What Fire Rating Do I Need?

It comes down to two things: where the glass is going, and whether it has to hold back heat as well as flame and smoke. A fire door vision panel is usually E30. A partition where people work close by is usually EI30. Use the finder below to match your location to the right rating, from E30 up to EI120, with the thickness, a spec sheet and a quote ready to go.

How the finder works

Pick where the glass is going: a fire door, a partition, a compartment wall. The finder lands on the rating usually specified there and draws it for you, with the fire on one side, a person on the other, and the glass shown at its real relative thickness.


Step through the ratings to see what changes, then print a spec sheet or request a quote with the details already filled in. Built for contractors, specifiers and facilities teams who need to get oriented fast.

E, EW and EI in short

Fire-rated glass is classified under BS EN 13501-2. E holds back flame, smoke and hot gases. EW does that and limits radiated heat. EI does both and also limits heat transfer, so people can stand right beside it. The number is the minutes of protection.

For the full explainer, read glass fire ratings explained. There is also a guide to the difference between integrity and insulation.

How thick is fire-rated glass?

Thickness follows the rating. A 30 minute E30 panel is a single toughened pane, 6 mm thick. Once you need insulation as well, the glass becomes a toughened and laminated build, so it gets thicker and heavier with every step up. As a guide for TG FR:

  • E30 (30 minutes, integrity): toughened single pane, 6 mm
  • EI30 (30 minutes, integrity and insulation): 24 mm in total
  • EI60 (60 minutes, one hour): 30 mm in total
  • EI90 (90 minutes): 40 mm in total
  • EI120 (two hours): 48 mm in total, vertical glazing only



Panels are available up to 1,388 by 2,389 mm. Thickness affects frame rebates and handling weight, so check both early. The full breakdown is on our fire-rated glass page.

Which rating for which location?

Fire door vision panels: usually E30. The glass must match the rating of the door, so an EI30 door needs EI30 glass.

Internal screens and partitions: usually EI30, because Approved Document B places no limit on the area of EI30 glazing.

Compartment walls and atria: usually EI60 to start, rising to EI90 or EI120 in taller, more complex or higher-occupancy buildings.

Overhead and sloped glazing: EI120 is for vertical glazing only, so talk to our team about the build.


These are the usual starting points. The right answer depends on the fire strategy for the building.

It is the system that is rated, not just the glass

A fire rating applies to the complete tested glazing system: the glass, frame, beads and seals together. So the right glass is only part of the answer. Our team confirms the full certified build for your project. Every TG FR panel is Kitemark-approved and certified to BS EN 1364-1:2015, with a Declaration of Performance for each build-up.

Get the right fire glass

Once you know the rating, see the fire-rated glass product page, or request a quote from the finder and our team will confirm the build. Specifying for fire doors? Start with our guide to UK fire door glass regulations.

Frequently asked questions

  • What fire rating do I need for a fire door?

    A fire door vision panel is usually E30, and the glass must match the rating of the door. The right rating depends on the building's fire strategy, so use the finder to get oriented, then confirm with our team or your fire engineer.

  • What fire rating does a glass partition need?

    Most office partitions are specified at EI30, because Approved Document B puts no limit on the area of EI30 glazing. EI60 is used where the building or its fire strategy demands more, such as larger or taller buildings.

  • What is the difference between E30 and EI30 glass?

    Both last 30 minutes. E30 holds back flame, smoke and hot gases, but heat still passes through. EI30 also limits heat transfer, so people can pass right beside it. E30 is a single 6 mm toughened pane. EI30 is a 24 mm toughened and laminated build.

  • How thick is 30 minute fire-rated glass?

    It depends on the type. TG FR E30 is a single toughened pane, 6 mm thick. TG FR EI30, which also insulates against heat, is 24 mm in total.

  • How thick is one-hour fire-rated glass?

    A one-hour rating is EI60. TG FR EI60 is a toughened and laminated build, 30 mm thick in total. That is a big step up from a 6 mm E30 pane in thickness and weight, so confirm the build with our team before you size the frames.

  • Is there two-hour fire-rated glass?

    Yes. TG FR EI120 holds back flame, smoke and heat for two hours. It is 48 mm thick in total and is for vertical glazing only.

  • Is it the glass that is fire rated, or the whole unit?

    The whole system. A fire rating applies to the tested build of glass, frame, beads and seals together, so the glass is only part of the answer.

  • What standard is fire-rated glass tested to?

    ToughGlaze fire glass is tested to BS EN 1364-1:2015 and classified under BS EN 13501-2, with a Declaration of Performance for each build.