Pass
Alarm Signals Fail at High Temperatures
November 30, 2005 -- Exposure to high temperature
environments may cause the loudness of Standard on Personal Alert Safety
Systems (PASS) alarm signals to be reduced, causing the alarm signal to become
indistinguishable from background noise at the incident scene.
This problem was brought to the attention of the IAFF and
the National Fire Protection Association (NFPA) Technical Correlating Committee
on Fire and Emergency Services Protective Clothing and Equipment and the NFPA
Technical Committee on Electronic Safety Equipment 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, PASS alarms were not heard
or were barely audible. The PASS alarms had been certified as compliant to NFPA
1982, 1998 Edition, and involved both stand-alone PASS and SCBA-integrated PASS.
Initial laboratory testing of PASS by the National Institute
for Standards and Technology’s (NIST) Fire Research Division has shown this
sound reduction to occur at temperatures as low as 300°F (150°C) and could
affect all PASS. However, additional work is required to better characterize
the thermal conditions (temperatures and exposure durations) that contribute to
alarm signal degradation.
While the NFPA Technical Committee on
Electronic Safety Equipment has been working to develop appropriate revisions
to NFPA 1982 to address this issue, adequate solutions have not yet been
presented. The Committee, in cooperation with NIOSH and NIST, will continue to
study the issue and will incorporate revisions into NFPA 1982 as solutions are
developed and consensus around addressing the issue is achieved.
PASS has always been a “last resort call for help” for
emergency services personnel who are unable to otherwise notify others that
they are in distress. Fire fighters should continue to activate and wear PASS
whenever in hazardous areas of any incident, but should also be aware that high
temperatures could cause degradation of the alarm signal. 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.
IAFF affiliates should report any PASS malfunctions and
other problems with PASS functioning to the IAFF Department of Occupational
Health and Safety by email at safety@iaff.org
or by phone at (202) 824-9304. The IAFF will maintain this information, as well
as notify NIOSH and NFPA.
