Mercedes-Benz Automobile Side & Rear Window Glass

As a standard feature on selected vehicles within its model lineup, automaker Mercedes-Benz offers an unusual window design.

As a standard feature on selected vehicles within its model lineup, automaker Mercedes-Benz offers an unusual window design. Although it will be a challenge to rescue personnel, it is one that won’t stop emergency responders from gaining access to patients. It’s just that it might be an unexpected surprise.

Thermopane Side Window Glass

Within the homebuilding industry, window glass is commonly a double layer of glass positioned side by side; a thermopane window. A thin strip of foam material bonds the two layers of window glass together to form the storm window design. The double-glazed home window reduces noise getting into the house and provides a greater degree of insulating ability for both heat and cold.

For its luxury car owners, Mercedes-Benz offers thermopane side window glass on selected models of their vehicles. Remember, if you’re willing to pay a base price of $80,000 for a four-door vehicle (up to $115,000 with available options), you expect it to be quiet and cool inside your vehicle. So what may appear to a rescuer as if it were a standard tempered glass side window may actually be the Mercedes-Benz thermopane window.

Just like a storm window on a house, the unique side window design actually incorporates two separate glass panes glued together by a thin foam weatherstripping-type material along the edges of the glass. When rolled down, a rescuer will be able to recognize the double glass window because of its thickness. A closer examination of the edge of the window will also reveal the two individual panes of glass sitting side by side.

A recent vandalism incident provides an example of what this thermopane window glass will look like at a crash scene. A late-model Mercedes-Benz S-500 sedan was vandalized both outside and inside. Besides slashing the leather seats, smashing the instrument panel apart and tearing up the interior of the car, the vandals broke out one layer of all the thermopane tempered glass side windows. With the outer layer of glass broken away, the double glass design becomes evident.

The broken tempered glass nuggets visible in these images are only the outside layer of glass. If a rescuer wants to completely break out a window at a crash scene, it is clear to see that the window would actually have to be attacked twice; once for the outer layer and a second time for the inner layer of glass in the thermopane window.

This should not be a problem and now that you know about this possibility, it shouldn’t be so much of a surprise either.

Laminated Rear Window Glass

There is something else different about this vandalized Mercedes-Benz S-500 automobile. A second window design that again may catch the rescuer off guard is the rear window glass may be laminated. All outward appearances will be that the glass is normal. The assumption will be that it is tempered glass just like all the other vehicle windows you’ve broken out on this vehicle at the crash scene.

So as you begin your attack to remove the glass, you use a sharp pointed object such as a center punch or other tempered glass breaking tool. Because the window is laminated however, the result will only be a popping sound, a small "BB" mark and some slight splintering of the glass; the window will remain intact. After a second attempt and possibly a third punch, it will become apparent that you don’t have a defective center punch and you don’t have a tempered glass window. Once recognized for what it is, the laminated rear window can be thought of as if it were a rear windshield. Any tool or technique that is used by the department to remove front windshields can be used to remove the rear "windshield" as well.

The GlasMaster windshield saw, chopping it out with an axe, or use of a reciprocating saw with a coarse tooth-per-inch saw blade (5-8 tpi) are all techniques to cut through the glass and the lamination to remove the window. You have to cut only three of the four sides of the window. Make one long cut across either the top or the bottom of the window and then cut both short sides. Depending on which long edge you cut, either lift the glass up towards the roofline or lay the glass out down on the trunk. Pull firmly on the sheet of glass to release the adhesive holding the final edge of glass to the vehicle and window removal will be complete. Just like with the windshield, once removed, place the laminated glass underneath the vehicle and out of your way.

TASK: Using a Mercedes S-500 sedan vehicle as an example, explain procedures for forcibly removing thermopane side window glass and laminated rear window glass.

Ron Moore, a Firehouse contributing editor, is a battalion chief and the training officer for the McKinney, TX, Fire Department. He also authors a monthly online article in the Firehouse.com “MembersZone” and serves as the Forum Moderator for the extrication section of the Firehouse.com website. Moore can be contacted directly at [email protected].