1、Basis of Analysis

Due to the uneven stress distribution in the glass during its tempering process, tempered glass can be easily identified by its stress lines on the surface using strengthened glass detector. 

2、Process of Analysis

Place the strengthened glass detector against the glass to be tested. If possible, allow a dark background (preferably black) behind the glass for easy observation.  Turn the detecting meter on and look through the viewing window for the reflection of light. You will see a column of light reflection for each surface area you inspect.

Single pane glass will show two columns of light reflection.  Slide the meter across the glass surface and pay close attention to changes in color of the columns.  If the color in column 2 changes to a color different from column 1, a stress line is detected and the glass is tempered. If the neither column changes color or both columns change their color together, the glass is not tempered.

Double-pane insulating glass will show four columns of light reflection in the viewing window in the order with column 1 on the right most side. Column 1 and 2 are the light reflection in the pane with which your detector has contact.  Column 3 and 4 are for the second pane.

3、Applicability and Limitations

(1)Applicability: This method can easily detect if the glass is tempered. It is especially convenient for double pane Insulating glass. Meanwhile, since the test is not destructive, this method has wide range of applications in the field. 

(2)Limitations: The detector has to have direct contact against the glass surface which may be difficult for areas not easily accessible.