When must a combination fire/smoke damper be used?

Use a combination fire/smoke damper where a penetration requires protection for both fire and smoke (the device must meet both UL 555 and UL 555S and the related CMC provisions in §606.4).

How and how often must dampers be tested and made accessible?

Periodic testing and inspection are required: smoke dampers per NFPA 105, fire dampers per NFPA 80, and combination dampers per both NFPA 80 and 105. Provide approved access openings sized for inspection/maintenance and permanently identify access points. See §606.6 and §606.8 (CMC) and the CBC access rules at §717.4.

Can a damper be omitted when ducts serve a smoke control system?

Yes — where the ductwork is part of an approved smoke control system and a damper would interfere with its operation, dampers may be omitted per the CBC and Fire Code coordination (see CBC §717 exceptions and Fire Code Section 909 requirements for smoke control).

Fire, smoke & dampers

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

CMC § 717.5.2.1 High relevance — show source text
2. Fire and smoke dampers are not required where ducts are used as part of an approved smoke control system in accordance with Section 909 and where the use of a fire or smoke damper would interfere with the operation of a smoke control system.

717.5.2.1 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 barrier that serves as a horizontal exit.

717.5.3 Shaft enclosures. Shaft enclosures that are permitted to be penetrated by ducts and air transfer openings shall be protected with listed fire and smoke dampers installed in accordance with their listing.

Exceptions:
1. Fire dampers are not required at penetrations of shafts where any of the following criteria are met: 1.1. Steel exhaust subducts having a wall thickness of not less than 0.0187 inch (0.4712 mm) are extended not less than 22 inches (559 mm) vertically in exhaust shafts, and an exhaust fan is installed at the upper terminus of the shaft that is powered continuously in accordance with Section 909.11, so as to maintain a continuous upward airflow to the outdoors. 1.2. Penetrations are tested in accordance with ASTM E119 or UL 263 as part of the fire-resistance-rated assembly. 1.3. Ducts are used as part of an approved smoke control system designed and installed in accordance with Section 909 and where the fire damper will interfere with the operation of the smoke control system. 1.4. The penetrations are in parking garage exhaust or supply shafts that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction.
2. In Group B and R occupancies equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, smoke dampers are not required at penetrations of shafts where all of the following criteria are met: 2.1. Kitchen, clothes dryer, bathroom and toilet room exhaust openings are installed with steel exhaust subducts, having a wall thickness of not less than 0.0187 inch (0.4712 mm). 2.2. The subducts extend not less than 22 inches (559 mm) vertically. 2.3. An exhaust fan is installed at the upper terminus of the shaft that is powered continuously in accordance with the provisions of Section 909.11, so as to maintain a continuous upward airflow to the outdoors.
3. Smoke dampers are not required at penetration of exhaust or supply shafts in parking garages that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction.
4. Smoke dampers are not required at penetrations of shafts where ducts are used as part of an approved mechanical smoke control system designed in accordance with Section 909 and where the smoke damper will interfere with the operation of the smoke control system.
5. Fire dampers and combination fire/smoke dampers are not required in kitchen and clothes dryer exhaust systems where dampers are prohibited by the California Mechanical Code .
717.5.3.1 Continuous upward airflow. Fire dampers and smoke dampers shall not be installed in shafts that are required to maintain a continuous upward airflow path where closure of the damper would result in the loss of the airflow.
CMC § 602.3 High relevance — show source text
602.3 Tall Wood (Mass Timber) Buildings . . . . . . . . . . . . . . . . . . . . 137

