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:
- 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.
- The HVAC system common trouble alarm shall be transmitted to the respective fire alarm panel and to the building/plant management system or DCS.
- 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.
- 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
- Multiple-level combustible gas detector shall be located in all outside air intake.
- 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.
- 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).