CMC · California Mechanical Code

How must dampers be actuated, tested and accessed for inspection?

Dampers that protect fire/smoke openings must be listed, have the correct actuators or detectors, be tested per NFPA 80/105, and be reachable by a tool‑free access opening (minimum 12 in where specified) with permanent labeling so inspectors can maintain and verify operation.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

In plain English: Fire dampers, smoke dampers and combination fire/smoke dampers must be listed and actuatable per the Building Code § 717.3, tested per the referenced standards, and provided with approved, tool‑free access and permanent identification so they can be inspected and maintained (see § 606.6, § 606.8, § 717.3). Testing references are to the NFPA standards for smoke and fire dampers; actuation requirements specify detector location, temperature ratings and other control conditions. These requirements are set out in the California Mechanical Code and cross‑referenced to the California Building Code provisions cited below (see § 606.6, § 606.8, § 717.3) .

Most important rule: Provide a listed damper with the correct actuator and temperature/detection device, provide an access opening large enough for inspection that does not reduce the assembly rating, and test the damper per the NFPA standard(s) referenced by the code (see § 606.6 and § 717.4).

Requirements in detail

What must be tested and which standard applies

  • Smoke dampers must be tested in accordance with NFPA 105 per § 606.6.
  • Fire dampers must be tested in accordance with NFPA 80 per § 606.6.
  • Combination fire/smoke dampers must be tested to both NFPA 80 and NFPA 105 per § 606.6.

Note: The CMC points you to the NFPA test/inspection standards but does not restate test frequencies or full procedures — those are in NFPA 80 and NFPA 105 (see § 606.6) .

How dampers must be actuated (triggering and operating elements)

  • Fire damper actuation (primary heat device) must have an operating temperature that is about 50°F (10°C) above normal duct temperature but not less than 160°F (71°C); a higher allowance (up to 350°F / 177°C) applies where the damper is in a smoke control system complying with Section 909 (see § 717.3.3.1) .
  • Smoke damper actuation: dampers close on actuation of a listed smoke detector installed per § 717.3.3.2. If the detector is in the duct it must be installed inside the duct or outside with sampling tubes and the detector (or sampling tubes) must be within 5 feet (1524 mm) of the damper; detectors must be listed for the expected air velocity, temperature and humidity at the installation point (see § 717.3.3.2(1)) .
  • Combination dampers follow both the fire and smoke actuation rules in § 717.3.3.3; dampers in smoke‑control shafts shall not be activated by local detectors unless secondary to smoke‑control system controls.

Access, identification and inspection openings

  • Provide an approved means of access large enough to permit inspection and maintenance of the damper and its operating parts; access shall not require the use of tools and shall not reduce the fire‑resistance rating or integrity of the assembly (see § 606.8 and § 717.4.1) .
  • For dampers equipped with fusible links or internal operators, provide an access door not less than 12 inches (305 mm) square or a removable duct section (see § 717.4.1). .
  • Access points must be permanently identified on the exterior with a label whose letters are not less than 1/2 inch (12.7 mm) in height reading “SMOKE DAMPER,” “FIRE DAMPER,” or “FIRE/SMOKE DAMPER” per § 606.8 and § 717.4.2. .
  • If space or barriers restrict access, the damper must be single‑ or multi‑blade and comply with the remote inspection provisions of NFPA 80 or NFPA 105 (see § 717.4.1.2) .

Ratings and minimums that affect actuation/testing/inspection

  • Fire damper minimum ratings: per Table 717.3.2.1 fire dampers must have minimum ratings of 1.5 hours for penetrations of assemblies less than 3 hours and 3 hours where the assembly is 3 hours or greater (see § 717.3.2.1) .
  • Smoke damper leakage rating: Class I or II and elevated temperature rating not less than 250°F (121°C) (see § 717.3.2.2) .
  • Corridor dampers must meet both UL 555 (fire) and UL 555S (smoke) and demonstrate acceptable closure when subjected to 150 feet per minute (0.76 m/s) across the damper face during a UL 555 fire test (see § 717.3.1 and § 717.3.2.4) .

Decision‑relevant dimensions and values (quick reference table)

Item Required value / limit Code Reference
Minimum access for dampers with fusible links/internal operators 12 in (305 mm) square access door or removable duct section § 717.4.1
Access labeling Letters not less than 1/2 in (12.7 mm) high reading the damper type § 606.8 and § 717.4.2
Access — tools Access shall not require the use of tools § 606.8
Fire damper actuation temperature ~50°F above normal duct temp but not less than 160°F (71°C) (350°F allowed for smoke control) § 717.3.3.1
Smoke damper elevated temp rating Not less than 250°F (121°C) § 717.3.2.2
Smoke detector location for in‑duct damper Detector or sampling tube within 5 ft (1524 mm) of damper; detector listed for air velocity/temp/humidity § 717.3.3.2(1)
Fire damper minimum rating 1.5 hrs (<3‑hr assembly); 3 hrs (≥3‑hr assembly) Table 717.3.2.1 (§ 717.3.2.1)
Corridor damper velocity test 150 fpm across damper face during UL 555 fire exposure § 717.3.1 / § 717.3.2.4
Required test standards NFPA 80 (fire), NFPA 105 (smoke), both for combination § 606.6

