Appeal 15420

602.3 Type III

Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less.

We are submitting this request for the use of regular wood stud framing with the stud cavity filled with mineral wool batt insulation instead of Fire Retardant Treated Wood (FRTW). The proposed design includes two (2) exterior wall assemblies (#40 and #50) included in the appendix section of the attached white paper prepared by an Oregon Fire Protection Engineer.

In addition to the above proposal the project will also satisfy the following conditions:

Exterior bearing walls shall be protected based on their fire separation distance as defined in the OSSC and as indicated in the attached white paper. All exterior wall coverings shall be of non-combustible material.

Combustible roof sheathing and framing shall be protected from exposure to fire from above with gypsum-based products, fire-retardant-treated wood sheathing or similar UL tested products installed above or below the roofing membrane and/or rigid insulation.

Selective smoke detection coverage shall be provided in the Type Ill portion of the building per NFPA 72, National Fire Alarm Code, beginning at the access point to the path of egress and continuing until reaching all exits. If the exit passes through a lobby or other intervening space, selective smoke detection coverage requirements shall be extended to such spaces until reaching the exit discharge.

At least one operable exterior window shall be provided in each dwelling unit with a minimum opening width of 3-1/2 inches.

Walls and floor assemblies separating dwelling units shall have tested fire resistance ratings of not less than 1-hour.

The base allowable building area specified in the OSSC for R occupancies in Types IllA and IIIB construction shall not exceed 12,000 square feet. Area increases in accordance with the OSSC are allowed.

All required egress stairs shall include access to the roof. Such access may be via any method listed in OSSC Chapter 10 for roof access.

All penetrations through the exterior wall covering will be fire-stopped at the exterior sheathing. "Penetrations" for purposes of this appeal includes elements such as conduits and piping and does not include "openings" such as doors, windows or wall-mounted HVAC units and louvers.

Ducts and vents penetrating exterior walls shall be 26 gage minimum.

No unprotected penetrations are permitted through the underside of fire-rated exterior wall projections that are required to be rated, including cornices, eaves, bays, exterior balconies, and similar projections extending beyond the exterior wall.

Elevator hoistways opening directly into corridors shall be pressurized or have smoke-tight protection as required for doors opening into fire-resistive corridors.

Framing connections at walls, floors, ceilings, roofs, and with the proposed exterior wall will be constructed as specified in the detail drawings numbered O - 19 contained in the City of Portland Code Guide OSSC/6/#4, unless greater fire resistance is provided, except that no sacrificial stud will be provided. 2-hour rated walls will be provided at these conditions. Conditions not covered in the guide will be constructed in accordance with the OSSC

The attached white paper provides the fire analysis that supports the use of mineral wool (aka Rock Wool) insulation in the wall cavity of untreated wood stud framing as an alternate to FRT wood stud framing permitted by the OSSC section 602.3. The analysis is based on published temperature data from full scale testing of multiple configurations of fire rated stud walls. The assemblies tested included 1 hour and 2 hour rated assemblies, with and without insulation, insulations included fiberglass and Rock wool types.

The analysis incorporates test data with the fire science fundamentals of gypsum calcification, pyrolysis of wood, and thermal conductivity of materials, accepted by the Society of Fire Protection Engineers, The National Bureau of Standards, and the American Wood Council. These are the accepted industry standards for this type of analysis.

The appeal includes additional conditions requested by the City of Portland. The equivalency analysis included in the white paper is a straight comparison between untreated wood and FRT wood framed wall assemblies, without any benefit from these additional conditions. The analysis documented in the attached white paper concludes that untreated wood framed walls with mineral wool insulation will outperform FRT wood framed walls without such insulation.

Therefore, we are very confident that the performance of mineral wool filled wood stud framed walls with these 16 additional conditions will far exceed the code intent of FRT wood framing.
Hence, we urge you to approve this appeal request.

602.3 Type III

Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less.

We are submitting this request for the use of regular wood stud framing with the stud cavity filled with mineral wool batt insulation instead of Fire Retardant Treated (FRTW). The proposed design includes the exterior wall assembly (#52) included in the appendix section of the attached white paper prepared by an Oregon Fire Protection Engineer.

In addition to the above proposal the project will also satisfy the following conditions:

Exterior bearing walls shall be protected based on their fire separation distance as defined in the OSSC and as indicated in the attached white paper. All exterior wall coverings shall be of non-combustible material.

