Yes, many types of doors are legally required to incorporate tempered glass for safety reasons, making it a common feature in both residential and commercial settings.
The Mandate for Tempered Glass in Doors
For enhanced safety, building codes generally require specific types of doors to feature tempered glass. This mandate ensures that if the glass breaks, it shatters into small, relatively harmless pieces rather than large, jagged shards that could cause severe injury.
Specifically, for doors in residential structures, all glass and panels must be tempered in a variety of door types, including:
- Swinging doors: Doors that pivot on hinges.
- Sliding doors: Such as patio doors that slide open and close.
- Operable doors: Doors that can be opened and closed regularly.
- Fixed glass panels within doors: Stationary glass sections that are part of a door assembly.
- Bifold doors: Doors that fold in sections.
This requirement applies universally to all glass and panels in these door types, regardless of the individual panel's size. These regulations are in place to protect occupants from potential hazards associated with glass breakage.
Why Tempered Glass is Preferred for Safety
Tempered glass, also known as safety glass, undergoes a special manufacturing process of extreme heating and rapid cooling. This process creates stresses within the glass, making it significantly stronger (typically four to five times stronger) than standard annealed glass.
The primary benefit of tempered glass is its distinctive breakage pattern. When shattered, tempered glass disintegrates into small, blunt, pebble-like fragments. This characteristic greatly reduces the risk of serious cuts and injuries compared to regular glass, which breaks into sharp, dangerous splinters. This safety feature is paramount in areas where human impact is possible, such as near walking surfaces or in high-traffic zones.
Common Applications of Tempered Glass in Doors
Tempered glass is widely utilized in various door applications where safety is a primary concern:
- Patio and Sliding Glass Doors: These are among the most common residential uses, as they are large panes of glass often subject to impact.
- French Doors: Doors with multiple glass panes (lites) frequently use tempered glass to meet safety standards.
- Storm and Screen Doors: Glass inserts in these doors are often tempered to withstand impacts and provide safety.
- Shower Doors: While not exterior doors, shower enclosures universally use tempered glass due to the high risk of impact in a confined space.
- Entry Doors with Glass Inserts (Lites): Many front and back entry doors feature decorative or functional glass lites, which are typically tempered.
- Commercial Storefront Doors: Due to high traffic and potential for accidental impact, commercial doors with glass are almost always tempered or laminated.
Identifying Tempered Glass
You can often identify tempered glass by a small, etched "bug" mark in one of the corners of the pane. This mark typically includes the manufacturer's name, the safety standard met (e.g., ANSI Z97.1 or CPSC 16 CFR 1201), and the words "TEMPERED" or "SAFETY GLASS." If the glass is older or the mark is faded, it might be harder to find, but its presence confirms the glass is tempered.
Types of Glass Commonly Used in Doors
While tempered glass is widely mandated for safety, other glass types may also be encountered, though less frequently in primary door applications due to safety regulations.
| Glass Type | Characteristics | Common Use in Doors |
|---|---|---|
| Tempered | Four to five times stronger than annealed glass; breaks into small, dull pieces. | Required in most residential and commercial doors for safety. |
| Laminated | Two or more panes of glass bonded with a plastic interlayer; stays in frame when broken. | Soundproofing, security, hurricane-resistant applications, some overhead glass. |
| Annealed | Standard, untreated glass; breaks into large, sharp shards. | Rarely used in doors due to significant safety hazards; typically for windows in non-impact areas. |
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