HomeMy WebLinkAbout407.004 - HVAC Shutoff for Fire Alarm SystemsEffective Date: August 2013 Justin H. Beal, Fire Prevention Engineer
Current Revision Date: 12/01/2022 Section 407.004
Next Revision (1) Date: 12/01/2025 Page 1 of 2
Fresno City Fire Department
400 Fire Prevention Manual
SECTION 407.004 HVAC SHUTOFF FOR FIRE ALARM SYSTEMS
PURPOSE
The purpose of this policy is to clarify the Fresno Fire Department’s (FFD or
Department) requirements regarding HVAC system shutoff and fire alarm system
interconnection.
APPLICATION
This policy applies to all buildings equipped with a building fire alarm within the
Department’s service area, including contract service areas. These requirements
apply to both required and voluntary building fire alarm systems.
OPERATIONAL POLICY
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OPERATIONAL GUIDELINE
Where a building fire alarm system is installed, and the HVAC system has a
cumulative total volume of supply air in excess of two thousand (2,000) cubic feet per
minute (cfm) (regardless of the number of actual HVAC units) the HVAC system is
required to be interconnected to the building fire alarm system.
Where an HVAC system has a cumulative total volume of supply air in excess of two
thousand (2,000) cfm (regardless of the number of actual units) and a duct detector
initiates an alarm or supervisory signal, the building fire alarm system must transmit
the appropriate signal as necessary, and every HVAC unit for the building must shutoff
simultaneously (global shutoff) by interrupting the power source of the air-moving
equipment.
Exceptions:
A. Where total coverage smoke detection is provided, global HVAC shutoff
is not required.
B. Dedicated function fire alarm systems used solely for the purpose of
waterflow supervision, valve supervision, fire pump supervision, HVLS
Effective Date: August 2013 Justin H. Beal, Fire Prevention Engineer
Current Revision Date: 12/01/2022 Section 407.004
Next Revision (1) Date: 12/01/2025 Page 2 of 2
fan shut off, elevator recall, or commercial cooking extinguishing system
supervision are not required to be interconnected to, or provide, HVAC
supervision or shutoff.
In an instance where no single HVAC unit is equipped with a smoke detector (i.e., no
one (1) HVAC unit flows in excess of two thousand (2,000) cfm of supply air) the
largest single unit must be fitted with a duct smoke detector to initiate HVAC shutoff.
PROCESS
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INFORMATION
The currently adopted version of the California Mechanical Code (CMC) requires
HVAC automatic shutoff where air moving systems supply air in excess of two
thousand (2,000) cfm. Where these systems are interconnected to a building fire
alarm system, the building fire alarm system must supervise these systems.
The CMC, however, does not provide information as to whether individual units must
shut off, or if all HVAC units must shut off in the event of an alarm or supervisory signal
based on a duct detector activation.
Standard engineering guidelines note that HVAC systems may move smoke from one
location in a building to another and potentially supply combustion air to an
undiscovered fire. Duct smoke detection and HVAC system shutoff can also aid in
detection of an undetected fire, especially in an unoccupied area.
Finally, nothing in this policy precludes any other requirements found in the CMC.
Where an air handling system exceeds two thousand (2,000) cfm, HVAC system
shutoff is still required by the CMC unless one of the CMC exceptions is met. FFD
does not regulate installations covered only under the CMC. Contractors are directed
to contact the City of Fresno Planning and Development Department, Building and
Safety Services Division for more information on CMC requirements.
DEFINITIONS
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CROSS-REFERENCES
California Mechanical Code (CMC)