Personal Alert Safety Systems (PASS) Research

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This USFA/National Institute of Standards and Technology (NIST) research partnership conducted research on ways to enhance the performance of PASS devices that involved well controlled, bench-scale laboratory experiments, as well as live fire operational testing. The results of this research are to improve the sensing of hazardous thermal exposures, aid the elimination of false activations, improved accuracy, and tie in with other technologies such as Global Positioning Systems (GPS), firefighter location, fireground accountability, gas analyzers, and physiological or stress monitors. Current project initiatives have involved the assessment of existing PASS technology and initial examination of the application of technology transfer in this area. Integration of research results into national consensus standards will be addressed as part of current project efforts.

Performance of Thermal Exposure Sensors in PASS Devices

Live fire test

Above: Live fire test!

According to National Fire Protection Association (NFPA) statistics for 1998, over 500 firefighters were trapped in structure fires that resulted in injury or death of firefighters. Firefighters can be quickly overcome by the heat or smoke of a fire and may be unable to alert other fire ground personnel to their need for assistance. Personal Alert Safety System (PASS) devices were originally designed to signal for aid via an audible alarm signal if a firefighter becomes incapacitated on the fire ground. Performance standards and testing protocols for motion or lack of motion detectors is described by NFPA Standard 1982. While the current NFPA Standard for PASS devices (NFPA1982) requires only a motion detector, some PASS device manufacturers are beginning to incorporate additional technology into PASS devices to improve fire ground safety. If properly implemented, new technology could significantly improve the safety and effectiveness of firefighters on the fire ground.

Thermal exposure sensor technology has already been included in a number of models of PASS devices. However, there are currently no standards or testing protocols with which to assess the performance of these thermal exposure sensors. While innovative manufacturers will always seek to include more technology in order to increase the safety of firefighters, the fire service does not have the resources to evaluate the thermal exposure sensor performance in all the various models that incorporate a thermal sensor. A well-designed testing protocol would include different fire conditions which firefighters encounter and allow the fire service to understand better the performance characteristics of the thermal sensors. In addition, a standardized testing protocol would allow the manufacturers to match the performance of their devices with the requirements of the fire service.

PASS Devices

Above: PASS Devices

Instrumented test mannequin

Above: Instrumented test mannequin

The first part of this USFA/NIST collaboration examines the performance of thermal exposure sensors in a series of laboratory as well as real scale experiments. Different PASS devices were instrumented and inserted into a static oven and a heated flow loop in order to characterize the response to conducted and convected heat energy. An instrumented mannequin was outfitted with six PASS devices (three front & three rear) and positioned inside a full-scale room fire to collect response data under realistic fire conditions.

Thermal Environment for Electric Equipment Used by First Responders

The increased use of electronic equipment by emergency responders where that equipment may be repeatedly exposed to elevated temperature, humidity and smoke conditions requires an examination of current manufacturing tests and standards used to certify this equipment. This paper provides a review of the current equipment standards for electronic equipment used by firefighters and other first responders. A thermal classification method is developed based on the protective characteristics of firefighter turn-out gear that should serve as the basis for developing thermal standards for electronic devices used by first responders. The Fire Equipment Evaluator that was constructed to investigate the performance of electronic equipment in simulated fire conditions will be described. Results of testing the Personal Alert Safety System (PASS) are presented along with recommendations for revised standards for PASS in the report Thermal Environment for Electronic Equipment Used by First Responders.

As part of this project, another report, Performance of Thermal Exposure Sensors in Personal Alert Safety System (PASS) Devices, NISTIR 7294 has been completed. The data in this report indicates that the thermal sensors respond differently under static, flowing, and radiant heat transfer conditions and that current thermal sensing implementations are unlikely to provide a firefighter with sufficient warning of an acute thermal hazard.

Support of Thermal Imaging Standards

The performance metrics and standard testing protocols developed from this USFA/NIST research partnership on thermal imaging technology have been incorporated into, and form the basis for, the new National Fire Protection Association (NFPA) Standard 1801, Thermal Imagers for the Fire Service. The metrics and protocols were provided to the NFPA Technical Committee on Electronic Safety Equipment and the Fire Service Thermal Imaging Camera Working Group meeting in September 2007 at NIST in Gaithersburg, Maryland. Once approved by the NFPA Standards Council, this standard will be released to the public for comment before being balloted by the entire NFPA membership. Through the partnership with NIST, a national consensus standard on this critical fire service equipment and technology has been developed. This standard will allow firefighters and other first responders to evaluate the performance of thermal imagers with a science-based set of metrics and testing protocols. Prior to this standard being developed, the fire service had no guidelines or procedures that could be utilized to evaluate thermal imager performance.

Enhancing the Performance of Future PASS Devices

In the future, additional capabilities and technologies may be incorporated into PASS devices. Emerging technologies which would provide valuable capabilities to the fire service include firefighter location, fire ground accountability, gas analyzers, and physiological or stress monitors. It is critical that a standardized testing protocol be in place as these technologies are integrated into PASS devices so that the fire service understands the performance as well as the limitations of their equipment. As more technology is incorporated into PASS devices, it will also be critical to communicate this information to incident command as well as network multiple PASS devices.

Exploring the new technology that might enhance performance of future PASS devices and developing a prioritized plan to incorporate new technology will also be addressed by this USFA/NIST project.

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