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Interior Glass Doors: Built for safety, size and style

Interior glass partitions and doors highlight the offices of financial planning software company PIEtech in Powhatan, Virginia. SMBW Architects chose large interior glass systems for the project, including: Pure Enclose Framed Glass Wall Systems with EML372 Magnetic Locks RTS88 COC and TG 138 49-inch Non-Locking Ladder Pulls featuring Universal Patch Fittings; and the Muto Manual Sliding Door System with TG 138 49-inch Non-Locking Ladder Pulls. Dormakaba supplied the interior glass systems.


The beauty of glass in interior spaces is highlighted by its ability to separate, while remaining clean and transparent. Architects and designers achieve this division with larger glass doors. To meet the demand for larger and larger interior glass door systems, glazing contractors and suppliers must provide safe glass and hardware solutions to meet both budgetary and aesthetic goals. Below are important considerations for working with large glass doors.


1. Track the size trends

Increasing requests for larger doors and walls push the limits of industry guidelines. As door heights increase, the build of a door changes. For example, once a glass swing door reaches 9 feet, it requires thicker glass, or a door pull, to limit deflection and stabilize the door. While ½-inch glass remains the default for most interior projects, glass thicknesses up to ¾ inch and even beyond are increasingly common.

As glass height and thickness increase, wider glass is expectedly more common as well, making appropriate support of the increasing glass weight vital. Proper support will ensure ongoing performance and prevent future problems. Verify all glass systems have testing or manufacturer approval prior to installation, particularly considering the different types and sizes of tempered glass available.

Designers are also opting for tempered laminated glass. TLG provides privacy, design and additional safety, supplementing overall value. With the added benefit of sound reduction, it’s no surprise the volume of interior glass with laminate is increasing substantially.


2. Understand the limits

The Glass Association of North America provides recommendations for the maximum sizes of glass doors (for current guides for patch fitting and rail doors, see the chart above). It’s important to note that much of this information is based on the typical available hardware, not on what is truly possible. If customers take deflection into account and use recommended installation methods with the proper hardware, these limits can be surpassed while meeting safety requirements.

Considerations should be made for the combination height, thickness and the resulting weight. Adjustments must be made to one or more of these factors to keep the total door weight with all applied hardware under the maximum limit of the supporting hardware. Consider a sliding glass door system with a maximum limit of 330 pounds. If a 9-foot-high door is required, the door width is likely limited to 60 inches or less to keep a ½-inch thick glass door under 330 pounds. If a thicker door is desired, the door must be either reduced in width or height, with thought given for the weight of applied hardware, such as handles.



3. Weigh cost versus aesthetic

Two main factors dictate design of large glass doors: size/weight and budget. There is often a balancing act between customer pricing and design. There are products on the market to support larger glass doors, while maintaining the desired clean, minimalist aesthetic. However, they come at a premium and could become targets of cost cutting.

For example, installation options, such as recessed mounts in the ceiling, limit visible hardware while providing the same support as wall- or ceiling-mounted options. In other cases, door closers that are necessary to hold door weight, are larger and thus less aesthetic. They can also be hidden in a header, or in the floor. Each option comes with its unique install and hardware costs and, unfortunately, value engineering may reduce the ability to achieve the design and visual appearance. Work with designers and owners early on a project to ensure a door system solution that meets aesthetic and budgetary requirements, while avoiding late-stage value engineering.


4. Know hardware requirements

To augment the visibility of glass, design is trending toward less visible hardware. Interior glass systems offer framed and frameless options. Across the industry, framed glass systems come with increasingly slimmer profiles. The same applies for hardware such as door rails, glazing channel and sliding systems. Just as it is necessary to properly support larger glass panels and doors, it’s important to ensure sufficient structural support as glass systems and hardware attempt to hold more glass, while being less visible.

For example, to further stabilize large, partial or full doors, pulls are recommended. Once glass reaches certain heights over 9 feet for ½-inch glass, it may deflect slightly. While not always noticeable, when a door pushes height and weight limitations, support requirements become more significant. A simple pull will help to limit deflection by adding posts at the top, bottom and center of the glass panel.

Another important hardware consideration is which closer should be used. With larger swing doors, moving from an overhead concealed closer to a floor closer to handle the weight is necessary. This improves the ability of the door to have a controlled close at the proper speed. If the closer is too light, the door will be subject to long-term stress or damage.

There’s no doubt that the industry will continue to see larger, thicker glass with less visible framing. Keep in mind the limitations of glass systems and work with manufacturers to evaluate products so that the industry can learn and grow together.


Derek Forney

Derek Forney

Derek Forney serves as Interior Glass Systems product manager for dormakaba.