Exceptions & special cases

  • Dampers located where a fire damper would interfere with an engineered smoke control system must use an approved alternative protection; the project's rational analysis for smoke control must address damper/duct performance in smoke‑control mode (see § 717.2.1) .
  • If access is restricted by space or physical barriers, the damper is allowed to be single‑ or multi‑blade and must meet remote inspection requirements of NFPA 80 or NFPA 105 (see § 717.4.1.2) .
  • When automatic activation of a smoke damper causes HVAC shutdown, there are limited exceptions (e.g., engineered smoke evacuation systems, analyses showing shutoff creates greater hazard); the HVAC must not restart until dampers are reset and fully opened (see § 606.4.1 and related text in § 606.4) .
  • Combination dampers in smoke‑control shaft penetrations must not be activated by local detectors unless those detectors are secondary to the smoke control system (see § 717.3.3.3) .

Common mistakes

  • Installing access panels that are smaller than 12 in where a fusible link or internal operator is present, or that require tools to open (violates § 717.4.1 and § 606.8) .
  • Placing a duct smoke detector more than 5 ft from the damper or using a detector not listed for the duct air velocity/temperature/humidity (violates § 717.3.3.2(1)) .
  • Using fusible links or actuators with the wrong temperature rating (remember not less than 160°F unless smoke control allowances apply — § 717.3.3.1) .
  • Failing to test dampers per NFPA 80/NFPA 105 because the CMC itself defers to those standards (see § 606.6) — do not invent test intervals; consult the NFPA standards for exact inspection/test frequency and procedures .
  • Omitting permanent exterior identification (label letters ≥ 1/2 in) on access points (violates § 606.8 and § 717.4.2) .

Worked example — concrete scenario

Scenario: A new HVAC duct penetrates a 2‑hour fire‑resistance‑rated floor assembly. You must install and detail the damper so it meets code.

  • Damper type and rating: The penetration is in a < 3‑hour assembly, so the fire damper must have a minimum rating of 1.5 hours (Table 717.3.2.1 / § 717.3.2.1) .
  • Actuation device: The duct normally runs at 70°F. The fire‑damper fusible link operating temperature must be approximately 50°F above normal but not less than 160°F, so you must use a 160°F link (per § 717.3.3.1) .
  • Smoke detection: If the damper is a combination fire/smoke damper and needs smoke actuation, install the smoke detector or sampling tube within 5 ft (1524 mm) of the damper and select a detector listed for the duct velocity and temperature expected (see § 717.3.3.2(1)) .
  • Access and identification: Provide an access door 12 in x 12 in (because the damper has a fusible link/internal operator) that does not require tools to open, that does not reduce the 2‑hour assembly’s rating, and label the exterior “FIRE/SMOKE DAMPER” with letters ≥ 1/2 in high (see § 717.4.1, § 606.8, § 717.4.2) .
  • Testing / commissioning: Test the fire portion per NFPA 80 and the smoke portion per NFPA 105 as required by § 606.6; follow the NFPA procedures for functional closure tests and recordkeeping (see § 606.6) .

Related provisions (quick list)

  • § 606.6 — Periodic testing and inspection of dampers; references NFPA 80 and NFPA 105.
  • § 606.8 — Access and identification requirements for fire and smoke dampers (access means, tool‑free, labeling).
  • § 717.3 — Damper testing, ratings and actuation rules; includes specific actuation and rating tables.
  • § 717.4 — Access and identification (minimum access size, restricted access remote‑inspection option).
  • § 717.3.2.2 — Smoke damper leakage class and elevated‑temperature rating requirement (≥ 250°F).
  • Section 909 (CBC) — Smoke control system requirements and verification (relevant where dampers interact with smoke control systems). See [F] 909.12 and related provisions for verification and control sequencing.

If you need, I can extract the specific NFPA 80 / NFPA 105 inspection intervals and test procedures referenced by § 606.6, but those are in the NFPA documents (the CMC defers to them rather than listing frequencies or full procedures) .

Code references

Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:

  • CMC § 606.5 High relevance — show source text

    (3) Where analysis demonstrates shutoff would create a greater hazard.

    The HVAC system shall not be restarted again until all the dampers are reset and fully opened. 606.5 Corridor Dampers. Corridor dampers shall comply with the requirements of combination fire/smoke dampers in Section 606.4.

    606.6 Periodic Testing and Inspection. Testing and inspection of dampers shall be in accordance with the following:

    (1) Smoke dampers shall be tested in accordance with NFPA 105.

    (2) Fire dampers shall be tested in accordance with NFPA 80.

    (3) Combination fire/smoke dampers shall be tested in accordance with NFPA 80 and NFPA 105.

    606.7 Multiple Arrangements. Where size requires the use of multiple dampers, each damper shall be listed for use in multiple arrangements and installed in accordance with the manufacturer’s installation instructions.

    606.8 Access and Identification. Fire and smoke

    dampers shall be provided with an approved means of access large enough to allow inspection and maintenance of the damper and its operating parts. The access shall not affect the integrity of the fire-resistance-rated assembly. The access openings shall not reduce the fire-resistance rating of the assembly.

