1、Designation:D684108Standard Practice forCalculating Design Value Treatment Adjustment Factors forFire-Retardant-Treated Lumber1This standard is issued under the fixed designation D6841;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,
2、the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers procedures for calculating treat-ment adjustment factors to be applied to design values fo
3、rfire-retardant-treated lumber used at ambient temperaturesservice temperatures up to 100F(38C)and as framing inroof systems.1.2 These design value treatment adjustment factors for theproperties of extreme fiber in bending,tension parallel to grain,compression parallel to grain,horizontal shear,and
4、modulus ofelasticity are based on the results of strength tests of matchedtreated and untreated small clear wood specimens after condi-tioning at nominal room temperatures 72F(22C)and ofother similar specimens after exposure at 150F(66C).Thetest data are developed in accordance with Test Method D566
5、4.Guidelines are provided for establishing adjustment factors forthe property of compression perpendicular to grain and forconnection design values.1.3 Treatment adjustment factors for roof framing applica-tions are based on computer generated thermal load profiles fornormal wood roof construction u
6、sed in a variety of climates asdefined by weather tapes of the American Society of Heating,RefrigeratingandAir-ConditioningEngineers,Inc.(ASHRAE).2The solar loads,moisture conditions,ventilationrates,and other parameters used in the computer model wereselected to represent typical sloped roof design
7、s.The thermalloads in this practice are applicable to roof slopes of 3 in 12 orsteeper,to roofs designed with vent areas and vent locationsconforming to national standards of practice and to designs inwhich the bottom side of the roof sheathing is exposed toventilation air.For designs that do not ha
8、ve one or more ofthese base-line features,the applicability of this practice needsto be documented by the user.1.4 The procedures of this practice parallel those given inPractice D6305.General references and commentary in Prac-tice D6305 are also applicable to this practice.1.5 The values stated in
9、inch-pound units are to be regardedas standard.The SI units listed in parentheses are provided forinformation only and are not considered standard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standa
10、rd to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D9 Terminology Relating to Wood and Wood-Based Prod-uctsD5664 Test Method for Evaluating the Effects of Fire-Retardant Treatments
11、 and Elevated Temperatures onStrength Properties of Fire-Retardant Treated LumberD6305 Practice for Calculating Bending Strength DesignAdjustment Factors for Fire-Retardant-Treated PlywoodRoof Sheathing3.Terminology3.1 Definitions:3.1.1 Definitions used in this practice are in accordance withTermino
12、logy D9.3.2 Definitions of Terms Specific to This Standard:3.2.1 bin mean temperature10F(5.5C)temperatureranges having mean temperatures of 105(41),115(46),125(52),135(57),145(63),155(68),165(74),175(79),and185F(85C).3.2.2 thermal load profilethe cumulative time per year ineach 10F(5.5C)temperature
13、bin.1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.Current edition approved Sept.1,2008.Published September 2008.Originallyapproved in 2002.Last previous edition approved in 2003 as D6841 03.DO
14、I:10.1520/D6841-08.2Available from American Society of Heating,Refrigerating,and Air-Conditioning Engineers,Inc.(ASHRAE),1791 Tullie Circle,NE,Atlanta,GA30329,http:/www.ashrae.org.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.Fo
15、r Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.Summary of Practice4.1 Test results developed in accordance with Test Meth
16、odD5664 are used in conjunction with computer generatedthermal load profiles to calculate treatment factors that areapplied to published design values for untreated lumber.Thesetreatment adjustment factors account for the combined effect offire-retardant-treatment and service temperatures.5.Significance and Use5.1 Fire-retardant-treatments are used to reduce the flame-spread characteristics of wood.Chemicals and redrying condi-tions employed in treatments are known to modify the strengthproperti