Tips for Matching Fire-Rated Glass to Fire-Rated Framing
When installing fire-rated glass and framing, you must meet the required codes for both assemblies. Mismatched fire-rated glass and frames in buildings happen more often than you think. A framing system’s tested and listed performance that doesn’t match the glazing can be a financial nightmare for the building owner, architect, general contractor, and subcontractor.
The entire assembly must fully meet code requirements to avoid costly mistakes. Some may still be confused about why fire-protective hollow metal frames used in fire barriers and stairwell enclosures are required in fire-resistive glass framing assemblies. In this post, we’ll explain the reasons the framing system can be confusing.
Decoding Fire-Rated Framing Requirements
Coder requirements for fire rated assemblies have changed significantly over the last few years, which is why there can be a lot of confusion over the current code requirements for fire-rated glass and framing products. Together with the updated code requirements, here are the common misunderstandings on fire-rated assemblies.
1. Even though standard hollow metal frames are listed up to 90 minutes, you cannot use them in all 60- and 90-minute applications.
Hollow metal is one of the most popular and widely used fire-rated framing materials. Fire-rated framing should be listed with a nationally recognized testing laboratory, like UL and Intertek/Warnock-Hersey, to ensure it’s up to code standards.
Fire-rated framing should also conform testing to code reference standards like:
- National Fire Protection Association (NFPA) 80: Fire Doors and Other Opening Protectives
- NFPA 252: Fire Tests of Door Assemblies
- NFPA 257: Fire Test for Window and Glass Block Assemblies
While checking if the hollow metal framing complies with the NFPA is important, it’s only the first step. Hollow metal must pass NFPA standards, which require up to 90 minutes of application on fire-rated doors, sidelites, transoms, and openings. However, it doesn’t mean that the code approves all 20-90 minute applications.
Building code occupancy types and size limitations may also require fire-rated frames with fire-resistive glazing to comply with American Society for Testing and Materials (ASTM) standards, particularly ASTM E119.
Even if hollow metal frames comply with the necessary fire ratings, since they are only tested for NFPA 252/257, you can’t use them in applications that require ASTM E-119. Table 716.1(2) in the 2021 International Building Code (IBC) indicates the code requirements for different assembly types that need ASTM E119.
2. Many are confused about what constitutes an assembly.
An assembly is the combination of materials put together in a specific way. For walls and window openings, a complete assembly consists of glass and frames. However, many people get confused when it comes to door assemblies.
According to NFPA, a door assembly is “any combination of a fire door, a frame, hardware, and other accessories that together provide a specific degree of fire protection to the opening.” Door assembly accessories also include sidelites and transoms.
For the whole assembly to meet its fire-resistance rating, both the glass and the frames should meet the required testing for the application. NFPA 80 states that “fire resistance glazing installed in a hollow metal frame is not a fire-resistance-rated assembly.” So, when you only use fire protection-rated framing like hollow metal with fire-resistance-rated glazing, it voids the fire resistance of the whole assembly.
3. Sidelite/transom and interior window applications using hollow metal frames over 45 minutes are limited.
As per the 2021 IBC Table 716.1(2), when you use fire protection-rated glazing in door vision panels, it is only limited to a maximum size of 100 sq. in. for fire door assemblies with more than 45 minutes (¾ hour) fire-rated protection. This means fire protection rated glazing such ceramic or wired glass are limited to 100 sq. in. in 60, 90 and 180 minute temperature rise doors.
Meanwhile, NFPA 252/257-tested hollow metal frames with sidelites and transoms are limited to openings with a required rating of 45 minutes or less. You can’t use hollow metal frames in 60- and 90-minute door assemblies with sidelites and transoms or where fire resistance rated glazing ASTM E-119 is permitted when tested as an assembly. The 60 minute sidelites/transoms used with 60 minute doors and 120 minute sidelites and transoms used with 90 minute doors must meet ASTM E-119.
For 45-minute window openings in 1-hour exit access corridors and other 1-hour fire partitions/barriers that exceed 25% of the wall area, the glazing must be fire-resistance-rated and should have the same rating as the wall. Using hollow metal frames is also limited in this situation as the framing should be fire-resistance rated as well.
Most 1-hour fire barrier applications don’t allow 45-minute fire-rated windows. However, using fire-resistance-rated glazing assemblies is permitted.
4. Misconceptions when sprinklers are present.
While temperature rise doors may not always be required in buildings that are fully sprinklered, it is necessary to have fire protection-rated glazing in 60- and 90-minute temperature-rise door vision panels limited to 100 sq. in. because of radiant heat concerns.
To exceed the 100 sq. in. door vision panel limitation, fire-resistance-rated glazing tested to ASTM E-119 can be used. The fire-resistance-rated glazing should match the rating of the door. Additionally, the fire door should be tested following NFPA 252, UL 10B, or UL 10C.
Sidelites and transoms in 1-2 hour exit enclosures (or stairwells) have a higher rating standard. Their ratings should be equal to the fire resistive ratings of the wall. Consequently, hollow metal sidelite and transom frames that are tested based only on NFPA 252 are not allowed, even if the building is fully sprinklered. Both the glass and framing must meet ASTM E-119.
Stay Safe and Informed
Fire-rated glass and framing have their own set of code standards. Meeting the compliance requirements of just one part, and not both, lowers its overall fire resistance purpose. Make sure that your fire-rated glass and framing match ratings and standards so that you can avoid severe disasters and financial woes.
You don’t have to sacrifice aesthetics when improving your building’s fire safety. SAFTI FIRST manufactures and provides USA-made, high-quality fire-rated solutions for commercial facilities worldwide. Whether you need fire-resistive walls, doors, opening, floors, or specialty service, SAFTI FIRST has got you covered.
Level up your project and get in touch with us today to learn more about how our fire-rated solutions can help you save money and keep you safe.