Appeal 14862

602 – Construction Classification

602.1 General.
Buildings and structures erected or to be erected, altered or extended in height or area shall be classified in one of the five construction types defined in Sections 602.2 through 602.5. The building elements shall have a fire-resistance rating not less than that specified in Table 601 and exterior walls shall have a fire-resistance rating not less than that specified in Table 602. Where required to have a fire-resistance rating in Table 601, building elements shall comply with the applicable provisions of Section 703.2. The protection of openings, ducts and air transfer openings in building elements shall not be required unless required by other provisions of this code.

602.2 Types I & II
Types I & II construction are those types of construction in which the building elements listed in Table 601 are of noncombustible materials, expect as permitted in Section 603 and elsewhere in this code.

From Table 601. Type IIB Construction
Primary structural frame – 0 Hr
Exterior bearing walls – 0 Hr
Interior bearing walls – 0 Hr
Exterior Nonbearing walls and partitions – 0 Hr
Interior Nonbearing walls and partitions – 0 Hr
Floor Construction and associated secondary members – 0 Hr
Roof Construction and associated secondary member – 0 Hr

The proposed design is to amend the existing construction classification from Type VA/IA to Type IIB/IA. The proposed building is built out of non-combustible materials; a combination of metal framing, metal decking, concrete. The proposed design contains three elements that would be considered deficiencies as a Type IIB building;

1.Stairs 1, 2 & 3.
Stairs 1 & 2 are wood constructed egress stairs, that are encased within a 2hr fire barrier shaft and directly egress to the ROW.
Stair 3 is a heavy timber, Glulam stair that connections the ground floor to the second floor only and is not part of the primary egress system.

2.Egress balcony on levels 2,3,4
A heavy timber constructed egress balcony, which was previously granted within an appeal to demonstrate at least 1 Hr fire resistance equivalency. Please refer to Appeal ID; 12743 Date: 11/18/15

3.Common Great Room Structure.
The common great room is located on the second floor, is only one story and is approximately 1262 SF. It is built utilizing heavy timber beams that are connected to non-combustible HSS columns with heavy timber roof framing consisting of 3x4 timber decking;
Beams, exposed only on one side (beams are shown as actual size)
6¾ x 19½ ”
All member would be considered as a 1 hour equivalent.

Please refer to g0.02a, g0.04 & g0.04 – Proposed, for the Type II-B code summary sheet and life safety egress plans. The existing code summary sheet and life safety egress plans have also been attached for convenience.

The building is currently under construction and was approved as a Type VA building, despite the fact that the building is constructed with metal framing above the Type I podium. The proposed design is requested per a correction notice from the inspector sighting the lack of continuity at the 1hr fire partitioned walls and 1hr load bearing walls within the rated ceiling assembly cavity as Type VA construction classification. The plans examiner noted that a detail for an appropriate alternative was required as per 704.3 & 708.4 that differs from the detail as designed and approved.

The installed metal joists are already load bearing and accomplishing the continuity requirements is unachievable. Subsequently, the Type IIB classification lends itself to this building’s actual construction method, given the decision to provide a more durable building and to build a Type VA building out of non-combustible materials.

The elements noted above which have been built out of combustible materials are either encased within a 2 hour fire barrier shaft, or demonstrate a at least a 1hr fire resistance equivalency as granted in a previous appeal or as noted above and provided for within the code for heavy timber members.

708.4 – Continuity

Fire partitions shall extend form the top of the foundation or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above or to the fire-resistance-rated floor/ceiling or roof/ceiling assembly above, and shall be securely attached thereto. In combustible construction where the fire partitions are not required to be continuous to the sheathing, deck or slab, the space between the ceiling and the sheathing, deck or slab above shall be fire-blocked or draft stopped in accordance with Sections 718.3 at the partition line. The supporting construction shall be protected to afford the required fire-resistance rating of the wall supported, except for walls separating tenant spaces in covered and open mall buildings, walls separating dwelling units, walls separating sleeping units and corridor walls, in buildings of Type IIB, IIB and VB construction.

