Part III — Building Planning and Construction

1 Part III Building Planning and ConstructionCHAPTER 3 Building PLANNINGSECTION R301 DESIGN and structures, and all parts thereof,shall be constructed to safely support all loads, including deadloads, live loads, roof loads, flood loads, snow loads, windloads and seismic loads as prescribed by this code. The con-struction of buildings and structures shall result in a system thatprovides a complete load path capable of transferring all loadsfrom their point of origin through the load-resisting elements tothe Alternative an alternative to therequirements in Section the following standards arepermitted subject to the limitations of this code and the limi-tations therein. Where engineered design is used in conjunc-tion with these standards the design shall comply with theNorth CarolinaBuilding American Forest and Paper Association (AF&PA)Wood Frame Construction Manual(WFCM).

2 2. American Iron and Steel Institute (AISI),Standardfor Cold-Formed Steel Framing PrescriptiveMethod for One- and Two-family Dwellings(COFS/PM). Construction requirements of thiscode are based on platform and balloon-frame constructionfor light-frame buildings. The requirements for concreteand masonry buildings are based on a balloon framing sys-tem. Other framing systems must have equivalent detailingto ensure force transfer, continuity and compatible Engineered a Building of other-wise conventional Construction contains structural elementsexceeding the limits of Section R301 or otherwise, not con-forming to this code, these elements shall be designed in ac-cordance with accepted engineering practice.

3 The extent ofsuch design need only demonstrate compliance ofnonconventional elements with other applicable provisionsand shall be compatible with the performance of the conven-tional framed system. Engineered design in accordancewith the North CarolinaBuilding Code is permitted for allbuildings and structures, and parts thereof, included in thescope of this code.[B] Climatic and geographic design shall be constructed in accordance with the provisions ofthis code as limited by the provisions of this section. Additionalcriteria shall be established by the local jurisdiction and setforth in Table (1). Wind and portions thereofshall be limited by wind speed, as defined in (1), and Construction methods in accordance withthis code.

4 Basic wind speeds shall be determined from Fig-ure (4). Where different Construction methods andstructural materials are used for various portions of a build-ing, the applicable requirements of this section for each por-tion shall apply. Where loads for windows, skylights andexterior doors are not otherwise specified, the loads listed inTable (2) adjusted for height and exposure per (3), shall be used to determine design load perfor-mance requirements for windows and Design in regionswhere the basic wind speeds from Figure (4)equal or exceed 110 miles per hour ( km/h) shall bedesigned in accordance with one of the following:1. American Forest and Paper Association (AF&PA)Wood Frame Construction Manual for One- andTwo-Family Dwellings(WFCM); Building Code Congress InternationalStandard for Hurricane Resistant ResidentialConstruction(SSTD 10); Design Loads for Buildings and OtherStructures(ASCE-7); or4.

5 American Iron and Steel Institute (AISI),Standardfor Cold-Formed Steel Framing PrescriptiveMethod for One- and Two-family Dwellings(COFS/PM).5. Concrete Construction shall be designed in accor-dance with the provisions of this wind Chapters 44 and Internal in buildings lo-cated in windborne debris regions shall have glazedopenings protected from windborne debris or the build-ing shall be designed as a partially enclosed Building inaccordance with the North CarolinaBuilding opening protection for windborne debris shallmeet the requirements of the Large Missile Test ofASTM E 1996 and of ASTM E 1886 referenced :Wood structural panels with a minimumthickness of7/16inch ( mm) and a maximum spanof 8 feet (2438 mm) shall be permitted for openingprotection in one- and two-story buildings.

6 Panelsshall be precut to cover the glazed openings with at-tachment hardware provided. Attachments shall beprovided in accordance with Table orshall be designed to resist the components and clad-ding loads determined in accordance with the provi-sions of theInternational Building NORTH CAROLINA RESIDENTIAL CODE13 TABLE DEBRIS PROTECTION FASTENING SCHEDULEFOR WOOD STRUCTURAL PANELSa,b,cFASTENERTYPEFASTENER SPACINGP anel span4 foot4 footpanel span6 foot6 footpanel span8 foot21/2 #6 Wood screws16 12 9 21/2 #8 Wood screws16 16 12 For SI: 1 inch = mm, 1 foot = mm, 1 pound = kg,1 mile per hour = This table is based on 130 mph wind speeds and a 33-foot mean roof Fasteners shall be installed at opposing ends of the wood structural Where screws are attached to masonry or masonry/stucco, they shall be at-tached utilizing vibration-resistant anchors having a minimum ultimatewithdrawal capacity of 490 Wind speed referenceddocuments are based on fastest mile wind speeds, thethree second gust wind velocities of Figure (4)

7 Shall be converted to fastest mile wind velocities usingTable Exposure each wind directionconsidered, an exposure category that adequately re-flects the characteristics of ground surface irregularitiesshall be determined for the site at which the Building orstructure is to be constructed. For a site located in thetransition zone between categories, the category result-ing in the largest wind forces shall apply. Account shallbe taken of variations in ground surface roughness thatarise from natural topography and vegetation as well asfrom constructed features. For any given wind direction,the exposure in which a specific Building or other struc-ture is sited shall be assessed as being one of the follow-ing categories:1.

8 Exposure A. Large city centers with at least 50 per-cent of the buildings having a height in excess of70 feet (21 336 mm). Use of this exposure categoryshall be limited to those areas for which terrain rep-resentative of Exposure A prevails in the upwinddirection for a distance of at least mile ( km)or 10 times the height of the Building or other struc-ture, whichever is greater. Possible channeling ef-fects or increased velocity pressures due to thebuilding or structure being located in the wake ofadjacent buildings shall be taken into Exposure B. Urban and suburban areas, woodedareas, or other terrain with numerous closelyspaced obstructions having the size of single-fam-ily dwellings or larger.

9 Exposure B shall be as-sumed unless the site meets the definition ofanother type Exposure C. Open terrain with scattered obstruc-tions, including surface undulations or other irreg-ularities, having heights generally less than 30 feet(9144 mm) extending more than 1,500 feet (457m) from the Building site in any quadrant. This ex-posure shall also apply to any Building locatedwithin Exposure B type terrain where the buildingis directly adjacent to open areas of Exposure Ctype terrain in any quadrant for a distance of morethan 600 feet (183 m). This category includes flatopen country, grasslands and shorelines in hurri-cane prone Exposure D. Flat, unobstructed areas exposed towind flowing over open water (excluding shore-lines in hurricane prone regions) for a distance of atleast 1 mile ( km).

10 Shorelines in Exposure Dinclude inland waterways, the Great Lakes andcoastal areas of California, Oregon, Washingtonand Alaska. This exposure shall apply only tothose buildings and other structures exposed to thewind coming from over the water. Exposure D ex-tends inland from the shoreline a distance of 1,500feet (457 m) or 10 times the height of the buildingor structure, whichever is NORTH CAROLINA RESIDENTIAL CODEBUILDING PLANNINGTABLE (1)CLIMATIC AND GEOGRAPHIC DESIGN CRITERIAROOFLOADWINDSPEED(mph)SEISMICDES IGNCATEGORYSUBJECT TO DAMAGE FROMWINTERDESIGNTEMPICE SHIELDUNDER-LAYMENTREQUIREDFLOODHAZARDbA IRFREEZINGINDEXMEANANNUALTEMPW eatheringaFrost (4) (2)Moderate12"Moderate -HeavyModerateLocalLocalLocalLocalLocalF or SI: 1 pound per square foot = kN/m2, 1 mile per hour = may require a higher strength concrete or grade of masonry than necessary to satisfy the structural requirements of this code.