Q. Does the code in all parts of the country require tempered glass for a window seat?
A. Glenn Mathewson, code educator and consultant from Colorado (buildingcodecollege.com), responds: Code questions like this can be tricky because the answer can vary with individual jurisdictions. While the International Code Council (ICC) does publish a standard for residential construction, it’s still up to each individual AHJ (authority having jurisdiction) to choose what model code to reference and whether to amend it. Whenever you have any doubt about a local code issue, the foolproof solution is to talk to your local authorities.
According to the 2018 International Residential Code (IRC), the easy answer to this question is “no.” Code does not require tempered glass for a window seat, but that doesn’t mean that tempered glass in this situation isn’t a good idea. Code standards are often mistakenly thought of as the best standards, even though building code requirements are actually the “minimum standard.” Meeting the code could be A-plus work, but it could also be D-minus, a mere passing grade and probably not something to brag about.
As far as the IRC is concerned, tempered glass, or “safety glazing,” is required in areas identified as “hazardous locations.” What these locations have in common is the existence of a hazard while occupants are on their feet. A few examples of hazardous locations are bathroom floors, stairs, ramps, and areas where glass is too close to the floor. All of the locations where safety glazing is required reference “walking surfaces,” “standing surfaces,” or “the floor.” A window seat is meant for sitting—and there is little probable hazard in that stationary activity.
It’s always possible to come up with “what if” scenarios in which someone, perhaps a child, could run across the seat or stand on it, but the code minimum standard is not meant to protect us from every bad idea we can imagine. Building codes are intended to protect us from probable hazards, not possible ones.
As responsible contractors, though, we can do better than D-minus. For ourselves and for our clients, we can look beyond what the government authority requires and consider what’s best for the occupants of the home at the time. Are there children? Do the clients already have safety concerns? Is there a high fall hazard outside the window? Is the seat going to get daily use as a seat for a breakfast nook or dining table, or is it going to be more of a decorative element? Should you even build a seat where the back is a window? And what about the fall hazard when the window is opened? These are just some of the questions to consider when deciding a client’s expected and affordable grade of safety.
While you weigh all the various issues around your client’s safety, consider that replacing or reglazing a window with tempered glass isn’t the only way to achieve the benefits of safety glazing. For situations that require safety glazing, the IRC details two standards. These standards can be met by applying various proprietary films on existing windows, somewhat like applying tint on your car windows. While typically marketed for security purposes, these products often meet the standards for safety glazing—CPSC 16, CFR 1201, or ANSI Z97.1—and might be a less expensive way to achieve peace of mind for your clients.
