Q: I read somewhere that the window in the bathroom is supposed to be safety glass. Is this true? We are replacing our windows this fall and I'm doing as much research as I can.
A: Yes, all glass that is within 60 inches vertically from the tub or shower drain must, according to Indiana Codes, be tempered glass. You can check with your local or state building authority, but it's really a safety issue.
If a person were in a tub where they could slip or lose their balance and their hand or arm hit the glass, a standard plate glass window or door could cut through flesh and bone. On the other hand, tempered glass will break under stress, but the glass shatters into tiny pieces like the windshield of a car.
I remember back in the late 1970s a company I owned had to sell all the standard glass shower doors we had in stock and replace them with either plastic doors or tempered glass doors. This means the code has been with us for a long time and the oldest code book I own that refers to tempered glass is a 1975 edition of the "One and Two Family Dwelling Code." While replacing your windows, you should also check your home for larger panes of glass that a person could accidentally fall against or the glass could be hit by a door or other object. These are considered "hazardous locations" requiring tempered glass. I found a few more locations while researching the 2003 edition of the "International Residential Code."
A window must be tempered glass if all of the following criteria are met: more than nine square feet in one single piece of glass that is 18 inches or less from the floor and the top of the glass is greater than 36 inches above the floor and has a 36-inch walkway on either side of the glass. Hazardous locations include entry and exit doors, sidelights within 24 inches of the door, storm doors, sliding doors, unframed swinging doors, French doors, tub and shower doors, glass enclosures for a pool, whirlpools, saunas, hot tubs, mirrored glass in a swinging or bi-fold closet door and windows next to a stair or landing. There are more unusual areas needing tempered glass, so it pays to do the research. Tempered glass can be determined by a permanent mark that is placed in the glazing by the manufacturer by acid etching, sandblasting, ceramic-fired, embossed mark, or any type of marking that cannot be removed without destroying the product.