CMC · California Mechanical Code
Where are emergency shutoff valves required for HPP systems?
For hazardous process piping (HPP) under the California Mechanical Code, emergency shutoff valves (manual or automatic fail‑safe) must be installed where HPP supply lines branch into a fabrication area and where they enter exit corridors; waste lines are excluded and corridor entries also need excess‑flow devices as required by the fire code (see §1406.2.1.5).
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Readily accessible manual or automatic remotely activated fail‑safe emergency shutoff valves are required on hazardous process piping (HPP) supply piping and tubing (other than waste lines) at two specific locations: (1) at branch connections into the fabrication area, and (2) at entries into exit corridors. This requirement is stated in § 1406.2.1.5.
The single most important rule: install a readily accessible fail‑safe shutoff valve on every HPP supply line where it branches into a fabrication area and where it enters an exit corridor. § 1406.2.1.5.
Requirements in detail
Scope / applicability
- Applies to HPP supply piping or tubing (not to waste lines). § 1406.2.1.5 requires the valves on piping/tubing other than waste lines.
- HPP piping is subject to the other HPP rules in § 1406.2 (identification, exposure to view, receptors for liquids, etc.), which remain applicable in addition to the shutoff valve requirement. § 1406.2.
What kind of valve / control
- The code requires manual or automatic remotely activated fail‑safe emergency shutoff valves. The term “fail‑safe” indicates the valve must move to the safe (closed) position on a system failure. The section does not further define “fail‑safe” in the excerpt retrieved. § 1406.2.1.5.
Where exactly (decision matrix)
| Decision dimension | Required value | Code Reference |
|---|---|---|
| Piping applicability | Supply piping or tubing other than waste lines | § 1406.2.1.5 |
| Location #1 | At branch connections into the fabrication area | § 1406.2.1.5 (1) |
| Location #2 | At entries into exit corridors | § 1406.2.1.5 (2) |
| Valve type | Manual OR automatic remotely-activated, fail‑safe | § 1406.2.1.5 |
| Accessibility | Readily accessible (valves must be placed so they can be reached quickly) | § 1406.2.1.5 |
| Additional hardware at corridor entries | Excess flow valves as required by the fire code | § 1406.2.1.5 (2) |
Notes about terms the section uses
- Readily accessible is required language in § 1406.2.1.5, but the retrieved text does not include a separate definition of “readily accessible.” The code user should confirm local AHJ interpretations for placement/clearance.
- The shutdown requirement applies to piping/tubing — the section explicitly excludes waste lines from this particular mandate. § 1406.2.1.5.
Exceptions & special cases
- Occasional transverse crossings of corridors by supply piping that is enclosed within the corridor are exempt from Sections 1406.2.1.1 through 1406.2.1.6 (which includes § 1406.2.1.5) — i.e., brief enclosed cross‑overs may not need the full set of controls. Confirm applicability with the AHJ. § 1406.2.1 (exception).
- Separate special rules apply to HPP gases (for example, fail‑safe shutdown on rupture and valve placement near outside bulk sources) in § 1406.3.1; those provisions supplement the shutoff valve rules for gas services. § 1406.3.1.
- The code references the fire code for some valve requirements (for example, excess flow valves at exit‑corridor entries); compliance means coordinating CMC requirements with the applicable fire code appliance/valve rules. § 1406.2.1.5.
Common mistakes
- Assuming the rule applies to waste lines — it does not; the shutoff‑valve mandate in § 1406.2.1.5 specifically excludes waste lines.
- Installing valves that are not readily accessible (e.g., locked, obstructed, or placed behind non‑labeled covers). The code explicitly requires “readily accessible” valves. § 1406.2.1.5.
- Forgetting to provide excess flow valves where required by the fire code at entries into exit corridors — the CMC points to that additional fire‑code requirement. § 1406.2.1.5.
- Treating remote (automatic) shutoff devices as acceptable without ensuring they are fail‑safe. The section requires remotely activated valves to be fail‑safe. § 1406.2.1.5.
- Not coordinating with adjacent HPP requirements (sprinklers, ventilation, receptor, separation) in § 1406.2.1.1–1.4 when locating shutoff valves.
Worked example — concrete scenario
Scenario: A semiconductor fabrication (fab) area has an HPP liquid supply main that runs in the ceiling above an exterior service corridor and branches into the cleanroom (fabrication area) at three separate branch connections. The main also passes through two exit‑corridor entry points on the way to other areas.
What the code requires:
- Install a readily accessible, fail‑safe manual or automatic remotely activated shutoff valve at each of the three branch connections into the fabrication area. This satisfies § 1406.2.1.5 (1).
