CFC · California Fire Code

When are smoke and heat vents or mechanical smoke removal required and how are they installed?

If your building meets the triggers in **§ 910.2** (for example, Group F‑1 or S‑1 over 50,000 ft² or high‑pile storage), the CFC requires smoke removal. You must either install listed roof smoke and heat vents sized per **§ 910.3** (A_VR = V/9000 if sprinklered; A_VR = A_FA/50 if not) and sited at the code distances, or install a mechanical smoke removal system that meets fan temperature rating, capacity, makeup air, control location and wiring requirements in **§ 910.4**; both systems have specified maintenance frequencies in **§ 910.5**.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Where the California Fire Code requires smoke removal, either smoke and heat vents or a mechanical smoke removal system must be provided and installed to the criteria in Chapter 9, Section § 910. The primary triggers are large Group F‑1 or S‑1 occupancies over 50,000 square feet of undivided area and buildings or portions storing high‑piled combustible storage (per Table 3206.2); see § 910.2. The design, location, vent area and operation rules for vents are in § 910.3 and the design, fan, makeup‑air, controls and wiring requirements for mechanical systems are in § 910.4.

The single most important rule: if the occupancy and floor area or storage type in § 910.2 require smoke removal, provide either listed roof vents sized per § 910.3 or a sprinkler‑required mechanical smoke removal system meeting § 910.4.

Requirements in detail

When smoke removal is required (decision thresholds)

  • For Group F‑1 or S‑1 occupancies having more than 50,000 square feet (4,645 m²) of undivided area — smoke and heat vents per § 910.3 or a mechanical system per § 910.4 are required. In occupied portions of sprinklered buildings where the upper surface of the story is not a roof assembly, a mechanical smoke removal system is required. § 910.2.1.
  • For buildings/portions containing high‑piled combustible storage, smoke removal required by Table 3206.2 must be provided. In unsprinklered high‑pile areas use smoke & heat vents per § 910.3; in sprinklered high‑pile areas either § 910.3 or § 910.4 is permitted, with mechanical required in occupied portions where the upper surface is not a roof assembly. § 910.2.2.
  • Exceptions: frozen food warehouses storing only Class I/II commodities (if sprinklered), areas protected with ESFR sprinklers, and areas protected with listed control‑mode special application sprinklers meeting the stated response index and listing — see § 910.2 exceptions.

Smoke and heat vents — design, listing, location, sizing, operation (§ 910.3)

Key required items for roof vents:

  • Listing/Labeling: Vents must be listed to UL 793, FM 4430, or ICC‑ES AC 331 — § 910.3.1.
  • Location: Vents must be located 20 feet (6,096 mm) or more from adjacent lot lines and fire walls, and 10 feet (3,048 mm) or more from fire barriers; vents should be uniformly located across the roof considering roof pitch, sprinklers and structure — § 910.3.2.
  • Aggregate vent area (decision‑critical):
    • If the area is equipped throughout with an approved automatic sprinkler system (903.3.1.1): use volume formula A_VR = V / 9,000 (vent area in ft² = volume in ft³ divided by 9,000). § 910.3.3.
    • If unsprinklered: use floor area formula A_VR = A_FA / 50 (vent area in ft² = floor area in ft² divided by 50). § 910.3.3.
  • Operation: Vents must be capable of approved automatic and manual operation — § 910.3.4.
  • Fusible link rating: Where vents are in areas with automatic sprinklers and vents operate by fusible link, the link rating must be 360°F (182°C) — § 910.3.5.

Table — quick decision/parameter summary (use this to choose vents vs mechanical)

Decision item Value / threshold What it controls Code Reference
Group F‑1 / S‑1 undivided area > 50,000 ft² Triggers requirement for smoke removal § 910.2.1
High‑piled combustible storage Per Table 3206.2 Triggers smoke removal for storage areas § 910.2.2 cite
Vent listing UL 793, FM 4430 or ICC‑ES AC 331 Acceptable vent products § 910.3.1
Minimum distance to lot line/fire wall 20 ft (6096 mm) Roof vent siting § 910.3.2
Minimum distance to fire barrier 10 ft (3048 mm) Roof vent siting § 910.3.2
Sprinklered vent area formula A_VR = V / 9000 Aggregate vent area (ft²) § 910.3.3
Unsprinklered vent area formula A_VR = A_FA / 50 Aggregate vent area (ft²) § 910.3.3
Fusible link rating (if used) 360°F (182°C) Fusible link selection in sprinklered areas § 910.3.5

Mechanical smoke removal systems — design & installation (§ 910.4)

If a mechanical system is selected or required, the CFC requires:

