Appeal 23941

OSSC 602 Section Construction Classification; Table 602 Fire-Resistance Rating for Exterior Walls based on Fire Separation Distance Chapter 2 Definitions: Open Parking Garage

Table 602 requires that Type IA construction shall have 1-hour rated exterior wall for S-2 occupancy, when fire separation distance is between 5’ and 10’. For FSD between 10’ and 30’ (including 10’), the base requirement is still a 1-hour rating, with an exception for Open Parking Garages conformant with Section 406 (Footnote C).

Per Section 406.5.2, the exterior sides of Open Parking Garage shall have opening on at least two sides, at not less than 40% of the perimeter lineal footage of the space, and 20% of the perimeter wall area.

Per Definitions, an Open Parking Garage is “a structure or portion of a structure that is used for the parking or storage of private motor vehicles.”

We request that a portion of the drive aisle, up to 10’ from the property line, be considered as covered exterior space, and not “structured parking.” The remainder would still be considered as Open Parking, and would meeting all applicable requirements.

The parking area occupies part of the west side of the Type IA ground floor portion of a 3-over-1 “podium” building, with Type VB construction on the upper floors. The concrete podium deck will be 3-hour fire rated construction. A dry-pipe sprinkler system conformant with NFPA-13 will serve the space. The wall to the east of the entry drive-aisle, outside the Sprinkler/Water Room and Trash Room, will maintain a 1-hour rating requirement, since it is less than 30’ to the property line. The west wall of Floors 2 through 4 is 1 hour rated construction, and the ground floor concrete columns supporting those floors are fire rated for 3 hours, as Type IA primary structural frame.

The proposed layout of the Open Parking Garage consists of a drive aisle area, approximately 148’ long and 20.5’ wide, against the west side, and a parking stall area approximately 95.5’ long and 18’ wide, tucked closer to the conditioned space, toward the east. The outer boundary of the “Open Parking Garage,” per discussion with City Staff, is the column line, whose outside faced is 5.5’ from the property line. The outer edge of the drive aisle is 7.5’ from the property line. The parking stalls, designed according to Zoning Code requirements, are 27.5’ from the property line.

The proposed design does not include a full-height west wall for to the parking area, leaving it primarily open to the west side of the site, with the exception of the concrete guard wall. This design optimizes open ventilation and airflow into the parking area, and admits more natural light and view for comfort and security.

Reference Figures A.2, A.7 and A.8.

In accordance with Table 602, a 1-hour rated exterior wall is required for spaces designated S-2, up to 30’ of fire separation distance from a property line. Per Exception c on this Table, Open Parking Garages are not required to have a rated wall—and therefore not required to have a wall—for distances between 10’ and 30’. The S-2 occupancy designation is set for parking garages, based on low-hazard storage of motor vehicles. The passage of motor vehicle, as in the case of a driveway, is not generally considered as “parking garage” but as covered exterior space, where generally open to the surrounding environment. In other words, if the drive aisle at the west side did not directly abut parking spaces, but passed through to a lot behind the building, it would not be subject to the need for a rated exterior wall. The drive aisle triggers the need for a rated wall in this case, only because it directly abuts parking beyond, further away from the property line.

By modifying the established west boundary of the area considered Open Parking, to omit a section of the drive aisle, we could demonstrate conformance with code. The west boundary of the “Open Parking” area would be shifted east slightly and set at the 10’ fire separation distance—which per footnote c on Table 602, would not require a rated exterior wall assembly. The rationale is that this portion of the space will remain clear and free from any flammable materials or other potential fuel or fire hazards, since it is a drive-aisle with clear dimensions designated by the City Zoning Code.

The baseline code requirement will trigger a rated wall at the west side of the parking area, at the ground level. The construction of a rated wall assembly at this location will restrict airflow into the parking structure, reducing light and natural ventilation. It will also limit allowable openings to the extent that the garage will be defined as an Enclosed Parking Garage per Section 406.6 of the OSSC, triggering requirements for mechanical ventilation, and increasing building energy use.

