Date: May 29, 2015 Author: Brandon Winters

Photo: Menkes

After a building fire is extinguished and building occupants have been evacuated, fire scene investigators perform forensic fire scene reconstructions to determine how the fire started, the manner in which it spread, and the damage it caused, among other concerns. In many cases, laser scanners can assist with forensic fire scene reconstruction by providing the following benefits.

Highly Accurate Data

A laser scanner works by projecting a thin laser beam that bounces off of objects and is registered by a sensor in the scanner. The scanner detects the 3D coordinates of objects and environments by directing multiple laser beams at the target and measuring how long it takes them to bounce back to the sensor.

From a distance of several yards, the best commercial laser scanners -- which can cost upwards of $100,000 -- can record physical dimensions within a range of less than 1 millimeter.    

More Investigation Time

A laser scanner can be used record the physical dimensions of the fire scene. In addition to reproducing an accurate representation of the general scene using 3D coordinates, it can also record the presence of small objects, such as knives and drinking glasses.

Ultimately, using a laser scanner to create a digital record of the fire scene gives fire investigators more time to study the scene. After a fire damaged building has been declared off limits, fire investigators can have the luxury of studying the scene using laser scanning data.

Collects Overlooked Evidence

Fire investigators only have so much time to perform forensic fire scene reconstruction at the burn site. Consequently, it is not unheard of for investigators to overlook evidence that is physically minute or does not seem to have anything to do with the building  fire.

By recording the 3D coordinates of a fire scene, a laser scanner creates a point cloud that allows investigators to view the fire scene from different angles, and review any physical objects that may have been overlooked, and have suddenly become important to the investigation.  

Creates Animations of the Fire Scene

After it records data, a laser scanner is commonly used to create 3D animations of crime and accident scenes to show how events occurred. It can also create animations based on fire scene data. Because the scanner records precise 3D coordinates, the point cloud can be used to create computer animations that show exactly how an event occurred.

Data is Easy to Archive

Photo: David Munniaux

The forensic evidence that laser scanners record can be conveniently downloaded to a high-density compact disc (CD) that takes up less room than paper records. The evidence in the point cloud can also be stored in onsite data silos or outsourced to a managed storage provider.

Finding a reliable format in which to store laser scanner data benefits fire departments in two ways: it prevents data from being destroyed by a disaster that destroys the IT system, and, when it is outsourced, it can free up space that was previously occupied by large data silos.

Need Help With Fire Scene Reconstruction?

If so, using a laser scanner to record the 3D coordinates of a fire scene, and then using the data to create a mathematically precise animation of how events occurred, may be exactly what you need. If your department doesn’t have room in the annual equipment budget to purchase a high-end laser scanner, it can outsource laser scanning to a laser scanning company.  

To learn about additional resources for forensic fire scene reconstruction, contact Firebooks. We carry a variety firefighting books that help fire scene investigators perform the their job as efficiently and thoroughly as possible. Visit our online bookstore and check out our titles!

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