- Install a readily accessible, fail‑safe shutoff valve at each entry into the exit corridors (two locations). Also ensure excess flow valves are installed at those corridor entries as required by the fire code. This satisfies § 1406.2.1.5 (2) and the cross‑reference to the fire code.
- Confirm that the valves are not placed on waste lines (the rule excludes waste lines) and that they are accessible (no locked cabinets unless the AHJ accepts that as “readily accessible”). § 1406.2.1.5.
Practical installation notes (from the retrieved text and common practice):
- Label the valves and leave clear access so emergency responders or operations staff can reach them quickly — the section requires “readily accessible,” though the retrieved text does not further define minimum clearances. § 1406.2.1.5.
- Coordinate with the fire code official to determine specific excess‑flow valve types and placement at corridor entries (the CMC defers to the fire code for excess flow valve requirements). § 1406.2.1.5.
Related provisions (CMC sections)
- § 1406.2 — Hazardous Process Piping (general HPP requirements: identification, exposure to view, liquid receptor, etc.).
- § 1406.2.1.1 — Automatic sprinklers requirement for the piping space.
- § 1406.2.1.2 — Ventilation requirement (minimum ACH) for piping space.
- § 1406.2.1.3 — Receptor (drain/containment) for HPP liquids under piping.
- § 1406.2.1.4 — Separation / 1‑hour construction requirements for HPP enclosures.
- § 1406.2.1.6 — Electrical wiring requirements for the piping space (hazardous location classification).
- § 1406.3.1 — Special provisions for HPP gases (fail‑safe shutoff on rupture; valve placement near outside bulk sources).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 1406.0 High relevance — show source text
1406.0 Pipe, Tubing, and Fittings.
1406.1 General. Process pipe, tubing, and fittings shall comply with ASME B31.3 and shall be installed in accordance with the manufacturer’s installation instructions. Materials shall be rated for the operating temperatures and pressures of the system, and shall be compatible with the type of liquid.
1406.2 Hazardous Process Piping (HPP). HPP supply piping or tubing in service corridors shall be exposed to view. HPP piping shall be identified in accordance with nationally recognized standards to indicate the material being transported. Liquid HPP piping shall have an approved means for directing spilled materials to an approved containment or drainage system.
Liquid HPP waste or drainage systems shall be installed in accordance with the plumbing code.
1406.2.1 Installation in Exit Corridors and Above Other Occupancies. Hazardous process supply pipe shall not be located within exit corridors, within a portion of a means of egress required to be enclosed in fire-resistive construction, or in concealed spaces in or above
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PROCESS PIPING
areas not classified as Group H Occupancies, except as permitted by this subsection.
Hazardous production material piping and tubing shall be permitted to be installed within the space defined by the walls of exit corridors and the floor or roof above, or in concealed spaces above other occupancies in accordance with Section 1406.2.1.1 through Section 1406.2.1.6.
1406.2.1.1 Automatic Sprinklers. Automatic sprinklers shall be installed within the space unless the space is less than 6 inches (152 mm) in the least dimension.
1406.2.1.2 Ventilation. Ventilation at not less than
6 air changes per hour (ACH) shall be provided. The space shall not be used to convey air from other
areas.
1406.2.1.3 Receptor. Where the piping or tubing is used to transport HPP liquids, a receptor shall be installed below such piping or tubing. The receptor shall be designed to collect discharge or leakage and drain it to an approved location. The 1 hour enclosure shall not be used as part of the receptor.
1406.2.1.4 Separation. HPP supply piping and tubing and HPP nonmetallic waste lines shall be separated from the exit corridor and from an occupancy other than a semi-conductor fabrication facility classified as a Group H Occupancy by construction, as required for walls or partitions that have a fire-protection rating of not less than 1 hour. Where gypsum wallboard is used, joints on the piping side of the enclosure need not be taped, provided the joints occur over framing members. Access openings into the enclosure shall be protected by approved fire assemblies.
1406.2.1.5 Emergency Shutoff Valves. Readily accessible manual or automatic remotely activated fail-safe emergency shutoff valves shall be installed on piping and tubing other than waste lines at the following locations:
(1) At branch connections into the fabrication area.
(2) At entries into exit corridors. Excess flow valves shall be installed as required by the fire code.
CMC § 1406.2.1.1 High relevance — show source text
1406.2.1.1 Automatic Sprinklers. Automatic sprinklers shall be installed within the space unless the space is less than 6 inches (152 mm) in the least dimension.
