In late 2005, NFPA published an alert notice titled "PASS Alarm Signals Can Fail at High Temperatures" on the NFPA Web site. The alert advised emergency responders, especially fire fighters, of high-temperature exposures causing the loudness of PASS alarm signals to be reduced and making the alarm signal indistinguishable from background noise at the incident scene. This problem was brought to the attention of the NFPA Technical Committee on Electronic Safety Equipment (the Technical Committee) by the National Institute for Occupational Safety and Health's (NIOSH) Fire Fighter Fatality Investigation and Prevention Program.
NIOSH reported that during the investigation of four fire fighter fatalities that occurred from 2001 to 2004, the PASS alarm signals were not heard or were barely audible. The PASS had been certified as compliant to NFPA 1982, Standard on Personal Alert Safety Systems (PASS), 1998 Edition, and involved both stand-alone PASS and SCBA-integrated PASS.
Laboratory testing of PASS by the National Institute for Standards and Technology's (NIST) Fire Research Division showed that this sound reduction begins to occur at temperatures as low as 300∞ F (150∞ C) and affected all PASS evaluated by NIST that were certified to the 1998 edition and earlier editions of NFPA 1982.
Principal Changes to NFPA 1982
Once notified of the possible deficiencies in PASS, the NFPA Technical Committee on Electronic Safety Equipment, in cooperation with NIOSH and NIST, studied the issue and incorporated revisions into the 2007 edition of NFPA 1982. The new edition of NFPA 1982 contains revisions providing for strengthened performance requirements and testing addressing the alarm signal degradation issue and also addresses other issues including problems caused by vibration, probably during transportation, and water ingress into the electronic and power supply compartments. The principal changes contained in the 2007 edition of NFPA 1982 are:
New water immersion requirements and testing - PASS is exposed to 350 F for 15 minutes and then to water submersion in 1.5 meters (4.9 feet), also for 15 minutes for each of 6 cycles. PASS must experience no water ingress; all PASS signals must function properly; and electronic data logging functions must operate properly. If this criteria is met, PASS is re-immersed in the test water for additional 5 minutes with the power source compartment(s) open. Following the 5 minutes, the PASS is removed from the water and wiped dry, then the electronics compartment is opened and examined to determine no water ingress;
New high temperature functionality requirements and testing - PASS is mounted in a circulating hot air oven at 500 F for 5 minutes and the PASS alarm signal must function at or above the required 95 dBA sound level; electronic data logging functions must operate properly; and no part of the PASS can show evidence of melting, dripping or igniting;
New tumble-vibration requirements and testing - PASS is "tumbled" in a rotating drum for 3 hours and the PASS alarm signal must function at the required 95 dBA sound level and electronic data logging functions must operate properly;
New "muffling" of the alarm signal requirements and testing for PASS - PASS is mounted on a test subject and evaluated in five positions (face down with arms extended, supine left, supine right, fetal right with knees drawn to chest, fetal left with knees drawn to chest), and the alarm signal must function at or above the required 95 dBA sound level.
Important Safety Recommendations Users
In spite of the problems with PASS, NFPA believes that PASS remain an important tool for firefighters and other emergency responders. NFPA recommends that, at least until PASS designed and certified to the new 2007 edition of NFPA 1982 become available, emergency responders continue to maintain and use existing PASS. Users are cautioned, however, that both the existing as well as the new PASS (when available) should always be considered a last resort call for help for emergency responder personnel who are unable to otherwise notify others that they are in distress.
Fire fighters and other emergency responders should continue to activate and wear PASS whenever in hazardous areas of any incident, but should also be aware of the possibility that hostile conditions may adversely affect the operation of PASS. Incident command should continue to apply all personnel accountability measures at all incidents to assure the safe entrance and exit of personnel from hazardous areas. Direct supervision of operating companies or teams should provide for the safe operating locations of personnel and ensure that members do not "freelance" on the incident scene.
Reporting PASS Malfunctions
Emergency services organizations and emergency responder personnel are encouraged to report any PASS malfunctions and other problems with proper functioning of PASS directly to both the certification organization whose certification mark appears on the PASS, and to NIOSH - NPPTL. Contacts include:
SEI - the Safety Equipment Institute (certification organization) - firstname.lastname@example.org
NIOSH - NPPTL, the National Institute for Occupational Safety and Health - National Personal Protection Technical Laboratory - NPPTL_PASS@cdc.gov.