Often it is difficult to tell if a window has safety glass installed unless the etching on the window indicating that it is safety glass is visible. Sometimes the glass will have a "wave" like appearance when viewed from the side, this is from the tempering process but it is not always visible. The picture to the left an example of a window "bug" or etching.
When a home inspector can not tell if a window has safety glass the normal recommendation is to have it installed or the window replaced with safety glass. This can be costly and with custom windows very time consuming, which in real estate transactions can become a problem.
Recently I have become aware of a product that has been around for many years but has gained a new use inside homes. For years it has been used to keep windows from being broken by burglars and from flying objects during storms.
It is called 3M Security Window Film. This specific product is called Safety S80 film. It is being used in place of tempered glass/safety glass on windows that are required to have it in pre-existing installations and in some instances new construction. Keep in mind that some local code officials are allowing its use with new construction.
So instead of replacing the windows glass with safety glass this film can now be applied to the interior of the window.
Before using this product, you need to check with your local code officials to see what their feelings are on this, not all of them will agree or know about this product.
3M Safety Film, Safety S80 is designed for use on the interior surface of windows. It is composed of a transparent and weather stable polyester film, scratch resistant surface and a strong acrylic adhesive. The films high tensile strength and elongation at break increases resistance of the glazing system to impact and pressure. The film also significantly reduces the transmission of UVA and UVB rays which are the main cause of fading.
3M Safety Films provide an effective protection from injuries to persons or damage to items caused the fragments of broken glass. In the case of glass breakage the fragments are held together by the strong acrylic adhesive.
This film can save you hundreds of dollars over replacing the glass. It is a viable option in many situations.