Combustible roof sheathing and framing shall be protected from exposure to fire from above with gypsum-based products, fire-retardant-treated wood sheathing or similar UL tested products installed above or below the roofing membrane and/or rigid insulation.

Selective smoke detection coverage shall be provided in the Type Ill portion of the building per NFPA 72, National Fire Alarm Code, beginning at the access point to the path of egress and continuing until reaching all exits. If the exit passes through a lobby or other intervening space, selective smoke detection coverage requirements shall be extended to such spaces until reaching the exit discharge.

At least one operable exterior window shall be provided in each dwelling unit with a minimum opening width of 3-1/2 inches.

Walls and floor assemblies separating dwelling units shall have tested fire resistance ratings of not less than 1-hour.

The base allowable building area specified in the OSSC for R occupancies in Types IllA and IIIB construction shall not exceed 12,000 square feet. Area increases in accordance with the OSSC are allowed.

All required egress stairs shall include access to the roof. Such access may be via any method listed in OSSC Chapter 10 for roof access.

All penetrations through the exterior wall covering will be fire-stopped at the exterior sheathing. "Penetrations" for purposes of this appeal includes elements such as conduits and piping and does not include "openings" such as doors, windows or wall-mounted HVAC units and louvers.

Ducts and vents penetrating exterior walls shall be 26 gage minimum.

No unprotected penetrations are permitted through the underside of fire-rated exterior wall projections that are required to be rated, including cornices, eaves, bays, exterior balconies, and similar projections extending beyond the exterior wall.

Elevator hoistways opening directly into corridors shall be pressurized or have smoke-tight protection as required for doors opening into fire-resistive corridors.

Framing connections at walls, floors, ceilings, roofs, and with the proposed exterior wall will be constructed as specified in the detail drawings numbered O - 19 contained in the City of Portland Code Guide OSSC/6/#4, unless greater fire resistance is provided, except that no sacrificial stud will be provided. 2-hour rated walls will be provided at these conditions. Conditions not covered in the guide will be constructed in accordance with the OSSC

The attached white paper provides the fire analysis that supports the use of mineral wool (aka Rock Wool) insulation in the wall cavity of untreated wood stud framing as an alternate to FRT wood stud framing permitted by the OSSC section 602.3. The analysis is based on published temperature data from full scale testing of multiple configurations of fire rated stud walls. The assemblies tested included 1 hour and 2 hour rated assemblies, with and without insulation, insulations included fiberglass and Rock wool types.

The analysis incorporates test data with the fire science fundamentals of gypsum calcification, pyrolysis of wood, and thermal conductivity of materials, accepted by the Society of Fire Protection Engineers, The National Bureau of Standards, and the American Wood Council. These are the accepted industry standards for this type of analysis.

The appeal includes additional conditions requested by the City of Portland. The equivalency analysis included in the white paper is a straight comparison between untreated wood and FRT wood framed wall assemblies, without any benefit from these additional conditions. The analysis documented in the attached white paper concludes that untreated wood framed walls with mineral wool insulation will outperform FRT wood framed walls without such insulation.

Therefore, we are very confident that the performance of mineral wool filled wood stud framed walls with these 16 additional conditions will far exceed the code intent of FRT wood framing.
Hence, we urge you to approve this appeal request.

602.3 Type III

Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2303.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less.

We are submitting this request for the use of regular wood stud framing with the stud cavity filled with mineral wool batt insulation instead of Fire Retardant Treated Wood (FRTW). The proposed design includes the exterior wall assembly (#42) included in the appendix section of the attached white paper prepared by an Oregon Fire Protection Engineer.

In addition to the above proposal the project will also satisfy the following conditions:

Exterior bearing walls shall be protected based on their fire separation distance as defined in the OSSC and as indicated in the attached white paper.

All exterior wall coverings shall be of non-combustible material.

Combustible roof sheathing and framing shall be protected from exposure to fire from above with gypsum-based products, fire-retardant-treated wood sheathing or similar UL tested products installed above or below the roofing membrane and/or rigid insulation.

