How to install fire-rated interior walls

Dilbert would agree: Floor-to-ceiling glass walls can revolutionize office life, ignite the shopping impulse in the most parsimonious people and expose residents to beautiful vistas throughout vacation homes. At least two such fire-rated systems distributed in the United States—the Vision 60 System from AFG Industries Inc. in Kingsport, Tenn., and  InterEdge Technologies of Sausalito, Calif.; and the SGG Swissflam Structure from Saint-Gobain Vetrotech—can be butt glazed, although the installation instructions are different for each system.

How can a manufacturer assure the fire rating on a 60-minute wall with panels merely butted together with silicone caulk? The answers are different for each system. According to the results of fire testing by InterEdge Technologies, the silicone caulk remains in place to 1,700 degrees Fahrenheit, says Scott Foote, InterEdge consultant.

“The space between two units—the butt joint—is a maximum of 4 millimeters; the depth almost 1-inch thick, the thickness of the glass,” he says. “We have found that neutral-cure silicone, after it cures for 30 days to outgas inflammables, will not burn through this very limited space during a 60-minute fire test. There might be some expansion of the intumescent interlayers at the butt edges to aid in maintaining compression with each lite, but truthfully we cannot verify this.”

Exacting tolerance
Each system has its own exacting installation instructions, and they cannot be interchanged. The recommended routine for one such system will give an idea on the precision required.

The Vision 60 System utilizes Pyrobel-60 fire-rated glazing, manufactured by Glaverbel, and InterEdge’s Quick-Frame, StileLite or HighLite framing at the perimeter.

Pyrobel-60 is available in maximum panel sizes of 4-by-8 feet and can be glazed either horizontally or vertically, but not stacked. Maximum panel size with a clear view cannot exceed the square-inch dimensions listed above, and are subject to stock sheet sizes available. Additionally, decorative profiles of aluminum, wood or steel may be applied to the face of the glazing to cover the silicone joints and add to the aesthetics of the surrounding area.

Installation requirements include:
• Pyrobel-60-25 glazing provided with arris cuts at butt edges of the glass
• The space between glazing panels should not exceed 4 millimeters
• Neutral-cure silicone caulking—100 percent pure silicone such as Dow Corning 794s—needs to be pressure-glazed at butt joints only and cured for a minimum of 30 days
• Pyrobel must be glazed with 3⁄16-by-11⁄4-inch closed cell foam glazing tape with neutral-cure silicone around the perimeter of both sides of glass; the perimeter silicone must not be pressure glazed
• Pemko 3000S45 intumescent tape must to be applied at the top stops in addition to closed cell foam tape. Apply Pemko tape on top of closed cell foam tape to form two layers of tape.
• Perimeter framing must be either Quick-Frame, StileLite or HighLite systems with a 11⁄2-inch stop height.

Due to the complex nature of this wall system, glazing instructions must be followed explicitly to maintain the manufacturer’s guarantee. Consult with the local authority with jurisdiction before specifying or purchasing any product for your project, the manufacturer advises. Details shown illustrate general installation guidelines. They are not to scale and should not be used to accurately detail your project. Specifications can be obtained from www.firesafe-glass.com, or by calling 877/376-3343.