2001 ASD Supplements - unprotected PDF - American Wood Council

ASD STRUCTURAL LUMBER SUPPLEMENTL-27and:where:e TE∆T = T −T oT = temperature at which the new dimension is-60°F ≤ T o≤ 130°Fcomputed (°F)= coefficient of thermal expansion (in./in./°F)The coefficient of thermal expansion of oven-drywood parallel to grain ranges from about 1.7x10 -6 to2.5x10 -6 per °F.The linear expansion coefficients across the grain (radialand tangential) are proportional to wood density.These coefficients are about five to ten times greater thanthe parallel-to-the-grain coefficients and are given as:Radial:−6( ) ⎤( )eTE= ⎡⎣18 G + 5.5⎦10 in./in./ ° FTangential:−6( ) ⎤( )eTE= ⎡⎣18 G + 10.2⎦10 in./in./ ° Fwhere:G is the tabulated specific gravity for the species.6Table 6.1Coefficient of Moisture Expansion, e ME, and Fiber Saturation Point,(FSP) for Solid WoodsRadial Tangential Volumetric FSPSpecies (in./in./%) (in./in./%) (in. 3 /in. 3 /%) (%)Alaska Cedar 0.0010 0.0021 0.0033 28Douglas Fir-Larch 0.0018 0.0033 0.0050 28Englemann Spruce 0.0013 0.0024 0.0037 30Redwood 0.0012 0.0022 0.0032 22Red Oak 0.0017 0.0038 0.0063 30Southern Pine 0.0020 0.0030 0.0047 26Western Hemlock 0.0015 0.0028 0.0044 28Yellow Poplar 0.0015 0.0026 0.0041 31e MEOTHER CONSIDERATIONS6.3 Fire AssembliesBuilding Code RequirementsFor occupancies such as stores, apartments, offices,and other commercial and industrial uses, building codescommonly require floor/ceiling and wall assemblies to befire-resistance rated in accordance with standard fire tests.Depending on the application, wall assemblies mayneed to be rated either from one side or both sides. Forspecific exterior wall applications, the 2000 InternationalBuilding Code (IBC), the 1999 National Building Code(NBC), and the 1999 Standard Building Code (SBC) allowwood-frame, wood-sided walls to be tested for exposureto fire from the inside only. Rating for both interiorand exterior exposure is only required when the wall hasa fire separation distance of less than 5 feet. Code recog-nition of one- and two-hour wood-frame wall systems isalso predicated on successful fire and hose stream testingin accordance with ASTM E119, Standard Test Methodsfor Fire Tests of Building Construction Materials.Fire Tested AssembliesFire-rated wood-frame assemblies can be found in anumber of sources including the IBC, Underwriters Laboratories(UL) Fire Resistance Directory, Intertek TestingServices’ Directory of Listed Products, and the GypsumAssociation’s Fire Resistance Design Manual. The AmericanForest & Paper Association (AF&PA) and its membershave tested a number of wood-frame fire-ratedAMERICAN FOREST & PAPER ASSOCIATION