  • Automatic sprinklers required: Building must be equipped throughout with approved automatic sprinklers per § 903.3.1.1 to use a mechanical smoke removal system — § 910.4.1.
  • Exhaust fan construction: Exhaust fans must be rated for operation at 221°F (105°C) and fan motors must be located outside the exhaust airstream — § 910.4.2.
  • System sizing: Size to provide a minimum of 2 air changes per hour based on the volume (without contents). Individual fan capacity must not exceed 30,000 cfm (14.2 m³/s) — § 910.4.3.
  • Makeup air: Provide makeup air openings within 6 feet (1,829 mm) of floor level; minimum gross area = 8 ft² per 1,000 cfm of exhaust; operation can be manual or automatic — § 910.4.3.1.
  • Activation / Controls: Mechanical systems are to be activated by manual controls only; manual controls must be accessible to the fire service from an exterior door and be separated from the building by not less than 1‑hour fire barriers (CBC §707) or horizontal assemblies (CBC §711) — §§ 910.4.4–910.4.5.
  • Control wiring: Wiring for operation and control must be connected ahead of the main disconnect per CEC §701.12E and be protected from interior fire exposure >1,000°F (538°C) for not less than 15 minutes — § 910.4.6.
  • Interaction with building HVAC: If building air‑handling and the smoke removal system are combined, fans shall automatically shut down per the California Mechanical Code, but the smoke system manual controls must be able to override that shutdown — § 910.4.7.

Table — mechanical design quick values

Parameter Required value Code reference
Min exhaust rate 2 air changes/hour (volume basis, without contents) § 910.4.3
Max fan capacity 30,000 cfm § 910.4.3
Fan temperature rating 221°F (105°C) § 910.4.2
Makeup air location Within 6 ft of floor § 910.4.3.1
Makeup air size 8 ft² per 1,000 cfm exhaust § 910.4.3.1
Activation Manual controls only § 910.4.4

Maintenance & testing (§ 910.5)

  • Smoke and heat vents and mechanical systems must be maintained and tested per § 910.5, generally in accordance with NFPA 204, with specific intervals: mechanically operated vents inspected annually and operationally tested at least every 5 years; gravity‑drop vents inspected annually; mechanical smoke removal systems inspected and operationally tested annually and testing must include makeup air openings and all controls. § 910.5, 910.5.1–910.5.2.

Exceptions & special cases

  • Frozen food warehouses for Class I and II commodities protected by an approved automatic sprinkler system are exempt from smoke removal requirements — § 910.2 exception.
  • Areas protected by ESFR sprinklers or by listed control‑mode special application sprinklers meeting the response index and listing for stored commodities (≤12 sprinklers) are exempt — § 910.2 exceptions.
  • Occupied portions of a sprinklered building where the “upper surface of the story is not a roof assembly” require a mechanical system rather than roof vents — §§ 910.2.1, 910.2.2. This typically applies to mezzanines, open‑topped floors, or where the ceiling is not directly the roof.

Common mistakes

  • Assuming any roof opening satisfies the vent area requirement — vents must be listed and sized using the formulas in § 910.3.3.
  • Using fusible links rated lower than 360°F in sprinklered areas — the code requires 360°F rating for fusible links where sprinklers are present and the vent uses a fusible link release — § 910.3.5.
  • Installing mechanical smoke removal without verifying the building is sprinkled throughout (required by § 910.4.1) or without properly locating manual controls accessible from the exterior (see § 910.4.5).
  • Omitting makeup air or undersizing makeup openings; makeup air must be provided within 6 ft of floor and sized at 8 ft² per 1,000 cfm of exhaust — § 910.4.3.1.

Worked example — concrete scenario

Scenario: A single undivided Group F‑1 manufacturing area, unsprinklered, with a single floor of 75,000 ft² and an average clear height of 30 ft.

  1. Does the code require smoke removal?

    • Yes. It's Group F‑1 and the undivided area is > 50,000 ft², so smoke removal is required per § 910.2.1.

  2. Choose smoke and heat vents (unsprinklered): use the unsprinklered formula A_VR = A_FA / 50 (ft²). § 910.3.3.

    • A_FA = 75,000 ft² → A_VR = 75,000 / 50 = 1,500 ft² aggregate vent area. You must provide vents listed to UL 793/FM 4430/ICC‑ES AC 331 and sited per § 910.3.2 (20 ft from lot lines/fire walls; 10 ft from fire barriers).

  3. If the owner installs sprinklers throughout, the vent sizing changes: use the volume formula A_VR = V / 9,000 where V = 75,000 × 30 = 2,250,000 ft³ → A_VR = 2,250,000 / 9,000 = 250 ft² aggregate vent area (much smaller because sprinklers are present). § 910.3.3.

  4. Alternatively, if the building is sprinklered and the owner prefers a mechanical system, a mechanical smoke removal system may be installed but only if the building is sprinkled throughout (required by § 910.4.1), sized to 2 air changes/hour, fans rated to 221°F, makeup air provided, manual exterior controls provided and wiring protected as required — see § 910.4.

Related provisions (other CFC/CBC/Codes to consult)

  • § 903.3.1.1 — Requirements for automatic sprinkler systems (referenced by § 910.4.1).
  • § 3206.2 (Table 3206.2) — High‑piled combustible storage smoke removal triggers (referenced by § 910.2.2).
  • § 707, § 711 of the California Building Code — 1‑hour fire barriers / horizontal assemblies required to separate manual controls for mechanical systems (referenced by § 910.4.5).
  • NFPA 204 — referenced standard for inspection, testing and maintenance of vents/mechanical smoke removal (see § 910.5).
  • California Mechanical Code — requirements for fan shutdown and HVAC interaction (referenced by § 910.4.7).