    Access shall not require the use of tools. Access doors in ducts shall be tight fitting and approved for the required duct construction. Access points shall be permanently identified on the exterior by a label with letters not less than [1] ⁄ 2 of an inch (12.7 mm) in height reading as one of the following:

    (1) Smoke Damper

    (2) Fire Damper

    (3) Fire/Smoke Damper

    606.9 Freedom from Interference. Dampers shall be installed in a manner to ensure positive closing or opening as required by function. Interior liners or insulation shall be held back from portions of a damper, its sleeve, or adjoining duct that would interfere with the damper’s proper operation. Exterior materials shall be installed so as to not interfere with the

    operation or maintenance of external operating devices needed for the function of the damper.

    606.10 Temperature Classification of Operating Ele- ments. Fusible links, thermal sensors, and pneumatic or electric operators shall have a temperature rating or classification as in accordance with the building code.

    607.0 Ventilating Ceilings.

    607.1 General. Perforated ceilings shall be permitted to be used for air supply within the limitations of this section. Exit corridors, where required to be of fire-resistive construction by the California Building Code, shall not have ventilating ceilings.

    607.1.1 [OSHPD 1, 1R, 2, 3, 4 & 5] Ventilating ceil- ings are not permitted in health facilities.

    607.2 Requirements. Ventilating ceilings shall comply with the following:

    (1) Suspended ventilating ceiling material shall have a Class 1 flame spread classification on both sides, determined in accordance with the building code. Suspended ventilating ceiling supports shall be of noncombustible materials.

    (2) Luminaires recessed into ventilating ceilings shall be of a type approved for that purpose.

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  • CMC § 909.11.2 High relevance — show source text

    [F] 909.11.2 Power sources and power surges. Elements of the smoke control system relying on volatile memories or the like shall be supplied with uninterruptable power sources of sufficient duration to span 15-minute primary power interruption. Elements of the smoke control system susceptible to power surges shall be suitably protected by conditioners, suppressors or other approved means.

    [F] 909.12 Detection and control systems. Fire detection systems providing control input or output signals to mechanical smoke control systems or elements thereof shall comply with the requirements of Section 907. Such systems shall be equipped with a control unit complying with UL 864 and listed as smoke control equipment.

    [F] 909.12.1 Verification. Control systems for mechanical smoke control systems shall include provisions for verification. Verification shall include positive confirmation of actuation, testing, manual override and the presence of power downstream of all disconnects. A preprogrammed weekly test sequence shall report abnormal conditions audibly, visually and by printed report. The preprogrammed weekly test shall operate all devices, equipment and components used for smoke control.

    The status of dampers shall be determined using limit or proximity switches installed at the damper or incorporated into the damper actuator. Where multiple dampers are grouped together in an assembly requiring one or more actuators, each damper shall be independently controlled by a separate actuator and provided with an individual limit or proximity switch, or the dampers shall be linked together by a reliable and durable mechanical or otherwise permanent means into one or more groups, with each group provided with a common limit or proximity switch.

    The status of fans shall be determined by sensing the air flow downstream of the fans using pressure differential switches or trans- mitters, or by other means of positive proof of air flow where approved by the enforcing authority.

    Exception: Where verification of individual components tested through the preprogrammed weekly testing sequence will interfere with, and produce unwanted effects to, normal building operation, such individual components are permitted to be bypassed from the preprogrammed weekly testing, where approved by the building official and in accordance with both of the following:

    1. Where the operation of components is bypassed from the preprogrammed weekly test, presence of power downstream of all disconnects shall be verified weekly by a listed control unit.
    2. Testing of all components bypassed from the preprogrammed weekly test shall be in accordance with Section 909.22.6 of the California Fire Code .

    [F] 909.12.2 Wiring. In addition to meeting requirements of the California Electrical Code, all wiring, regardless of voltage, shall be fully enclosed within continuous raceways.

    [F] 909.12.3 Activation. Smoke control systems shall be activated in accordance with this section.

    [F] 909.12.3.1 Pressurization, airflow or exhaust method. Mechanical smoke control systems using the pressurization, airflow or exhaust method shall have completely automatic control.

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    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

    [F] 909.12.3.2 Passive method. Passive smoke control systems actuated by approved spot-type detectors listed for releasing service shall be permitted.

  • CMC § 90.1 High relevance — show source text

    [ASHRAE 90.1: TABLE 6.4.3.4.3]

    Col1 OUTDOOR AIR INTAKE (CFM/ft2) Col3 EXHAUST/RELIEF (CFM/ft2) Col5
    CLIMATE ZONE NONMOTORIZED1 MOTORIZED NONMOTORIZED3 MOTORIZED
    0, 1, 2 0, 1, 2 0, 1, 2 0, 1, 2 0, 1, 2
    Any height 20 4 20 4
    3 3 3 3 3
    Any height 20 10 20 10
    4, 5B, 5C 4, 5B, 5C 4, 5B, 5C 4, 5B, 5C 4, 5B, 5C
    Fewer than three stories 204 10 20 10
    Three or more stories 204 10 204 10
    5A, 6, 7, 8 5A, 6, 7, 8 5A, 6, 7, 8 5A, 6, 7, 8 5A, 6, 7, 8
    Fewer than three stories 204 4 20 4
    Three or more stories 204 4 204 4

    For SI units: 1 square foot = 0.0929 m [2], 1 cubic foot per minute = 0.00047 m [3] /s, 1 cubic foot per minute = 0.4719 L/s, 1 cubic foot per minute per square foot = 5.08 [(L/s)/m [2] ], 1 inch water gauge = 0.249 kPa

    Notes:

    1 When tested in accordance with AMCA 500D.

    2 Dampers smaller than 12 inches (305 mm) in height, width, or diameter need not be tested but shall be of the same design and construction as the smallest tested damper meeting the listed leakage rate requirement.

