Wash. Admin. Code § 51-54A-1020
1020.6 Air movement in corridors. Corridors shall not serve as supply, return, exhaust, relief or ventilation air ducts.
EXCEPTIONS: | 1. Use of a corridor as a source of makeup air for exhaust systems in rooms that open directly onto such corridors, including toilet rooms, bathrooms, dressing rooms, smoking lounges and janitor closets, shall be permitted provided that each such corridor is directly supplied with outdoor air at a rate greater than the rate of makeup air taken from the corridor. |
2. Where located within a dwelling unit, the use of corridors for conveying return air shall not be prohibited. | |
3. Where located within tenant spaces of 1,000 square feet (93 m2) or less in area, utilization of corridors for conveying return air is permitted. | |
4. Incidental air movement from pressurized rooms within health care facilities, provided that a corridor is not the primary source of supply or return to the room. | |
5. Where such air is part of an engineered smoke control system. | |
6. Air supplied to corridors serving residential occupancies shall not be considered as providing ventilation air to the dwelling units subject to the following: | |
6.1. The air supplied to the corridor is 100 percent outside air; and | |
6.2. The units served by the corridor have conformingtilation air independent of the air supplied to the corridor; and | |
6.3. For other than high-rise buildings, the supply fan will automatically shut off upon activation of corridor smoke detectors which shall be spaced at no more than 30 feet (9144 mm) on center along the corridor; or | |
6.4. For high-rise buildings, corridor smoke detector activation will close required smoke/fire dampers at the supply inlet to the corridor at the floor receiving the alarm. |
Wash. Admin. Code § 51-54A-1020