Device to predict flashover in development

By Aaron Nicodemus
The Telegram & Gazette

STOW, Mass. — If you're an engineer developing a device to predict a flashover, you've got to know if the device is going to work in deadly conditions.

Last week, engineers and graduate students at Worcester Polytechnic Institute placed thousands of dollars worth of sensitive test equipment inside a concrete room at the Massachusetts Firefighting Academy burn building. They painstakingly assembled just the right amount of combustible material to create a hot, smoky fire. Once lit, the fire burned at temperatures topping out at 1,600 degrees Fahrenheit. Instead of watching the developing smoke and fire, the eyes of WPI engineers and graduate students were glued to data streaming into their laptops from the devices inside.

WPI engineers are developing a device to predict when a flashover occurs, one that will give firefighters a 20- to 30-second warning, so they can clear the room. Flashover happens when a fire gets so hot that all the combustible material in a room ignites at once.

"The prediction of the time to flashover will give the incident commander a critical piece of information that, when combined with the location of each firefighter, will greatly enhance the natural decision-making process," said Kathy A. Notarianni, head of WPI's Department of Fire Protection Engineering. WPI is also working on technology that will allow an incident commander to know where each firefighter is in a multistory or industrial building.

The research is funded in part by a $1 million federal grant from the Department of Homeland Security.

Last week's test was meant to see if the still-in-development flashover devices could transmit data on the progress of the fire through thick concrete walls to their laptops. They also wanted to see if they could survive intense heat.

"Both our devices died," WPI electrical and computer engineering professor David Cyganski told fellow WPI professor R. James Duckworth as the fire raged. "They suddenly stopped transmitting," he said, because the heat scorched the devices' antennae.

"We don't really care if it dies," Mr. Duckworth said after the test. "It's like saying your airbag has died when it activated. If it works and dies, it's done its job."

The two flashover detection devices were attempting to predict flashover in different ways, both to overcome problems unique to high-intensity fire.

The first problem is that soot from the fire blocks devices that measure heat, so they built a device to measure the fire's radio waves instead.

The second is that the beginnings of a flashover occur on the ceiling of a burning room, not the floor. (By the time it's that hot on the floor, the flashover has occurred). It is impractical to expect firefighters to attach a device to the ceiling as they enter a smoke-filled room.

The engineers are trying two different approaches. Both devices contain electrical circuitry inside small metal boxes that are about the size of a cigar box.

One device has a small triangular antenna sticking out of it, which measures radio waves emitted by a fire. Engineers hope they can obtain accurate data on the radio waves, to help them to predict when a flashover will occur.

The other device has a switch that the firefighter would hit as the device was placed on the ground. Within seconds, a small pole would rise out of the box, powered by a small motor inside, and rise all the way to the ceiling. The pole would also transmit data to an outside laptop with a wireless transmitter.

But that device was having mechanical problems last week, so the researchers attached the measuring devices to a metal pole.

Mr. Duckworth declared last week's tests a success.

"They both carried on working long enough to catch the data," he said. Now researchers need to compare that data to actual temperature data collected by Ms. Notarianni, and then figure out how the device should warn firefighters that a flashover is imminent.

"We've still got work to do. This was an important step," Mr. Duckworth said.

Copyright 2010 Worcester Telegram & Gazette, Inc.
All Rights Reserved