1406.2.1.2 Ventilation. Ventilation at not less than
6 air changes per hour (ACH) shall be provided. The space shall not be used to convey air from other
areas.
1406.2.1.3 Receptor. Where the piping or tubing is used to transport HPP liquids, a receptor shall be installed below such piping or tubing. The receptor shall be designed to collect discharge or leakage and drain it to an approved location. The 1 hour enclosure shall not be used as part of the receptor.
1406.2.1.4 Separation. HPP supply piping and tubing and HPP nonmetallic waste lines shall be separated from the exit corridor and from an occupancy other than a semi-conductor fabrication facility classified as a Group H Occupancy by construction, as required for walls or partitions that have a fire-protection rating of not less than 1 hour. Where gypsum wallboard is used, joints on the piping side of the enclosure need not be taped, provided the joints occur over framing members. Access openings into the enclosure shall be protected by approved fire assemblies.
1406.2.1.5 Emergency Shutoff Valves. Readily accessible manual or automatic remotely activated fail-safe emergency shutoff valves shall be installed on piping and tubing other than waste lines at the following locations:
(1) At branch connections into the fabrication area.
(2) At entries into exit corridors. Excess flow valves shall be installed as required by the fire code.
1406.2.1.6 Electrical Wiring. Electrical wiring and equipment located in the piping space shall be approved for Class I, Division 2, Hazardous Locations.
Exception: Occasional transverse crossing of the corridors by supply piping that is enclosed within the corridor need not comply with Section 1406.2.1.1 through Section 1406.2.1.6.
1406.3 Special Requirements for HPP Gases. In addition to other requirements of this section, HPP gases shall comply with this subsection and the fire code.
1406.3.1 Special Provisions. Where HPP supply gas is carried in pressurized piping, a fail-safe system shall shut off flow due to a rupture in the piping. Where the piping originates from outside the building, the valve shall be located outside the building as close to the bulk source as practical.
1406.3.2 Piping and Tubing Installation. Piping and tubing shall be installed in accordance with approved standards. Supply piping for hazardous production materials having a health hazard ranking of 3 or 4 shall have welded connections throughout, unless an exhausted enclosure is provided.
Exception: Material that is incompatible with ferrous piping shall be permitted to be installed in nonmetallic piping with approved connections.
CMC § 1406.2.1.5 High relevance — show source text
1406.2.1.5 Emergency Shutoff Valves. Readily accessible manual or automatic remotely activated fail-safe emergency shutoff valves shall be installed on piping and tubing other than waste lines at the following locations:
(1) At branch connections into the fabrication area.
(2) At entries into exit corridors. Excess flow valves shall be installed as required by the fire code.
1406.2.1.6 Electrical Wiring. Electrical wiring and equipment located in the piping space shall be approved for Class I, Division 2, Hazardous Locations.
Exception: Occasional transverse crossing of the corridors by supply piping that is enclosed within the corridor need not comply with Section 1406.2.1.1 through Section 1406.2.1.6.
1406.3 Special Requirements for HPP Gases. In addition to other requirements of this section, HPP gases shall comply with this subsection and the fire code.
1406.3.1 Special Provisions. Where HPP supply gas is carried in pressurized piping, a fail-safe system shall shut off flow due to a rupture in the piping. Where the piping originates from outside the building, the valve shall be located outside the building as close to the bulk source as practical.
1406.3.2 Piping and Tubing Installation. Piping and tubing shall be installed in accordance with approved standards. Supply piping for hazardous production materials having a health hazard ranking of 3 or 4 shall have welded connections throughout, unless an exhausted enclosure is provided.
Exception: Material that is incompatible with ferrous piping shall be permitted to be installed in nonmetallic piping with approved connections.
1406.3.3 Gas-Detection System. Where hazardous production material gas is used or dispensed and the physiological warning properties of the gas are at a higher level than the accepted permissible exposure limit (PEL) of the gas, a continuous gas-monitoring system shall be provided to detect the presence of the short-term hazard condition. Where dispensing occurs and flammable gases or vapors are capable of being present in quantities in excess of 25 percent of the lower explosive limit (LEL), a continuous gas-monitoring system shall be connected to the emergency control station. The maximum permitted time-weighted average exposures to be utilized shall be as published in 29 CFR 1910.1000.
