PASS Sound Muffle Tests Using A Structural Firefighter Protective Ensemble Method.
PASS Sound Muffle Tests Using A Structural Firefighter
Protective Ensemble Method.
Lawson, J. R.
NIST Technical Note 1641; NIST TN 1641; 28 p. July
protective equipment; fire fighters; first responders;
fire alarm systems; safety; noise (sound); NFPA 1982;
NFPA 1971; fire fighting; attenuation; fire fighting
equipment; instruments; fire tests
Firefighters and other emergency responders often work
in adverse environments. The operating environments can
be very noisy. Personal Alert Safety Systems (PASS)
devices are safety systems that emit an audible alarm
signal when an emergency responder stops moving. This
alarm signal serves as a means for others to rapidly
locate a responder who may be injured or incapacitated.
The 2007 edition of National Fire Protection
Association, NFPA 1982, Standard on Personal Alert
Safety Systems (PASS) established a means to evaluate
the muffling (attenuation) of sound level from a PASS
device worn by an emergency responder who is down on the
floor. The standard prescribes five different test
positions that are assumed when measuring sound level
attenuation from a firefighter, fully dressed in their
NFPA 1971 fire fighting ensemble, while wearing a PASS
device that is in full alarm. NIST tested five different
pass devices in an open room environment to determine
relative signal level attenuation for each device. These
tests demonstrate sound level losses ranging from
approximately 9% dBA to 19% dBA. These signal losses are
associated with the type of device, direction of
measurement relative to the orientation of the PASS
device, and attenuation from the firefighter's body
obstructing the sound path. This report also contains
background sound level measurements with dBA
measurements from fire fighting apparatus and power
tools that are commonly used on the fireground.