I work in a university building designed in the 1930s, located in western New York State (not in NYC). To enter classrooms, offices or labs one passes through a single door. However, the restrooms ALL have two layers of door with a closet-sized compartment in between. This poses issues for people with mobility impairments. All the inner doors have transoms, with a ventilation grating above each transom. Both the men's and women's restrooms have these two-layer doors.
The two door system is awkward and wastes space. Surely there are better ways to prevent hallway users from peeping in. And the bathrooms are not noisy; I've been in classrooms that share a wall with a restroom and have never heard any water-related noise. Finally, the grating between the restroom and the compartment eliminates the argument that the reason is odor control. I suspect the reason relates to the building codes in force when the building was designed - but why would a building code require two layers of door on a restroom?
Thanks for any insights!