Non-tempered Glass BreakMany accidents and injuries in the home are related to breakage of glass in windows and doors and are typically attributed to failure to see the glass; slips and falls; and intentional breakage.   In the 1960's the National Safety Council and National Glazing Association worked together to form a standard for impact resistance of glass since hundreds of thousands of injuries occurred annually in the United States from impacting glass in doors and windows during that time period.  The first standard was created in 1966 and given the designation of ANSI Z97.1.  The Consumer Product Safety Commission (CPSC) also created a similar standard, CPSC 16 CFR 1201, which became law in 1977.  Both standards have been revised (as with most building standards) since their adoption, but still provide guidelines for current building codes to identify specific hazardous locations in the home where safety glazing is required.

The Different Types of Safety Glaze

Tempered Safety GlassWhat is safety glazing and what types of safety glazing are common in the building industry? Most types of standard annealed glass will break up into large shards upon impact which can cause serious injury and (in some cases) death due to excessive blood loss.  Safety glazing was developed to prevent such serious injury in event of impact and breakage of glass.  There are two basic types of glass approved as safety glazing by the ANSI and CPSC standards;  laminated glass and tempered glass.  Laminated glass can shatter from impact on one side of the glass without shattering the opposite side of the glass into large shards.  This type of glass is more common in commercial building applications (i.e. stairway guardrails) and rarely seen in residential homes.  Tempered glass can be seen in almost every home built after the 1960's.  Tempered glass is four times more resistant than standard annealed glass and will break into small cubes (rather than large shards) which will minimize significant injury.   Tempered glass can be identified in two ways.  The most common way to determine if glass in a window or door is tempered is to look for a white etched "bug" at one corner of the glass.  The "bug" should identify the glass as being "tempered".  In some cases, the "bug" may be missing from glass rated as safety glazing in homes built after the 1960's.  In this case, a licensed glass contractor should be consulted to perform a simple non-destructive test to determine if safety glazing is present.

Is Safety Glazing Required In My Home?

Safety glazing is required for glass in all doors and for windows in hazardous locations subject to impact.  This includes glass in shower doors; sliding glass doors; windows adjacent to showers and bathtubs within 60 inches above standing or walking surfaces; large windows (greater than 9 square feet in area) within 18 inches above and 36 inches away from walking surfaces (interior and exterior); windows adjacent to swimming pools and hot tubs; windows in stairways within 36 inches from walking surfaces; and glass in stairway guardrails.

As a home inspector, I look to make sure safety glazing is present in all areas considered as hazardous impact locations in the home per the International Residental Code (Section R308) regardless if the home is old or new since the safety of a home's occupants is one of my main concerns.   Unfortunately, I discover many homes (old and new) that have no safety glazing in windows where required per current building standards.   So what if you have an older home (built prior to the 1960's) with original glass in doors and windows where safety glazing is not present but now required?  In lieu of replacement, glazing in windows and doors for older homes can be strengthened via safety film which would qualify as safety glazing if installed properly.  One approved safety film is Scotchshield safety film from 3M.  Some municipalities in the United States require homeowners to have safety film installed (as a minimum) on glass for windows and doors where considered a hazardous impact location (and where safety glazing is not present) prior to selling their home.   If you have a newly constructed home where safety glazing is not present in hazardous impact location, your local building code enforcement agency will likely require you (or your builder) to have the window or door replaced.

If you wish to learn more about the specific requirements for safety glazing, feel free to comment on this blog or obtain a copy of the 2009 International Residential Code and review Section 308.  Also feel free to comment on this post or join Heartland Inspection Solutions on Facebook: for more home maintenance and safety tips.