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Tuesday, September 10, 2013

Improving The Alert System For Firefighters In Danger

(thewhitewolves/Flickr)

(thewhitewolves/Flickr)

Every year, dozens of firefighters are killed in the line of duty across the U.S. But there are hundreds more close calls — when a firefighter needs to be rescued.

Both volunteer and professional fire departments rely on a simple device designed to alert their fellow firefighters when they need help. It’s called a PASS device, which stands for Personal Alert Safety System.

From the Here & Now Contributors Network, Matt Largey of KUT reports on the work some researchers at the University of Texas are doing to try to figure out if that little PASS device could be tweaked to save even more lives.

Reporter

Transcript

MEGHNA CHAKRABARTI, HOST:

This is HERE AND NOW. Every year across the U.S., dozens of firefighters are killed in the line of duty. But there are hundreds more close calls, when a firefighter is trapped and needs to be rescued. Both volunteer and professional fire departments rely on a simple device designed to alert their fellow firefighters when they need help. It's called PASS, a PASS device, for Personal Alert Safety System. Well, researchers at the University of Texas are looking into whether that little PASS device could save even more lives. From the HERE AND NOW Contributors Network, KUT's Matt Largey reports.

MATT LARGEY, BYLINE: When firefighters rush into a burning building, they're usually dressed head to toe in protective gear - helmet, gloves, breathing mask, thick coat and boots. After all, a burning building is a dangerous place.

BOB NICKS: A very hostile environment, very heated.

LARGEY: That's Bob Nix.

NICKS: I'm a battalion chief at the Austin Fire Department.

LARGEY: And sometimes inside that burning building, firefighters can get into trouble. Maybe they get disoriented.

NICKS: There's a lot of confusion. You don't know the layout.

LARGEY: Firefighters can get stuck, maybe something falls on them. Something happens and they need help.

NICKS: And so some of the analysis of that showed that just by simply putting an alarm on somebody so they went down and stopped moving, that would help the location of these individuals.

LARGEY: That alarm is called a personal alert safety system, or a PASS device.

JOELLE SUITS: So a PASS device continuously tries to figure out if the person is moving.

LARGEY: That's Joelle Suits. She's a grad student at U.T.

SUITS: I'm studying fireground acoustics and having fun.

LARGEY: So the PASS - it's basically a little sensor that measures whether the person wearing it is moving.

SUITS: And so after about five seconds of the firefighter not moving, it sends out a warning signal.

(SOUNDBITE OF ALARM)

SUITS: If the device doesn't get any movement, doesn't get any input from the firefighter, it goes into full-on alarm system.

(SOUNDBITE OF ALARM)

LARGEY: And for the most part it works really, really well. Suits says lots of firefighters owe their lives to the PASS, but there are times when it doesn't work as well as it should.

SUITS: There were cases where firefighters would hear the device outside the house, but once they got inside, they couldn't hear it or they couldn't find it, and they're not entirely sure why.

LARGEY: Now, to find out why, the first thing to understand is the sensory environment for a firefighter when they're inside a burning building.

D.K. EZEKOYE: So when there's a room on fire, typically people think, oh, you know, you see the bright fire and you can still see other things. Well, that's Hollywood.

LARGEY: D.K. Ezekoye is a mechanical engineering professor who's working on the PASS problem too, and he says in a real fire you can't see a thing.

EZEKOYE: You can stick your hand in front of your face, and you won't be able to see it because of the smoke. So they are in pitch black conditions, and they have to rely on these other senses, particularly auditory in this case, to try to determine what's going on.

LARGEY: And even hearing what's going on isn't so easy either, and that's the trouble. It's really, really noisy.

EZEKOYE: As everybody knows, the first thing that happens when the firefighters are coming in is that you hear the sirens on the trucks.

(SOUNDBITE OF SIRENS)

NICKS: Your pump's operating.

EZEKOYE: All the radio traffic that's going on...

UNIDENTIFIED MAN: Engine 303, go ahead.

NICKS: You have fans going off, ventilating the structure, trying to push the smoke, the hazardous gases, the fuels out.

EZEKOYE: Water splashing all over the place.

NICKS: You've got saws operating. Car alarms could be sounding. You have people chopping.

EZEKOYE: Smoke detectors could still be sounding in different parts of the structure.

NICKS: The fire itself creates sounds.

EZEKOYE: You have the breathing, the self-induced noise.

LARGEY: Oh, one more thing, you've also got a bunch of fire-resistant stuff wrapped around your head.