    3 Nonmotorized dampers smaller than 24 inches (610 mm) in height, width, or diameter shall be permitted to have a leakage rate of 40 CFM/ft 2 [0.203 (m 3 /s)/m 2 ].

    4 Where permitted by Section E 503.4.6.4.1, exception 2.

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    APPENDIX E

    (2) Systems serving zones where humidity levels are required to be maintained with precision of not more than ±5 percent relative humidity to comply with applicable codes or accreditation standards or as approved by the Authority Having Jurisdiction.

    [ASHRAE 90.1:6.4.3.6.2]

  • CMC § 606.2 High relevance — show source text

    606.2 Fire Dampers. Fire dampers shall comply with UL 555, and shall be installed in accordance with the manufacturer’s installation instructions where required by the building code. Fire dampers shall have been tested for closure under airflow conditions and shall be labeled for both maximum airflow permitted and direction of flow. Where more than one damper is installed at a point in a single air path, the entire airflow shall be assumed to be passing through the smallest damper area.

    Ductwork shall be connected to damper sleeves or assemblies in accordance with the fire damper manufacturer’s installation instructions.

    606.3 Ceiling Radiation Dampers. Ceiling radiation dampers shall comply with UL 555C or shall be tested as part of a fire-resistance-rated floor-ceiling or roof-ceiling assembly in accordance with ASTM E119 or UL 263, and shall be installed in accordance with the manufacturer’s installation instructions in the fire-resistive ceiling membrane of floorceiling and roof-ceiling assemblies where required by the building code. Fire dampers not meeting the temperature limitation of ceiling radiation dampers shall not be used as a substitute.

    606.4 Combination Fire/Smoke Dampers. Combination fire/smoke dampers shall comply with UL 555 and UL 555S and the requirements in Section 606.1 and Section 606.2.

    606.4.1 When the automatic activation of a smoke damper or a combination smoke-fire damper occurs, the HVAC system serving such dampers shall immediately shut down.

    Exceptions:

    (1) HVAC systems that are part of an engineered smoke evacuation system.

    (2) Where the automatic activation causes all the smoke dampers and combination smoke-fire dampers to close in the enclosed space having a common atmos- phere where openings are required to be protected.

    (3) Where analysis demonstrates shutoff would create a greater hazard.

    The HVAC system shall not be restarted again until all the dampers are reset and fully opened. 606.5 Corridor Dampers. Corridor dampers shall comply with the requirements of combination fire/smoke dampers in Section 606.4.

    606.6 Periodic Testing and Inspection. Testing and inspection of dampers shall be in accordance with the following:

    (1) Smoke dampers shall be tested in accordance with NFPA 105.

    (2) Fire dampers shall be tested in accordance with NFPA 80.

    (3) Combination fire/smoke dampers shall be tested in accordance with NFPA 80 and NFPA 105.

    606.7 Multiple Arrangements. Where size requires the use of multiple dampers, each damper shall be listed for use in multiple arrangements and installed in accordance with the manufacturer’s installation instructions.

    606.8 Access and Identification. Fire and smoke

    dampers shall be provided with an approved means of access large enough to allow inspection and maintenance of the damper and its operating parts. The access shall not affect the integrity of the fire-resistance-rated assembly. The access openings shall not reduce the fire-resistance rating of the assembly.

    Access shall not require the use of tools. Access doors in ducts shall be tight fitting and approved for the required duct construction. Access points shall be permanently identified on the exterior by a label with letters not less than [1] ⁄ 2 of an inch (12.7 mm) in height reading as one of the following:

    (1) Smoke Damper

    (2) Fire Damper

  • CMC § 6-3 High relevance — show source text

    601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    602 Alteration—Level 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    603 Alteration—Level 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    604 Alteration—Level 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    605 Change of Occupancy. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    606 Additions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    607 Historic Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    CHAPTER 7 ALTERATIONS—LEVEL 1 . . . . . . . . . . . . . . . . . .7-3

    701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

    702 Building Elements and Materials . . . . . . . . . . . . . . . . . 7-3

    703 Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    704 Means of Egress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    705 Reroofing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

    706 Structural. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

    707 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

    708 Energy Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

    CHAPTER 8 ALTERATIONS—LEVEL 2 . . . . . . . . . . . . . . . . . .8-3

    801 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

    802 Building Elements and Materials . . . . . . . . . . . . . . . . . 8-3

  • CMC § 909.12.4 High relevance — show source text

    [F] 909.12.4 Automatic control. Where completely automatic control is required or used, the automatic-control sequences shall be initiated from an appropriately zoned automatic sprinkler system complying with Section 903.3.1.1, manual controls provided with ready access for the fire department and any smoke detectors required by engineering analysis.

    [F] 909.13 Control air tubing. Control air tubing shall be of sufficient size to meet the required response times. Tubing shall be flushed clean and dry prior to final connections and shall be adequately supported and protected from damage. Tubing passing through concrete or masonry shall be sleeved and protected from abrasion and electrolytic action.

