ASTM_C_318_-_C_318M_-_13.pdf

Designation:C318/C318M13Standard Specification forGypsum Formboard1This standard is issued under the fixed designation C318/C318M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1.Scope*1.1 This specification covers the minimum requirements forgypsum formboard designed for use as a permanent form forpoured-in-place reinforced gypsum concrete roof decks.1.2 The values stated in either inch-pound units or SI(metric)are to be regarded separately as standard.Within thetext,the SI units are shown in brackets.The values stated ineach system shall be used independent of the other.Valuesfrom the two systems shall not be combined.1.3 The text of this standard references notes which provideexplanatory material.These notes shall not be consideredrequirements of the standard.2.Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsC22 Specification for GypsumC473 Test Methods for Physical Testing of Gypsum PanelProductsC1264 Specification for Sampling,Inspection,Rejection,Certification,Packaging,Marking,Shipping,Handling,and Storage of Gypsum Panel ProductsG21 Practice for Determining Resistance of Synthetic Poly-meric Materials to Fungi3.Terminology3.1 DefinitionsDefinitions of terms used in this standardshall be in accordance with Terminology C11.4.Materials and Manufacture4.1 Gypsum formboard shall consist of a noncombustiblecore,essentially gypsum complying with Specification C22,containing not more than 15%by weight of fiber,eithermineral or organic,synthetic or natural.4.2 The face surface shall be specifically treated to resistfungus growth.5.Physical Properties5.1 Specimens shall be tested in accordance with TestMethods C473.NOTE1Since this product is laid between subpurlins without me-chanical attachment,a nail pull requirement is not specified for thisgypsum panel product.5.1.1 Specimens shall be taken from the samples obtained inaccordance with Specification C1264.5.1.2 Flexural StrengthThe specimens shall be tested faceup and face down.The average breaking load shall be not lessthan the following:Bearing Edges AcrossFiber of Surfacing,lbf NBearing Edges Par-allel Fiber of Sur-facing,Face,lbf NBearing Edges Par-allel Fiber of Sur-facing,Back,lbf NMethod A160 71560 27040 180Method B157 70056 25036 1605.1.3 Humidified DeflectionThe specimens shall have anaverage deflection of not more than the following:Thickness,in.(mm)Humidified Deflection,Eighths of an in.(mm)1212.710 325.1.4 Core,End,and Edge HardnessThe specimens shallhave an average hardness of 15 lbf 65 N when tested byMethod A and 11 lbf 50 N when tested by Method B.5.1.5 Resistance to FungiThe specimens shall obtain arating not more than 1(one)when judged in accordance withPractice G21,paragraph 9.3,(Observation for Visible Effects).6.Dimensions and Tolerances6.1 Specimens shall be taken from the samples obtained inaccordance with Section 8.6.2 Thickness,width,length,and end squareness shall bedetermined in accordance with Test Methods C473.6.2.1 ThicknessThe nominal thickness shall be12in.12.7mm with tolerances in the nominal thickness of 6164in.0.4mm with local variations of 6132in.0.8 mm from thenominal thickness.1This specification is under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and Systems and is the direct responsibilityof Subcommittee C11.01Specifications and Test Methods for Gypsum Products.Current edition approved Oct.1,2013.Published October 2013.Originallyapproved in 1953.Last previous edition approved in 2010 as C318/C318M 00(2010).DOI:10.1520/C0318_C0318M-13.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2.2 WidthThe nominal width shall be 32 in.813 mmwith a tolerance of18in.3 mm over the specified width,and14in.6 mm under the specified width.6.2.3 LengthThe nominal length of gypsum formboardshall conform to the purlin spacing of multiples thereof,withtolerances of 614in.6 mm from the nominal length.6.2.4 End SquarenessCorners shall be square with atolerance of 618in.63 mm in the full width of the board.6.3 Edges and EndsThe edges and ends shall be square(90 6 10),straight,and solid.7.Finish and Appearance7.1 The surfaces of gypsum formboard shall be true and freefrom imperfections that would render it unfit for use with orwithout decoration.8.Sampling,Inspectio