Printer Friendly

Listening for hidden fires.

The snap and crackle of a moonlit campfire can gently set a scene for romance. But the subtle strains and creaks of a house catching fire certainly do not.

Either way, the distinct sounds of combustion have led scientists to a new way to detect hidden fires: Listen for them. Acoustic sensors can be tuned to catch the unique vibrations of materials about to burst into flames.

William Grosshandler and Margaret Jackson, at the Building and Fire Research Laboratory of the National Institute of Standards and Technology in Gaithersburg, Md., have tested sound sensors, called piezoelectric transducers, in experimental fires. The sensors are able to detect the specific acoustic signals of typical housing materials that are about to burst into flames. Using different types of wood, plastic, aluminum, and gypsum board, the researchers have found distinct acoustic signatures associated with the rapid heating of these materials.

Grosshandler calls this fire detection method "a viable but undeveloped concept."

A smoldering fire or overloaded electrical circuit creates heat, which causes surrounding materials to expand. That stress produces sound, at frequencies up to 500 kilohertz, which can signal a serious overheating event even before actual ignition, the researchers say.

The detection technique has many potential advantages, they add. It can scan a large area and is unaffected by the presence of people or machinery, both of which can sometimes give false clues of fire. The sounds of thermal expansion spread more quickly than combustion products or infrared radiation (heat). And an acoustic sensor may serve in an integrated, intelligent fire-detection system, which can locate and analyze hidden hot spots in a building.
COPYRIGHT 1993 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:acoustic sensors can detect sound of materials about to burst into flame
Publication:Science News
Article Type:Brief Article
Date:Jul 24, 1993
Previous Article:The logic to molecular computers.
Next Article:Maya mountain towns found in Belize.

Related Articles
Sound sensing.
Neurons may take a panoramic view of sounds.
Tiny acoustic wave sensors will find food applications.
Fire casualties: is a smoke detector to blame?
100% pipe QC comes to the U.S. (Extrusion).
Fire-sensitive dryers.
Fire-sensitive dryers.
Fire-sensitive dryers.
Truck crews test anti-sniper acoustic sensors.
Hand on the trigger: forward operating bases (and troops) are some of the most valuable and definitely the most vulnerable assets available to any...

Terms of use | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters