Home Smoke Alarm Tests
While there is no question that smoke alarms have successfully prevented thousands of residential fire deaths, their beneficial effect may be beginning to plateau. It is recognized that reducing the number of non-working alarms may produce some further reduction in fire deaths. Further, introducing more effective alarms in residential dwellings could have a greater impact in reducing deaths. However, there seems to be little incentive to produce and install better residential fire alarms until performance improvements can be demonstrated through objective, realistic, and accurate testing.
In co-operation with the United States Fire Administration (USFA), other sponsors, and U.S. Consumer Product Safety Commission (CPSC), NIST has conducted an evaluation of current and emerging smoke alarm technology responses to common residential fire scenarios and nuisance alarm sources. The research was performed at by the National Institute of Standards and Technology (NIST), under the general guidance of a steering committee of the sponsoring organizations.
The results of the project provide details of the response of a range of residential smoke alarm technologies in a controlled laboratory test and in a series of real-scale tests conducted in two different residential structures. These are intended to provide both insight into siting and response characteristics of residential smoke alarms and a set of reference data for future enhancements to alarm technology based on fires from current materials and constructions. Several areas of focus were included in the project:
- Evaluate the performance of current smoke-alarm technology.
- Test conditions representative of current fatal residential fires.
- Evaluate the efficacy of current requirements for number and location of smoke alarms.
- Develop standard nuisance alarm sources to be included in the test program.
- Examine other fire detection technologies in combination with smoke alarms (example: residential sprinkler and heat detectors).
- Obtain data on the potential for improvements in performance by new technologies.
- Include fuel items that incorporate materials and constructions representative of current residential furnishings.
- Fully characterize test detectors and alarms in a consistent manner to facilitate comparisons.
- Utilize fire models to extend the applicability of the test arrangements and maximize the test instrumentation.
- Make all of the data collected as widely accessible as possible.
- Provide opportunities to enhance public fire safety education.
Smoke alarms of either the ionization type or the photoelectric type consistently provided time for occupants to escape from most residential fires, although in some cases the escape time provided can be short. Consistent with prior findings, ionization type alarms provided somewhat better response to flaming fires than photoelectric alarms, and photoelectric alarms provide (often) considerably faster response to smoldering fires than ionization type alarms.
Escape times in this study were systematically shorter than those found in a similar study conducted in the 1970's. This is related to some combination of faster fire development times for today's products that provide the main fuel sources for fires, such as upholstered furniture and mattresses, different criteria for time to untenable conditions, and improved understanding of the speed and range of threats to tenability. The original 1970's studies are available in two reports as NBS GCR 75-51 and NBS GCR 77-82.
Final Project Report
Since its initial publication in 2004, NIST TN 1455 has been scrutinized by fire research professionals and several inconsistencies have been identified. Analysis of noted inconsistencies has led to the identification of a number of errors in data and computations that impact the alarm performance assessment. These errors did not impact the major conclusions of the study. Details of the changes since the initial publication are included in a section entitled "Revision History" on page v of the report preface.
NIST Technical Note 1455-1, February 2008 Revision, Full Report (3/3/2008) Performance of Home Smoke Alarms Analysis of the Response of Several Available Technologies in Residential Fire Settings
Other Related Information
Supplementary Questions and Answers Clarifying “Detector Sensitivity and Siting Requirements for Dwellings,” Phase I (NBS GCR 75-51) and Phase II (NBS GCR 77-82) (9/11/07)
Statement for the Record, National institute of Standards and Technology to the Boston City Council Committee on Public Safety, August 2007 (8/6/07)