§ 380. Lunchrooms. No lunchroom in any mercantile establishment where females are employed shall be next to or adjoining a watercloset, unless a permit therefor is granted by the commissioner in a city or by the local board or department of health in a village. Such permit shall be granted if proper sanitary conditions exist and may be revoked at any time by the granting authority if the lunchroom is kept in such a manner or is so located as to be injurious to the health of the employees.