The proposed design is to provide an alternate method for the continuation of individually encasing the 1hr fire partition that separates dwelling units, at the intersection of the horizontal assembly and wall. The alternate method to running type X gypsum board to the underside of the floor/roof decking is:

a. Demising Walls (1hr Fire Partitions); To continue the type X gypsum wall board of the interior wall assembly (UL 425) to the underside of the metal deck via fire taped and finished joint as best as possible, keying around the already installed metal C joists and infilling the rim track. Where the perpendicular C joist penetrates the wall assembly, 4” Semi-Rigid Mineral Wool Insulation will be securely fitted within the depth of the joist to provide continuity at the penetration. All penetrations through the membrane will be fire caulked in accordance with Section 714. Please refer to SKA 0.82a

The construction type is IIB. Walls to receive this detail are on the second, third and fourth floor, 1 hr fire partitions between individual unit dwellings. Please refer to g0.02, g0.04 & g0.05 – Proposed, for specific locations. Please also refer to 0.82a for a specific detail.

The proposed design is requested per a correction notice from the inspector sighting the lack of continuity at the 1hr fire partitioned walls within the ceiling assembly cavity. The plans examiner noted that a detail for an appropriate alternative was required as per 708.4.

The demising walls cannot be corrected with the continuous gypsum wall board layer to the underside of the metal decking since the structural rim joist is already taking loads from the floor decking and topping slab; correction would require removal of the rim joist. Due to this as-built condition, an alternative solution is required to provide continuity of the individual encasement to the demising wall

The proposed design provides equivalent fire protection for the encasement of the load bearing wall for the following reasons:

• Per consultation with a fire engineer the 4” Semi-Rigid Mineral Wool Insulation provides an equivalency to the encasement of at least a 1hr resistance.
• The semi-rigid mineral wool product specified is tested in accordance with UL 1479 for penetration firestop systems.
• All attempts are made to continue the gypsum wall board up to the metal deck as best as possible and to provide continuity through 4” Semi-Rigid Mineral Wool Insulation where the gypsum board cannot be installed.

711.4 Continuity

Assemblies shall be continuous without openings, penetrations or joints except as permitted by this section and Sections 712.1, 714.4, 715. 1009.3 and 1022.1. Skylights and other penetrations through a fire-resistance-rated roof deck or slab are permitted to be unprotected, provided that the structural integrity of the fire-resistance-rated roof assembly is maintained. Unprotected skylights shall not be permitted in roof assemblies required to be fire-resistance rated in accordance with Section 705.8.6. The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported.

The proposed design is to provide an alternate method for maintaining continuity of the 1 hr fire rated horizontal assemblies at the load bearing walls and interior non-rated wall partitions within the individual dwelling units. The alternate method to running the interior gypsum wall board to the underside of the metal joist is: To terminate the interior gypsum wall board of the wall assembly at the horizontal membrane of the fire rated/floor ceiling assembly (UL G551 & UL G553) via fire taped and finished joint, and to friction fit 4” Semi-Rigid Mineral Wool Insulation (mechanically fastened to maintain its position and durability) in line with the ceiling membrane, fit between at the O.C spacing between the vertical studs, and to be run continuously as possible. Where the horizontal assembly is at a different level, 2” of Semi-Rigid Mineral Wool Insulation will be installed continuously from the top track of the wall to the top of the lower horizontal membrane, to ensure fire protection is maintained.

The construction type is IIB. Horizontal assemblies to receive this detail are C-2 and C-6 (UL G551 & UL G553) where internal unit partitions interrupt the horizontal assembly on the second, third and fourth floor. Please refer to g0.02, g0.04 & g0.05 - Proposed attached key plan for specific locations. Please also refer to SKA 0.79-0.85 for specific details.

The proposed design is requested per a correction notice from the inspector sighting the lack of continuity at the horizontal assembly. The plans examiner noted that a detail for a load bearing wall and a non-load bearing partition wall penetration at the horizontal assembly for the condition was required in accordance with 711.4 – Continuity. The C-2 ceiling type rim joist, exterior wall and ceiling are installed per the approved structural and architectural drawings, and referenced test assemblies.

