Door Lites and Fire Rated Doors | Ask the Experts | Ask the Door Guys

I would like the exterior fire exit door to have a large door lite in it to bring natural light into the hallway.  Can I have a door lite in a fire-rated door and if so, what size can I get away with?


Great question.  Unfortunately, there are limitations to how many lites you can have and what sizes you can have, which is determined by the overall rating of the door.  For a 60-min. rated door, the maximum size lite that you can have is 12″x 46″.  For a 90 min. rated door, the maximum size lite you can have is 12″ x 33″.  You are unable to have a door lite if your door is 3-hour rated unless allowed by the local authority having jurisdiction.  All of these restrictions are assuming the glass being installed is 1/4” wire glass.

Edited for clarification, June 1, 2016:
For any fire rated opening, there is a limitation to the size of the window unless there is special glazing (firelite, fire glass, etc.) applied to the door.

The local jurisdiction having authority is the only agency to determine if a fire door should be used in an exterior opening. If it is determined that the authority wants a fire rated opening then the following rules will apply to hollow metal doors.

Fire Door Rating (hr) Maximum Area of Glazing (per Door leaf)
3-hour NO GLASS
1-1/2-hour 100 in.2
3/4-hour 1296 in.2 with no dimension exceeding 54″
1/3-hour / 20-min Same as 3/4-hour

Do you have a question, or need a quote? Contact your local IDN Branch, or ask the Door Guy through our website.

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