602.4 Metallic . . . . . . . . . . . . . . . . . . . . . 138

602.5 Nonmetallic Ducts. . . . . . . . . . . . . 138

602.6 Vibration Isolators. . . . . . . . . . . . . 138

602.7 Corridors. . . . . . . . . . . . . . . . . . . . 138

603.0 Installation of Ducts . . . . . . . . . . . 138

603.1 General. . . . . . . . . . . . . . . . . . . . . 138

603.2 Under-Floor or Crawl Space. . . . . 138

603.3 Metal Ducts. . . . . . . . . . . . . . . . . . 138

603.4 Flexible Air Ducts . . . . . . . . . . . . . 138

603.5 Plastic Ducts. . . . . . . . . . . . . . . . . 139

603.6 Protection of Ducts . . . . . . . . . . . . 139

603.7 Support of Ducts. . . . . . . . . . . . . . 139

603.8 Protection Against Flood Damage . 139

603.9 Joints and Seams of Ducts. . . . . . 139

Table 603.9.1 Closure Markings . . . . . . . . . . . . . 140

603.10 Cross Contamination . . . . . . . . . . 140

603.11 Underground Installation . . . . . . . 140

603.12 Air Dispersion Systems . . . . . . . . 140

603.13 Clearances . . . . . . . . . . . . . . . . . . 140

604.0 Furnace Plenums and Air Ducts

Used in Fuel-Gas Appliances . . . . 141

604.1 Furnace Plenums and Air Ducts. . 141

604.2 Supplied as a Part of Furnace . . . 141

604.3 Not Supplied with the Furnace . . . 141

604.4 Return Air . . . . . . . . . . . . . . . . . . . 141

605.0 Insulation of Ducts . . . . . . . . . . . . 141

605.1 General. . . . . . . . . . . . . . . . . . . . . 141

606.0 Smoke Dampers, Fire Dampers, and Ceiling Dampers . . . . . . . . . . 142

606.1 Smoke Dampers. . . . . . . . . . . . . . 142

606.2 Fire Dampers . . . . . . . . . . . . . . . . 142

606.3 Ceiling Radiation Dampers. . . . . . 142

606.4 Combination Fire/Smoke

Dampers . . . . . . . . . . . . . . . . . . . . 142

606.5 Corridor Dampers . . . . . . . . . . . . . 142

606.6 Periodic Testing and Inspection . . 142
CMC § 605.2 High relevance — show source text
605.2 [OSHPD 1, 3 (Surgical Clinics), 4 & 5] Thermal acoustical lining materials shall not be installed within ducts, terminal boxes, sound traps, and other in-duct systems serving areas such as operating, cesarean operating rooms, delivery rooms, class 3 imaging, hybrid operating rooms, post anesthe- sia care units, cystoscopy, cardiac catheterization labs, nurs- eries, intensive care units, newborn intensive care units, protective environment rooms and airborne infection isolation rooms unless filters with 90 percent average efficiency based on ASHRAE Standard 52.2 or minimum efficiency rating value (MERV) of 14 are installed downstream of the duct lining. See ASHRAE 170, Section 6.9 for duct lining for non-sensitive

areas or rooms.

605.3 [OSHPD 1, 2, 4 & 5] Thermal or acoustical lining materials shall not be installed within ducts which are down- stream of the 99.97 percent high-efficiency particulate air (HEPA) filter required in Section 408.2.1 for protective envi-

ronment rooms.

2025 CALIFORNIA MECHANICAL CODE 141

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DUCT SYSTEMS

606.0 Smoke Dampers, Fire Dampers, and Ceiling Dampers.

606.1 Smoke Dampers. Smoke dampers shall comply with UL 555S, and shall be installed in accordance with the manufacturer’s installation instructions where required by the California Building Code or California Residential Code .

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.
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 § 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 § 717.3.2.4 High 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.
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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 § 0.76 High relevance — show source text

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.

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

One-hour fire-resistance rating.
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:

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).
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:

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.

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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142 2025 CALIFORNIA MECHANICAL CODE

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CMC § 717.2.3 Medium 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.

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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.

Fire dampers shall comply with the requirements of UL 555.
Smoke dampers shall comply with the requirements of UL 555S.
Combination fire/smoke dampers shall comply with the requirements of both UL 555 and UL 555S.
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.
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).

CMC § 1.4. Medium relevance — show source text
1.4. The penetrations are in parking garage exhaust or supply shafts that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction. 2. In Group B and R occupancies equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, smoke dampers are not required at penetrations of shafts where all of the following criteria are met: 2.1. Kitchen, clothes dryer, bathroom and toilet room exhaust openings are installed with steel exhaust subducts, having a wall thickness of not less than 0.0187 inch (0.4712 mm). 2.2. The subducts extend not less than 22 inches (559 mm) vertically. 2.3. An exhaust fan is installed at the upper terminus of the shaft that is powered continuously in accordance with the provisions of Section 909.11, so as to maintain a continuous upward airflow to the outdoors. 3. Smoke dampers are not required at penetration of exhaust or supply shafts in parking garages that are separated from other building shafts by not less than 2-hour fire-resistance-rated construction. 4. Smoke dampers are not required at penetrations of shafts where ducts are used as part of an approved mechanical smoke control system designed in accordance with Section 909 and where the smoke damper will interfere with the operation of the smoke control system. 5. Fire dampers and combination fire/smoke dampers are not required in kitchen and clothes dryer exhaust systems where dampers are prohibited by the California Mechanical Code .

717.5.3.1 Continuous upward airflow. Fire dampers and smoke dampers shall not be installed in shafts that are required to maintain a continuous upward airflow path where closure of the damper would result in the loss of the airflow.

717.5.4 Fire partitions. In other than Group A, E, I 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 that penetrate fire partitions shall be protected with listed fire dampers installed in accordance with their listing.

Exceptions: In occupancies other than Group H and L, fire dampers are not required where any of the following apply:
1. Corridor walls in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and the duct is protected as a through penetration in accordance with Section 714.
2. Tenant partitions in covered and open mall buildings where the walls are not required by provisions elsewhere in the code to extend to the underside of the floor or roof sheathing, slab or deck above.
3. The duct system is constructed of approved materials in accordance with the California Mechanical Code and the duct penetrating the wall complies with all of the following requirements: 3.1. The duct shall not exceed 100 square inches (0.06 m [2] ). 3.2. The duct shall be constructed of steel not less than 0.0217 inch (0.55 mm) in thickness.
3.3. The duct shall not have openings that communicate the corridor with adjacent spaces or rooms. 3.4. The duct shall be installed above a ceiling. 3.5. The duct shall not terminate at a wall register in the fire-resistance-rated wall. 3.6. A minimum 12-inch-long (305 mm) by 0.060-inch-thick (1.52 mm) steel sleeve shall be centered in each duct opening.
CMC § 603.11 Medium relevance — show source text
603.11 Underground Installation . . . . . . . 140