NICKS: You're basically in a very thick winter coat with a helmet, with a lot of protection around your ears. So you're already isolated from the environment as far as acoustically.

LARGEY: But wait. Then? Then things get weird.

SUITS: Not only do you have all these sounds going off, but inside the structure that's on fire, the air has a temperature gradient.

LARGEY: The air is hotter or cooler in different places around the room that's on fire.

SUITS: And sound moves faster in hotter temperatures than it does in cooler temperatures.

LARGEY: So the speed of sound changes as it moves through the room.

SUITS: And so you have the sound speed changing, which can distort and actually bend sound.

LARGEY: What?

SUITS: You could have the sound going off in one direction, and it's pointed at the ceiling, but before it gets to the ceiling, it bends, you can say, and then it comes back down to the floor.

EZEKOYE: And so when a firefighter goes down and this PASS alarm sounds...

(SOUNDBITE OF ALARM)

EZEKOYE: ...your mind has to differentiate that particular sound and then have to locate it.

(SOUNDBITE OF MACHINERY)

LARGEY: So here you are. You're basically blind. There's fire and all these other sounds, and those sounds may or may not be bending as they move through the air.

(SOUNDBITE OF WARNING SIGNAL)

SUITS: And so the possibility of detection because of these other sounds that are as loud or louder than the PASS device itself is low, is very low because of that.

LARGEY: And yet remarkably, it works most of the time. But could it work better?

EZEKOYE: I mean, certainly just having a loud noise going off is a big help. But beyond that, nobody studied the other aspects that can make it more efficient.

LARGEY: So what Suits and Ezekoye are doing is trying to quantify all those other sounds in the fire and figure out how you might design an alarm signal that can compete.

SUITS: There's most likely not going to be a specific signal that we come up with where we say, OK, this signal right here is the best signal.

LARGEY: More like some guidelines.

SUITS: Mainly, we're going to come up with something and say, OK, these are the frequency ranges where you have the best possibilities and possibly you need to make it louder.

LARGEY: But there is no magic signal.

SUITS: There's not going to be a magic signal.

LARGEY: Of course, all this raises a big question. With all its problems, is sound really the best way to find a firefighter who's in trouble?

EZEKOYE: You know, this is not the only perhaps approach.

LARGEY: What about GPS or some kind of homing beacon?

EZEKOYE: All these other technologies, none of them has worked as well and as reliably as this simple sound beacon at this point. So we're not trying to create a revolution but we're trying to evolve. And so it's an evolution in terms of this particular technology.

LARGEY: Maybe in the future, Ezekoye says, there'll be some kind of hearing aid or something specially tuned to pickup and locate a signal from a PASS device. But change in the fire service is slow to happen. PASS devices last got a major update in 2007 when their resistance to heat and water were improved. But up until just this year, there was actually no universal standard for what a PASS alarm should sound like. Different manufacturers had different alarms. The idea with the new standard is that no matter where you are, if you hear this sound...

(SOUNDBITE OF WARNING SIGNAL)

LARGEY: ...you'll know a firefighter is in trouble.

(SOUNDBITE OF WARNING SIGNAL)

LARGEY: But the alarm is just supposed to be universally recognizable, not necessarily be a better PASS alarm. The UT researchers hope to have their guidelines for what that alarm should sound like sometime next year. For HERE AND NOW, I'm Matt Largey in Austin.

JEREMY HOBSON, HOST:

Well, Meghna, up next, we are going to talk about the change of the seasons. You know, here in New England, it is getting a bit cooler. It's starting to feel like fall. I know that many people in many parts of the country today feels very summer-like. Up in the upper 90s, I think, in Chicago. But one of the things that you do in the fall is you try to preserve your vegetables and fruits...

CHAKRABARTI: Exactly.

HOBSON: ...by pickling them perhaps. HERE AND NOW Chef Kathy Gunst is going to be here to tell us all about that. I know you're from Portland, Oregon.

CHAKRABARTI: Well, I hail from a town close to Portland, but yes, I'm a native Oregonian.

HOBSON: Well, the famous "Portlandia" story about we can pickle that, we'll talk all about that.

CHAKRABARTI: Bicycles, we can pickle that.

(LAUGHTER)

HOBSON: That's coming up next, HERE AND NOW. Transcript provided by NPR, Copyright NPR.


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  • David H. Brown

    Wonderful audio editing to help tell the story… though I feel sorry for anyone who was driving during this piece!

Robin and Jeremy

Robin Young and Jeremy Hobson host Here & Now, a live two-hour production of NPR and WBUR Boston.

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