R301.3 CODE CHANGE PROPOSAL FORM (See instructions on page 2) Code: IRC–12/13 Section R301.3 Proponent: Charles S. Bajnai, Chesterfield County, VA, ICC Building Code Action Committee Revise as follows: R301.3 Story height. The wind and seismic provisions of this code shall apply to buildings with story heights not exceeding the following: 1. For wood wall framing, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the laterally unsupported bearing wall stud height shall not exceed that permitted by Table R602.3(5) plus a height of floor framing not to exceed 16 inches (406 mm). Exception: For wood-framed wall buildings with bracing in accordance with Tables R602.10.3(1) and R602.10.3(3), the wall stud clear height used to determine the maximum permitted story height may be increased to 12 feet (3658 mm) without requiring an engineered design for the building wind and seismic force-resisting systems provided that the length of bracing required by Table R602.10.3(1) is increased by multiplying by a factor of 1.10 and the length of bracing required by Table R602.10.3(3) is increased by multiplying by a factor of 1.20. Wall studs are still subject to the requirements of this section. 2. For steel wall framing, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the a maximum unsupported bearing wall stud height shall not exceed of 10 feet (3048 mm), plus a height of floor framing not to exceed 16 inches (406 mm). 3. For masonry walls, the maximum story height shall not exceed 13 feet 7 inches (4140 mm) and the a maximum bearing wall clear height shall not exceed of 12 feet (3658 mm) plus a height of floor framing not to exceed 16 inches (406 mm). Exception: An additional 8 feet (2438 mm) of bearing wall clear height is permitted for gable end walls. 4. For insulating concrete form walls, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the maximum unsupported bearing wall height per story as permitted by Section R611 tables shall not exceed 10 feet (3048 mm) plus a height of floor framing not to exceed 16 inches (406 mm). 5. For structural insulated panel (SIP) walls, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the maximum bearing wall height per story as permitted by Section R613 tables shall not exceed 10 feet (3048 mm) plus a height of floor framing not to exceed 16 inches (406 mm). Individual walls or walls studs shall be permitted to exceed these limits as permitted by Chapter 6 provisions, provided story heights are not exceeded. Floor framing height shall be permitted to exceed these limits provided the story height does not exceed 11 feet 7 inches (3531 mm). An engineered design shall be provided for the wall or wall framing members when they exceed the limits of Chapter 6. Where the story height limits of this section are exceeded, the design of the building, or R301.3 the noncompliant portions thereof, to resist wind and seismic loads shall be in accordance with the International Building Code. Reason: This proposal is submitted by the ICC Building Code Action Committee (BCAC) The BCAC was established by the ICC Board of Directors to pursue opportunities to improve and enhance an assigned International Code or portion thereof. This includes both the technical aspects of the codes as well as the code content in terms of scope and application of referenced standards. Since its inception in July, 2011, the BCAC has held 6 open meetings and numerous workgroup calls which included members of the BCAC as well as any interested party to discuss and debate the proposed changes. Related documentation and reports are posted on the BCAC website at: http://www.iccsafe.org/cs/BCAC/Pages/default.aspx. The purpose of this proposal is to revise the story height limits. Proposal S100-06/07 introduced the 11’-7” story height limit into the IBC and IRC as an alternative to limiting the floor framing height to 16” where wall stud heights were less than 10’-0”. In the IBC this change was implemented directly into the equivalent provision under Section 2308 to Item #1 above. In the IRC, the exception was added to the paragraph following the five individual limits. This has led to confusion with Chapter 6 provisions including stud size/height and wall bracing. This revision relocates the story height limit to each of the individual material limits and coordinates it with the material-specific provisions. The current exception for wood wall studs is deleted as it is redundant with other provisions of Chapter 6 and not necessary. Table R602.3(5) covers when studs in non-bearing walls can exceed 10’-0”. Table R602.3.1 provides limited cases when studs in bearing walls can exceed 10’-0”. The wall bracing section provides adjustments to wind and seismic bracing amounts for heights up to 12’0”. It is not necessary to repeat that requirement here, in fact that could result in an accidental double-application of the increase factors. Finally, simply applying the wall bracing provisions for walls permitted to be 12’-0” high does not automatically address other structural concerns resulting from an overall increase in story height. This is why only the limited conditions in Table R602.3.1 are allowed for studs greater than 10’ in height and supporting floor or roof loads. Cost Impact: ???????????????