603.12 Air Dispersion Systems . . . . . . . . 140

603.13 Clearances . . . . . . . . . . . . . . . . . . 140

604.0 Furnace Plenums and Air Ducts

Used in Fuel-Gas Appliances . . . . 141

604.1 Furnace Plenums and Air Ducts. . 141

604.2 Supplied as a Part of Furnace . . . 141

604.3 Not Supplied with the Furnace . . . 141

604.4 Return Air . . . . . . . . . . . . . . . . . . . 141

605.0 Insulation of Ducts . . . . . . . . . . . . 141

605.1 General. . . . . . . . . . . . . . . . . . . . . 141

606.0 Smoke Dampers, Fire Dampers, and Ceiling Dampers . . . . . . . . . . 142

606.1 Smoke Dampers. . . . . . . . . . . . . . 142

606.2 Fire Dampers . . . . . . . . . . . . . . . . 142

606.3 Ceiling Radiation Dampers. . . . . . 142

606.4 Combination Fire/Smoke

Dampers . . . . . . . . . . . . . . . . . . . . 142

606.5 Corridor Dampers . . . . . . . . . . . . . 142

606.6 Periodic Testing and Inspection . . 142

606.7 Multiple Arrangements . . . . . . . . . 142

606.8 Access and Identification . . . . . . . 142

606.9 Freedom from Interference. . . . . . 142

606.10 Temperature Classification of Operating Elements . . . . . . . . . 142

607.0 Ventilating Ceilings . . . . . . . . . . . . 142

607.1 General. . . . . . . . . . . . . . . . . . . . . 142

607.2 Requirements . . . . . . . . . . . . . . . . 142

608.0 Use of Under-Floor Space as Supply Plenum for Dwelling Units. . 143

xxxiii

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TABLE OF CONTENTS

608.1 General. . . . . . . . . . . . . . . . . . . . . 143

608.2 Dwelling Units. . . . . . . . . . . . . . . . 143

608.3 Enclosed. . . . . . . . . . . . . . . . . . . . 143

608.4 Flammable Materials . . . . . . . . . . 143

608.5 Access . . . . . . . . . . . . . . . . . . . . . 143

608.6 Automatic Control . . . . . . . . . . . . . 143

608.7 Temperature Limit . . . . . . . . . . . . 143

608.8 Noncombustible Receptacle. . . . . 143

CMC § 04-15 Medium relevance — show source text

. . . . . . . . . 063928

Table	1 Description of Items to be Furnished and Installed by Customer
Item	Description
1	Option 1: Meter Adapter, Cooper B-Line Cat. No. MARR20L45GRSD (160A) Use with Customer’s Panel Rated at 160A Continuous1, 2
1	Option 2: Meter Adapter, Ekstrom Industries No. 722B (175A). Specify Left, Right, or Bottom Hub
2	Combination Service Meter and Breaker Panel (rating as required)
3	Pull Termination Box, 8” x 12” x 4”, Rain-Tight, Circle A-W (Cooper B-Line) No. R-9007A or Equivalent (see Note 4M on Page 2)
4	Conduit, See Notes 4C and 4G on Page 1
5	Hub to Be Closed and Made Tamper Proof
6	Pull Termination Box, 12” x 26” x 6”, Rain-Tight, Circle A-W Catalog Number R-90008, or Equivalent (see Note 4K on Page 2)

1 Fifth jaw accessory, use Cooper B-Line Cat. No. 50365. 2 Reducer hub and gasket accessories for 2” conduit, use Cooper B-Line Cat. No. AW200 and 12750A.

061032 Page 2 of 4 Rev. #04: 04-15-11

UG-1: Services Greenbook Residential and Small Commercial Overhead to Underground Electric Service Conversion

Optional Removable by Customer To Be Removed by PG&E Meter Socket (see Figure 2 through Figure 7 on Pages 3 through 4) For Riser and Pull Box Detail (see Figure 2 through Figure 7 on Pages 3 through 4) For Gas and Water Sealing Requirements, see Documents 063927 and Document 063928 48” Min. 72” Max. Customer Shall Dig and Backfill Trench (see Note 4B on Page 1) Min. Bend Depth To PG&E Distribution System As required by	Col2	Col3
Customer Shall Dig and Backfill Trench (see Note 4B on Page 1) For Riser and Pull Box Detail (see Figure 2 through Figure 7 on Pages 3 through 4) Meter Socket (see Figure 2 through Figure 7 on Pages 3 through 4) To Be Removed by PG&E For Gas and Water Sealing Requirements, seeDocuments 063927 andDocument 063928 To PG&E Distribution System Optional Removable by Customer 48” Min. 72” Max. As required by Min. Bend Depth

Document 063927 and Document 063928

Figure 1 Typical Service Conversion

PG&E Service Termination Point

See Note 4K on Page 2

PG&E Service Termination Point (see Note 4L on Page 2)

Fire, smoke & dampers

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