1、Designation: D3746/D3746M 85 (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
2、, 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.1NOTEUnits information was editorially corrected in November 2015.1. Scope1.1 This test method covers the determinat
3、ion 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
4、 be exact equivalents; 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
5、 of the user of this 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 Exis
6、tingBuilt-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 he
7、ight 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 temperatu
8、re.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 mm238 in. in inside d
9、iameter, 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 differi
10、ng 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 scre
11、ens 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.
12、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
13、in 10.7.3. Trichloroethane and xyleneare toxic and good ventilation should be provided.1This test method is under the jurisdiction of ASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.20 onRoofing Membrane Systems.Current edition approved Nov. 1, 201
14、5. Published December 2015. Originallyapproved in 1978. Last 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 ASTMStanda
15、rds 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 States17. Sampling7.1 Field SamplesCut test specimens directly from anactual roof, following the instruct
16、ions in 8.1. Package eachspecimen separately in a sealed plastic bag.7.2 Laboratory 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
17、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 from an actualroof
18、or cut from a laboratory-prepared sample using a 305 by305-mm 12 by 12-in. metal template as described in PracticeD2829 and shall include all of the aggregate and insulation inthe area of the specimen. Any loose aggregate must bedistributed evenly over the surface of the specimen prior totesting.NOT
19、E 1When the roofing system specimen contains roof insulation, itis recommended that a buffer strip be removed around the metal templatearea prior to removal of the specimen in order to reduce damage to theinsulation. The buffer zone should be a “V” type wedge extending to thebottom of the specimen t
20、hickness to be removed for testing. The inside topof the “V” wedge area should be the edge of the metal template. It isnormally 75 to 100 mm 3 to 4 in. wide. Pressure is normally applied tothe template to keep it from moving while cutting the “V” wedge.9. Conditioning9.1 Condition the apparatus and
21、all specimens at the desiredtemperature for a minimum of 8 h prior to testing.FIG. 1 Guide Tube, Test Table, and Centering JigFIG. 2 Steel MissileD3746/D3746M 85 (2015)1210. Procedure10.1 Place the test specimen in position beneath the guidetube so the missile will strike the center of one quadrant.
22、10.2 Place the missile in the top of the guide tube supportedby the instantaneous release mechanism.10.3 Adjust the height of the guide tube so the bottom of themissile is 1350 mm 53 in. above the surface of the specimenand lock the guide tube in position.10.4 Release the missile, allowing it to fal
23、l and strike thespecimen.10.5 Return the missile to its support in the top of the guidetube, and rotate the specimen 90 to center the second quadrantbeneath the guide tube.10.6 Repeat 10.4 and 10.5 until all four quadrants of thespecimen have been subjected to impact.10.7 Damage Assessment:10.7.1 Re
24、move any slag or gravel surfacing from thespecimen carefully with a hot scraper, such as a putty knife.10.7.2 Record the extent of obvious damage to themembrane, such as dents or fractures, by photograph or sketchand written description.10.7.3 Cut the four impact areas from the specimen using ahot k
25、nife. Staple the felts in each area together and extract thebitumen by immersing in warm 1,1,1 trichloroethane in a fumehood. Do not heat the trichloroethane to boiling. (For tarredfelt and pitch membranes, use xylene in place of trichloroeth-ane.)10.8 Rating of Impact Damage:10.8.1 Rate the impact
26、damage which occurs in each ply ineach of the four quadrants by assigning the number which mostaccurately describes the impact damage, as follows:0 = no damage;2 = dents, indentations only;4 = any cracks or splits10.8.2 After assigning the numbers to all plies within eachquadrant, add up all the num
27、bers and divide by four times thenumber of plies to obtain an average for the membrane.11. Report11.1 The report shall include the following:11.1.1 Source and type of all materials employed in thesample roofs,11.1.2 Complete description of the construction tested,11.1.3 Age of the specimens,11.1.4 T
28、est temperature,11.1.5 Average damage incurred over the four impactsdefined by means of a pictorial representation and a writtendescription,11.1.6 Overall numerical average which rates the mem-branes impact damage in the specific system tested, and11.1.7 Date of test and operators signature.12. Prec
29、ision and Bias12.1 No statement is made about either the precision or thebias of this test method since the result merely indicates therating of impact damage by this procedure.13. Keywords13.1 impact; loads; missile; resistance; roofing systems;temperatureASTM International takes no position respec
30、ting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This sta
31、ndard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Internati
32、onal Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below
33、.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 85 (2015)13
