I copied this info from the Portland Online Website. These are the codes used for Portland Oregon.
29.30.210 Sleeping Room Requirements.
Every room used for sleeping purposes:
A. Shall be a habitable room as defined in this title;
B. Shall not be a kitchen;
C. Shall have natural light, ventilation, and windows or other means for escape purposes as required by this Title; and
D. Shall comply with the following minimum requirements for floor area:
1. Shall have a minimum area of at least 70 square feet of floor area, except that where more than two persons occupy a room used for sleeping purposes, the required floor area shall be increased at the rate of 50 square feet for each person in excess of two. No portion of a room measuring less than 5 feet from the finished floor to the finished ceiling shall be included in any computation of the roomâ€™s minimum area.
2. Any dwelling or portion of any dwelling constructed pursuant to permit or lawfully constructed prior to permit requirements shall be deemed in compliance with respect to sleeping room area provided that the deficiency in floor area is no more than 15 percent of that required by Subsection 29.30.210 D 1. This subsection shall not apply where any occupancy has been changed, or the number of occupants has been increased, contrary to the provisions of this Title.
3. Floor area requirements for single-room occupancy housing units shall be in accordance with Section 29.30.290 of this Title.