1、Designation:C 931/C 931M 04e1Standard Specification forExterior Gypsum Soffit Board1This standard is issued under the fixed designation C 931/C 931M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number i
2、n parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEThe word rating(s)was added to the term fire resistance throughout ed
3、itorially October 2004.1.Scope*1.1 This specification covers exterior gypsum soffit board,designed to be used for exterior soffits and carport ceilings thatare completely protected from contact with liquid water.NOTE1Specification C 840 contains application procedures for exte-rior gypsum soffit boa
4、rd.1.2 The values stated in either inch-pound units or SI(metric)are to be regarded separately as the standard.Withinthe text,the SI units are shown in brackets.The values statedin each system shall be used independently of the other.Valuesfrom the two systems shall not be combined.1.3 The text of t
5、his standard references notes and footnotesthat provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.2.Referenced Documents2.1 ASTM Standards:2C 11 Terminology Relating to Gypsum and Related Build-ing Mate
6、rials and SystemsC 473 Test Methods for Physical Testing of Gypsum PanelProductsC 645 Specification for Nonstructural Steel Framing Mem-bersC 840 Specification for Application and Finishing of Gyp-sum BoardC 1264 Specification for Sampling,Inspection,Rejection,Certification,Packaging,Marking,Shippin
7、g,Handling,and Storage of Gypsum BoardE 84 Test Method for Surface Burning Characteristics ofBuilding MaterialsE 119 Test Methods for Fire Tests of Building Constructionand Materials3.Terminology3.1 Definitions of terms shall be in accordance with Termi-nology C 11.4.Materials and Manufacture4.1 Gyp
8、sum soffit board shall consist of a noncombustiblecore,essentially gypsum,surfaced with paper bonded to thecore.4.2 Exterior gypsum soffit board,type X(special fire-resistant)designates exterior gypsum soffit board complyingwith this specification that provides not less than 1-h fireresistance ratin
9、g for boards58-in.(15.9-mm)thick or34-h fireresistance rating for boards12-in.(12.7-mm)thick,appliedparallel with and on each side of load bearing 2 by 4 woodstuds spaced 16 in.(406 mm)on center with 6d coated nails,178-in.(48-mm)long,0.0915-in.(2.3-mm)diameter shank,14-in.(6.4-mm)diameter heads,spa
10、ced 7 in.(178 mm)oncenter with exterior gypsum soffit board joints staggered 16 in.(406 mm)on each side of the partition and tested in accordancewith Test Methods E 119.NOTE2Consult producers for independent test data on assemblydetails and fire resistance ratings for other types of construction.See
11、 testreports or listings from recognized fire testing laboratories for assemblyparticulars,materials,and ratings.4.3 Gypsum soffit board shall have a flame spread index ofnot more than 25 when tested in accordance with the require-ments of Test Method E 84.5.Physical Properties5.1 Specimens shall be
12、 taken from samples obtained inaccordance with Specification C 1264.5.2 Specimens shall be test in accordance with Test MethodsC 473.5.2.1 Flexural Strength:5.2.1.1 The specimens shall be tested face up and facedown.The average breaking load shall be not less than thefollowing:1This specification is
13、 under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and Systems and is the direct responsibilityof Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.Current edition approved Jan.1,2004.Published January 2004.Originallyapproved in 1980.Last p
14、revious edition approved in 2003 as C 931/C 931M 03.2For 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.1*A Summary of
15、 Changes section appears at the end of this standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.NOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the
16、 latest information Method AMethod BThickness,in.(mm)Load,lbf(N)Bearing EdgesAcross Fiberof SurfacingLoad,lbf(N)Bearing EdgesParallel toFiber ofSurfacingLoad,lbf(N)Bearing EdgesAcross Fiberof SurfacingLoad,lbf(N)Bearing EdgesParallel toFiber ofSurfacing12(12.7)110(489)40(178)107(476)36(160)58(15.9)150(668)50(222)147(654)46(205)5.2.2 Humidified Deflection:5.2.2.1 The specimens shall have an average deflection ofnot more than the following:Thickness,in.(mm)Humidified Deflection,Eighths of an in.(m