    [F] 909.13.1 Materials. Control-air tubing shall be hard-drawn copper, Type L, ACR in accordance with ASTM B42, ASTM B43, ASTM B68/B68M, ASTM B88, ASTM B251 and ASTM B280. Fittings shall be wrought copper or brass, solder type in accordance with ASME B16.18 or ASME B16.22. Changes in direction shall be made with appropriate tool bends. Brass compression-type fittings shall be used at final connection to devices; other joints shall be brazed using a BCuP-5 brazing alloy with solidus above 1,100°F (593°C) and liquids below 1,500°F (816°C). Brazing flux shall be used on copper-to-brass joints only.

    Exception: Nonmetallic tubing used within control panels and at the final connection to devices provided that all of the following conditions are met:

    1. Tubing shall comply with the requirements of Chapter 6 of the California Mechanical Code .
    2. Tubing and connected devices shall be completely enclosed within a galvanized or paint-grade steel enclosure having a minimum thickness of 0.0296 inch (0.7534 mm) (No. 22 gage). Entry to the enclosure shall be by copper tubing with a protective grommet of neoprene or Teflon or by suitable brass compression to male barbed adapter.
    3. Tubing shall be identified by appropriately documented coding.
    4. Tubing shall be neatly tied and supported within the enclosure. Tubing bridging cabinets and doors or moveable devices shall be of sufficient length to avoid tension and excessive stress. Tubing shall be protected against abrasion. Tubing connected to devices on doors shall be fastened along hinges.

    [F] 909.13.2 Isolation from other functions. Control tubing serving other than smoke control functions shall be isolated by automatic isolation valves or shall be an independent system.

    [F] 909.13.3 Testing. Control air tubing shall be tested at three times the operating pressure for not less than 30 minutes without any noticeable loss in gauge pressure prior to final connection to devices.

    [F] 909.14 Marking and identification. The detection and control systems shall be clearly marked at all junctions, accesses and terminations.

    [F] 909.15 Control diagrams. Identical control diagrams showing all devices in the system and identifying their location and function shall be maintained current and kept on file with the fire code official, the fire department and in the fire command center in a format and manner approved by the fire code official.

  • CMC § 904.2.1 High relevance — show source text

    904.2.1 Restriction on using automatic sprinkler system exceptions or reductions. Automatic fire-extinguishing systems shall not be considered alternatives for the purposes of exceptions or reductions allowed for automatic sprinkler systems or by other requirements of this code.

    904.2.2 Commercial hood and duct systems. Each required commercial kitchen exhaust hood and duct system required by Section 606 to have a Type I hood shall be protected with an approved automatic fire-extinguishing system installed in accordance with this code.

    904.3 Installation. Automatic fire-extinguishing systems shall be installed in accordance with this section.

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    904.3.1 Electrical wiring. Electrical wiring shall be in accordance with the California Electrical Code.

    904.3.2 Actuation. Automatic fire-extinguishing systems shall be automatically actuated and provided with a manual means of actuation in accordance with Section 904.14.1. Where more than one hazard could be simultaneously involved in fire due to their proximity, all hazards shall be protected by a single system designed to protect all hazards that could become involved.

    Exception: Multiple systems shall be permitted to be installed if they are designed to operate simultaneously.

    904.3.3 System interlocking. Automatic equipment interlocks with fuel shutoffs, ventilation controls, door closers, window shutters, conveyor openings, smoke and heat vents and other features necessary for proper operation of the fire-extinguishing system shall be provided as required by the design and installation standard utilized for the hazard.

    904.3.4 Alarms and warning signs. Where alarms are required to indicate the operation of automatic fire-extinguishing systems, distinctive audible, visible alarms and warning signs shall be provided to warn of pending agent discharge. Where exposure to automatic-extinguishing agents poses a hazard to persons and a delay is required to ensure the evacuation of occupants before agent discharge, a separate warning signal shall be provided to alert occupants once agent discharge has begun. Audible signals shall be in accordance with Section 907.5.2.

    904.3.5 Monitoring. Where a building fire alarm system is installed, automatic fire-extinguishing systems shall be monitored by the building fire alarm system in accordance with NFPA 72.

    904.4 Inspection and testing. Automatic fire-extinguishing systems shall be inspected and tested in accordance with the provisions of this section prior to acceptance.

    904.4.1 Inspection. Prior to conducting final acceptance tests, all of the following items shall be inspected:

    1. Hazard specification for consistency with design hazard.

    2. Type, location and spacing of automatic- and manual-initiating devices.

    3. Size, placement and position of nozzles or discharge orifices.

    4. Location and identification of audible and visible alarm devices.

    5. Identification of devices with proper designations.

    6. Operating instructions.

    904.4.2 Alarm testing. Notification appliances, connections to fire alarm systems and connections to approved supervising stations shall be tested in accordance with this section and Section 907 to verify proper operation.

    904.4.2.1 Audible and visible signals. The audibility and visibility of notification appliances signaling agent discharge or system operation, where required, shall be verified.

    904.4.3 Monitor testing. Connections to protected premises and supervising station fire alarm systems shall be tested to verify proper identification and retransmission of alarms from automatic fire-extinguishing systems.