Selective smoke detection coverage shall be provided in the Type Ill portion of the building per NFPA 72, National Fire Alarm Code, beginning at the access point to the path of egress and continuing until reaching all exits. If the exit passes through a lobby or other intervening space, selective smoke detection coverage requirements shall be extended to such spaces until reaching the exit discharge.

At least one operable exterior window shall be provided in each dwelling unit with a minimum opening width of 3-1/2 inches.

Walls and floor assemblies separating dwelling units shall have tested fire resistance ratings of not less than 1-hour.

The base allowable building area specified in the OSSC for R occupancies in Types IllA and IIIB construction shall not exceed 12,000 square feet. Area increases in accordance with the OSSC are allowed.

All required egress stairs shall include access to the roof. Such access may be via any method listed in OSSC Chapter 10 for roof access.

All penetrations through the exterior wall covering will be fire-stopped at the exterior sheathing. "Penetrations" for purposes of this appeal includes elements such as conduits and piping and does not include "openings" such as doors, windows or wall-mounted HVAC units and louvers.

Ducts and vents penetrating exterior walls shall be 26 gage minimum.

No unprotected penetrations are permitted through the underside of fire-rated exterior wall projections that are required to be rated, including cornices, eaves, bays, exterior balconies, and similar projections extending beyond the exterior wall.

Elevator hoistways opening directly into corridors shall be pressurized or have smoke-tight protection as required for doors opening into fire-resistive corridors.

Framing connections at walls, floors, ceilings, roofs, and with the proposed exterior wall will be constructed as specified in the detail drawings numbered O - 19 contained in the City of Portland Code Guide OSSC/6/#4, unless greater fire resistance is provided, except that no sacrificial stud will be provided. 2-hour rated walls will be provided at these conditions. Conditions not covered in the guide will be constructed in accordance with the OSSC

The attached white paper provides the fire analysis that supports the use of mineral wool (aka Rock Wool) insulation in the wall cavity of untreated wood stud framing as an alternate to FRT wood stud framing permitted by the OSSC section 602.3. The analysis is based on published temperature data from full scale testing of multiple configurations of fire rated stud walls. The assemblies tested included 1 hour and 2 hour rated assemblies, with and without insulation, insulations included fiberglass and Rock wool types.

The analysis incorporates test data with the fire science fundamentals of gypsum calcification, pyrolysis of wood, and thermal conductivity of materials, accepted by the Society of Fire Protection Engineers, The National Bureau of Standards, and the American Wood Council. These are the accepted industry standards for this type of analysis.

The appeal includes additional conditions requested by the City of Portland. The equivalency analysis included in the white paper is a straight comparison between untreated wood and FRT wood framed wall assemblies, without any benefit from these additional conditions. The analysis documented in the attached white paper concludes that untreated wood framed walls with mineral wool insulation will outperform FRT wood framed walls without such insulation.

Therefore, we are very confident that the performance of mineral wool filled wood stud framed walls with these 16 additional conditions will far exceed the code intent of FRT wood framing.
Hence, we urge you to approve this appeal request.

602.3 1014 OSSC

Oregon Structural Specialty Code, OSSC 602.3 Type III
Type III construction is that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code. Fire-retardant-treated wood framing complying with Section 2033.2 shall be permitted within exterior wall assemblies of a 2-hour rating or less.

The building is a 5/1 using the prescriptive method of the 2014 OSSC. The building is a Type III-B over a Type I-A. The building is a mix of stucco, metal panel and brick. The brick requires steel angles to support the brick at each floor line and over openings. Structurally the lintel cannot be attached through gypsum sheathing and must extend above and below the lintel an incremental distance to prevent crushing and provide for minimum nailing patterns to attach the wood sheathing to the wood framing. We propose to install 5/8” FR wood sheathing from the floor lintel down to the top of window, approximately 16”, to prevent crushing and provide proper nailing. This sheathing would only occur behind the brick veneer, which while not considered as part of the 2-hr Exterior Wall will provide significantly more fire protection than the 5/8” gypsum sheathing that would have been there, 120 minutes for 3.625” of hollow brick for the brick alone versus 40 minute for gypsum. The detail would be used on all elevations of the building. The interior side is unchanged utilizing a full UL tested 1-hr floor ceiling assembly and a minimum / full block of 6x12 wood at the floor – wall condition providing an additional 1-hour of protection. The 6x12 ledger/blocking will always be present at this condition, i.e whether joists are parallel or perpendicular, as it is also required for attachment of the ledger angle, see exhibit A detail. The wood sheeting runs below the ledger to the top of window to prevent crushing when the angle twists, however, this small section of ~2” wood sheathing below the protection of the brick is considered part of the window opening as the exposed horizontal 2x framing members are sacrificial to the structural integrity of the overall building.