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CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE
CHAPTER 15 – SOLAR ENERGY SYSTEMS
(Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
|Adopting Agency
Adopt Entire Chapter
Adopt Entire Chapter as
amended (amended sections
listed below)
Adopt only those sections
that are listed below
Chapter/Section
1502.CMC § 12.7 High relevance — show source text
Where mounted on a concrete base, a means shall be provided and installed within [1] / 2 inch (12.7 mm) of the top of the concrete base that will prevent flow from the supply piping in the event that the dispenser is displaced from its mounting. 2. A manual shutoff valve and an excess flow-control check valve shall be located in the liquid line between the pump and the dispenser inlet where the dispensing device is installed at a remote location and is not part of a complete storage and dispensing unit mounted on a common base. 3. An excess flow-control check valve or an emergency shutoff valve shall be installed in or on the dispenser at the point at which the dispenser hose is connected to the liquid piping. 4. A listed automatic-closing type hose nozzle valve with or without a latch-open device shall be provided on island-type dispensers.
2307.6.2 Hoses. Hoses and piping for the dispensing of LP-gas shall be provided with hydrostatic relief valves. The hose length shall not exceed 18 feet (5486 mm). An approved method shall be provided to protect the hose against mechanical damage.
2307.6.3 Emergency breakaway devices. Dispenser hoses shall be equipped with a listed emergency breakaway device designed to retain liquid on both sides of the breakaway point. Where hoses are attached to hose-retrieving mechanisms, the emergency breakaway device shall be located such that the breakaway device activates to protect the dispenser from being displaced.
2307.6.4 Vehicle impact protection. Where installed within 10 feet of vehicle traffic, LP-gas storage containers, pumps and dispensers shall be protected in accordance with Section 2307.5, Item 2.
2307.7 Public fueling of motor vehicles. Self-service LP-gas dispensing systems, including key, code and card lock dispensing systems, shall be limited to the filling of permanently mounted containers providing fuel to the LP-gas powered vehicle.
The requirements for self-service LP-gas dispensing systems shall be in accordance with the following:
The arrangement and operation of the transfer of product into a vehicle shall be in accordance with this section and Chapter 61.
The system shall be provided with an emergency shutoff switch located within 100 feet (30 480 mm) of, but not less than 20 feet (6096 mm) from, dispensers.
The owner of the LP-gas motor fuel-dispensing facility or the owner’s designee shall provide for the safe operation of the system and the training of users.
The dispenser and hose-end valve shall release not more than [1] / 8 fluid ounce (4 cc) of liquid to the atmosphere upon breaking the connection with the fill valve on the vehicle.
Portable fire extinguishers shall be provided in accordance with Section 2305.5.
Warning signs shall be provided in accordance with Section 2305.6.
The area around the dispenser shall be maintained in accordance with Section 2305.7.
2307.8 Overfilling. LP-gas containers shall not be filled with LP-gas in excess of the volume determined using the fixed maximum liquid level gauge installed on the container, the volume determined by the overfilling prevention device installed on the container or the weight determined by the required percentage of the water capacity marked on the container.
SECTION 2308—COMPRESSED NATURAL GAS MOTOR FUEL-DISPENSING FACILITIES
CMC § 7.8.1.1 High relevance — show source text
** System shutoff valves shall be readily accessible for operation and installed so as to be protected from physical damage. System shutoff valves shall be marked with a metal tag or other permanent means attached by the installing agency so that the gas piping systems supplied through them can be readily identified. [NFPA 54:7.8.1.1, 7.8.1.2]
1310.11.1.1 Shutoff Valves for Multiple House Lines. In multiple-tenant buildings supplied through a master meter, through one service regulator where a meter is not provided, or where meters or service regulators are not readily accessible from the appliance or equipment location, an individual shutoff valve for each apartment or tenant line shall be provided at a convenient point of general accessibility. In a common system serving a number of individual buildings, shutoff valves shall be installed at each building. [NFPA 54:7.8.3.1] 1310.11.2 Emergency Shutoff Valves. An exterior shutoff valve to permit turning off the gas supply to each building in an emergency shall be provided. The emergency shutoff valves shall be plainly marked as such and their locations posted as required by the Authority Having Jurisdiction. [NFPA 54:7.8.3.2] 1310.11.3 Shutoff Valve for Laboratories. Each laboratory space containing two or more gas outlets installed on tables, benches, or in hoods in educational, research,
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FUEL GAS PIPING
commercial, and industrial occupancies shall have a single shutoff valve through which all such gas outlets are supplied. The shutoff valve shall be accessible, located within the laboratory or adjacent to the laboratory’s egress door, and identified. [NFPA 54:7.8.3.3] 1310.11.4 System Shutoff Valves. Where a system shutoff valve is installed, the valve shall comply with Section 1308.12. [NFPA 54:7.8.4]
1310.12 Prohibited Devices. Devices shall not be placed within the interior of gas piping or fittings where such devices reduce the cross-sectional area or otherwise obstruct the free flow of gas, except where allowance in the piping system design has been made for such devices. [NFPA 54:7.9] 1310.13 Systems Containing Gas-Air Mixtures Out- side the Flammable Range. Where gas-air mixing machines are employed to produce mixtures above or below the flammable range, they shall be provided with stops to prevent adjustment of the mixture to within or approaching the flammable range. [NFPA 54:7.10] 1310.14 Systems Containing Flammable Gas-Air Mixtures. Systems containing flammable gas-air mixtures shall be in accordance with Section 1310.14.1 through Section 1310.14.6.
