When glass breaks, it often forms large, dangerous shards that can pose significant safety risks. By heating glass at a high temperature then rapidly cooling it, manufacturers create tempered safety glass, which crumbles into small pieces when broken. Residential building codes specify where this safety glass must be installed in the home in order to reduce the risk of injury or death.
Per the International Residential Code, all glass or panels in fixed, operable, swinging, sliding and bifold doors must be constructed from safety glass, regardless of size. In addition, any glass located adjacent to a door within a 24-inch arc of the door must be constructed from safety glass if the bottom edge of the glass is less than 60 inches above the walking surface. The only exception to these rules is decorative glass. and any glass opening too small for a 3-inch ball to pass through. While these IRC rules apply to all residences in the United States, San Francisco law also requires all glass located within 40 inches of an exterior or interior dwelling unit door be tempered or burglar-resistant.
Fixed or operable windows must include safety glass if they measure larger than 9 feet square, the bottom edge is less than 18 inches above the floor, the top edge is more than 36 inches above the floor, and there is a walking surface within 36 inches of the glass. Tempered glass is not required unless all four of these conditions are met.
The IRC states that stair rails must be made from safety glass, as well as structural baluster panels and nonstructural infill panels. Tempered glass must be used for all glass adjacent to stairs, ramps and landings if the glass is located within 36 inches of a walking surface. and the exposed surface of the glass is less than 60 inches above any walkway. Finally, all glazing on surfaces adjacent to stairs must be made from safety glass when the surface sits within 60 inches of the bottom tread, and the glass is less than 60 inches above the nose of the bottom tread.
The higher risk of slips and falls in wet areas means most glass located in bathrooms or near a hot tub or sauna must be constructed from safety glass. All glass in the bathroom or around a hot tub or sauna must consist of safety glass if the bottom edge is less than 60 inches above a standing or walking surface, such as the shower floor. In outdoor areas around a hot tub, all glazing must be constructed from safety glass if the bottom of the glass is less than 60 inches above the walkway and also within 60 inches of the edge of the water, according to the IRC.
- California Energy Commission: 2010 San Francisco Building Code
- International Code Council: International Residential Code of One and Two Family Dwellings -- 2009
- International Association of Certified Home Inspectors: Safety Glass for Inspectors
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