The load bearing walls and interior partition walls cannot be corrected with the continuous gypsum wall board layer to the underside of the metal joist as the ceiling grid and metal stud wall is already installed; correction would require removal of the significant ceiling grid and stud wall. Due to this as-built condition, an alternative solution is required to provide continuity of the fire rated horizontal assembly.

The proposed design provides equivalent fire protection at the wall to floor intersection joint without a fire tested assembly for the following reasons:

• Per consultation with a fire engineer and consistent with OSSC 711.4 Exception, the Semi-Rigid Mineral Wool Insulation provides an equivalency to a double wood top plate and continues protection of the horizontal assembly when interrupted.
• The semi-rigid mineral wool product specified is tested in accordance with UL 1479 for penetration firestop systems.
• Penetrations are allowed per ‘Section 714.4.1.2 Membrane Penetrations’, where penetrations of membranes that are a part of a horizontal assembly shall comply with Section 714.4.1.1.1 or 714.4.1.1.2. Section 714.4.1.2 - Exception 7 permits for the ceiling membrane of 1- and 2-hour fire-resistance-rated horizontal assemblies to be interrupted with double wood top plate of a fire-resistance-rated.

704.3 – Protection of the Primary Structural Frame Other Than Columns

Members of the primary structural frame other than columns that are required to have protection to achieve a fire-resistance rating and support more than two floors or one floor and roof, or support load-bearing wall or a non load-bearing wall more than two stories high, shall be provided individual encasement protection by protecting them on all side for the full length, including connections to other structural members, with materials having the required fire-resistance rating.

From Table 601. Type VA Construction interior bearing walls are required to be 1 hr rated.

As an alternate to appeal item #1, the proposed design is to provide an alternate method for the continuation of individually encasing the 1hr fire rated load bearing walls at the intersection of the horizontal assembly and wall. The alternate method to running type X gypsum board to the underside of the floor/roof decking is:

a. Interior Load Bearing Walls & Demising Walls (1hr Fire Partitions); To continue the type X gypsum wall board of the interior wall assembly (UL 425) to the underside of the metal deck via fire taped and finished joint as best as possible, keying around the already installed metal C joists and infilling the rim track. Where the perpendicular C joist penetrates the wall assembly, 4” Semi-Rigid Mineral Wool Insulation will be friction fitted within the depth of the joist to provide continuity at the penetration.

The construction type is VA. Walls to receive this detail are on the second, third and fourth floor, 1 hr fire rated, load-bearing, and located within individual unit dwellings or are located at demising walls between individual unit dwellings. Please refer to g0.02, g0.04 & g0.05 - Existing attached key plan for specific locations. Please also refer to SKA 0.79-0.87 for specific details.

The proposed design is requested per a correction notice from the inspector sighting the lack of individual protection to the load bearing walls within the ceiling assembly cavity. The plans examiner noted that a detail for an appropriate alternative encasement method for load bearing partition walls was required as per 704.3. The C-2 ceiling type rim joist, exterior wall and ceiling are installed per the approved structural and architectural drawings, and referenced test assemblies.

The interior load bearing walls cannot be corrected with the continuous gypsum wall board layer to the underside of the metal decking since the structural rim joist is already taking loads from the floor decking and topping slab; correction would require removal of the rim joist. Due to this as-built condition, an alternative solution is required to provide continuity of the individual encasement to the load bearing wall.

The proposed design provides equivalent fire protection for the encasement of the load bearing wall for the following reasons:

• Per consultation with a fire engineer the 4” Semi-Rigid Mineral Wool Insulation provides an equivalency to the encasement of at least a 1hr resistance.
• The semi-rigid mineral wool product specified is tested in accordance with UL 1479 for penetration firestop systems.
• Penetrations are allowed per ‘Section 714.4.1.2 Membrane Penetrations’, where penetrations of membranes that are a part of a horizontal assembly shall comply with Section 714.4.1.1.1 or 714.4.1.1.2. Section 714.4.1.2 - Exception 7 permits for the ceiling membrane of 1- and 2-hour fire-resistance-rated horizontal assemblies to be interrupted with double wood top plate of a fire-resistance-rated.