RTU Duct Smoke Detectors
Did you know that duct smoke detectors are installed on air handler units over 2000 cfm and they shut the air handler down to avoid spreading smoke throughout the building? See NFPA 72 Chap 17 and NFPA 90A Some AHJ Fire Marshals require gobal shut down rather than just individual RTU shut down. That means they want all the air handlers to shut off at the same time when there is an alarm. Verify with your local fire marshal as to their requirements.