For many clients, fire-resistant glass is the way to achieve compartmentalization without a closed wall: light and sightlines are preserved, while the separation still meets the required WBDBO. But fire-resistant glass is not a standalone product - it is a system of glass, frame, hardware, and seal, tested as a whole. This article explains what the classifications mean, where glass is applied, and what determines the costs.
EI 30 versus EI 60: what is the difference?
Just as with penetrations and doors, fire-resistant glass is classified according to NEN-EN 13501-2, with the letters E (integrity - no penetration of flames or hot gases) and I (insulation - the non-fire side stays cool enough to allow safe presence and escape). The number is the duration in minutes.
| Classification | Meaning | Typical application |
|---|---|---|
| E 30 / E 60 | Integrity only: holds back flames and smoke, but gets hot. | Escape routes where distance from the glass is maintained. |
| EI 30 | 30 minutes of integrity and insulation. | Office partitions, doors with a glazed panel, corridor walls. |
| EI 60 | 60 minutes of integrity and insulation. | Compartment boundaries with a heavier WBDBO requirement, stairwells. |
EI glass is almost always the right choice when people can stand or walk near the glass on the non-fire side: only then does the temperature stay low enough to be safe up close.
The frame counts toward the classification
This is the most common mistake with fire-resistant glass: the classification applies to the tested combination of glass, frame profile, glazing system, and hardware. The same glass in a different frame - or an original frame with a different type of rubber or setting blocks after replacement - is not automatically still EI 30 or EI 60. During renovation of existing fire-resistant façades, this is a recurring pitfall: the glass looks intact, but if the frame system no longer matches the test report, the classification can no longer be demonstrated.
Where is fire-resistant glass applied?
- Stairwells and escape routes, where a closed wall would limit orientation and daylight too much.
- Office partitions between units or between corridor and office space in multi-tenant real estate, where transparency is desired.
- High-rise, in shared spaces where daylight is the primary architectural requirement alongside compartmentalization.
- Education and healthcare, in walls between corridors and classrooms or treatment rooms, for visibility without compromising fire safety.
What determines the cost?
Fire-resistant glass is priced per m² and depends heavily on the classification (EI 30 or EI 60), the size of the panels, and whether the existing frame can be reused or must be replaced. Large, dividable panels in standard sizes are more cost-effective than custom on-site work with non-standard dimensions. Because glass and frame are quoted together, you receive one price including glazing, frame, and installation - without separate line items that only become clear later.
Not sure whether your existing fire-resistant glazing still demonstrably meets its classification? Request an inspection, or first try the free quickscan.
Frequently asked questions
E glass holds back flames and smoke but gets hot on the non-fire side. EI glass also keeps the temperature on the non-fire side within the standard, and is therefore required where people can get close to the glass.
Only if that combination of glass and frame has been tested and certified. A different frame profile, different hardware, or different glazing rubbers can invalidate the classification, even if the glass itself is original EI glass.
Not automatically. Those properties must be specified and tested separately; include them in the brief in advance if you need them.
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Compartmentalize with glass: preserve natural light and sightlines without compromising on fire safety.
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