This is a multifamily housing project with a portion of the units set aside for a vulnerable population who have experiences trauma. Trauma-informed design encourages light, openness, and visibility. Having to close in the east wall of the parking would reduce the natural light and view to the outside, and decrease the sense of safety and comfort for occupants, especially those with mobility issues who rely on vehicles.

A rated wall at this side would only be protecting an empty drive aisle with no combustion or fuel sources, which is already protected by a sprinkler system and rated assemblies above. We propose to omit the rated wall by way of a slight adjustment to the areas designated as “Open Parking Garage,” in order to reduce the use of cost, material, and energy in building operations, and to maximize natural light and ventilation for the occupants of the space.

OCCS Section 1024 Exit Passageways

Per OSSC Section 1024.3, walls of exit passageways shall be constructed as fire barriers, with a rating to match the connecting egress stair, in accordance with Section 707. Per 1024.5, openings are allowed but “shall be limited to those necessary for exit access to the exit passageway from normally occupied spaces” unless they are the egress opening. Section 1024.1 notes that an exit passageway may be used as part of an egress path.

Exit passageway opening protectives shall be in accordance with the requirements of Table 716.1(2). For a “fire barrier having a required fire-resistance rating greater than 1 hour,” with the required assembly rated at 2 hours, the minimum fire door or fire shutter shall be 1 ½ hours.

The exit passageway must also conform to Section 1023.3.1, which requires separation of the exit stair and the exit passageway by a fire barrier and a fire door meeting requirements per Section 707 and Section 716, respectively.

We request that a rated fire curtain be allowed to be installed between the Lobby (101) and Exit Passageway (117), as an opening that closes to become part of a continuous rated fire barrier assembly.

The project is a podium building, with Type IA construction at grade and Type VB on floor 2 through 4. The building will be fully sprinkled in conformance with NFPA 13. The proposed design—for egress from the south-side units on Floors 2, 3, and 4 of this multifamily housing project—relies on an interior exit stair that connects to an exit passageway, discharging to the street. The exit stair is a 2-hour rated shaft, and the exit passageway is designed with 2-hour fire barriers on both sides to meet this rating. The ceiling will exceed the 2-hour rating. Note that the egress stair wall at the ground floor maintains a three-hour rating, but this is specific to a City of Portland (not yet formalized but in practice) code exception, allowing wood stair framing at the ground floor, where this wall rating is provided. The 2-hour rating is established for the exit stair in its entirety, and it governs. The exit passageway is otherwise constructed in conformance with all applicable codes.

The stair and the exit passageway are to be separated by the 3-hour fire barrier and a 90-minute fire-rated door. An emergency egress and security door for the adjacent office--which will be rated for 90 minutes—also opens onto the passageway. The proposed design also includes an 8’-0” wide by 8’-0” high opening between the Lobby and the passageway. The opening provides access from the building’s main lobby to the main stair, to encourage use of the stair and promote occupant health. The opening is protected by a 2-hour rated fire curtain, conformant with NFPA 80. Once the curtain has descended, the total assembly acts as a continuous fire barrier. It protects egress from the exit stair, and egress from the Lobby occurs through the street-side doors, or exit into the central courtyard. The shutter is released upon activation of the building’s smoke detection system, fire alarm system or power failure.

Reference Figures A.1 and A.5.

If the fire barrier at the east side of the exit passageway is constructed with no doors to the Lobby, or with a single, 90-minute door that is in a typically closed position, it will deter tenants from using the stairs in favor of the elevator that is stationed directly adjacent to the exit passageway. By constructing the large opening, the stair door is kept within clear view of tenants in the Lobby, more effectively encouraging them to use this means of vertical circulation to the units above. Moreover, since a portion of the tenant group are survivors of trauma in permanent supportive housing, the opening from the Lobby to the stairs assists in meeting their needs for safety and comfort, by increasing the visibility and openness of the circulation spaces.

