Building, design and construction experts have a special responsibility to conduct due diligence and create safe, code-compliant living and working spaces for their clients. Specifying proper fire-rated glazing products is an important part of this process. While there is no single formula for narrowing down the product lens given the many life safety and other demands present in today's buildings, the following fire-rated glass and framing tips can help guide proper selection. The information is meant to be a starting point; manufacturers or suppliers can answer specific questions regarding a given product’s make-up and performance.
One of the first steps when specifying fire-rated glazing is to ensure it provides sufficient defense against fire. Locations will either require fire-protective or fire-resistive glazing products. Fire-protective glazing defends against flames and smoke. Fire-resistive glazing goes a step beyond and also defends against radiant and conductive heat transfer.
Correct specification is crucial since fire-rated glazing that provides protection other than intended could jeopardize the safety of building occupants. Consider doors in egress areas such as stair enclosures, which occupants must pass by or through to exit a building. If the assembly does not provide the necessary defense against heat transfer and temperatures reach high levels on the non-fire side of the door, the exit stair may be impassable when needed for use.
It is essential to check the required fire rating since code standards vary by occupancy and location in the building. Fire ratings for glass and frames range from 20 minutes to three hours, and are shown on the product's label. The given number corresponds with testing in accordance with national fire test standards. To ensure a product's fire rating matches building codes, reference requirements for fire-rated glass in Chapter 7 of the International Building Code (IBC). The 2012 code edition includes updated language to clarify confusion around the required performance levels for fire-protective and fire-resistive glazing.
To receive a fire rating and listing for use, glass must pass the fire test. Products with greater than a 20-minute fire rating must also pass the hose stream test. Depending on the specific application in which the product will be used, additional tests for fire-rated glass are available (i.e., impact resistance, bullet resistance, hurricane resistance, etc.). Fire-rated glazing in compliance with the IBC carries marks that indicate its conformance with these tests, and whether it is suitable for use in doors, openings or walls.
As of the 2006 IBC, fire-rated glazing in hazardous locations must also pass an impact safety test. This includes all fire-rated glass in doors. It also typically applies to fire-rated glazing adjacent to or near the door, including sidelites or glass located near the floor. Since not all products provide both fire and impact safety protection, it is important to verify the selected offering meets either CPSC 16CFR (Category I) or CPSC 16CFR 1201 (Category II) impact classifications, as determined by the application. Today, numerous products meet this criteria and also have the capability to provide supplemental security protection, such as bullet and hurricane resistance.
Today's sophisticated fire-rated glass and framing products have made it possible for design teams to tailor fire-rated glazing assemblies to specific project goals. In order for these custom solutions to maintain compliance with the IBC, it is important to ensure all assembly components have the same or greater ratings than the required code minimums for the opening. This includes the frame, glass, seals and other components.
Modern fire-rated framing systems make it possible to ensure smooth visual integration with surrounding non-rated window, door and curtain wall systems. For example, new generation steel frames are much narrower than the wraparound form of traditional hollow metal steel frames. Their slender aesthetic is advantageous if fire-rated glazing is in a highly visible location where it can be readily compared to other building elements, such as an expansive curtain wall in an entryway, lobby or atrium. Fire-rated frames can also be custom wet painted, anodized or powder coated to match virtually any color scheme. Some manufacturers also offer custom cover caps in various shapes and sizes, from H and I shapes to custom configurations.
Fire-rated glass’ primary purpose will always be to satisfy fire and life safety codes. However, multifunctional systems like fire-rated glass curtain walls and fire-rated glass floor systems can now do significantly more, from supporting daylighting goals to visually integrating with non-rated glazing. While there may be a desire to overlook these products due to unfamiliarity, they are a value-added offering that can simplify specification by meeting a range of building criteria.
The rapid growth in the fire-rated industry often leads to questions about use. Don't be afraid to communicate early and often with manufacturers and suppliers. They can provide insight and recommendations about the product. There is no need to rush through the process. Taking time upfront to understand the ins and outs of today's fire-rated glazing products will ultimately lead to correct specification.
As originally published in the June 2018 edition of On Spec: Understanding Fire-rated Glass & Framing, a supplement of The Construction Specifier, sponsored by TGP. View the full supplement here.
