Section 321.05. Natural light and natural ventilation.

 

(1)   Natural light. Each habitable room shall be provided with natural light by means of glazed openings. The area of the glazed openings shall be at least 8% of the net floor area, except under the following circumstances:

(a) Exception. Habitable rooms, other than bedrooms, located in basements, ground floors or above garages do not require natural light.

(b) Exception. Natural light may be obtained from adjoining areas through glazed openings, louvers or other approved methods. Door openings into adjoining areas may not be used to satisfy this requirement.

(1m)   Net floor area. For the purposes of subs. (1) and (2) , "net floor area" does not include any area with a ceiling height of less than 5 feet.

(2)   Ventilation.

(a) Natural ventilation.

1. Natural ventilation shall be provided to each habitable room by means of openable doors, skylights or windows. The net area of the openable doors, skylights or windows shall be at least 3.5% of the net floor area of the room, except as provided in subd. 2. Balanced mechanical ventilation may be provided in lieu of openable exterior doors, skylights or windows provided the system is capable of providing at least one air change per hour of fresh outside air while the room is occupied. Infiltration may not be considered as make-up air for balancing purposes.

2. Any area with a ceiling height of less than 5 feet may be excluded from the net floor area.

(b) Exhaust ventilation. All exhaust ventilation shall terminate outside the building.

(3)   Safety glass.

(am) Except as provided in par. (bm) , glazing shall consist of safety glass meeting the requirements of either 16 CFR Part 1201 or ANSI Z97.1 when installed in any of the following locations:

1. In any sidelight or glazing adjacent to a door, that meets all of the following:

a. The nearest point of the glazing is within 2 feet of the door when the door is in the closed position.

b. The nearest point of the glazing is within 5 feet of the floor.

c. The plane of the glazing is within 30 degrees of the plane of the door when the door is in the closed position.

2. In any wall where the glazing is within 5 feet vertically of the lowest drain inlet and within 3 feet horizontally of the nearest part of the inner rim of a bathtub, hot tub, shower, spa or whirlpool appliance.

3. Within 4 feet vertically of a tread or landing in a stairway and within one foot horizontally of the near edge of the tread or landing.

4. Within 4 feet vertically of the floor and 3 feet horizontally of the nosing of the top or bottom tread of a stair.

5. In guard assemblies.

(bm) Safety glass is not required where glazing meets any of the following:

1. The size of an individual pane of glass is 8 inches or less in the least dimension.

2. The safety glass is required by sub. (3) (am) 1. and the only door within 2 feet of the glazing is the fixed panel of a patio door.

3. The safety glass is required by sub. (3) (am) 1. and there is an intervening wall or other permanent barrier between the door and the glazing.

Cr. Register, November, 1979, No. 287 , eff. 6-1-80; r. and recr. (1) and (2), Register, February, 1985, No. 350 , eff. 3-1-85; r. and recr. (3) and (4), Register, July, 1986, No. 367 , eff. 1-1-87; am. (4), Register, January, 1989, No. 397 , eff. 2-1-89; am. (2) (a), (4) and (5), Register, March, 1992, No. 435 , eff. 4-1-92; am. (2) (a), Register, November, 1995, No. 479 , eff. 12-1-95; am. (3), r. and recr. (4) and (5), Register, January, 1999, No. 517 , eff. 2-1-99; CR 02-077 : am. (1) (a) and (5) (b) Register May 2003 No. 569 , eff. 8-1-03; CR 08-043 : am. (title), r. (3) and (4), renum. (5) to be (3) and am. (3) (intro.), r. and recr. (3) (a) and (b) Register March 2009 No. 639 , eff. 4-1-09; CR 15-041 : am. (1) (intro.), cr. (1m), renum. (2) (a) to (2) (a) 1. and am., cr. (2) (a) 2., renum. (3) (intro.) and (a) to (d) to (3) (am) (intro.) and 1. to 4. and am. (am) (intro.), 1. (intro.), a., cr. (3) (am) 5., renum. (3) (e) to (3) (bm) (intro.) and am., cr. (3) (bm) 1. to 3. Register December 2015 No. 720 , eff. 1-1-16; CR 15-089 : am. (1) (a) Register May 2016 No. 725 , eff. 6-1-16.

Note

The U.S. Consumer Product Safety Commission requires safety glass for glazing in internal and external doors, including storm doors and patio doors, as well as for the tub or shower enclosures themselves. These federal rules, contained in 16 CFR, subchapter B, part 1201, apply in addition to any state rules or statutes. Microsoft Windows NT 6.1.7601 Service Pack 1 Glass blocks are considered to be masonry products and are regulated under the ACI 530 standard adopted under s. SPS 320.24 . They are not required to be safety glazing. Microsoft Windows NT 6.1.7601 Service Pack 1