Researchers used a laser detection and ranging (LADAR) system to image three-dimensional (3-D) objects melting in flames. The method may provide a precise, safe, and compact method of measuring structures as they collapse in fires.
Optical range measurements, already used in manufacturing and other fields, may assist in overcoming practical challenges posed by structural fires, which are too hot to measure with traditional electromechanical sensors mounted on buildings.
A commercial LADAR system was used in the demonstration to map distances to objects melting behind flames that produced varying amounts of soot. From a distance of 2 meters, the experiment measured 3-D surfaces with a precision of 30 micrometers (millionths of a meter). According to the paper, this level of precision meets the requirements for most structural fire research applications.
The NIST demonstration featured chocolate and a plastic toy.
As a tool for imaging through flames, LADAR has several advantages. The technique is extremely sensitive, and it can image objects even when there is a trace of soot in flames. The method also works at a distance, from a safe distance away from the intense heat of a fire. Furthermore, the instrument can be compact and portable using fiber optics and simple photodetectors.