Reducing fire deaths in older adults

NFPA Journal, Sep/Oct 2006 by Almand, Kathleen H

Optimizing the smoke alarm signal

The use of smoke alarm and signaling systems is associated with a reduction in fire fatalities in the general population-reducing the chances of dying in a fire by 40 to 50 percent when present. However, recent studies suggest that older adults may not fully benefit from conventional smoke alarm systems, particularly during sleeping hours because of the prevalence of high frequency hearing loss.

In 2005, the Fire Protection Research Foundation received a Department of Homeland Security Fire Prevention and Safety grant to assess and optimize the performance requirements for alarm and signaling systems to meet the needs of an aging population.

The major portion of the Foundation's study was a series of sleep studies, carried out at the Victoria University of Technology in Australia, which provided insights into the human behavior aspects of waking older adults exposed to varying types of signals and varying sound levels.

Forty-two older adults, ranging in age from 65-85 years, participated in the study. Four signals were examined, including a 3000 Hz high-frequency T-3 alarm signal (typical of that used in U.S. smoke alarms), a 500 Hz low-frequency T-3 alarm signal, a 500-2500 Hz mixed frequency T-3 alarm signal, and a male voice (200-2500Hz) alarm signal. The results showed that the mixed frequency T-3 alarm signal provided the greatest waking effectiveness of the signals evaluated, including the high frequency T-3, typical of most current alarms. In fact, the high-frequency T-3 performed the most poorly of the alternative signals tested. There was a substantial difference in the median auditory arousal thresholds (20 dBA) between the high-frequency T-3 alarm signal and the mixed frequency T-3. The results also indicate that a male voice alarm is not suitable for older adults. In terms of the cognitive and physical abilities of older adults upon waking to an alarm, a decrement in physical functioning of around 10-17 percent was observed, with no important effects on simple or cognitive functioning.

In summary, the sleep study concluded that the high frequency alarm signal that is typically used in current smoke alarms should be replaced by an alternative signal that offers significantly better waking effectiveness across the general population, once the nature of the best signal has been determined. Further sleep research is underway at Victoria University of Technology to address this issue. In the interim, the study recommends that the use of interconnected smoke alarm in bedrooms be encouraged to provide the maximum potential benefit of current and future alarms. Proper use and maintenance of smoke alarms is also critical to realizing the benefits of smoke alarms.

Two reports have been published from this project-one is a summary report, which describes the risk and technology assessments of the project and one reports on the sleep studies themselves. They are available at www.nfpa.org/foundation.

The Foundation is currently in receipt of a second Fire Prevention and Safety grant, which will explore the broader issue of notification effectiveness for various high-risk groups in the general population.

Detection, signaling systems research

Smoke Detector Performance for Level Ceilings With Deep Beams and Deep Beam Pocket Configurations documents a comprehensive review of smoke detector parameters for a wide variety of beam spacings, ceiling heights, and room areas. Computational fluid dynamics were used in the analysis.

Direct Visual Signaling as a Means for Occupant Notification in Large Spaces documents the effectiveness of occupant notification in "big box" spaces by strobes, installed per the requirements of the performance-based section of NFPA 72.

BY KATHLEEN H. ALMAND, P.E., FSFPE

KATHLEEN H. ALMAND is the executive director of the Fire Protection Research Foundation.