SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE 2021 SEATTLE BUILDING CODE
1. In Group R-1, R-2 or R-3 occupancies, exit access stairways and ramps connecting four stories or less serving and contained within an individual dwelling unit, sleeping unit or live/work unit.
2. Exit access stairways serving and contained within a Group R-3 congregate residence or a Group R-4 facility.
3. Exit access stairways and ramps within an atrium complying with Section 404.
4. Exit access stairways and ramps in open parking garages that serve only the parking garage.
5. Exit access stairways and ramps serving open-air assembly seating complying with the exit access travel distance requirements of Section 1030.7.
6. Exit access stairways and ramps between the balcony, gallery or press box and the main assembly floor in occu- pancies such as theaters, places of religious worship, auditoriums and sports facilities.
7. Exterior exit access stairways and ramps between occupied roofs. 1006.3.3 Egress based on occupant load. Each story and occupied roof shall have the minimum number of separate and distinct exits, or access to exits, as specified in Table 1006.3.3. A single exit or access to a single exit shall be permitted in accordance with Section 1006.3.4. The required number of exits, or exit access stairways or ramps providing access to exits, from any story or occupied roof shall be maintained until arrival at the exit discharge or a public way.
TABLE 1006.3.3
MINIMUM NUMBER OF EXITS OR ACCESS TO EXITS PER STORY
[W][S] 1006.3.4 Single exits. A single exit or access to a single exit shall be permitted from any story or occupied roof where one of the following conditions exists:
1. The occupant load, number of dwelling units and exit access travel distance wi thin the portion of the building served by the single exit do not exceed the values in Table 1006.3.4(1) or 1006.3.4(2).
2. Rooms, areas and spaces comply ing with Section 1006.2.1 with exits that discharge directly to the exterior at the level of exit discharge, are permitted to have one exit or access to a single exit.
3. Parking garages where vehicles are mechanical ly parked shall be permitted to have one exit or access to a single exit.
4. Group R-3 and R-4 occupancies shall be permitted to have one exit or access to a single exit.
5. Individual single-story or multistory dwelling units shall be permitted to have a single exit or access to a single exit from the dwelling unit provided that both of the following criteria are met:
5.1. The dwelling unit complies with Section 1006.2.1 as a space with one means of egress.
5.2. Either the exit from the dwelling unit discharges directly to the exterior at the level of exit discharge, or the exit access outside the dwelling unit’s entrance door provides access to not less than two approved indepen- dent exits.
6. Occupied roofs with an occupant load of ten or less are permitted to have a single exit or access to a single exit.
7. Not more than 5 stories of Group R-2 occupancy are permitted to be served by a single exit under the following conditions:
7.1. The building has not more than six stories above grade plane.
7.2. The building does not contain a boarding house.
7.3. There shall be no more than four dwelling units on any floor.
7.4. The building shall be of not less than one hour fi re-resistive construction a nd shall also be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. Residential-type sprinklers shall be used in all habitable spaces in each dwelling unit.
7.5. There shall be no more than two single exit stairway conditions on the same property.
7.6. An exterior stairway or in terior exit stairway shall be provided. The interior exit stairway, including any related exit passageway, shall be pressurized in accordance with Section 909.20.6. Doors in the stairway shall swing into the interior exit stairway regardless of the occupant load served, provided that doors from the interior exit stairway to the building exterior are permitted to swing in the direction of exit travel.
7.7. A corridor shall separate each dwelling unit entry/exit door from the door to an interior exit stairway, including any related exit passageway, on each floor. Dwelling unit doors shall not open directly into an interior exit stairway. Dwelling unit doors are permitted to open directly into an exterior stairway.
OCCUPANT LOAD PER STORY MINIMUM NUMBER OF EXITS OR ACCESS TO EXITS FROM STORY 1-500 2
501-1,000 3
More than 1,000 4
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SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY AND USE 2021 SEATTLE BUILDING CODE
7.8. There shall be no more than 20 feet (6096 mm) of travel to the exit stairway from the entry/exit door of any dwelling unit.
