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Designing with fire rated glass

Clearing Up Confusion About 60-minute Fire Rated Applications

Many incorrectly assume that building codes require 60 minute doors and glazing assemblies in every 1-hour rated wall. In truth, there are only a few applications where 60-minute doors are required in 1-hour rated walls. And in some instances, doors and glazing with 45-minute or 20-minute fire ratings are allowed in 1-hour rated walls.

Revised Chapter 7 tables in the 2012 IBC provide guidance on which fire rated applications are allowed in which types of openings in 1-hour rated walls (e.g., firewalls, fire barriers, fire partitions and firewall openings.)  For the most part, the revised Chapter 7 tables in 2012 IBC simply clarify requirements contained in the 2006 and 2009 IBC. Below are table excerpts and requirements for various 60-minute fire rated applications.

60 minute doors in 1-hour rated walls

Under the IBC, a 60-minute door is required in a 1-hour rated “Fire Barrier having a required fire-resistance rating of 1 hour: Enclosures for shafts, exit access stairways, exit access ramps, interior exit ramps and exit passageway walls.”

Under the 2012 IBC, where 60‐minute fire doors are required, vision panels glazed with fire protection rated glazing (e.g., filmed and laminated ceramics, filmed wired glass and specialty tempered) are limited to 100 sq. inches. However, fire resistance rated glazing (i.e., ASTM E‐119 tested fire resistive filled tempered units such as SuperLite II‐XL) is not limited, and may be used to the maximum size tested. Click here to read about the differences between fire protection and fire resistance rated glazing.

A Special Note about the Sprinkler Exemption – Under the 2006 and 2009 IBC, larger fire protection glazing vision panels may be used in 1‐hour exit enclosure and exit passageway doors only where the building is fully sprinklered. In the 2012 IBC, fire protection glazing used in the vision panel of a 60 minute door is always limited to 100 sq. inches, whether the building is fully sprinklered or not.

Sidelites and Transoms in a 60-minute Door Assembly

The IBC (2006, 2009 and 2012 versions) makes it clear that for sidelites and transoms surrounding the 60‐minute door assembly, fire protection glazing (e.g., filmed and laminated ceramics, filmed wired glass and specialty tempered) is not permitted. However, the code does allow 60 min fire resistance glazing (i.e., ASTM E‐ 119 tested fire resistive filled tempered units such as SuperLite II‐XL) for the sidelites and transoms.

20‐minute and 45‐minute Door Assemblies in 1-hour fire partitions and smoke barriers

In 1‐hour fire partitions used as an exit corridors, and in a 1‐hour smoke barrier, the code allows a 20‐ minute rated door with a vision panel tested without hose stream. The sidelites and transoms, however, must have a minimum fire protection rating of 45‐minutes with hose stream.  In other 1‐hour fire partitions, a 45‐minute door, sidelite and transom are required.

Fire Window Openings and Walls in Interior Applications

There are no IBC requirements for 60‐minute fire windows in either interior or exterior walls. In some interior 1-hour walls, a 45‐minute fire window is permitted up to 25% area limits. To use more glass, fire resistance rated glazing assemblies must be used.

For 1‐hour fire partitions, smoke barriers, incidental use areas and mixed occupancy separations, 45‐minute fire protection windows are allowed as long as they are limited to 25% of the common wall (to exceed 25%, 1‐hour fire resistance glazing tested to ASTM E119 must be used.)

For most 1‐hour fire barriers (e.g., exit access stairways, interior exit stairways, interior exit ramps, exit passageway walls, control areas, fire areas), 45‐minute, fire protection windows are not permitted. Footnote ‘a’ makes an exception for resistance rated glazing. Architects and designers can still use glass in these situations, as long as the assembly is tested to ASTM E‐119 and is fire rated to 60 minutes, which equals the rating of the wall.

Fire Window Openings and Walls in Exterior Applications

Where the code permits a fire rated window opening in a 1‐hour exterior wall, the required fire rating for the window and glazing is 45 minutes, with the caveat of 25% width and length limits. If a designer wants to exceed those limits, then the required rating for the window/wall assembly is 60 minutes tested to ASTM E‐119.  It is important to note that even where the code disallows openings in a 1‐hour exterior wall (e.g., where the lot line is 0 to 3 feet), the code allows the use of a 1‐hour fire resistive glazed assembly tested to ASTM E‐119.

Conclusions

The IBC treats 20-min, 45-min, and 60-min fire rated applications differently depending on where the door or glazing is installed. A 60-min door is required in 1-hour rated fire barriers having a fire-resistance rating of 1 hour in enclosures for shafts, exit access stairways, exit access ramps, interior exit ramps and exit passageway walls. Under the 2012 IBC, vision panels in 60-minute door assemblies are limited to 100 square inches unless the glass is fire resistance rated (tested to ASTM E-119.)  Sidelites and transoms surrounding a 60 min door assembly must be fire resistance rated tested to ASTM E‐119.

For interior, 1‐hour fire partitions, smoke barriers, incidental use areas and mixed occupancy separations, 45-minute sidelites and transoms, and 45‐minute fire protection windows are allowed as long as they are limited to 25% of the common wall.

For most interior 1‐hour fire barriers (e.g., exit access stairways, interior exit stairways, interior exit ramps and exit passageway walls), 45‐minute, fire protection windows are not permitted; to increase the amount of glazing in these 1 hour walls, designers need to use fire resistance rated glazing. There are similar limitations on the installation of fire protective glazing on exterior walls with similar allowances for the use of a 1‐hour fire resistive glazed assemblies tested to ASTM E‐119.

Still Confused?

If you have additional questions on this topic, or if you have other code‐related questions, please send them to codesupport@safti.com. Our team of experts will be happy to help you select the correct, code‐approved fire rated glass and framing products for any current or upcoming project that you may have.

You may also contact us toll‐free at 888.653.3333 or view our comprehensive selection of fire rated glass and framing products at www.safti.com.

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