NFPA 72 Section 126.96.36.199 states that in spaces served by air-handling systems, (smoke) detectors shall not be located where airflow prevents operation of the detectors.
Annex A Explanatory Material A.188.8.131.52 Detectors should not be located in a direct airflow or closer than 36 in. (910 mm) from an air supply diffuser or return air opening. Supply or return sources larger than those commonly found in residential and small commercial establishments can require greater clearance to smoke detectors. Similarly, smoke detectors should be located farther away from high velocity air supplies. See B.4.10. “