Chances are good that you have noticed markings on your car's windows or windshield, but it is even more likely that you have never thought much about what they mean. These seemingly cryptic markings do have a purpose, however, as each particular symbol or series of letters and numbers provide valuable information for consumers and glass-repair professionals. Below is a quick reference to help you better understand what these markings signify.
Overview of markings
Automotive glass contains multiple markings that are not necessarily in any particular order, and not all glass contains the same number of markings. This can make interpretation more challenging for vehicle owners who are not familiar with auto-glass markings. However, there is a degree of standardization for common markings, and knowing these universal standards can help you easily interpret most of the important ones. Further, most of these markings are divided into three broad categories, as below.
Manufacturer identification markings
Automotive glass contains markings that designate the manufacturer of the glass, and these markings usually are in the form of a logo, initials, or the spelled-out name of the manufacturer. This information is required for vehicles and auto glass sold in the United States. In addition, cars that come from the factory may also have the vehicle's manufacturer on the glass, though this is not required by law. However, the absence of this particular mark may be a clue that the glass has been replaced, especially if other glass on the car contains vehicle manufacturer information.
Glass characteristics markings
In addition to manufacturer information, automotive glass also contains markings that describe the specific physical characteristics of that glass. The most commonly used markings for glass characteristics include the American Standard classifications, which describe where the glass can be used on the vehicle. Here are the abbreviated descriptors as they appear on the glass:
AS1 - Glass with this designation is typically used on the vehicle's windshield, as AS1 glass must be laminated and allow no less than 70% of incoming light to pass through it.
AS2 - This glass designation describes tempered glass with 70% light passage and may be used in any non-windshield application.
AS3 - Glass with an AS3 designation can either be laminated or tempered, but it does not permit more than 70% of incoming light to pass. This glass cannot be used on the windshields nor the driver or passenger side front windows.
Besides the AS numbers, each specific variation of auto glass is required to be assigned a model number, which is designated as "M" followed by a number. This number is provided by the glass manufacturer as mandated by United States law.
Finally, glass may also contain written descriptors such as "tinted," "laminated," "safety," "sunshade," or other manufacturer-specified words. In some situations, the manufacturer may provide a trademark name for a specific piece of auto glass, though this is optional.
Approval and certification markings
Other markings that appear on automotive glass are those that indicate some type of government certification or official approval. These markings are not assigned by the manufacturer but an organization that has oversight for automotive glass safety.
In the United States, all glass manufacturers approved to produce glass used in autos are assigned a Department of Transportation (DOT) code; auto manufacturers are not permitted to use glass from glass manufacturers who do not have a DOT code, including manufacturers from any location outside the United States
Automotive glass approved for use in Europe also contains its own series of codes; these codes include an "E" code with a one- or two-digit number that designates which European nation approved the glass, and European-approved glass also contains a variety of symbols that designate the construction type.
Talk to a company such as Becky's Glass Works for help reading your windshield.