Dear Glass Detective,
Can either tempered glass or laminated glass be used in a 90 minute rate fire door?
This is an excellent question with an easy answer! Neither regular tempered glass nor normal laminated glass qualify as a fire-rated material, so in short, no- neither one can be used in a 90 minute labeled door.
For those who are not familiar with these terms, they apply to fire doors. Fire-rated doors are doors that can withstand exposure to the conditions of a fire (mainly heat) for an extended period of time. Fire doors are rated by how long they can withstand these conditions without deforming enough to compromise safety, with ratings normally ranging from 20 minutes up to 3 hours. Doors of different ratings doors are used in different parts of buildings. For example, a 20 minute door would usually be found in an interior hallway, whereas a 90 minute door might be used for the interior stairwells of a building. The more essential a door is to the structural integrity of the building and escape from fire, the higher the necessary time rating.
Fire Door Glass Regulations:
So if normal tempered glass and regular laminated glass are not suitable for fire doors, what is? Certain types of wired glass and ceramic glass, as well as chambered glass with specialized interlayers are used widely in fire-rated doors because they are able to better withstand the extreme temperatures. However, they are not fire-proof, so the size of the pane allowed generally decreases as the fire rating time increases.
(In fact, there is no such thing as “fire-proof” glass, though there are different levels of “fire-resistant” glass.)
The Glass Detective attempts to answer all questions accurately but cannot be held liable for any information provided or omitted. You should always work with a licensed, insured and reputable glass shop that can assess your specific needs and local building codes and offer professional services. Never attempt to cut, install, or otherwise work with glass yourself. The Glass Detective answers questions on an informational basis only.