Type III B construction allows wood sheathing/framing on the exterior 2-hr Walls provided the material is FR treated. This building is also seeking an appeal to use rock wool insulation in the wall cavity in lieu of using FRT lumber framing. The FRT lumber plywood is proposed to be used only behind the brick ledger angle & up to the floor line. See Exhibits A& B.

The building north elevation does have a condition where the exterior will need to be rated. This project is also seeking an appeal to approve this condition. Please reference all appeals submitted by Samir Mokashi of Code Unlimited at this time for this particular project. The interior side is not proposed to be changed and will provide 2-hour protection. The exterior side will only have FR wood sheathing behind the locations of the brick which will provide 2-hour protection, as a finish, on its own with at least 15 additional minutes from wood sheathing (value if for non-FR so the value is at least this number). We believe since the FR wood sheathing will only be behind a 2-hour finish and the interior remains unchanged at 2-hour that the condition is equivalent to the intent of the OSSC.

716 2014 OSSC

Oregon Structural Specialty Code, OSSC 716.6.7.2
716.6.7.2 Area Limitations. The total area of the glazing in fire-protection-rated windows assemblies shall not exceed 25 percent of the area of a common wall with any room.

Propose to utilize up to 49% common wall ratio (ratio INCLUDEs the full area of the glazed door as part of the glass to wall ratio) from 6th Floor Club room to Corridor. Glazing system will be a glass partition system (frame & glass) with additional sprinkler coverage on both sides of glass in a 30 minute fire partition/corridor wall. (See Exhibits A & B).

The function of this room, i.e. Club Room, is to provide visual connection to the exterior common space providing as much transparency between spaces as is possible yet maintaining fire & life safety. The transparency enables the space to feel larger by visually including the corridor and exterior space as well as bringing additional natural light into this space. These features further enhances current and prospective building residents’ perceptions of the building while also keeping these spaces energetic, active, naturally lit, and connected the outdoors.

703.3 2014 OSSC

703.3 Alternative methods for determining fire resistance. The application of any of the alternative methods listed in this section shall be based on fire exposure and acceptance criteria specified in ASTME 199 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.

Fire-resistance designs documented in sources.
Prescriptive designs of fire-resistance-rated building elements, components or assemblies as prescribed in section 720.
Calculations in accordance with section 721.
Engineering analysis based on comparison of building element, component or assemblies designs having fire-resistance ratings as determined by the test procedures set forth in ASTME 119 or UL 263.
Alternative protection methods as allowed by section 104.11.

The proposed project is a new multi-family residential development located at the intersection of NW 17th and NW Kearney Street. Construction is fully sprinkled (NFPA 13) with 5 stories of Type III-A over 1 story of Type I-A.
The proposed floor/ceiling assembly at corridors (see exhibit A), includes the following layers from top to bottom:

1. 1” self-leveling underlayment
2. 7/8” APA rated wood sheathing (subfloor)
3. 3x T&G laminated lumber decking
4. A non-rated suspended gypsum ceiling will also be provided below the above mentioned rated floor assembly

Per the American Wood Council Technical Report 10-2014, Wood chars at a generally accepted rate of 1 ½” inches per hour and this char rate is assumed to be a constant rate (see Exhibit B). As such the 3x laminated wood decking (2 1/2” actual depth) will be reduced to a 1” depth after one hour of fire exposure per ASTM E-119. The reduced floor assembly would then consist of:

1. 1” self-leveling underlayment
2. 7/8” APA rated wood sheathing (subfloor)
3. 3x T&G laminated lumber decking reduced to 1” actual depth

The structural engineer has confirmed that the reduced floor assembly would still support the design load with a loss of 1 ½” of section depth. (See Exhibit C).

The alternate design is required in order to provide:
• The clearance needed for installation of mechanical, electrical, plumbing, and fire suppression systems.
• The corridor ceiling height necessary for the owner’s program.
• A finished non-rated suspended ceiling assembly within the corridor.