  • CMC § 717.3.3.5 High relevance — show source text

    717.3.3.5 Corridor damper actuation. Corridor damper actuation shall be in accordance with Sections 717.3.3.1 and 717.3.3.2.

    717.4 Access and identification. Access and identification of fire and smoke dampers shall comply with Sections 717.4.1 through 717.4.2.

    717.4.1 Access. Fire and smoke dampers shall be provided with an approved means of access that is large enough to permit inspection and maintenance of the damper and its operating parts. Dampers equipped with fusible links, internal operators, or both shall be provided with an access door that is not less than 12 inches (305 mm) square or provided with a removable duct section.

    717.4.1.1 Access openings. The access shall not affect the integrity of fire-resistance-rated assemblies. The access openings shall not reduce the fire-resistance rating of the assembly. Access doors in ducts shall be tight fitting and suitable for the required duct construction.

    717.4.1.2 Restricted access. Where space constraints or physical barriers restrict access to a damper for periodic inspection and testing, the damper shall be a single- or multi-blade type damper and shall comply with the remote inspection requirements of NFPA 80 or NFPA 105.

    717.4.2 Identification. Access points shall be permanently identified on the exterior by a label having letters not less than [1] / 2 inch (12.7 mm) in height reading: “FIRE/SMOKE DAMPER,” “SMOKE DAMPER” or “FIRE DAMPER.”

    717.5 Where required. Fire dampers, smoke dampers, combination fire/smoke dampers, ceiling radiation dampers and corridor dampers shall be provided at the locations prescribed in Sections 717.5.1 through 717.5.7 and 717.6. Where an assembly is required to have both fire dampers and smoke dampers, combination fire/smoke dampers or a fire damper and a smoke damper shall be provided.

    717.5.1 Fire walls. Ducts and air transfer openings permitted in fire walls in accordance with Section 706.11 shall be protected with listed fire dampers installed in accordance with their listing.

    717.5.1.1 Horizontal exits. A listed smoke damper designed to resist the passage of smoke shall be provided at each point a duct or air transfer opening penetrates a fire wall that serves as a horizontal exit.

    717.5.2 Fire barriers. In other than Group A, E, H, I, L and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal. Ducts and air transfer openings of fire barriers shall be protected with listed fire dampers installed in accordance with their listing. Ducts and air transfer openings shall not penetrate enclosures for interior exit stairways and ramps and exit passageways, except as permitted by Sections 1023.5 and 1024.6, respectively.

    Exceptions: Fire dampers are not required at penetrations of fire barriers where any of the following apply:

    1. Penetrations are tested in accordance with ASTM E119 or UL 263 as part of the fire-resistance-rated assembly.
    2. Ducts are used as part of an approved smoke control system in accordance with Section 909 and where the use of a fire damper would interfere with the operation of a smoke control system.
  • CMC § 6-2021 High relevance — show source text

    ANSI/NEMA WD 6-2021 Wiring Devices—Dimensional Specifications

    ANSI Z21.40.4a-1998 (R2022)/CGA 2.94a-M98 (R2022) Performance Testing and Rating of Gas-Fired, Air-Conditioning and Heat Pump Appliances

    ANSI Z21.47-2021/CSA 2.3:21 Gas-Fired Central Furnaces

    288 2025 CALIFORNIA ENERGY CODE

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    STANDARDS AND DOCUMENTS REFERENCED IN THE ENERGY CODE

    ANSI Z83.8-2016/CSA 2.6-2016 (R2021)

    Gas Unit Heaters, Gas Packaged Heaters, Gas Utility Heaters and Gas-Fired Duct Furnaces (2016)

    Available from:

    American National Standards Institute 25 West 43rd Street, 4th floor New York, NY 10036 (212) 642-4900

    ANSI/APSP/ICC-5-2011 American National Standard For Residential Inground Swimming Pools (2011 w/Addendum A)

    Available from: Association of Pool & Spa Professionals 2111 Eisenhower Ave. Alexandria, VA 22314 (703) 838-0083

    AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS (NATIONAL PUBLICATIONS)

    ASHRAE GUIDELINE 36-2021 High-Performance Sequences of Operation for HVAC Systems

    ANSI/ASHRAE Standard 52.2-2017

    Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size

    ANSI/ASHRAE Standard 55-2023

    Thermal Environment Conditions for Human Occupancy

    ANSI/ASHRAE Standard 62.1-2022 Ventilation and Acceptable Indoor Air Quality

    ANSI/ASHRAE Standard 62.2-2022

    Ventilation and Acceptable Indoor Air Quality in Residential Buildings

    ANSI/ASHRAE Standard 84-2020 Method of Testing Air-to-Air Heat/Energy Exchangers

    ANSI/ASHRAE/IES Standards 90.1-2022 Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings

    ANSI/ASHRAE Standard 154-2022 Ventilation for Commercial Cooking Operations

    ANSI/ASHRAE Standard 193-2010 (RA2014) Method of Test for Determining the Airtightness of HVAC Equipment

    ASHRAE Handbooks

    2023 ASHRAE Handbook - HVAC Applications Inch-Pound Edition

    2020 ASHRAE Handbook - HVAC Systems and Equipment I-P Edition

    2021 ASHRAE Handbook - Fundamentals I-P Edition

    Available from: American Society of Heating,

                             Refrigerating and Air Conditioning Engineers

    (ASHRAE) 1791 Tullie Circle N.E. Atlanta, GA 30329 www.ashrae.org

    AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS (REGIONAL PUBLICATION)

    ASHRAE Climatic Data for Region X Arizona, California, Hawaii, Nevada, Publication SPCDX, 1982, ISBN #20002196 and Supplement, 1994, ISBN #20002596

    Available from: Order Desk Building News 10801 National Boulevard Los Angeles, CA 90064 (800) 873-6397 or (310) 474-7771 www.bnibooks.com/

  • CMC § 717.2.3 High relevance — show source text

    717.2.3 Static dampers. Fire dampers and ceiling radiation dampers that are listed for use in static systems shall only be installed in heating, ventilation and air-conditioning systems that are automatically shut down in the event of a fire.