7.9. Travel distance measured in accordance with Section 1017 shall not exceed 125 feet.
7.10. The exit shall not terminate in an egress court where the court depth exceeds the court width unless it is possible to exit in either direction to the public way.
7.11. Elevator hoistways shall be pressurized in accordance with Sectio n 909.21 or shall op en into elevator lobbies that comply with Section 713.14. Where approved by the building official, natural ventilation is permitted to be substitut ed for pressurization wher e the ventilation would prevent the accumulation of smoke or toxic gases.
7.12. Other occupancies are permitted in the same building provided they comply with all the requirements of this code. Other occupancies shall not communicate with the Group R occupancy portion of the building or with the single-exit stairway.
Exception: Parking garages and occupied roofs accessory to the Group R occupancy are permitted to communicate with the exit stairway.
7.13. The exit serving the Group R occupancy shall not discharge through any other occupancy, including an accessory parking garage.
7.14. There shall be no openings within 10 feet (3048 mm) of unprotected openings into the stairway other than required exit doors having a one-hour fire-resistance rating. 1006.3.4.1 Mixed occupancies. Where one exit, or exit access stairway or ramp providing access to exits at other stories, is permitted to serve individual stories, mixed occupancies shall be permitted to be served by single exits provided that each individual occupancy complies with the applicable requirements of Table 1006.3.4(1) or 1006.3.4(2) for that occupancy. Where applicable, cumulative occupant loads from adjacent occupancies shall be considered to be in accordance with the provisions of Section 1004.1. In each story of a mixed occupancy building, the maximum number of occupants served by a single exit shall be such that the sum of the ratios of the calculated number of occupants of the space divided by the allowable number of occupants indicated in Table 1006.3.4(2) for each occupancy does not exceed one. Where dwelling units are located on a story with other occupancies, the actual number of dwelling units divided by four plus the ratio from the other occupancy does not exceed one.
For SI: 1 foot = 304.8 mm.
NP = Not Permitted.
NA = Not Applicable.
a. Buildings classified as Group R-2 equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and provided with emergency escape and rescue openings in accordance with Section 1031. b. This table is used for R-2 occupancie s consisting of dwelling units. For R-2 occupancies consisting of sleeping units, use Table 1006.3.4(2).
For SI: 1 foot = 304.8 mm.
NP = Not Permitted.
NA = Not Applicable.
a. Buildings classified as Group R-2 equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and provided with emergency escape and rescue openings in accordance with Section 1031. b. Group B, F and S occupancies in buildings equipped throughout w ith an automatic sprinkler system in accordance with Section 9 03.3.1.1 shall have a maximum exit access travel distance of 100 feet.
c. This table is used for R-2 occupancie s consisting of sleeping units. For R-2 occupancies consisting of dwelling units, use Table 1006.3.4(1). d. The length of exit access travel distance in a Group S- 2 open parking garage shall be not more than 100 feet.
TABLE 1006.3.4(1)
STORIES WITH ONE EXIT OR ACCESS TO ONE EXIT FOR R-2 OCCUPANCIES
STORY OCCUPANCY MAXIMUM NUMBER OF
DWELLING UNITS
MAXIMUM EXIT ACCESS
TRAVEL DISTANCE
Basement, first, second or third story above grade plane R-2a, b 4 dwelling units 125 feet Fourth story above grade plane and higher NP NA NA
TABLE 1006.3.4(2)
STORIES WITH ONE EXIT OR ACCESS TO ONE EXIT FOR OTHER OCCUPANCIES
STORY OCCUPANCY MAXIMUM OCCUPANT
LOAD PER STORY
MAXIMUM EXIT ACCESS
TRAVEL DISTANCE (feet)
First story above or below grade plane
A, Bb, E, Fb, M, U 49 75
H-2, H-3 3 25
H-4, H-5, I, R-1, R-2a, c 10 75
Sb, d 29 75
Second story above grade plane B, F, M, Sd 29 75
Third story above grade plane and higher NP NA NA
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