Using glass in means of egress to meet code and add light and beauty

Since the catastrophic New York City Triangle Shirt Factory fire in 1911, regularly updated fire and building codes have been implemented to limit the spread of fire, smoke and heat, with an emphasis on maintaining a safe means of egress for people exiting in the event of a fire. Today, there are two primary code standards that regulate the means of egress: the International Building Code (IBC) and the National Fire Protection Association’s (NFPA) 101 Life Safety Code.

In response to fire tragedies and upgrades in fire rated building materials, each code cycle brings additional refinement and tighter rules for paths of egress.  After the Rhode Island Station Nightclub fire killed 100 people in 2003, code changes lowered the capacity threshold for exit requirements. After 2004, the IBC prohibited traditional wired glass in fire doors in exit enclosures and other hazardous locations because it fails to meet the minimum safety-glazing impact-resistance requirements. A revision within IBC 2012  removes the “sprinkler tradeoff” for fire rated glazing in doors located in exit enclosures and exit passageways. Under the new code, when glazing in a fire door exceeds 100 square inches, it must be fire resistive rated, meaning that the glazing must provide a barrier to flames, smoke and radiant heat. Fire protective glazing only addresses flames and smoke. (Click here to read more about the differences between fire resistive and fire protective glass.)

Three Components of Means of Egress

The IBC defines means of egress as “a continuous and unobstructed path of vertical and horizontal egress travel from an occupied portion of a building or structure to a public way. A means of egress consists of three separate and distinct parts.”

•     Exit access – the portion that leads from the occupied area of a building or structure to an exit. A corridor is an enclosed exit access providing a path of egress travel to an exit.

•     Exit — the portion of a means of egress system which is separated from other interior spaces of a building or structure by fire-resistance-rated construction and opening protectives as required to provide a protected path of egress travel between the exit access and the exit discharge. Components of an exit include doors at grade level, interior enclosed stairs and ramps, exterior stairs and ramps, horizontal exits, exit enclosures and exit passageways.

•     Exit Discharge — the portion between the termination of an exit and a public way. There are some exceptions which allow vestibules and lobbies within the exit discharge. To qualify, they have to be separated from the floors below by a fire-resistance rating equal to the exit enclosure. In addition, lobbies must be separate from other areas of the same level by a fire-resistance rating equal to the exit enclosure.

Fire Rated Glass Products that Meet Code Requirements

The IBC’s Chapter 10 outlines regulations related to means of egress including rules on occupancy load, accessibility, illumination, width, doors, stairways, ramps, exit access, exit doorways, exit access travel distance, corridors, exits, exit enclosures, and exit passageways. The requirements vary based on building size, occupancy, use and other factors. The following are some examples of code requirements and fire rated glazing products that meet the code requirements.  Please refer to FAQs on this website to learn more.

Glazing in 1-hour exit corridor (Exit access)

The IBC requires different ratings for protected openings in a 60-minute exit corridor depending on the glazing application.

20-minute fire doors with 20-minute vision panels without hose stream are permitted in a 1-hour exit corridor.

Exit access example 1: Location — National Center for International Schools in San Francisco. Since the openings are less than 25% of the wall area in a 1-hour exit corridor, SuperLite I is used in the door vision panel and SuperLite I-XL 45  is used in the sidelites.

Exit access example 2: Location — Durham County H ealth and Human Services Building, Durham, North Carolina. To increase the amount of glazing used in this 1-hour corridor to be more than 25% of the wall area, SuperLite II-XL 60 in GPX framing is used for the wall and Superlite II-XL 60 in HMTR door framing is used for the door.

Glazing in exit passageway doors (Exit)

The codes specify extra fire protection levels for fire doors in exit enclosures and passageways, requiring the use of doors that limit temperature rise to 450F degrees.  In the 2000 IBC, an exception was provided that allowed the use of non-temperature rise doors if the building is fully sprinklered in accordance with Chapter 9.  But what about the glazing in the door? The 2012 IBC has been amended to clarify that the maximum allowable vision panel in a 60 or 90 minute exit enclosure or passageway door is 100 sq. inches, regardless of whether or not the building is fully sprinklered. No restriction applies if the glazing product is fire resistive, like SuperLite II-XL, which limits temperature rise as it blocks radiant heat.

Exit passageway door example 1: Location — University of Wisconsin Marathon County Center for Civic Engagement, Wausau, WI. In order to use the maximum amount of glazing possible while still meeting code requirements, SuperLite II-XL 60 in HMTR door framing and SuperLite II-XL 60 in GPX framing are used in this 1-hour stairwell enclosure.

Exit passageway door example 2: Location — Troy High School, Troy, OH. Be cause the glazing area is less than 100 sq. inches in these 90-minute doors, fire protective PYRAN Platinum F by SAFTI FIRST was allowed in the door vision areas.

Fire windows in exit stairwell enclosures (Exit)

Fire protective rated windows are NOT permitted in exit enclosures and stairwells.  However, fire resistive rated glazing assemblies that limit radiant heat ARE permitted. For the same reason that vision panels in fire doors used in exit enclosures are limited to 100 sq. inches, it is important to understand that fire protective wired glass and ceramics are not permitted at all in other openings in an exit enclosure, including sidelights and transoms, or fire windows. Where glazing is desirable in greater amounts in exit enclosures, fire resistive products are allowed around and over the door, and in other openings, provided the glazing is installed in a fire resistive framing, and the whole assembly meets the same rating requirement as the wall.

Exit stairwell example: Location — Pomona College, Pomona, CA. To provide natural lighting and security to this 2-hour stairwell, SuperLite II-XL 120 in GPX Framing was used to create a transparent, fire resistive wall assembly meeting the ASTM E-119 requirement.

Sidelites and Transoms around Fire Doors (Exit Access and Exit)

When the code requires fire doors rated for 60 minutes or more, the sidelites and transoms around that door must be fire resistive and rated to match the wall itself (e.g., 60 or 120 minutes). Sidelites and transoms around a 20-minute fire door in a 60-minute exit require a 45-minute fire rating with hose stream. Sidelites and transoms around 60 and 90 minute fire doors must be a fire resistive (not wired glass or ceramic, which are fire protective materials), and the rating of the sidelite and transom must equal that of the wall, not of the door opening.  Click here to download Table 716.5 from 2012 IBC.

Exit access and exit sidelites and transoms example 1: Location — Freedom High School, Bethlehem, PA. SuperLite II-XL 120 in GPX framing was used in the sidelites and transoms to match the 2-hour wall rating. SuperLite II-XL 90 in GPX framing was used for the doors. The entire assembly meets ASTM E-119 wall requirements.

Exit access and exit sidelites and transoms example 2: Location — U.S. Marines Bachelor’s Enlisted Quarters, Camp Pendelton, CA. Since the doors in this 1-hour corridor only required a 20-minute rating, SuperLite I was used for the door vision area. The sidelites, however, required a 45-minute rating, so SuperLite II-XL 45 in HM framing was used.