in accordance with one the following:
(1) For positive displacement compressors:
(a) When systems are protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
(b) When systems are not protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than the system’s highside design pressure.
(2) For nonpositive displacement compressors:
(a) When systems are protected by a highside pressure relief device, the compressor’s pressure limiting device shall be set not more than 90 percent of the operating pressure for the highside pressure relief device.
(b) When systems are protected by a lowside pressure relief device that is only subject to lowside pressure, and is provided with a permanent relief path between the systems’ highside and lowside, without intervening valves, the compressor’s pressure limiting device shall be set not more than the systems’ highside design pressure. [ASHRAE 15:9.9.2]
1111.3 Location. Stop valves shall not be installed between the pressure imposing element and pressure limiting devices serving compressors. [ASHRAE 15:9.9.3] 1111.4 Emergency Stop. Activation of a pressure-limiting device shall stop the action of the pressure-imposing element.
[ASHRAE 15:9.9.4]
CRC § 1107.1.10 High relevance — show source text
1107.1.10 Remote Control. Remote control of the
mechanical equipment in the refrigeration machinery room shall be provided immediately outside the machinery room door solely for the purpose of shutting down the equipment in an emergency. Ventilation fans shall be on a separate electrical circuit and have a control switch located immediately outside the machinery room door.
1108.0 Refrigeration Machinery Room Equipment and Controls.
1108.1 General. 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.
1108.2 Electrical. Electrical equipment and installations shall comply with California Electrical Code . The refrigeration machinery room shall not be classified as a hazardous location except as provided in Section 1107.1.7 or Section 1107.1.8.
1108.3 Emergency Shutoff. A clearly identified emergency shutoff switch of the break-glass type or with an approved tamper-resistant cover shall be provided immediately adjacent to and outside of the principal refrigeration machinery room entrance. The switch shall provide off-only control of refrigerant compressors, refrigerant pumps, and normally-closed automatic refrigerant valves located in the machinery room. For other than A1 and B1 refrigerants, emergency shutoff shall be automatically activated by refrigerant Alarm 2 in accordance with Section 1106.2.5.
1108.4 Installation, Maintenance, and Testing. Detection and alarm systems in accordance with Section 1106.2.5 shall be installed, maintained, and tested in accordance with the California Fire Code and with the equipment manufac- turer’s specification . 1108.5 Emergency Pressure Control System. Where required by the fire code, an emergency pressure control system shall be installed in accordance with applicable fire code requirements.
1109.0 Refrigeration Piping, Containers, and Valves.
1109.1 Materials. Materials used in the construction and installation of refrigerating systems shall be suitable for conveying the refrigerant used. Materials shall not be used that will deteriorate because of the refrigerant, the lubricant, or their combination in the presence of air or moisture to a degree that poses a safety hazard. [ASHRAE 15:9.1.1] Refrigerant piping shall be metallic. Materials for refrigerant piping, tubing, and fittings shall comply with the applicable standards in Table 1109.1.
2025 CALIFORNIA MECHANICAL CODE 237
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REFRIGERATION
For SI Units: 1 pound = 0.453 kg, 1 cubic foot per minute = 0.47194 L/s, 1 pound-force per square inch = 6.8947 kPa
FIGURE 1106.11.11.4
LEVEL 2 VENTILATION RATE FOR CLASS 2L REFRIGERANTS
[ASHRAE 15: FIGURE 8-1]
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REFRIGERATION
CRC § 3.3. High relevance — show source text
= On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d.
Frequently asked questions
Do these requirements apply to small residential split systems?
Yes—stop valves and piping support rules apply when the system charge exceeds the thresholds in the code (for stop valves, > 6.6 lb). Some small, factory-sealed or truly self-contained units may be exempt under the listed exceptions; check § 1110.1 for the exceptions.
Where do I find the numeric OEL and RCL values for detector set points?
The code references Table 1102.3 for OEL and RCL values; those numeric values were not included in the retrieved excerpts. Consult Table 1102.3 in CMC Chapter 11 of the adopted California code or ask the AHJ. § 1106.11.9.
Can a multiport detector be used to monitor several machinery rooms from one sensor?
No. Multiport-type devices are prohibited for machinery room detectors; each machinery room must contain detector(s) sited where refrigerant will concentrate. § 1106.11.8.
How often must detectors be tested?
Detectors must provide automatic self-testing and be tested at installation and annually, or per the manufacturer's instructions or the Fire Code interval (whichever is less). § 1106.11.9.
If the detection level reaches the alarm threshold, what must happen immediately?
Detection of refrigerant at 25% of the LFL or the detector’s upper limit (whichever is lower) shall automatically de-energize compressors, pumps, and normally-closed automatic refrigerant valves and initiate ventilation response per the code. § 1106.11.6.2 / § 1106.11.8.
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