By providing the fire shutter to close in the event of a fire, the design achieves the desired fire protection with an alternative solution. The design will also include a smoke detector directly adjacent to the opening on each side.

Building Code Appeal Precedent: 12660, Item 3 (11/4/15)

OSSC Section 1010.1.9 Door Operations

Per OCCS 1010.1.9 egress doors shall be readily openable from the egress side without the use of a key or special knowledge.

Allow a door with an electronic lock, released upon activation of the fire alarm or in the event of power failure to meet the requirements of this code section.

Door 101D connects the small structured parking area on the ground floor to the building Lobby. It also provides part of the second on-grade egress route from this parking area, the Electrical Room 111 and the Transformer Vault Room 112 (the first egress being through the parking entry). Although it is unlikely that this door would be used for egress in any practical situation, in the event of an emergency, per code it provides part of the path for 12 occupants total. Since it links the unsecured parking area to the interior of the building, it will be operated from the exterior push side, on a key fob, to maintain security at times when staff are not observing this building entry point. The door is self-closing and self-latching.

We propose to install electromagnetic locks that connect the door lock to the building alarm system, so that it opens in case the alarm is triggered, and so that in the event of a power failure, it fails safe to an unlocked position. The door will self-close and latch in all cases. When the door is deactivated, a trouble signal will be sent to property management or monitoring services. Signage indicating the other exit from the space will be posted adjacent to the door. A fire alarm pull station will also be added adjacent to the door, on the Garage side. The entire building will be sprinkled per NFPA 13 standards, including both the Parking and Lobby spaces.

Reference Figures A.1, A.3, and A.6.

The project is a multifamily affordable housing apartment building, with nine units specifically reserved as permanent supportive housing. Security of the Lobby area and the other spaces in the building is a significant concern to the building ownership and operations, for the safety and comfort of the tenant population. Since the on-grade parking area is open to the street, there is a need for the connecting door between Parking and Lobby to be able to be locked, while remain compliant with code requirements as an egress door.

By being connected to the alarm system and allowed to fail safe for passage, the door provides for the emergency egress requirements established by the code. Additional signage will ensure that the alternate egress path is clear to occupants. The Type IA construction on this floor, and the NFPA 13 sprinkler system, further increase the overall fire safety of the space.

Building Code Appeal Precedent: 18818, Item 1 (12/26/2018)

2019 OZERCC / ASHRAE 90.1-2016, 5.4.3.4 Vestibules

Building entrances that separate conditioned space from the exterior shall be protected with an enclosed vestibule, with self-closing doors that operate independently. Exception 2 excludes doors not intended as building entrances from the requirements. Exception 7 excludes doors that open directly from a space that is less than 3000 square feet in area and is separate from the building entrance.

We request to add an exception or alternate to the vestibule requirement for the connecting door to the parking garage, such that an air curtain may be used as a substitute to a vestibule.

The project is a multifamily apartment building offering affordable units, including nine permanent supportive housing units, to its tenants. To serve this population, the lobby and common area of the ground floor maximizes clear, open space with multiple connections to the central courtyard provided by swing and sliding doors. Most of these doors meet one or both of the exceptions for the vestibule requirement, as they are not building entrances, and/or they do not access a space more than 3,000 square feet in area that is not connected to the building entrance. Door 100, the building entry door from the street, includes a vestibule with a separate Door 101A, meeting all of the requirements listed in ASHRAE 90.1-2016, 5.4.3.4.

Door 101D, connecting the Parking Garage to the Lobby, is a “building entrance” as defined in the ASHRAE User Manual. It is not a primary entry, as it serves only the eight-stall parking area, and acts as secondary emergency egress for the typically unoccupied Electrical Room and Transformer Vault Room at the northwest corner of the building. It is designed without a dedicated vestibule, but with an air curtain mounted above the door to control contaminants and maintain a sufficient air seal at the conditioned space during door operation.

Reference Figures A.1, A.6.

