ASTM_C_1178_-_C_1178M_-_13.pdf

Designation:C1178/C1178M13Standard Specification forCoated Glass Mat Water-Resistant Gypsum Backing Panel1This standard is issued under the fixed designation C1178/C1178M;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.1.Scope*1.1 This specification covers coated glass mat water-resistant gypsum backing panel designed for use on ceilingsand walls in bath and shower areas as a base for the applicationof ceramic or plastic tile.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.Within the text,the SI units are shown inbrackets.1.3 The text of this 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:2C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsC22 Specification for GypsumC473 Test Methods for Physical Testing of Gypsum PanelProductsC645 Specification for Nonstructural Steel Framing Mem-bersC1264 Specification for Sampling,Inspection,Rejection,Certification,Packaging,Marking,Shipping,Handling,and Storage of Gypsum Panel ProductsE119 Test Methods for Fire Tests of Building Constructionand Materials3.Terminology3.1 Definitions shall be in accordance with TerminologyC11.3.2 Definitions of Terms Specific to This Standard:3.2.1 glass mat,na mat of glass fibers with or without abinder.3.2.2 edge,nthe bound edge as manufactured.3.2.3 face,nthe coated surface.3.2.4 nominal thickness,nthe manufacturer-stated frac-tional value of thickness of the gypsum panel product ex-pressed in decimal value to the nearest one-thousandth(0.001)of an inch.4.Materials and Manufacture4.1 Coated glass mat water-resistant gypsum backing panelshall consist of a noncombustible water-resistant core,essen-tially gypsum complying with Specification C22,surfaced withglass mat,partially or completely embedded in the core,andwith a water-resistant coating on one surface.4.2 Coated glass mat water-resistant gypsum panels,type X(special fire-resistant)designates glass mat gypsum panelscomplying with this specification that provide not less than 1-hfire resistance rating for boards58in.15.9 mm thick or34-hfire resistance rating for panels12in.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,178in.48-mm long,0.0915 in.2.3 mm diameter shank,14in.6.4 mm diameter heads,spaced 7 in.178 mm on centerwith glass mat gypsum panel joints staggered 16 in.406 mmon each side of the partition and tested in accordance with TestMethods E119.NOTE1Consult manufacturers for independent test data on assemblydetails and fire resistance ratings for other types of construction.See firetest reports or listings from recognized fire testing laboratories forassembly particulars,materials,and ratings.5.Physical Properties5.1 Specimens shall be taken from the samples obtained inaccordance with Specification C1264.5.2 Specimens shall be tested in accordance with TestMethods C473.1This specification is 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 Oct.1,2013.Published October 2013.Originallyapproved in 1991.Last previous edition approved in 2011 as C1178/C1178M 11.DOI:10.1520/C1178_C1178M-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 5.2.1 Flexural StrengthThe specimens shall be tested faceup and face down.The average breaking load shall not be lessthan the following:Method BLoad,lbf NThickness,in.mmBearing edges perpendicularto the board edgeBearing edges parallelto the board edge146.450 22240 1785167.965 28950 2221212.7100 44580 3565815.9140 623100 4455.2.2 Humidified DeflectionSpecimens shall have an av-erage deflection of not more than the following:Thickness,in.mmHumidified deflection,eighths of an in.mm146.4not required5167.9not required1212.72 65815.91 35.2.3 Core,End and Edge HardnessSpecimens shall havean average hardness of not less than 15 l