Code references

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

  • CFC § 910.3 High relevance — show source text

    910.3 Smoke and heat vents. The design and installation of smoke and heat vents shall be in accordance with Sections 910.3.1 through 910.3.3.

    910.3.1 Listing and labeling. Smoke and heat vents shall be listed and labeled to indicate compliance with UL 793 or FM 4430 or ICC-ES AC 331.

    910.3.2 Smoke and heat vent locations. Smoke and heat vents shall be located 20 feet (6096 mm) or more from adjacent lot lines and fire walls and 10 feet (3048 mm) or more from fire barriers. Vents shall be uniformly located within the roof in the areas of the building where the vents are required to be installed by Section 910.2, with consideration given to roof pitch, sprinkler location and structural members.

    910.3.3 Smoke and heat vents area. The required aggregate area of smoke and heat vents shall be calculated as follows:

    For buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1:

    Equation 9-3 A VR = V /9000

    where:

    A VR = The required aggregate vent area (ft [2] ). V = Volume (ft [3] ) of the area that requires smoke removal.

    For unsprinklered buildings:

    Equation 9-4 A VR = A FA /50

    where:

    A VR = The required aggregate vent area (ft [2] ).

    A FA = The area of the floor in the area that requires smoke removal.

    910.3.4 Vent operation. Smoke and heat vents shall be capable of being operated by approved automatic and manual means.

    910.3.5 Fusible link temperature rating. Where vents are installed in areas provided with automatic fire sprinklers and the vents operate by fusible link, the fusible link shall have a temperature rating of 360°F (182°C).

    910.4 Mechanical smoke removal systems. Mechanical smoke removal systems shall be designed and installed in accordance with Sections 910.4.1 through 910.4.7.

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    910.4.1 Automatic sprinklers required. The building shall be equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1.

    910.4.2 Exhaust fan construction. Exhaust fans that are part of a mechanical smoke removal system shall be rated for operation at 221°F (105°C). Exhaust fan motors shall be located outside of the exhaust fan airstream.

    910.4.3 System design criteria. The mechanical smoke removal system shall be sized to exhaust the building at a minimum rate of two air changes per hour based on the volume of the building or portion thereof without contents. The capacity of each exhaust fan shall not exceed 30,000 cubic feet per minute (14.2 m [3] /s).

  • CFC § 910.3.4 High relevance — show source text

    where:

    A VR = The required aggregate vent area (ft [2] ).

    A FA = The area of the floor in the area that requires smoke removal.

    910.3.4 Vent operation. Smoke and heat vents shall be capable of being operated by approved automatic and manual means.

    910.3.5 Fusible link temperature rating. Where vents are installed in areas provided with automatic fire sprinklers and the vents operate by fusible link, the fusible link shall have a temperature rating of 360°F (182°C).

    910.4 Mechanical smoke removal systems. Mechanical smoke removal systems shall be designed and installed in accordance with Sections 910.4.1 through 910.4.7.

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    910.4.1 Automatic sprinklers required. The building shall be equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1.

    910.4.2 Exhaust fan construction. Exhaust fans that are part of a mechanical smoke removal system shall be rated for operation at 221°F (105°C). Exhaust fan motors shall be located outside of the exhaust fan airstream.

    910.4.3 System design criteria. The mechanical smoke removal system shall be sized to exhaust the building at a minimum rate of two air changes per hour based on the volume of the building or portion thereof without contents. The capacity of each exhaust fan shall not exceed 30,000 cubic feet per minute (14.2 m [3] /s).

    910.4.3.1 Makeup air. Makeup air openings shall be provided within 6 feet (1829 mm) of the floor level. Operation of makeup air openings shall be manual or automatic. The minimum gross area of makeup air inlets shall be 8 square feet per 1,000 cubic feet per minute (0.74 m [2] per 0.4719 m [3] /s) of smoke exhaust.

    910.4.4 Activation. The mechanical smoke removal system shall be activated by manual controls only.

    910.4.5 Manual control location. Manual controls shall be located where they are able to be accessed by the fire service from an exterior door of the building and separated from the remainder of the building by not less than 1-hour fire barriers constructed in accordance with Section 707 of the California Building Code or horizontal assemblies constructed in accordance with Section 711 of the California Building Code, or both.

    910.4.6 Control wiring. Wiring for operation and control of mechanical smoke removal systems shall be connected ahead of the main disconnect in accordance with Section 701.12E of the California Electrical Code and be protected against interior fire exposure to temperatures in excess of 1,000°F (538°C) for a period of not less than 15 minutes.

    910.4.7 Controls. Where building air-handling and mechanical smoke removal systems are combined or where independent building air-handling systems are provided, fans shall automatically shut down in accordance with the California Mechanical Code . The manual controls provided for the smoke removal system shall have the capability to override the automatic shutdown of fans that are part of the smoke removal system.

