WAC 51-50-0509   Section 509 -- Special provisions.  


509.2 Group S-2 enclosed or open parking garage with Group A, B, M, R or S above. A building shall be considered as two separate and distinct buildings for the purpose of determining area limitations, continuity of fire walls, limitation of number of stories and type of construction, where all of the following conditions are met:

     1. The buildings are separated with a horizontal assembly having a minimum 3-hour fire-resistance rating.

     2. The building below the horizontal assembly is no more than one story above grade plane.

     3. The building below the horizontal assembly is of Type IA construction.

     4. Shaft, stairway, ramp and escalator enclosures through the horizontal assembly shall have not less than a 2-hour fire-resistance rating with opening protectives in accordance with Table 715.4.

EXCEPTION:	Where the enclosure walls below the horizontal assembly have not less than a 3-hour fire-resistance rating with opening protectives in accordance with Table 715.4, the enclosure walls extending above the horizontal assembly shall be permitted to have a 1-hour fire-resistance rating, provided:
	1. The building above the horizontal assembly is not required to be of Type I construction,
	2. The enclosure connects less than four stories, and
	3. The enclosure opening protectives above the horizontal assembly have a minimum 1-hour fire-protection rating.

     5. The building above the horizontal assembly shall be permitted to have multiple Group A uses each with an occupant load of less than 300, or Group B, M, R or S uses;

     6. The building below the horizontal assembly is a Group S-2 enclosed or open parking garage, used for the parking and storage of private motor vehicles.

EXCEPTIONS:	1. Entry lobbies, mechanical rooms and similar uses incidental to the operation of the building shall be permitted.
	2. Multiple Group A uses, each with an occupant load of less than 300, or Group B or M uses shall be permitted in addition to those uses incidental to the operation of the building (including storage areas), provided that the entire structure below the horizontal assembly is protected throughout by an approved automatic sprinkler system.

     7. The maximum building height in feet shall not exceed the limits set forth in Section 503 for the building having the smaller allowable height as measured from grade plane.


509.3 Group S-2 enclosed parking garage with Group S-2 open parking garage above. A Group S-2 enclosed parking garage with no more than one story above grade plane and located below a Group S-2 open parking garage shall be classified as a separate and distinct building for the purpose of determining the type of construction where the following conditions are met:

     1. The allowable area of the building shall be such that the sum of the ratios of the actual area divided by the allowable area for each separate occupancy shall not exceed 1.0.

     2. The Group S-2 enclosed parking garage is of Type I or II construction and is at least equal to the fire-resistance requirements of the Group S-2 open parking garage.

     3. The height and number of tiers of the Group S-2 open parking garage shall be limited as specified in Table 406.3.5.

     4. The floor assembly separating the Group S-2 enclosed parking garage and Group S-2 open parking garage shall be protected as required for the floor assembly of the Group S-2 enclosed parking garage. Openings between the Group S-2 enclosed parking garage and Group S-2 open parking garage, except exit openings, shall not be required to be protected.

     5. The Group S-2 enclosed parking garage is used exclusively for the parking or storage of private motor vehicles, but shall be permitted to contain an office, waiting room and toilet room having a total area of not more than 1,000 square feet (93 m²), and mechanical equipment rooms incidental to the operation of the building.



[Statutory Authority: RCW 19.27.074, 19.27.020, and chapters 70.92, 19.27, and 34.05 RCW. 07-01-091, § 51-50-0509, filed 12/19/06, effective 7/1/07.]