1、Designation:D3746/D3746M85(Reapproved 2015)1Standard 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
2、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.1NOTEUnits information was editorially corrected in November 2015.1.Scope1.1 This test method covers the determination of the
3、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 equiv
4、alents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith 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
5、standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specificprecautionary statements,see Section 6.2.Referenced Documents2.1 ASTM Standards:2D2829 Practice for Sampling and Analysis of ExistingBuilt-Up Roof System
6、s3.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
7、 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 T
8、his 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 6
9、10-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 maintainconstan
10、t 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
11、 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
12、 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
13、 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 Nov.1,2015.Published December 2015.Originallyapproved in 1978.Last
14、previous edition approved in 2008 as D3746 85(2008).DOI:10.1520/D3746_D3746M-85R15E01.2For 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
15、 onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Sampling7.1 Field SamplesCut test specimens directly from anactual roof,following the instructions in 8.1.Package eachspecimen separately in a sealed plastic bag.7.2 La
16、boratory Samples:7.2.1 Condition all components at 50 6 5%relative hu-midity and 25 6 1C 77 6 2F for 24 h prior to constructingthe sample membrane.7.2.2 Prepare sample membranes at least 0.90 by 1.20 m 3by 4 ft as required by the roofing system specification beingtested,including insulation and top surfacing.The quantity ofmaterial in each layer of the membrane shall be within 10%ofthat specified and the entire sample shall be within 5%.8.Test Specimens8.1 Test specimens may be taken directly fr
