Auto Glass: quality of replacement glass, mercedes e 320, economic commission for europe

Question
Hello,
I drive a 2002 Mercedes E-320, I receantly replaced the windshield and all drivers side glass due to severe sandblasting, I asked for MB replacement glass.Only one of 4 pieces replaced had the MB on it I noticed on all windows with the MB that there was a circle with E1,on the replacement glass the circle had an E2. What does this mean?
Thank you
Daniel

Answer
Hi Daniel,

Here is a very good summary of "E" numbers from the UN Economic Commission for Europe.  For additional information, you can visit www.unece.org

The letter "E" and a number in a small circle in the corner of car windows indicate that the glass has reached a certain standard of security.  The “E” and numbers are the result of the Agreement on Regulations for Motor Vehicle Equipment and Parts, which was reached at UNECE in Geneva in 1958, and updated in 1995. So far, a total of 123 vehicle regulations have been established, setting standards for almost all vehicle parts. These car parts are certified with a circle surrounding an “E” followed by the distinguishing number of country that has granted approval. For example, “E1” is used for car parts certified in Germany, “E2” for France, “E3” for Italy, etc.

Thanks for your rating,
Kevin