Appeal 13911

Table 503 , 302.1 General

This specific appeal concerns the COP’s plan checksheet item #20 applying an A occupancy to the building's 6th floor roof deck(s) whereby the Table 503 states such an occupancy (A) at that story is not permitted. Based upon the written and attached analysis submitted by the Architect, this is a misapplication of the code.

West & East decks on Level 6 of building allowed.

Below are applicable OSSC Definitions (202) to consider in determining the building’s exterior roof deck requirements:

Building: Any structure used or intended for supporting or sheltering any use or occupancy.

Court: An open, uncovered space, unobstructed to the sky, bounded on three or more sides by exterior building walls or other enclosing devices.
Area, Building:
The area included within surrounding exterior walls (or exterior walls and fire walls) exclusive of vent shafts and courts. Areas of the building not provided with surrounding walls shall be included in the building area if such areas are included within the horizontal projection of the roof or floor above.
Fire Area.
The aggregate floor area enclosed and bounded by fire walls, fire barriers, exterior walls or horizontal assemblies of a building. Areas of the building not provided with surrounding walls shall be included in the fire area if such areas are included within the horizontal projection of the roof or floor next above.
A Story:
That portion of the building included between the upper surface of a floor and the upper surface of the floor or roof next above. It is measured as the vertical distance from the top of two successive tiers of beams or finished floor surfaces and, for the topmost story, from the top of the floor finish to the top of the ceiling joists or, where there is not a ceiling, to the top of the roof rafters.
Structure:
That which is built or constructed. A structure may contain one or more buildings separated by fire rated construction elements in accordance with the prevailing building codes.

The relevant question is what parts of the code are applicable to the regulation of rooftop decks that are intended to be used by building occupants?

1. Occupancy classification: Section 302.1 states that “Structures or portions of structures shall be classified with respect to occupancy in one or more of the groups listed in this section.”

Conclusion: A rooftop deck intended for use by the building occupants should be classified with an occupancy classification since the there is a “use” of the roof and the roof is part of a “structure.”

1. Story limitations of roof uses: The definition of a story only includes the portion of a building between a floor or a roof above.

Conclusion: A roof, irrelevant of whether it has a use or not, is not a story, since a story, as defined, has a roof or floor above. (A roof has no roof or story above.) So a roof with a deck “use” is not required to comply with the provisions of Chapter 5 and Table 503 for limiting the height or stories, in which the use on a roof occurs.

1. Building area limitations of roof uses: The definition of building area only includes the portion of a building within walls or under a covered floor or roof above.

Conclusion: A roof, irrelevant of whether it has a use or not, is not part of a building area, since building area, as defined, has walls and/ or a roof above. So a roof with a deck use is not required to comply with the provisions of Chapter 5 and Table 503 for limiting the building area in which the use on a roof occurs.

1. Type of Construction and structural requirements of roof uses:

Conclusion: A roof with a use is required to meet the construction type requirements of Chapter 6 for roofs and the structural loading requirements of Chapter 16 for roofs and the intended use.

1. Other requirements of roof uses:

Conclusion: A roof with a use is required to meet the applicable provisions for its intended use for Chapter 10 Means of Egress, Chapter 11 Accessibility, and Chapter 15 Roofing. It is also required to meet limited applicable provisions of Chapter 7 and 9.

This code analysis concludes that placing a use on a roof (per 302.1) creates an occupancy classification for the use. That classification then properly requires rooftop uses to comply with means of egress, accessibility, structural and potentially limited other requirements such as detection requirements. This analysis also properly concludes that other aspects of the code (table 503) are not applicable. The code does not regulate story or height limitations in an open-air-non-story, non-building area, as defined, such as a rooftop deck use, because it is not within walls and is not under a structure. This is consistent with the code’s assumption of increased fire hazards only in confined spaces within and under something, not on a roof.

Furthermore, the International Code Council reviewed multiple proposals and approved one proposal concerning rooftop uses for its 2018 IBC. The proposed change G24-15 PC#2 was Approved as Modified by Public Comment (AMPC) (Public Comment #2) in its Final Action for Group A proposed changes for the 2018 IBC with the addition of new section 503.1.4 Occupied roofs. The multiple proponents, consisting of various code specialists, joined together and created clarifications for rooftop uses. Their public comment reason statement drew the same code analysis conclusions of this submitted analysis. They also further regulated those uses only in non sprinklered buildings.

2018 IBC Commentary Attached (7 pages.)

403.4.6 Fire command and specifically: 911.1.3 size

The room shall be a minimum of 200 square feet with a minimum dimension of 10ft.

The new fire command center (FFC) footprint is configured so that a portion of the room is less than the 10 foot minimum. Overall the area of the FCC exceeds code at 205 square feet. Refer to attached Towne Storage floor plan.

This is an existing historic building under renovation where the geometry of this renovated building’s main floor lobby and elevator, the exiting column layout and the FFC’s door placement has created this layout. The 200 SF area requirement meets code. This a new renovated historic building with a new automatic sprinkler system for protection.

PCC 24.50.050 & 24.50.06 OSSC code : 3403.2 & 1612.5

Per Site Development check sheet provided by Ericka Koss:
Meeting current Flood Hazard Code per FEMA requirements: Specifically item:

B) Floodwater openings shall be located on two different sides of the enclosed area.

The two required openings will be provided along the West side of the enclosed are only. Refer to attached floor plan and elevation.

Due to the NW corner location of the defined enclosed area (trash room & exit stair landing) a flood water opening cannot be provided on the North side of the building due the zero lot-line property line location. Refer to attached partial plan of the area.

703.3

The application of any of the alternate methods listed in this section shall be based on the fire exposure and acceptance criteria specified in ASTM E119 or UL 263. The required fire resistance of a building element, component or assembly shall be permitted to be established by any of the following methods or procedures:

1.Calculations in accordance with Section 722.

The building being renovated is Towne Storage in the city of Portland, Oregon and is currently in compliance with Type IIIB construction. The building is now classified as Type IIIA. Under Type IIIA construction, the typical floor construction and associated secondary members must have a minimum one-hour fire resistance rating.

The proposed design involves locating structural steel drag struts within an approved 1 hour floor assembly as follows:
1.Floor/Ceiling Construction: The proposed design is to leave the existing 2x6 wood (edgewise) decking. Ceiling/Floor construction will be exposed on the underside and no additional fire resistance is to be applied. Building is fully sprinklered. Using char rate analysis, the unimpaired decking depth will meet or exceed minimum requirements for a 1-Hour fire resistance. Note: loadbearing UL E119 requirements are met for this floor.

The assembly is required to be listed, approved, 1-hour fire-resistance-rated construction per OSSC 602. There is no known tested assembly that matches the provided assemblies.

See the attached floor plan for extent of the drag strut, and the attached engineering judgment letter for assembly details.

The proposed design uses an analysis from an Oregon registered Fire Protection Engineer to provide equivalent life safety and fire protection to what the code requires. The drag strut is being inserted into an assembly approved by appeal 13471, therefore we request that this appeal be granted.