  • CFC § 909.22.5 High relevance — show source text

    909.22.5 Nondedicated smoke control systems. Nondedicated smoke control systems shall be operated for each control sequence annually. The system shall be tested under standby power conditions.

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    909.22.6 Components bypassing weekly test. Where components of the smoke control system are bypassed by the preprogrammed weekly test required by Section 909.12.1, such components shall be tested semiannually. The system shall be tested under standby power conditions.

    SECTION 910—SMOKE AND HEAT REMOVAL

    910.1 General. Where required by this code, smoke and heat vents or mechanical smoke removal systems shall conform to the requirements of this section.

    910.2 Where required. Smoke and heat vents or a mechanical smoke removal system shall be installed as required by Sections 910.2.1 and 910.2.2.

    Exceptions:

    1. Frozen food warehouses used solely for storage of Class I and II commodities where protected by an approved automatic sprinkler system.
    2. Smoke and heat removal shall not be required in areas of buildings equipped with early suppression fast-response (ESFR) sprinklers.
    3. Smoke and heat removal shall not be required in areas of buildings equipped with control mode special application sprinklers with a response time index of 50(m × s) [1/] 2 [ or less that are listed to control a fire in stored commodities with 12] or fewer sprinklers.

    910.2.1 Group F-1 or S-1. Smoke and heat vents installed in accordance with Section 910.3 or a mechanical smoke removal system installed in accordance with Section 910.4 shall be installed in buildings and portions thereof used as a Group F-1 or S-1 occupancy having more than 50,000 square feet (4645 m [2] ) of undivided area. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    Exception: Group F-1 aircraft manufacturing buildings and Group S-1 aircraft repair hangars.

    910.2.2 High-piled combustible storage. Smoke and heat removal required by Table 3206.2 for buildings and portions thereof containing high-piled combustible storage shall be installed in accordance with Section 910.3 in unsprinklered buildings. In buildings and portions thereof containing high-piled combustible storage equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a smoke and heat removal system shall be installed in accordance with Section 910.3 or 910.4. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    910.3 Smoke and heat vents. The design and installation of smoke and heat vents shall be in accordance with Sections 910.3.1 through 910.3.3.

  • CFC § 910.2.1 High relevance — show source text

    910.2.1 Group F-1 or S-1. Smoke and heat vents installed in accordance with Section 910.3 or a mechanical smoke removal system installed in accordance with Section 910.4 shall be installed in buildings and portions thereof used as a Group F-1 or S-1 occupancy having more than 50,000 square feet (4645 m [2] ) of undivided area. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    Exception: Group F-1 aircraft manufacturing buildings and Group S-1 aircraft repair hangars.

    910.2.2 High-piled combustible storage. Smoke and heat removal required by Table 3206.2 for buildings and portions thereof containing high-piled combustible storage shall be installed in accordance with Section 910.3 in unsprinklered buildings. In buildings and portions thereof containing high-piled combustible storage equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a smoke and heat removal system shall be installed in accordance with Section 910.3 or 910.4. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    910.3 Smoke and heat vents. The design and installation of smoke and heat vents shall be in accordance with Sections 910.3.1 through 910.3.3.

    910.3.1 Listing and labeling. Smoke and heat vents shall be listed and labeled to indicate compliance with UL 793 or FM 4430 or ICC-ES AC 331.

    910.3.2 Smoke and heat vent locations. Smoke and heat vents shall be located 20 feet (6096 mm) or more from adjacent lot lines and fire walls and 10 feet (3048 mm) or more from fire barriers. Vents shall be uniformly located within the roof in the areas of the building where the vents are required to be installed by Section 910.2, with consideration given to roof pitch, sprinkler location and structural members.

    910.3.3 Smoke and heat vents area. The required aggregate area of smoke and heat vents shall be calculated as follows:

    For buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1:

    Equation 9-3 A VR = V /9000

    where:

    A VR = The required aggregate vent area (ft [2] ). V = Volume (ft [3] ) of the area that requires smoke removal.

    For unsprinklered buildings:

    Equation 9-4 A VR = A FA /50

    where:

    A VR = The required aggregate vent area (ft [2] ).

    A FA = The area of the floor in the area that requires smoke removal.

    910.3.4 Vent operation. Smoke and heat vents shall be capable of being operated by approved automatic and manual means.

  • CFC § 903.3.1.1 High relevance — show source text

    In buildings and portions thereof containing high-piled combustible storage equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a smoke and heat removal system shall be installed in accordance with Section 910.3 or 910.4. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    [F] 910.3 Smoke and heat vents. The design and installation of smoke and heat vents shall be in accordance with Sections 910.3.1 through 910.3.3.

    [F] 910.3.1 Listing and labeling. Smoke and heat vents shall be listed and labeled to indicate compliance with UL 793 or FM 4430 or ICC-ES AC 331.

