This is totally unrelated to HVAC, but maybe someone can help.
I recall seeing a high security door lock, that had a bracing bar that was unlockable from the outside, but locked the door against the bracing bar which sat in a pocket in the floor.
I can find info on door braces made to be used only if you are inside the door, but not on the type that I seek.
Thanks in advance,
(cause this may be my last post(unregistered))