1310.14.1 Required Components. A central premix system with a flammable mixture in the blower or compressor shall consist of the following components:
(1) Gas-mixing machine in the form of an automatic gas-air proportioning device combined with a downstream blower or compressor.
(2) Flammable mixture piping, minimum Schedule 40.
(3) Automatic firecheck(s).
CMC § 5505.1.2 High relevance — show source text
5505.1.2 Piping systems. Piping, tubing, valves and joints and fittings conveying cryogenic fluids shall be installed in accordance with the material-specific provisions of Section 5501.1 and Sections 5505.1.2.1 through 5505.1.2.6.
5505.1.2.1 Design and construction. Piping systems shall be suitable for the use intended through the full range of pressure and temperature to which they will be subjected. Piping systems shall be designed and constructed to provide adequate allowance for expansion, contraction, vibration, settlement and fire exposure.
5505.1.2.2 Joints. Joints on container piping and tubing shall be threaded, welded, silver brazed or flanged.
5505.1.2.3 Valves and accessory equipment. Valves and accessory equipment shall be suitable for the intended use at the temperatures of the application and shall be designed and constructed to withstand the maximum pressure at the minimum temperature to which they will be subjected.
5505.1.2.3.1 Shutoff valves on containers. Shutoff valves shall be provided on all container connections except for pressure relief devices. Shutoff valves shall be provided with access thereto and located as close as practical to the container.
5505.1.2.3.2 Shutoff valves on piping. Shutoff valves shall be installed in piping containing cryogenic fluids where needed to limit the volume of liquid discharged in the event of piping or equipment failure. Pressure relief valves shall be installed where liquid is capable of being trapped between shutoff valves in the piping system (see Section 5503.2).
5505.1.2.4 Physical protection and support. Piping systems shall be supported and protected from physical damage. Piping passing through walls shall be protected from mechanical damage.
5505.1.2.5 Corrosion protection. Above-ground piping that is subject to corrosion because of exposure to corrosive atmospheres, shall be constructed of materials to resist the corrosive environment or otherwise protected against corrosion. Belowground piping shall be protected against corrosion.
5505.1.2.6 Testing. Piping systems shall be tested and proven free of leaks after installation as required by the standards to which they were designed and constructed. Test pressures shall be not less than 150 percent of the maximum allowable working pressure where hydraulic testing is conducted or 110 percent where testing is conducted pneumatically.
5505.2 Indoor use. Indoor use of cryogenic fluids shall comply with the material-specific provisions of Section 5501.1.
5505.3 Outdoor use. Outdoor use of cryogenic fluids shall comply with the material specific provisions of Sections 5501.1, 5505.3.1 and 5505.3.2.
5505.3.1 Separation. Distances from lot lines, buildings and exposure hazards shall comply with Section 5504.3 and the materialspecific provisions of Section 5501.1.
5505.3.2 Emergency shutoff valves. Manual or automatic emergency shutoff valves shall be provided to shut off the cryogenic fluid supply in case of emergency. An emergency shutoff valve shall be located at the source of supply and at the point where the system enters the building.
5505.4 Filling and dispensing. Filling and dispensing of cryogenic fluids shall comply with Sections 5505.4.1 through 5505.4.3.
CMC § 5003.1.2 High relevance — show source text
Exempted materials and conditions listed in this table are required to comply with provisions of this code that are not based on exceeding maximum allowable quantities in
Section 5003.|5003.1.2 Conversion. Where quantities are indicated in pounds and where the weight per gallon of the liquid is not provided to the fire code official, a conversion factor of 10 pounds per gallon (1.2 kg/L) shall be used.
5003.1.3 Quantities not exceeding the maximum allowable quantity per control area. The storage, use and handling of hazardous materials in quantities not exceeding the maximum allowable quantity per control area indicated in Tables 5003.1.1(1) through 5003.1.1(4) shall be in accordance with Sections 5001 and 5003.
