ASTM_D_3746_-_D_3746M_-_85_2022.pdf

Designation:D3746/D3746M85(Reapproved 2022)Standard Test Method forImpact Resistance of Bituminous Roofing Systems1This standard is issued under the fixed designation D3746/D3746M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the resis-tance of bituminous roofing systems to impact loads at anydesired temperature,with a missile of the weight,size,andshape specified herein.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 nonconformancewith the standard.1.3 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.For specific precautionary statements,see Section 6.1.4 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:2D2829/D2829M Practice for Sampling and Analysis of Ex-isting Built-Up Roof Systems3.Summary of Test Method3.1 This test method subjects 305 by 305-mm 12 by 12-in.specimens of a roofing system(insulation and membranecomplete with top surfacing)to a series of four impacts,one ineach quadrant,from a standard missile falling freely from apredetermined height with an impact energy of 30.0 J22 lbfft.Damage to the membrane is assessed by visualexamination of the felts after solvent extraction of the bitumen.3.2 The effect of specimen temperature on impact resistancecan be studied by running the test in an environmental chamberat any desired temperature.4.Significance and Use4.1 This test method provides a means of evaluating roofingsystems for resistance to impact loads of many kinds.It shouldalso be useful in developing performance criteria for roofingsystems.5.Apparatus5.1 Vertical Guide Tube,1.22 m 4.0 ft long by 60 mm238in.in inside diameter,suitably positioned over a 610-mm24-in.square,horizontal test table constructed of wood 2 by4s on edge,through-bolted and fitted with a centering jig toensure proper alignment of the specimen beneath the guidetube(see Fig.1).The guide tube is adjustable in height toaccommodate differing specimen thicknesses and maintainconstant missile impact energy.Provision is made at the top ofthe guide tube to support the missile during alignment of thespecimen,and for instantaneous release of the missile tofree-fall within the guide tube until contact is made with thespecimen.Gravel screens are attached to the edges of the testtable to retain any loose gravel that might fly from the impactarea.5.2 Missile(see Fig.2),consisting of a steel cylinder 50 mm2 in.in diameter by 150 mm 6 in.long,with a case-hardened hemispherical head.The mass of the missile isadjusted to 2.27 kg 5.0 lb by the addition of lead shot to acavity machined into the cylindrical portion and sealed with ascrew cap.6.Safety Precautions6.1 Employ suitable devices for eye protection when carry-ing out steps in 10.1 10.7.3.6.2 Use a fume hood when extracting specimens with 1,1,1trichloroethane or xylene in 10.7.3.Trichloroethane and xyleneare toxic and good ventilation should be provided.1This test method is under the jurisdiction ofASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.20 onRoofing Membrane Systems.Current edition approved May 1,2022.Published May 2022.Originallyapproved in 1978.Last previous edition approved in 2015 as D3746/D3746M 85(2015)1.DOI:10.1520/D3746_D3746M-85R22.2For 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.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.17.Sampling7.1 Field SamplesCut test specimens directly from anactual roof,followi