    7-34 2025 CALIFORNIA BUILDING CODE

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    FIRE AND SMOKE PROTECTION FEATURES

    717.2.4 Mechanical, electrical and plumbing controls. Mechanical, electrical and plumbing controls shall not be installed in air duct systems.

    Exception: Controls where the wiring is directly associated with the air distribution system. The wiring shall comply with the requirements of Section 601 of the California Mechanical Code and be as short as practicable.

    717.2.4.1 Controls not permitted to be installed through dampers. Mechanical, electrical and plumbing controls shall not be installed through fire dampers, smoke dampers, combination fire/smoke dampers or ceiling radiation dampers unless otherwise permitted by the manufacturer and the listing.

    717.3 Damper testing, ratings and actuation. Damper testing, ratings and actuation shall be in accordance with Sections 717.3.1 through 717.3.3.

    717.3.1 Damper testing. Dampers shall be listed and labeled in accordance with the standards in this section.

    1. Fire dampers shall comply with the requirements of UL 555.
    2. Smoke dampers shall comply with the requirements of UL 555S.
    3. Combination fire/smoke dampers shall comply with the requirements of both UL 555 and UL 555S.
    4. Ceiling radiation dampers shall comply with the requirements of UL 555C or shall be tested as part of a fire-resistancerated floor/ceiling or roof/ceiling assembly in accordance with ASTM E119 or UL 263.
    5. Corridor dampers shall comply with requirements of both UL 555 and UL 555S. Corridor dampers shall demonstrate acceptable closure performance when subjected to 150 feet per minute (0.76 mps) velocity across the face of the damper during the UL 555 fire exposure test.

    717.3.2 Damper rating. Damper ratings shall be in accordance with Sections 717.3.2.1 through 717.3.2.4.

    717.3.2.1 Fire damper ratings. Fire dampers shall have the minimum rating specified in Table 717.3.2.1.

    TABLE 717.3.2.1—FIRE DAMPER RATING Col2
    TYPE OF PENETRATION MINIMUM DAMPER RATING (hours)
    Less than 3-hour fire-resistance-rated assemblies 1.5
    3-hour or greater fire-resistance-rated assemblies 3

    717.3.2.2 Smoke damper ratings. Smoke damper leakage ratings shall be Class I or II. Elevated temperature ratings shall be not less than 250°F (121°C).

    717.3.2.3 Combination fire/smoke damper ratings. Combination fire/smoke dampers shall have the minimum rating specified for fire dampers in Table 717.3.2.1 and shall have the minimum rating specified for smoke dampers in Section 717.3.2.2.

  • CMC § 717.3.2.4 Medium relevance — show source text

    717.3.2.4 Corridor damper ratings. Corridor dampers shall have the following minimum ratings:

    1. One-hour fire-resistance rating.
    2. Class I or II leakage rating as specified in Section 717.3.2.2.

    717.3.3 Damper actuation. Damper actuation shall be in accordance with Sections 717.3.3.1 through 717.3.3.5 as applicable.

    717.3.3.1 Fire damper actuation. Primary heat responsive devices used to actuate fire dampers shall meet one of the following requirements:

    1. The operating temperature shall be approximately 50°F (10°C) above the normal temperature within the duct system, but not less than 160°F (71°C).
    2. The operating temperature shall be not more than 350°F (177°C) where located in a smoke control system complying with Section 909.

    717.3.3.2 Smoke damper actuation. The smoke damper shall close upon actuation of a listed smoke detector or detectors installed in accordance with Section 907.3 and one of the following methods, as applicable:

    1. Where a smoke damper is installed within a duct, a smoke detector shall be installed inside the duct or outside the duct with sampling tubes protruding into the duct. The detector or tubes within the duct shall be within 5 feet (1524 mm) of the damper. Air outlets and inlets shall not be located between the detector or tubes and the damper. The detector shall be listed for the air velocity, temperature and humidity anticipated at the point where it is installed. Other than in mechanical smoke control systems, dampers shall be closed upon fan shutdown where local smoke detectors require a minimum velocity to operate.
    2. Where a smoke damper is installed above smoke barrier doors in a smoke barrier, a spot-type detector shall be installed on either side of the smoke barrier door opening. The detector shall be listed for releasing service if used for direct interface with the damper.
    3. Where a smoke damper is installed within an air transfer opening in a wall, a spot-type detector shall be installed within 5 feet (1524 mm) horizontally of the damper. The detector shall be listed for releasing service if used for direct interface with the damper.