    [F] 910.3.2 Smoke and heat vent locations. Smoke and heat vents shall be located 20 feet (6096 mm) or more from adjacent lot lines and fire walls and 10 feet (3048 mm) or more from fire barriers. Vents shall be uniformly located within the roof in the areas of the building where the vents are required to be installed by Section 910.2 with consideration given to roof pitch, sprinkler location and structural members.

    [F] 910.3.3 Smoke and heat vents area. The required aggregate area of smoke and heat vents shall be calculated as follows:

    For buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1:

    Equation 9-3 A VR = V /9000

    where:

    A VR = The required aggregate vent area (ft [2] ). V = Volume (ft [3] ) of the area that requires smoke removal.

    For unsprinklered buildings:

    Equation 9-4 A VR = A FA /50

    where:

    A VR = The required aggregate vent area (ft [2] ).

    A FA = The area of the floor in the area that requires smoke removal.

    [F] 910.3.4 Vent operation. Smoke and heat vents shall be capable of being operated by approved automatic and manual

    means.

    [F] 910.3.5 Fusible link temperature rating. Where vents are installed in areas provided with automatic fire sprinklers and the vents operate by fusible link, the fusible link shall have a temperature rating of 360°F (182°C).

    [F] 910.4 Mechanical smoke removal systems. Mechanical smoke removal systems shall be designed and installed in accordance with Sections 910.4.1 through 910.4.7.

    [F] 910.4.1 Automatic sprinklers required. The building shall be equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1.

    [F] 910.4.2 Exhaust fan construction. Exhaust fans that are part of a mechanical smoke removal system shall be rated for operation at 221°F (105°C). Exhaust fan motors shall be located outside of the exhaust fan air stream.

  • CFC § 909.21.5 High relevance — show source text

    909.21.5 Standby power. The pressurization system shall be provided with standby power in accordance with Section 2702.

    909.21.6 Activation of pressurization system. The elevator pressurization system shall be activated upon activation of the elevator lobby smoke detectors.

    909.21.7 Testing. Testing for performance shall be required in accordance with Section 909.18.8. System acceptance shall be in accordance with Section 909.19.

    909.21.8 Marking and identification. Detection and control systems shall be marked in accordance with Section 909.14.

    909.21.9 Control diagrams. Control diagrams shall be provided in accordance with Section 909.15.

    909.21.10 Control panel. A control panel complying with Section 909.16 shall be provided.

    909.21.11 System response time. Hoistway pressurization systems shall comply with the requirements for smoke control system response time in Section 909.17.

    SECTION 910—SMOKE AND HEAT REMOVAL

    [F] 910.1 General. Where required by this code, smoke and heat vents or mechanical smoke removal systems shall conform to the requirements of this section.

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    [F] 910.2 Where required. Smoke and heat vents or a mechanical smoke removal system shall be installed as required by Sections 910.2.1 and 910.2.2.

    Exceptions:

    1. Frozen food warehouses used solely for storage of Class I and II commodities where protected by an approved automatic sprinkler system.
    2. Smoke and heat removal shall not be required in areas of buildings equipped with early suppression fast-response (ESFR) sprinklers.
    3. Smoke and heat removal shall not be required in areas of buildings equipped with control mode special application sprinklers with a response time index of 50 (m × s) [1/2] or less that are listed to control a fire in stored commodities with 12 or fewer sprinklers.

    [F] 910.2.1 Group F-1 or S-1. Smoke and heat vents installed in accordance with Section 910.3 or a mechanical smoke removal system installed in accordance with Section 910.4 shall be installed in buildings and portions thereof used as a Group F-1 or S-1 occupancy having more than 50,000 square feet (4645 m [2] ) of undivided area. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    Exception: Group F-1 aircraft manufacturing buildings and Group S-1 aircraft repair hangars.

    [F] 910.2.2 High-piled combustible storage. Smoke and heat removal required by Table 3206.2 of the California Fire Code for buildings and portions thereof containing high-piled combustible storage shall be installed in accordance with Section 910.3 in unsprinklered buildings.

  • CFC § 910.2.1 High relevance — show source text

    Exceptions:

    1. Frozen food warehouses used solely for storage of Class I and II commodities where protected by an approved automatic sprinkler system.
    2. Smoke and heat removal shall not be required in areas of buildings equipped with early suppression fast-response (ESFR) sprinklers.
    3. Smoke and heat removal shall not be required in areas of buildings equipped with control mode special application sprinklers with a response time index of 50 (m × s) [1/2] or less that are listed to control a fire in stored commodities with 12 or fewer sprinklers.

    [F] 910.2.1 Group F-1 or S-1. Smoke and heat vents installed in accordance with Section 910.3 or a mechanical smoke removal system installed in accordance with Section 910.4 shall be installed in buildings and portions thereof used as a Group F-1 or S-1 occupancy having more than 50,000 square feet (4645 m [2] ) of undivided area. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    Exception: Group F-1 aircraft manufacturing buildings and Group S-1 aircraft repair hangars.