5003.1.4 Quantities exceeding the maximum allowable quantity per control area. The storage and use of hazardous materials in quantities exceeding the maximum allowable quantity per control area indicated in Tables 5003.1.1(1) through 5003.1.1(4) shall be in accordance with this chapter.
5003.2 Systems, equipment and processes. Systems, equipment and processes utilized for storage, dispensing, use or handling of hazardous materials shall be in accordance with Sections 5003.2.1 through 5003.2.9.
5003.2.1 Design and construction of containers, cylinders and tanks. Containers, cylinders and tanks shall be designed and constructed in accordance with approved standards. Containers, cylinders, tanks and other means used for containment of hazardous materials shall be of an approved type. Pressure vessels not meeting DOTn requirements for transportation shall comply with the ASME Boiler and Pressure Vessel Code.
5003.2.2 Piping, tubing, valves and fittings. Piping, tubing, valves, and fittings conveying hazardous materials shall be designed and installed in accordance with ASME B31.1 or other approved standards, and shall be in accordance with Sections 5003.2.2.1 and 5003.2.2.2.
5003.2.2.1 Design and construction. Piping, tubing, valves, fittings and related components used for hazardous materials shall be in accordance with the following:
- Piping, tubing, valves, fittings and related components shall be designed and fabricated from materials that are compatible with the material to be contained and shall be of adequate strength and durability to withstand the pressure, structural and seismic stress and exposure to which they are subject.
- Piping and tubing shall be identified in accordance with ASME A13.1 to indicate the material conveyed.
- Manual valves or automatic remotely activated fail-safe emergency shutoff valves shall be installed on supply piping and tubing and provided with ready access at the following locations: 3.1. The point of use. 3.2. The tank, cylinder or bulk source.
- Manual emergency shutoff valves and controls for remotely activated emergency shutoff valves shall be clearly visible, provided with ready access and identified in an approved manner.
- Backflow prevention or check valves shall be provided where the backflow of hazardous materials could create a hazardous condition or cause the unauthorized discharge of hazardous materials.
Exceptions:
- Piping for inlet connections designed to prevent backflow.
- Piping for pressure relief devices.
CMC § 1325.13 High relevance — show source text
1325.13 Performance Criteria and Testing — Gas, Medical–Surgical Vacuum, and WAGD. Category 2 systems shall comply with Section 1324.0. [NFPA 99:5.2.12]
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HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICAL VACUUM SYSTEMS
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1326.6 Station Outlets and Inlets. Category 3 systems shall comply with Section 1315.0. [NFPA 99:5.3.5]
1326.7 Pressure and Vacuum Indicators. Category 3 systems shall comply with Section 1316.2. [NFPA 99:5.3.8] 1326.8 Warning Systems. Warning systems associated with Category 3 systems shall provide the master, area, and local alarm functions of a Category 1 system as required in Section 1317.0, except as follows:
(1) Warning systems shall be permitted to be a single alarm panel (i.e., a combination master/area alarm panel).
(2) The alarm panel shall be located in an area of continuous surveillance while the facility is in operation.
(3) Pressure and vacuum switches/sensors shall be mounted at the source equipment with a pressure indicator at the master alarm panel.
(4) Electrical power for warning systems shall be in accordance with Section 6.6 of NFPA 99 for Category 3 and Category 4 spaces. [NFPA 99:5.3.9]
1326.9 Distribution. Category 3 systems shall comply with Section 1318.0 through Section 1323.12. [NFPA 99:5.3.10]
1326.10 Labeling and Identification. Category 3 systems shall comply with Section 1323.13 through Section 1323.15.
[NFPA 99:5.3.11]
Part V – Dental Gas and Vacuum Systems.
1327.0 Dental Gas and Vacuum Systems. 1327.1 General. Dental gas and vacuum systems shall comply with this code and NFPA 99. 1327.2 Emergency Shutoff Valves (Oxygen and Nitrous Oxide).
(1) All Category 2 medical gas systems shall have an emergency shutoff valve accessible from all use-point locations in an emergency.
(2) Where a central medical gas supply system supplies two treatment facilities, each facility shall be provided with an emergency shutoff valve located in that treatment facility so as to be accessible from all use-point locations in an emergency.
(3) Emergency shutoff valves shall be labeled to indicate the gas controlled by the shutoff valve and shall shut off only the gas to the treatment facility that they serve.