    2025 CALIFORNIA BUILDING CODE 7-35

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    FIRE AND SMOKE PROTECTION FEATURES

    1. Where a smoke damper is installed in a corridor wall or ceiling, the damper shall be permitted to be controlled by a smoke detection system installed in the corridor.
    2. Where a smoke detection system is installed in all areas served by the duct in which the damper will be located, the smoke dampers shall be permitted to be controlled by the smoke detection system.

    717.3.3.3 Combination fire/smoke damper actuation. Combination fire/smoke damper actuation shall be in accordance with Sections 717.3.3.1 and 717.3.3.2. Combination fire/smoke dampers installed in smoke control system shaft penetrations shall not be activated by local area smoke detection unless it is secondary to the smoke control system controls.

    717.3.3.4 Ceiling radiation damper actuation. The operating temperature of a ceiling radiation damper actuation device shall be 50°F (27.8°C) above the normal temperature within the duct system, but not less than 160°F (71°C).

  • CMC § 904.2 Medium relevance — show source text

    [F] 904.2 Where permitted. Automatic fire-extinguishing systems installed as an alternative to the required automatic sprinkler systems of Section 903 shall be approved by the fire code official.

    [F] 904.2.1 Restriction on using automatic sprinkler system exceptions or reductions. Automatic fire-extinguishing systems shall not be considered alternatives for the purposes of exceptions or reductions allowed for automatic sprinkler systems or by other requirements of this code.

    [F] 904.2.2 Commercial hood and duct systems. Each required commercial kitchen exhaust hood and duct system required by Section 606 of the California Fire Code or Chapter 5 of the California Mechanical Code to have a Type I hood shall be protected with an approved automatic fire-extinguishing system installed in accordance with this code.

    [F] 904.3 Installation. Automatic fire-extinguishing systems shall be installed in accordance with this section.

    [F] 904.3.1 Electrical wiring. Electrical wiring shall be in accordance with the California Electrical Code.

    2025 CALIFORNIA BUILDING CODE 9-17

    on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

    [F] 904.3.2 Actuation. Automatic fire-extinguishing systems shall be automatically actuated and provided with a manual means of actuation in accordance with Section 904.13.1. Where more than one hazard could be simultaneously involved in fire due to their proximity, all hazards shall be protected by a single system designed to protect all hazards that could become involved.

    Exception: Multiple systems shall be permitted to be installed if they are designed to operate simultaneously.

    [F] 904.3.3 System interlocking. Automatic equipment interlocks with fuel shutoffs, ventilation controls, door closers, window shutters, conveyor openings, smoke and heat vents and other features necessary for proper operation of the fire-extinguishing system shall be provided as required by the design and installation standard utilized for the hazard.

    [F] 904.3.4 Alarms and warning signs. Where alarms are required to indicate the operation of automatic fire-extinguishing systems, distinctive audible and visible alarms and warning signs shall be provided to warn of pending agent discharge. Where exposure to automatic-extinguishing agents poses a hazard to persons and a delay is required to ensure the evacuation of occupants before agent discharge, a separate warning signal shall be provided to alert occupants once agent discharge has begun. Audible signals shall be in accordance with Section 907.5.2.

    [F] 904.3.5 Monitoring. Where a building fire alarm system is installed, automatic fire-extinguishing systems shall be monitored by the building fire alarm system in accordance with NFPA 72.

    [F] 904.4 Inspection and testing. Automatic fire-extinguishing systems shall be inspected and tested in accordance with the provisions of this section prior to acceptance.

    [F] 904.4.1 Inspection. Prior to conducting final acceptance tests, all of the following items shall be inspected:

    1. Hazard specification for consistency with design hazard.

    2. Type, location and spacing of automatic- and manual-initiating devices.

    3. Size, placement and position of nozzles or discharge orifices.

    4. Location and identification of audible and visible alarm devices.

    5. Identification of devices with proper designations.

    6. Operating instructions.

Frequently asked questions

What inspection/test frequency does the CMC require for dampers?

The CMC (§ 606.6) requires testing “in accordance with” NFPA 80 (fire dampers) and NFPA 105 (smoke dampers) but does not list the inspection/test intervals itself; consult NFPA 80 and NFPA 105 for the required frequencies and procedures.

How large must an access opening be?

For dampers with fusible links or internal operators, provide an access door at least 12 in (305 mm) square, or a removable duct section. Access must also allow inspection/maintenance without tools and must not reduce the assembly rating (see § 717.4.1 and § 606.8).

Where do I install a smoke detector that will actuate an in‑duct smoke damper?

Install the detector inside the duct or outside with sampling tubes entering the duct, with the detector/tubes within 5 ft (1524 mm) of the damper. The detector must be listed for the duct’s expected air velocity, temperature and humidity (see § 717.3.3.2(1)).

Can a combination fire/smoke damper be actuated by a local detector in a smoke‑control shaft?

No — combination dampers in smoke‑control shaft penetrations shall not be activated by local area smoke detection unless that local actuation is secondary to the smoke control system controls (see § 717.3.3.3).

What size/type lettering is required to identify access points?

Labels must use letters not less than 1/2 inch (12.7 mm) high and read “SMOKE DAMPER,” “FIRE DAMPER,” or “FIRE/SMOKE DAMPER” on the exterior of the access point (see § 606.8 and § 717.4.2).

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