ASTM_D_7746_-_21.pdf

Designation:D774621Standard Practice forCalculating the Superimposed Load on Wood-frame Floor-Ceiling Assemblies for Standard Fire-Resistance Tests1This standard is issued under the fixed designation D7746;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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 thesuperimposed load required to be applied to load-bearingwood-frame floor-ceiling assemblies throughout standard fire-resistance tests.1.2 These calculations determine the maximum superim-posed load to be applied to the floor-ceiling assembly duringthe fire resistance test.The maximum superimposed load,calculated in accordance with nationally-recognized structuraldesign criteria,shall be designed to induce the maximumallowable stress in the wood floor-ceiling fire test configurationbeing tested.1.3 This practice is only applicable to those wood-framefloor-ceiling assemblies for which the nationally recognizedstructural design criteria are contained in the National DesignSpecification for Wood Construction(NDS).1.4 The text of this standard references notes and footnoteswhich provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.1.5 The values stated in inch-pound units are to be regardedas standard.No other units of measurement are included in thisstandard.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 standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD6513 Practice for Calculating the Superimposed Load onWood-frame Walls for Standard Fire-Resistance TestsE119 Test Methods for Fire Tests of Building Constructionand MaterialsE176 Terminology of Fire StandardsE1529 Test Methods for Determining Effects of Large Hy-drocarbon Pool Fires on Structural Members and Assem-blies2.2 Other Standards:3ANSI/AWC National Design Specification(NDS)for WoodConstructionNDS Supplement Design Values for Wood Construction3.Terminology3.1 DefinitionsDefinitions used in this practice are inaccordance with Terminology D9 and Terminology E176,unless otherwise indicated.3.2 Definitions of Terms Specific to This Standard:3.2.1 gross cross-sectional area,nsection area calcu-lated from overall actual dimensions of member.3.2.1.1 DiscussionFor sawn lumber and glue laminatedtimber,gross cross-sectional area is based on the standarddressed size of the member as given in the NDS Supplement.For I-joists and structural composite lumber,the gross cross-sectional areas or product dimensions are given in the productliterature or code evaluation report.3.2.2 net section area,nsection area calculated by deduct-ing from the gross cross-sectional area the projected area of allmaterials removed by boring,grooving,dapping,notching,orother means.1This practice is under the jurisdiction of ASTM Committee D07 on Wood andis the direct responsibility of Subcommittee D07.05 on Wood Assemblies.Current edition approved July 1,2021.Published August 2016.Originalapproved in 2011.Last previous edition approved in 2016 as D774611(2016).DOI:10.1520/D7746-21.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American Wood Council(AWC),222 Catoctin Circle SE,Suite201,Leesburg,VA 20175,http:/www.awc.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.2.2.1 DiscussionFor nailed or screwed connections,thenet section area equals the gross cross-sectional area.3.2.3 span of member,ndistance from face to face ofsupports,plus half of the required bearing length at each end.3.2.4 superimposed load,nadditional external loadneeded to be applied to the assembly duri