(4) A remotely activated shutoff valve at a gas supply manifold shall not be used for emergency shutoff. For clinical purposes, such a remote valve actuator shall not fail-close in the event of loss of electric power. Where remote actuators are the type that fail-open, it shall be mandatory that cylinder shutoff valves be closed whenever the system is not in use. [NFPA 99:15.4.2.6.1 – 15.4.2.6.4.2]
CMC § 7.8.1.1 High relevance — show source text
[NFPA 54:7.8.1.1 – 7.8.1.2] 1210.9.2 Shutoff Valves for Multiple House Lines. In multiple-tenant buildings supplied through a master meter, through one service regulator where a meter is not provided, or where meters or service regulators are not readily accessible from the appliance or equipment location, an individual shutoff valve for each apartment or tenant line shall be provided at a convenient point of general accessibility. In a common system serving a number of individual buildings, shutoff valves shall be installed at each building. [NFPA 54:7.8.3.1] 1210.9.3 Emergency Shutoff Valves. An exterior shutoff valve to permit turning off the gas supply to each building in an emergency shall be provided. The emergency shutoff valves shall be plainly marked as such and their locations posted as required by the Authority Having Jurisdiction. [NFPA 54:7.8.3.2]
1210.9.4 Shutoff Valve for Laboratories. Each laboratory space containing two or more gas outlets installed on tables, benches, or in hoods in educational, research, commercial and industrial occupancies shall have a single shutoff valve through which all such gas outlets are supplied. The shutoff valve shall be accessible, located within the laboratory or adjacent to the laboratory’s egress door, and identified. [NFPA 54:7.8.3.3] 1210.9.5 System Shutoff Valves. Where a system shutoff valve is installed, the valve shall comply with Section 1208.13. [NFPA 54:7.8.4]
1210.10 Prohibited Devices. Devices shall not be placed within the interior of gas piping or fittings where such devices reduce the cross-sectional area or otherwise obstruct the free flow of gas, except where allowance in the piping system design has been made for such devices. [NFPA 54:7.9] 1210.11 Systems Containing Gas-Air Mixtures Out- side the Flammable Range. Where gas-air mixing machines are employed to produce mixtures above or below the flammable range, they shall be provided with stops to prevent adjustment of the mixture to within or approaching the flammable range. [NFPA 54:7.10] 1210.12 Systems Containing Flammable Gas-Air Mixtures. Systems containing flammable gas-air mixtures shall be in accordance with Section 1210.12.1 through Section 1210.12.6.
1210.12.1 Required Components. A central premix system with a flammable mixture in the blower or compressor shall consist of the following components:
(1) Gas-mixing machine in the form of an automatic gas-air proportioning device combined with a downstream blower or compressor.
(2) Flammable mixture piping, minimum Schedule 40.
(3) Automatic firecheck(s).
2025 CALIFORNIA PLUMBING CODE 227
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FUEL GAS PIPING
(4) Safety blowout(s) or backfire preventers for systems utilizing flammable mixture lines above 2 [1] ⁄ 2 inches (65 mm) nominal pipe size (NPS) or the equivalent.
CMC § 1310.10 High relevance — show source text
(6) The provisions of Section 1310.10(4) and Section 1310.10(5) shall not apply to listed quick-disconnect devices of the flush-mounted type or listed gas convenience outlets. Such devices shall be installed in accor dance with the manufacturer’s installation instructions.
[NFPA 54:7.7.1.1 – 7.7.1.6] 1310.10.1 Cap Outlets. Each outlet, including a valve, shall be closed gastight with a threaded plug or cap immediately after installation and shall be left closed until the appliance or equipment is connected thereto. When an appliance or equipment is disconnected from an outlet and the outlet is not to be used again immediately, it shall be capped or plugged gastight.
Exceptions:
(1) Laboratory appliances installed in accordance with Section 1312.3.1 shall be permitted.
