Appeal 35053

Table 1006.3.4(2) Stories with one exit or access to one exit

A first story above or below grade plane with an R-1 occupancy, a maximum occupant load of 10 per story, and a maximum exit access travel distance of 75 feet is permitted. A second story above grade plane with an R-1 occupancy is not permitted with one exit.
As the plans examiner has explained, under this interpretation, the “first story above grade plane” in our project is the second physical story of the building, and the “second story above grade plane” is the third physical story.

Approval to allow a second story above grade plane with an R-1 occupancy and one exit, provided that the occupancy load does not exceed 10 persons per story and the maximum exit access travel distance does not exceed 75 feet.

The project involves the conversion of existing R-2 occupancies on the second and third stories of an existing three-story building to R-1 occupancies. Each floor will have a maximum of 10 occupants, with egress provided via a single exterior exit stairway. The building is of Type V-B construction and is equipped throughout with an NFPA 13 fire sprinkler system.

This existing building currently contains R-2 occupancies on portions of the second floor and the entirety of the third floor—both allowed under the current code. We believe that R-1 occupancies present the same, or lower, hazard risk as R-2 occupancies.
Per Table 1006.3.4(1), R-2 occupancies up to three stories in height, fully equipped with an automatic sprinkler system, and with a maximum of four dwelling units per story, may have a single exit. Table 1006.3.4(2) applies broadly to all R-1 occupancies, including large hotels with hundreds of units, and does not distinguish smaller, low-load buildings like ours. The design and scale of this building are more comparable to a typical apartment building than to a large hotel.
Supporting this position, a FEMA/USFA study comparing fire risk shows R-1 occupancies averaging 0.7 deaths per 1,000 fires, compared to 2.0 deaths per 1,000 fires for R-2 occupancies—indicating that R-1 occupancies have fewer fire-related fatalities than R-2. In our experience working on more than 20 post-fire buildings, fatalities were generally linked to occupant possessions and behaviors (e.g., re-entering to retrieve pets or belongings, fires from unattended cigarettes, blocked heaters, or uncleared ovens). R-1 occupants are transient, units are cleaned between guests, and possessions are minimal—reducing fuel load and obstructions compared to R-2.
Additional code provisions also imply equivalent hazard levels:
• Table 504.3 allows any sprinklered R occupancy to be up to 60 feet in height.
• Table 504.4 allows both sprinklered R-1 and R-2 occupancies to be up to three stories.
Finally, per IEBC § 701.2, alterations—including changes in occupancy or egress—must not render a building less safe than its existing condition. Comparable fully sprinklered R-3 buildings—also transient in nature and with a similar occupant load of only two dwelling units served by each exit—operate with a single exit from the third floor without compromising life safety. Our proposed configuration maintains equal or greater safety compared to existing conditions.
Supporting Research — Single-Stair Safety Evidence
• A recent analysis by Pew and the Center for Building in North America found that modern four- to-six-story residential buildings with only one stairway are “at least as safe as other types of housing.”
• International comparisons, including research in the Netherlands, similarly indicate that single-stairway buildings of comparable size maintain safety levels on par with dual-stairway configurations.
• As summarized concisely: “In both Seattle and New York City, no fire deaths were associated with having only one stairway.”
Conclusion:
Given the building’s sprinkler protection, limited occupant load, reduced fuel load, and code provisions demonstrating equivalency between R-1 and R-2, the change from R-2 to R-1 in this building does not increase hazard risk. This conclusion is further supported by national research and by State of Oregon and City of Portland code amendments that permit even larger single-stair R-2 buildings under similar or less restrictive conditions. Approval to apply the same single-exit provision allowed for R-2 occupancies is therefore warranted.