(a) Corridors and other means of egress must be kept clear of obstructions and must not be used for any purpose which would interfere with its use as an exit, such as for storage, vending machines, seating, or similar purposes. The corridor width must be maintained at all times.(b) Doors within the means of egress must not be equipped with a latch or lock which requires the use of a key or tool to open from the inside of the building. A latch or other fastening device on a door must be provided with a knob, handle, panic bar, or other simple type of releasing device, the method of operation of which is obvious, even in darkness. An exception is that large facilities are permitted to have doors which are locked, if residents can be rapidly removed using remote control of locks or by keying all locks to keys readily available to staff who are in constant attendance.(c) A hold-open device must be installed on each exit door of large facilities.