Re: Smoke Detector location?
Check out this link from a manufacturer which indicates proper smoke detector placement:
http://www.systemsensor.com/html/guides/A05-1003.pdf
"When air supply and/or air return ducts are present in a room or space, the detector(s) should not be placed in the path of the air flow supply or return duct (NFPA 72, 1999 Edition)."
"Smoke tests are helpful in determining proper placement. Special attention should be given to smoke travel directions and velocity, since either can affect detector performance. Placement of detectors near air conditioning or incoming air vents can also cause excessive accumulation of dust and dirt on the detectors. This dirt can cause detectors to malfunction and cause unwanted alarms. Detectors should not be located closer than 3 feet from an air supply diffuser or an air return vent. Spot type detectors, in properly engineered systems, may also be placed in return air ducts, or in approved duct detector housings designed for this application. Although duct detectors are not a substitute for open area detectors, they can provide an effective method of initiating building control functions to prevent smoke from being transported from the fire area to other parts of a building. (See Duct Smoke Detector Applications Guide.)"
Sorry for the long post. The PDF above has more details and diagrams. Hope this helps.
James