(2) The use of a listed quick-disconnect device with integral shutoff or listed gas convenience outlet shall be permitted. [NFPA 54:7.7.2.1] 1310.10.1.1 Appliance Shutoff Valves. Appliance shutoff valves installed in fireplaces shall be removed and the piping capped gastight where the fireplace is used for solid fuel burning. [NFPA 54:7.7.2.2] 1310.11 Manual Gas Shutoff Valves. An accessible gas shutoff valve shall be provided upstream of each gas pressure regulator. Where two gas pressure regulators are installed in series in a single gas line, a manual valve shall not be required at the second regulator. [NFPA 54:7.8.2] 1310.11.1 Accessibility of Gas Valves. System shutoff valves shall be readily accessible for operation and installed so as to be protected from physical damage. System shutoff valves shall be marked with a metal tag or other permanent means attached by the installing agency so that the gas piping systems supplied through them can be readily identified. [NFPA 54:7.8.1.1, 7.8.1.2]
1310.11.1.1 Shutoff Valves for Multiple House Lines. In multiple-tenant buildings supplied through a master meter, through one service regulator where a meter is not provided, or where meters or service regulators are not readily accessible from the appliance or equipment location, an individual shutoff valve for each apartment or tenant line shall be provided at a convenient point of general accessibility. In a common system serving a number of individual buildings, shutoff valves shall be installed at each building. [NFPA 54:7.8.3.1] 1310.11.2 Emergency Shutoff Valves. An exterior shutoff valve to permit turning off the gas supply to each building in an emergency shall be provided. The emergency shutoff valves shall be plainly marked as such and their locations posted as required by the Authority Having Jurisdiction. [NFPA 54:7.8.3.2] 1310.11.3 Shutoff Valve for Laboratories. Each laboratory space containing two or more gas outlets installed on tables, benches, or in hoods in educational, research,
2025 CALIFORNIA MECHANICAL CODE 287
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FUEL GAS PIPING
CMC § 1212.3.1 High relevance — show source text
Exceptions:
(1) Laboratory appliances installed in accordance with Section 1212.3.1 shall be permitted.
(2) The use of a listed quick-disconnect device with integral shutoff or listed gas convenience outlet shall be permitted. [NFPA 54:7.7.2.1] 1210.8.2 Appliance Shutoff Valves. Appliance shutoff valves installed in fireplaces shall be removed, and the piping capped gastight where the fireplace is used for solid fuel burning. [NFPA 54:7.7.2.2] 1210.9 Manual Gas Shutoff Valves. An accessible gas shutoff valve shall be provided upstream of each gas pressure regulator. Where two gas pressure regulators are installed in series in a single gas line, a manual valve shall not be required at the second regulator. [NFPA 54:7.8.2]
1210.9.1 Accessibility of Gas Valves. System shutoff valves shall be readily accessible for operation and installed so as to be protected from physical damage. System shutoff valves shall be marked with a metal tag or other permanent means attached by the installing agency so that the gas piping systems supplied through them can be readily identified. [NFPA 54:7.8.1.1 – 7.8.1.2] 1210.9.2 Shutoff Valves for Multiple House Lines. In multiple-tenant buildings supplied through a master meter, through one service regulator where a meter is not provided, or where meters or service regulators are not readily accessible from the appliance or equipment location, an individual shutoff valve for each apartment or tenant line shall be provided at a convenient point of general accessibility. In a common system serving a number of individual buildings, shutoff valves shall be installed at each building. [NFPA 54:7.8.3.1] 1210.9.3 Emergency Shutoff Valves. An exterior shutoff valve to permit turning off the gas supply to each building in an emergency shall be provided. The emergency shutoff valves shall be plainly marked as such and their locations posted as required by the Authority Having Jurisdiction. [NFPA 54:7.8.3.2]
1210.9.4 Shutoff Valve for Laboratories. Each laboratory space containing two or more gas outlets installed on tables, benches, or in hoods in educational, research, commercial and industrial occupancies shall have a single shutoff valve through which all such gas outlets are supplied. The shutoff valve shall be accessible, located within the laboratory or adjacent to the laboratory’s egress door, and identified. [NFPA 54:7.8.3.3] 1210.9.5 System Shutoff Valves. Where a system shutoff valve is installed, the valve shall comply with Section 1208.13. [NFPA 54:7.8.4]
CMC § 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]
238 2025 CALIFORNIA MECHANICAL CODE
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REFRIGERATION
Frequently asked questions
Who must install these shutoff valves?
The owner/installer of HPP supply piping serving fabrication areas and exit corridor entries must provide the valves to meet § 1406.2.1.5.
Do the requirements apply to waste lines?
No. § 1406.2.1.5 applies to piping and tubing other than waste lines.
Are remote actuators allowed?
Yes — the code allows automatic remotely activated valves, but they must be fail‑safe per § 1406.2.1.5. Confirm AHJ acceptance and reliability testing.
Are excess flow valves required anywhere?
Yes — the section specifies that excess flow valves shall be installed as required by the fire code at entries into exit corridors. § 1406.2.1.5.
Is there an exception for occasional piping crossings?
Yes — occasional transverse crossings that are enclosed within the corridor may be exempt from Sections 1406.2.1.1–1.6 (including the shutoff‑valve rule) per the exception in § 1406.2.1. Confirm with the AHJ.
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