L.E.T.A. - Cold Climate Imaging

The Use of Thermal Imaging to Detect Unsafe Air Brakes

By: Cst. Joe Carignan
Royal Canadian Mounted Police
Courtenay, British Columbia

One of the new applications of the thermal imager presently being investigated in the Province of British Columbia, Canada is the detection of unsafe air brakes on vehicles.

Air brakes are a means of stopping heavy vehicles with the use of air. With the correct amount of air pressure applied to the brake system the vehicle can be slowed or stopped. The brake linings are forced against the machined surfaces of the brake drums creating FRICTION, which in turn produces HEAT.

Air brakes have to be adjusted often and set to compensate for any wear. Unsafe brakes occur when the brakes are not set properly and therefore not braking equally. This will result in one or more wheels braking heavier, causing more friction and heat on that brake. If the brakes are worn to an unsafe level or not set properly, that brake will show much less heat. Most brake linings operate best around 250 degrees Celsius and should not exceed 425 degrees Celsius. Usually, more and more heat is generated the harder the brakes are applied. Heavy or panic braking can cause the brake drums to heat up to as much as 1100 degrees Celsius.

A thermal imager can be used from a stationary or mobile position to view the wheels of larger vehicles equipped with air brakes. A vehicle with improperly adjusted brakes can be distinguished from others with the use of the thermal imager. If the brakes are not braking equally and overheated for one reason or another, or colder than the others, the thermographer will be able to determine this. With the use of the thermal imager the suspect vehicle can be detected alone or amongst others and the investigator can check the vehicle further. This use of the thermal imager can allow more problem vehicles to be identified and checked.

This use of the thermal imager has not been used in any cases that have gone before the courts and is still in its infancy stage. This is yet another use of the thermal imager that is still being investigated.