Fire-Rated Glass and Metal Frame Assemblies for Architects

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A fire-rated glass and metal frame assembly is a tested combination of fire-resistant glazing and a steel or aluminum frame that holds its integrity for a specified time under fire conditions. The frame, glass, seals and fixings must be specified together, since the assembly is only as strong as its weakest component.

What a fire-rated assembly actually is

A fire-rated assembly is not just a piece of fire-resistant glass. It is the complete system: the glazing unit, the frame profile, intumescent seals, fixing method and the wall it sits in. Each part is tested together, and the rating applies only to the tested configuration.

For architects this means the drawing must show the full system detail, not a generic glass line. Any change to profile depth, glass build-up or fixing can affect the approved performance.

Frame materials and their behavior in fire

Steel frames are the most common choice for fire-rated partitions because they keep their shape well under heat when correctly detailed. Aluminum frames can work in certain tested systems, but they soften at lower temperatures and need to be specified with care.

Steel profiles with intumescent strips in the rebate
Thermally broken aluminum only where the test report allows it
Concealed fixings that do not weaken the profile

Glazing options and what to ask for

Fire-resistant glass is typically laminated and built up from several layers that expand or hold together in a fire. Some products block only smoke and heat transfer, while others also limit radiant heat. These are different classes, and the required class depends on the location and local regulation.

Ask the glass supplier for the test certificate that matches your exact build-up, thickness and frame system. A certificate for a different thickness does not transfer to your project.

Finishes that suit fire-rated work

Finishes must not compromise the fire performance. Hot-dip galvanizing gives steel long corrosion protection and is compatible with many fire-rated systems. Powder coating adds color and a clean architectural look, but the coating thickness and curing should be confirmed against the tested build-up.

Discuss finish selection early so that the frame is prepared correctly before coating, and keep the finish consistent across all partitions on the project.

Installation and interface details

Critical points on site

Most failures in fire-rated partitions come from poor interfaces rather than the frame itself. The gap between the frame and the wall, the sealing at the head and sill, and the fixing into the structure must all follow the tested detail.

Coordinate with the general contractor and the fire engineer before ordering, so that openings, wall types and service penetrations are fixed at the right stage.

Specifying with the factory from the start

Early input from the metalwork manufacturer helps avoid redesign later. We can review your sections and profile choices, advise on how the frame will be fabricated and finished, and flag details that may need the fire engineer's review. The final approved detail should always be confirmed by the project's fire consultant and the local authority requirements.

Frequently asked questions

Can any metal frame be used for fire-rated glass?

No. The frame must be part of a tested system with the specific glazing. Using an untested frame can void the fire rating even if the glass itself is certified.

Is steel always better than aluminum for fire-rated partitions?

Steel is generally the more common choice because it holds its shape well under heat. Aluminum can be used only in systems whose test reports include it.

Does powder coating affect fire performance?

It can, depending on coating thickness and the tested build-up. Confirm the finish with the system documentation before production.

Who should approve the fire-rated detail?

The project's fire consultant and the relevant authority should approve the detail. The manufacturer can support the design but should not be the sole approver.

Common mistakes to avoid

Specifying the glass and frame separately from different sources is a common error that breaks the tested system. Also avoid changing profile depths or fixings late in the project without re-checking the approved detail.

Our recommendation

Send your typical wall section and the required fire rating to the manufacturer at the design stage, and ask for the test documentation that matches the full assembly. Confirm the detail with your fire engineer before fabrication begins.

Summary

Fire-rated glass and metal frame assemblies must be specified and built as one tested system, with attention to frame material, glazing class, finish and installation details.

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