§ 379. Dressing rooms. In every mercantile establishment or restaurant where more than five women are employed and in every terminal or car barn where more than five women employees of a street, surface, electric, subway or elevated railroad report for duty a sufficient number of dressing rooms conveniently located shall be provided for their use. All dressing rooms shall be separated from waterclosets by partitions, shall have adequate floor space in proportion to the number of employees, shall be provided with seats and with suitable means for hanging clothes and shall be constructed, heated, ventilated, lighted and maintained in accordance with the rules of the board.