White Paper September 1, 2006 Smoke Detector Spacing on Level Ceilings with Beams and Joists
Smoke Detector Spacing on Level Ceilings with Beams and Joists Executive Overview NFPA 72, The National Fire Alarm Code, recommends using 900 square feet (30 feet on center) as a guideline for spacing spot type smoke detectors on smooth ceilings. While this is only a recommendation, virtually all manufacturers of smoke detectors follow this guideline. There has always been a question of how detector spacing needs to change when the ceiling is not smooth, but is interrupted by beams or joists.
Smoke Detector Spacing on Level Ceilings with Beams and Joists and Vision Systems Ltd. using Fire Dynamics Simulator and Smokeview Version 41 (developed by the National Institute of Science and Technology). The results of this research were published in a report entitled, “Smoke Detector Performance for Level Ceilings with Deep Beams and Deep Beam Pocket Configurations.”2 The report was issued March 28, 2006 and was the basis for recommended changes to NFPA 72.
Smoke Detector Spacing on Level Ceilings with Beams and Joists Recommendations Based on these findings, the report authors proposed language for addition to the body and annex of NFPA 72. The language clarifies how smoke detectors shall be placed on ceilings with beams and joists. These changes are expected to be incorporated into the 2007 edition of NFPA 72, which will be released in late 2006, to quell some of the debate surrounding the current requirements for smoke detectors on beam ceilings.
