PASS Audibility Project
An important part of signal detection and distinction is the strength of the signal compared to the levels of background noise. There are cases in which firefighters never heard the signal or could not localize it if the signal was heard. We aimed to quantify the amount of background noise levels at an active fire scene coming from other firefighting equipment. We measured across a wide frequency level content and directionality of several pieces of fireground equipment and compared this to the signal emitted by a PASS device.
Current Work
Here are some of the things that the UT Fire Research Group has done in our analysis of PASS in the fireground environment. Read more about the sonar equation first here.
This portion of the project uses experimental and computational modeling to try to understand sound transmission in the burning environment. This portion of the project explores structure-scale modeling; the human-scale modeling can be found in the "Firefighter Response to PASS Signal" section.
One part of the analysis of PASS devices is the effect of the protective equipment (helmet, eye protection, hood, coat) that is worn by the firefighters on their ability to hear. Results indicate a reduced received level at the ear when the full complement of gear is worn, as might be expected, potentially causing a reduced detection range. In addition, the helmet and eye protection significantly affect the received signal which could cause inhibit localization.
Characterization of the PASS Device
More coming soon!