    [F] 910.2.2 High-piled combustible storage. Smoke and heat removal required by Table 3206.2 of the California Fire Code for buildings and portions thereof containing high-piled combustible storage shall be installed in accordance with Section 910.3 in unsprinklered buildings. In buildings and portions thereof containing high-piled combustible storage equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, a smoke and heat removal system shall be installed in accordance with Section 910.3 or 910.4. In occupied portions of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, where the upper surface of the story is not a roof assembly, a mechanical smoke removal system in accordance with Section 910.4 shall be installed.

    [F] 910.3 Smoke and heat vents. The design and installation of smoke and heat vents shall be in accordance with Sections 910.3.1 through 910.3.3.

    [F] 910.3.1 Listing and labeling. Smoke and heat vents shall be listed and labeled to indicate compliance with UL 793 or FM 4430 or ICC-ES AC 331.

    [F] 910.3.2 Smoke and heat vent locations. Smoke and heat vents shall be located 20 feet (6096 mm) or more from adjacent lot lines and fire walls and 10 feet (3048 mm) or more from fire barriers. Vents shall be uniformly located within the roof in the areas of the building where the vents are required to be installed by Section 910.2 with consideration given to roof pitch, sprinkler location and structural members.

    [F] 910.3.3 Smoke and heat vents area. The required aggregate area of smoke and heat vents shall be calculated as follows:

    For buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1:

    Equation 9-3 A VR = V /9000

    where:

  • CFC § 903.3.1.1 High relevance — show source text

    For buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1:

    Equation 9-3 A VR = V /9000

    where:

    A VR = The required aggregate vent area (ft [2] ). V = Volume (ft [3] ) of the area that requires smoke removal.

    For unsprinklered buildings:

    Equation 9-4 A VR = A FA /50

    where:

    A VR = The required aggregate vent area (ft [2] ).

    A FA = The area of the floor in the area that requires smoke removal.

    [F] 910.3.4 Vent operation. Smoke and heat vents shall be capable of being operated by approved automatic and manual

    means.

    [F] 910.3.5 Fusible link temperature rating. Where vents are installed in areas provided with automatic fire sprinklers and the vents operate by fusible link, the fusible link shall have a temperature rating of 360°F (182°C).

    [F] 910.4 Mechanical smoke removal systems. Mechanical smoke removal systems shall be designed and installed in accordance with Sections 910.4.1 through 910.4.7.

    [F] 910.4.1 Automatic sprinklers required. The building shall be equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1.

    [F] 910.4.2 Exhaust fan construction. Exhaust fans that are part of a mechanical smoke removal system shall be rated for operation at 221°F (105°C). Exhaust fan motors shall be located outside of the exhaust fan air stream.

    [F] 910.4.3 System design criteria. The mechanical smoke removal system shall be sized to exhaust the building at a minimum rate of two air changes per hour based on the volume of the building or portion thereof without contents. The capacity of each exhaust fan shall not exceed 30,000 cubic feet per minute (14.2 m [3] /s).

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    [F] 910.4.3.1 Makeup air. Makeup air openings shall be provided within 6 feet (1829 mm) of the floor level. Operation of makeup air openings shall be manual or automatic. The minimum gross area of makeup air inlets shall be 8 square feet per 1,000 cubic feet per minute (0.74 m [2] per 0.4719 m [3] /s) of smoke exhaust.

    [F] 910.4.4 Activation. The mechanical smoke removal system shall be activated by manual controls only.

    [F] 910.4.5 Manual control location. Manual controls shall be located where they are able to be accessed by the fire service from an exterior door of the building and separated from the remainder of the building by not less than 1-hour fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both.

  • CFC § 909.21.11 High relevance — show source text

    [BF] 909.21.11 System response time. Hoistway pressurization systems shall comply with the requirements for smoke control system response time in Section 909.17.

    909.22 Maintenance. Smoke control systems shall be maintained to ensure to a reasonable degree that the system is capable of controlling smoke for the duration required. The system shall be maintained in accordance with the manufacturer’s instructions and Sections 909.22.1 through 909.22.6.

    909.22.1 Schedule. A routine maintenance and operational testing program shall be initiated immediately after the smoke control system has passed the acceptance tests. A written schedule for routine maintenance and operational testing shall be established.

    909.22.2 Records. Records of smoke control system testing and maintenance shall be maintained. The record shall include the date of the maintenance, identification of the servicing personnel and notification of any unsatisfactory condition and the corrective action taken, including parts replaced.

    909.22.3 Testing. Operational testing of the smoke control system shall include all equipment such as initiating devices, fans, dampers, controls, doors and windows.

    909.22.4 Dedicated smoke control systems. Dedicated smoke control systems shall be operated for each control sequence semiannually. The system shall be tested under standby power conditions.

    909.22.5 Nondedicated smoke control systems. Nondedicated smoke control systems shall be operated for each control sequence annually. The system shall be tested under standby power conditions.

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    909.22.6 Components bypassing weekly test. Where components of the smoke control system are bypassed by the preprogrammed weekly test required by Section 909.12.1, such components shall be tested semiannually. The system shall be tested under standby power conditions.

    SECTION 910—SMOKE AND HEAT REMOVAL

    910.1 General. Where required by this code, smoke and heat vents or mechanical smoke removal systems shall conform to the requirements of this section.

