National Fire Alarm Code® issues
NFPA 72® builds on the latest smoke detection and alarm research.

NFPA Journal®,  January/February 2008

SMOKE ALARMS have been in the news a lot recently and many questions about detecting and effectiveness are being asked. Some are familiar, some cover new ground, but all reveal there are unknowns involving the current detecting and alarming capabilities of alarm systems in various occupancies. These questions, and the introduction of new technology, have raised the profile of this very important component of the overall fire safety system in buildings. To learn more about the issues raised, the Fire Protection Research Foundation has undertaken a number of studies. The information garnered from this work will be given to the NFPA technical committees addressing these issues in NFPA 72®, National Fire Alarm Code®.

Detecting capability
To better understand the performance of smoke detectors in a wide range of building fires, the Foundation has undertaken two major studies.

The recently completed Smoke Characterization project, carried out in collaboration with Underwriters’ Laboratories, studied the properties of smoke from modern household contents under a variety of burning conditions. The results are now under consideration by both NFPA and UL as part of an overall look at the requirements for testing and installation of smoke detectors. The Foundation’s current study focuses on incipient fires with low-energy smoke and the ability of our current design methods to predict smoke detector actuation. This study will help to inform spacing requirements for detectors as well as help us understand the movement of smoke in the important early stages of fire development.

NFPA 72 currently contains provisions for smoke detector spacing in conventional spaces. The Foundation recently completed two projects that inform the expansion of those rules to include unique ceiling configurations, such as waffle ceilings, ceilings with deep beams, and sloped ceilings. We worked with Hughes Associates, Schirmer Engineering Corporation, and the University of Maryland to develop specific recommendations for consideration by NFPA technical committees.

Two other projects near completion focus on unique applications in which new technologies are being introduced. A cooperative project with the National Research Council of Canada has shed light on detector performance in the very challenging roadway tunnel environment (for NFPA 502, Road Tunnels, Bridges, and Limited Access Highways). Full-scale fire tests and tests in real tunnel environments have provided difficult challenges for detector actuation. The Foundation is currently working with domestic and international manufacturers of video imaging detection systems to develop performance objectives for this emerging technology so that it can be appropriately recognized in the National Fire Alarm Code.

Waking effectiveness of alarms
Another important area of study for the Foundation is the effectiveness of smoke alarms. These devices play their biggest life saving role when alerting sleeping people to possible danger. However, the effectiveness of these devices to awaken us is tempered by our age, our hearing ability, and our consumption of alcohol and other substances. The Foundation has completed three studies on this topic through Victoria University of Technology in Australia. The results demonstrate that the most effective alarm signal for the aged, the moderately hard of hearing, and moderate consumers of alcohol is substantially different from that in widespread use in today’s fire alarm systems. An optimum signal has been recommended in the studies and is under consideration by NFPA technical committees.

Research, technology and code requirements
Many ideas and people inspire the Foundation’s commitment to fire alarm research. The importance of fire detection in building fire safety and understanding the new technologies that are introduced to this field with increasing rapidness make this research critical. The Foundation’s active participation is also sustained by the willingness of the fire alarm community—engineers, manufacturers, and the National Fire Alarm Code committees—to work together toward a common fire safety goal.