§ 275-42 — Ventilation

275-42. Ventilation.

1. GENERAL. All spaces or rooms shall be provided sufficient natural or mechanical ventilation so as not to endanger health and safety. Where mechanical ventilation is provided in lieu of natural ventilation, the mechanical ventilation system shall be maintained in operation during the occupancy of any structure or portion thereof. 2. ADEQUATE VENTILATION. Every habitable room shall have at least one window or skylight which can easily be opened, or such other device as will adequately ventilate the room. The total openable window area in every habitable room shall be equal to at least 50% of the minimum window area size or minimum skylight-type size, as required in s. 275-41-2, except where there is supplied some other device affording adequate ventilation. 3. BATHROOMS AND TOILET ROOMS. Every bathroom and toilet room shall comply with the light and ventilation requirements for habitable rooms contained in sub. 2 and s. 275-41-2 except that no windows or skylights shall be required in adequately ventilated bathrooms and toilet rooms equipped with an adequate mechanical ventilation system. 4. WINDOW SCREENS. a. Every window required for ventilation, including bath and toilet room, shall be supplied with approved screening having a wire mesh of not less than number 16 covering at least 1/3 of the window area, except that screens shall not be required for window areas above the 5th floor. b. Notwithstanding any provision of par. a, in any rental dwelling unit, every openable window shall have a window screen with a wire mesh of not less than number 16 covering at least 1/3 of the window area. Except as provided in par. d, the property owner shall be responsible for the installation and maintenance of window screens. c. Every dwelling having 2 or more basement windows shall have at least 2 window screens which cover the entire window. Where there is only one basement window, it shall be similarly screened. Such screens shall have a wire mesh of not less than number 16. d. In any rental dwelling or rental dwelling unit, the responsibility for installing the screens shall be assumed by the owner, except that in one and 2-family dwellings the tenants shall be responsible for insertion of pre-fit screens. Screens shall be hung not later than June 1 of each year. Tenants in multiple dwellings shall be responsible for the installation of adjustable frame screens when the same are provided by the owner or operator and can be easily installed from the inside.