    910.2 Where required. Smoke and heat vents or a mechanical smoke removal system shall be installed as required by Sections 910.2.1 and 910.2.2.

    Exceptions:

    1. Frozen food warehouses used solely for storage of Class I and II commodities where protected by an approved automatic sprinkler system.
    2. Smoke and heat removal shall not be required in areas of buildings equipped with early suppression fast-response (ESFR) sprinklers.
    3. Smoke and heat removal shall not be required in areas of buildings equipped with control mode special application sprinklers with a response time index of 50(m × s) [1/] 2 [ or less that are listed to control a fire in stored commodities with 12] or fewer sprinklers.
  • CFC § 909.21.1.1 High relevance — show source text

    909.21.1.1 Use of ventilation systems. Ventilation systems, other than hoistway supply air systems, are permitted to be used to exhaust air from adjacent spaces on the fire floor, two floors immediately below and one floor immediately above the fire floor to the building’s exterior where necessary to maintain positive pressure relationships as required in Section 909.21.1 during operation of the elevator shaft pressurization system.

    909.21.2 Rational analysis. A rational analysis complying with Section 909.4 shall be submitted with the construction documents.

    909.21.3 Ducts for system. Any duct system that is part of the pressurization system shall be protected with the same fire-resistance rating as required for the elevator shaft enclosure.

    909.21.4 Fan system. The fan system provided for the pressurization system shall be as required by Sections 909.21.4.1 through 909.21.4.4.

    909.21.4.1 Fire resistance. Where located within the building, the fan system that provides the pressurization shall be protected with the same fire-resistance rating required for the elevator shaft enclosure.

    909.21.4.2 Smoke detection. The fan system shall be equipped with a smoke detector that will automatically shut down the fan system when smoke is detected within the system.

    909.21.4.3 Separate systems. A separate fan system shall be used for each elevator hoistway.

    909.21.4.4 Fan capacity. The supply fan shall be either adjustable with a capacity of not less than 1,000 cubic feet per minute (0.4719 m [3] /s) per door, or that specified by a registered design professional to meet the requirements of a designed pressurization system.

    909.21.5 Standby power. The pressurization system shall be provided with standby power in accordance with Section 2702.

    909.21.6 Activation of pressurization system. The elevator pressurization system shall be activated upon activation of the elevator lobby smoke detectors.

    909.21.7 Testing. Testing for performance shall be required in accordance with Section 909.18.8. System acceptance shall be in accordance with Section 909.19.

    909.21.8 Marking and identification. Detection and control systems shall be marked in accordance with Section 909.14.

    909.21.9 Control diagrams. Control diagrams shall be provided in accordance with Section 909.15.

    909.21.10 Control panel. A control panel complying with Section 909.16 shall be provided.

    909.21.11 System response time. Hoistway pressurization systems shall comply with the requirements for smoke control system response time in Section 909.17.

    SECTION 910—SMOKE AND HEAT REMOVAL

    [F] 910.1 General. Where required by this code, smoke and heat vents or mechanical smoke removal systems shall conform to the requirements of this section.

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    [F] 910.2 Where required. Smoke and heat vents or a mechanical smoke removal system shall be installed as required by Sections 910.2.1 and 910.2.2.

  • CFC § 910.4.3.1 High relevance — show source text

    910.4.3.1 Makeup air. Makeup air openings shall be provided within 6 feet (1829 mm) of the floor level. Operation of makeup air openings shall be manual or automatic. The minimum gross area of makeup air inlets shall be 8 square feet per 1,000 cubic feet per minute (0.74 m [2] per 0.4719 m [3] /s) of smoke exhaust.

    910.4.4 Activation. The mechanical smoke removal system shall be activated by manual controls only.

    910.4.5 Manual control location. Manual controls shall be located where they are able to be accessed by the fire service from an exterior door of the building and separated from the remainder of the building by not less than 1-hour fire barriers constructed in accordance with Section 707 of the California Building Code or horizontal assemblies constructed in accordance with Section 711 of the California Building Code, or both.

    910.4.6 Control wiring. Wiring for operation and control of mechanical smoke removal systems shall be connected ahead of the main disconnect in accordance with Section 701.12E of the California Electrical Code and be protected against interior fire exposure to temperatures in excess of 1,000°F (538°C) for a period of not less than 15 minutes.

    910.4.7 Controls. Where building air-handling and mechanical smoke removal systems are combined or where independent building air-handling systems are provided, fans shall automatically shut down in accordance with the California Mechanical Code . The manual controls provided for the smoke removal system shall have the capability to override the automatic shutdown of fans that are part of the smoke removal system.

    910.5 Maintenance and testing. Maintenance and testing of smoke and heat vents and mechanical smoke removal systems shall be in accordance with Sections 910.5.1 and 910.5.2. A written record of inspection, testing and maintenance that includes the date, identification of personnel involved, any unsatisfactory result, corrective action taken and replaced parts shall be maintained on the premises.

