HVAC Interface with Fire and Gas Detection Systems

HVAC Interface with Fire and Gas Detection Systems

• Smoke detectors associated with the fire detection systems shall be installed in the HVAC air distribution system as per NFAP 90A requirements.
• Gas detectors, as applicable, shall be located outside, as close as possible to the outside air intake to monitor the hazardous content of the ambient air. Open/close status of the damper located at the outside air intake shall be indicated on the HVAC control panel.
• Air conditioning equipment shall be provided with equipment failure alarm at the HVAC control panel,  and  a  common  trouble  alarm  signal  generated  at  the  control  panel  for  remote transmission to the respective fire alarm panel and to the building management system. On/off status of each piece of equipment shall be indicated on the HVAC control panel.
• Interface with Fire Detection System: as minimum the following signals shall be exchanged between the HVAC and fire detection system:

1. 1. Upon detection of fire, the fire alarm control panel shall send a signal to the HVAC control panel to shutdown the HVAC system immediately for the building where fire has been detected.
   2. The HVAC system common trouble alarm shall be transmitted to the respective fire alarm panel and to the building/plant management system or DCS.
   3. A remote signal from the main fire alarm panel to shutdown individually or jointly all building

HVAC system(s), other than control building and analyzer houses. Control rooms/buildings and analyzer houses shall be put on re-circulation, unless fire is detected in the control building or analyzer house, where the requirements of 26.4a shall apply.

1. For control rooms/buildings and analyzer houses, confirmation and failure signals shall be provided at the HVAC control panel and at the respective fire alarm panel, to indicate the re-circulation status.

Interface with Gas Detection System: : as minimum the following signals shall be exchanged between the HVAC and gas detection system

1. Multiple-level combustible gas detector shall be located in all outside air intake.
2. On detection of combustible gas at low (20% LEL) and high concentrations (50% LEL), and or from building and analyzer houses detectors, upon detection of hazardous gases at the outside air intake, the control system shall send a signal to the HVAC control panel through respective fire alarm panel to put HVAC system on re-circulation mode.
3. On detection of combustible gas at high concentrations high concentrations (50% LEL), for all buildings other than control building and analyzer houses, upon detection of hazardous gases at the outside air intake, the control system shall send a signal to the HVAC control panel through respective plant fire alarm panels, to shutdown the complete building HVAC system(s).