We are proposing an air curtain as an equivalent-performance alternate to the vestibule, since an additional vestibule at this location, even minimally sized, would diminish available lobby space for the tenants and would create additional impediments to the egress route that passes through these doors, as well as adding cost to this affordable housing project.

Also note that, while the current energy code does not directly address compliance for this item by use of an air curtain, the upcoming energy code revision references ASHRAE 90.1-2019. Section 10.4.5 in that document allows air curtains outright, as an alternate to the vestibule. In conformance with the upcoming standard, the proposed air curtain shall:

• be tested in accordance with ANSI/AMCA 220 or ISO 27327-1
• have a jet velocity of not less than 6.6 ft/s at 6.0 in above the floor
• have a direction not less than 20 degrees toward the opening
• be equipped with automatic controls that will operate the air curtain with opening and closing of the door

The established testing and modeling for these systems indicates a performance and energy saving comparable to a vestibule, which is indicated by the upcoming adoption of the air curtain as an allowable code alternate.

Building Code Appeal Precedent: 18690, Item 2 (11/21/2018)

OSSC Section 2902.1 Minimum number of fixtures OSSC Section 2902.3 Employee and public toilet facilities Section 2902.2.1 Family or assisted-use toilet facilities serving as separate facilities

Section 2902.1 establishes criteria for calculating minimum fixtures through Table 2902.1. For community areas in a residential building, the requirements for water closets is 1 per 125 for men’s facilities, and 1 per 65 for women’s. For residential units, 1 water closet is required per dwelling unit.

Section 2902.3 requires public toilet facilities for employees and patrons or users of public tenant spaces, which may be combined for employees and other users both.

Section 2902.2.1 allows for two non-gendered family facilities in lieu of two gendered facilities, in cases where each requires only one water closet.

Reduce the calculated fixture requirement for water closets by 50% for non-residential, ground floor areas of the building that are for resident use.

The project is an apartment building. The top three floors are residential units, and the ground floor is dedicated to parking, building employee use, utility spaces, and spaces for community use by the tenant. Community Room 1 (104) and Community Room 2 (105), and the Lobby (101) all include communal space for tenant use. There are also three B-occupancy spaces—two front Offices (102 and 118) and a Meeting Room (103)—and an S-occupancy—a Maintenance Office (110)—that will necessitate some ground floor restrooms. The project includes two restrooms to the east of the north stair, for use by building employees and by any tenants—or their friends and family—who are using the ground floor. The facilities are two non-gendered “family” facilities, each with one water closet, as permitted by Section 2902.2.1.

2902.3.3 sets a maximum path of travel of 500 feet from any public and employee toilet facility to a space served by the facility. The proposed location is less than 200’ from the farthest point (south office).

Reference A.4 and A.6.

If one calculates the number of water closets required for the full area of communal and employee spaces, the requirement is one men’s WC and two women’s WCs. The women’s water closets are factored at a higher multiplier for the assembly spaces, yielding approximately 1.5, which rounds up to two. This assumes that all communal spaces are taken as public, and calculated as if they support an independent set of occupants. However, these communal spaces are not truly “public” per the intent of the code, as they serve the tenant group for the building, not outside users. Many residents will use the toilet facilities in their own apartments, rather than those provided at the ground floor bathrooms. As a result, use by the public/tenant base and employees will be a fraction of what the code would calculate for an independent community center with similar employee/public programming.

The table on Figure A.4 shows the calculation for water closets if all employee spaces are calculated at their full occupant load, and all communal spaces are calculated at 50%. This yields a water closet count of 1 per gender. By assuming the family restroom provision in Section 2902.2.1, two family restrooms with 1 water closet each satisfy the requirement for the ground floor users. Note that there are multiple precedent appeals that eliminate counts for resident use spaces entirely in similar projects, and that we are requesting only a 50% reduction.

Precedent Appeals:
13334, Item 1 (4/20/2016)
13042, Item 2 (2/17/2016)
13885, Item 4 (8/24/2016)
12010, Item 1 (5/20/2016)