    910.5.1 Smoke and heat vents. Smoke and heat vents shall be maintained in an operative condition. Inspection, testing and maintenance shall be in accordance with NFPA 204 except as follows:

    1. Mechanically operated smoke and heat vents shall be inspected annually and operationally tested not less than every 5

    years. 2. Gravity dropout smoke and heat vents shall be inspected annually. 3. Fused, damaged or painted fusible links shall be replaced.

    910.5.2 Mechanical smoke removal systems. Mechanical smoke removal systems shall be maintained in accordance with NFPA 204 and the equipment manufacturer’s instructions except as follows:

    1. Systems shall be inspected and operationally tested annually.
    2. Testing shall include the operation of all system components, controls and ancillary equipment, such as makeup air openings.
    3. A written schedule for routine maintenance and operational testing shall be established and testing shall be conducted in accordance with the schedule.

    SECTION 911—EXPLOSION CONTROL

    911.1 General. Explosion control shall be provided in the following locations:

    1. Where a structure, room or space is occupied for purposes involving explosion hazards as identified in Table 911.1.
    2. Where quantities of hazardous materials specified in Table 911.1 exceed the maximum allowable quantities in Table 5003.1.1(1).
  • CFC § 910.4.2 High relevance — show source text

    [F] 910.4.2 Exhaust fan construction. Exhaust fans that are part of a mechanical smoke removal system shall be rated for operation at 221°F (105°C). Exhaust fan motors shall be located outside of the exhaust fan air stream.

    [F] 910.4.3 System design criteria. The mechanical smoke removal system shall be sized to exhaust the building at a minimum rate of two air changes per hour based on the volume of the building or portion thereof without contents. The capacity of each exhaust fan shall not exceed 30,000 cubic feet per minute (14.2 m [3] /s).

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    [F] 910.4.3.1 Makeup air. Makeup air openings shall be provided within 6 feet (1829 mm) of the floor level. Operation of makeup air openings shall be manual or automatic. The minimum gross area of makeup air inlets shall be 8 square feet per 1,000 cubic feet per minute (0.74 m [2] per 0.4719 m [3] /s) of smoke exhaust.

    [F] 910.4.4 Activation. The mechanical smoke removal system shall be activated by manual controls only.

    [F] 910.4.5 Manual control location. Manual controls shall be located where they are able to be accessed by the fire service from an exterior door of the building and separated from the remainder of the building by not less than 1-hour fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both.

    [F] 910.4.6 Control wiring. Wiring for operation and control of mechanical smoke removal systems shall be connected ahead of the main disconnect in accordance with Section 701.12E of the California Electrical Code and be protected against interior fire exposure to temperatures in excess of 1,000°F (538°C) for a period of not less than 15 minutes.

    [F] 910.4.7 Controls. Where building air-handling and mechanical smoke removal systems are combined or where independent building air-handling systems are provided, fans shall automatically shut down in accordance with the California Mechanical Code . The manual controls provided for the smoke removal system shall have the capability to override the automatic shutdown of fans that are part of the smoke removal system.

    [F] 910.5 Maintenance. Smoke and heat vents and mechanical smoke removal systems shall be maintained in accordance with the California Fire Code .

    SECTION 911—FIRE COMMAND CENTER

    [F] 911.1 General. Where required by other sections of this code, in buildings classified as high-rise buildings by this code and in all F-1 and S-1 occupancies with a building footprint of over 500,000 square feet (46 452 m [2] ) and Group I-2 occupancies having occupied floors located more than 75 feet above the lowest level of fire department vehicle access, a fire command center for fire department operations shall be provided and shall comply with Sections 911.1.1 through 911.1.7.

    [F] 911.1.1 Location and access. The location and access to the fire command center shall be approved by the fire code official.

Frequently asked questions

When do I have to submit smoke removal calculations with my permit?

You must follow the thresholds in § 910.2; when smoke removal is required (e.g., >50,000 ft² F‑1/S‑1 or high‑pile storage), provide sizing calculations (vent area or mechanical design) consistent with § 910.3 or § 910.4 as part of your construction documents.

Can I mix roof vents and mechanical systems in the same building?

Yes — the code allows either approach when required, but follow the siting, sizing and control rules for whichever system you use. In sprinklered high‑pile areas either § 910.3 or § 910.4 is permitted; occupied portions where the upper surface is not a roof assembly require mechanical per § 910.2.

Are fusible links allowed where sprinklers are installed?

Yes, but fusible links used to release vents in sprinklered areas must be rated 360°F (182°C) per § 910.3.5.

Who must be able to access mechanical smoke removal controls?

Manual controls must be accessible by the fire service from an exterior door and separated from the remainder of the building by not less than 1‑hour fire barriers or horizontal assemblies, per § 910.4.5.

How often must the vents or mechanical smoke removal systems be tested?

Smoke and heat vents and mechanical systems must be maintained per § 910.5 and NFPA 204 with specific intervals: mechanically operated vents – inspected annually and operationally tested at least every 5 years; gravity dropout vents – inspected annually; mechanical systems – inspected and operationally tested annually.

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