[MosesKnows]

I love capitalism.

Is this for use when you are behind a door that opens into the room?
I'm pondering this because I thought classroom doors opened outward to prevent a rush of people from not allowing the door to open inward in an emergency evacuation.

[Mastador1]

This is the pertinent code for California, and I can't see it as being different elsewhere.

Exception: Existing buildings may be less than 3 feet in width if the clear width of the exitway is not less than 28 inches. (Title 24, Part 2, Section 2-3303(e).) (c) Door Leaf Width. No leaf of an exit door shall exceed 4 feet in width. (Title 24, Part 2, Section 2-3303(f).) (d) Swing. Exit doors shall swing in the direction of exit travel ...

So if that's the case, the invention has existed for a long time, a bracket on the left and right side of the door into which a cross bar is dropped making it impossible for the door to swing out.

[trebb]

I think actual exit doors have to swing out - most schools I have been in, the classroom doors opened in so they wouldn’t be out in the flow of traffic when everyone was on the move.

[dila813]

I think it depends on your fire code, if you state follows the International Fire Code it says the door must open in the direction of egress if the room has a capacity rated at 50 or more, must classrooms are rated 50+

Fire Code: 1010.1.2

https://codes.iccsafe.org/public/document/IFC2015/chapter-10-means-of-egress