NIST Demonstrates Laser Ranging's Use in Analyzing Fires
Laser ranging can "see" three-dimensional objects melting in fires, according to an article posted Aug. 8 by the agency.
Researchers at the National Institute of Standards and Technology (NIST) have used a laser detection and ranging (LADAR) system to image three-dimensional objects melting in flames, with their results published on Aug. 8. This method could offer a precise, safe, and compact way to measure structures as they collapse in fires.
Optical range measurements, already used in manufacturing and other fields, may help overcome the challenges posed by structural fires, which are too hot to measure with conventional electromechanical sensors mounted on buildings. An article posted on the NIST website said the demonstration used a commercial LADAR system to map distances to objects melting behind flames that produced varying amounts of soot. The experiment measured 3D surfaces with a precision of 30 micrometers or better from 2 meters away. The NIST demonstration focused on pieces of chocolate and a plastic toy.
"We needed something that doesn't melt too fast or too slow, but you still see an effect," said project leader Esther Baumann. "And I like chocolate."
LADAR can image objects even when small amounts of soot are present in the flames and it works at a distance far enough away that the equipment is safe from the intense heat of a fire.
"The project came together somewhat serendipitously when we got 'fire people' talking with 'optics people,'" said NIST structural engineer Matthew Hoehler. "The collaboration has not only been fruitful, it's been fun."
According to the online article about their research, the initial experiments were conducted with flames 50 millimeters wide on lab burners at the University of Colorado Boulder, and preliminary results suggest LADAR could be applied to larger objects and fires. The NIST team plans to scale up the experiment, first to make 3D images of objects through flames about 1 meter wide. If that works, they will make quantitative observations of larger structural fires.