1、Designation: D 3746 85 (Reapproved 2002)Standard Test Method forImpact Resistance of Bituminous Roofing Systems1This standard is issued under the fixed designation D 3746; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 anydes
3、ired temperature, with a missile of the weight, size, andshape specified herein.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wit
4、h its use. It is theresponsibility 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:D 2829 Practice
5、 for Sampling and Analysis of Built-UpRoofs23. 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 f
6、rom apredetermined height with an impact energy of 30.0 J (22lbfft). Damage to the membrane is assessed by visual exami-nation 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 chambe
7、rat 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
8、by 60 mm (238in.) in inside diameter, suitably positioned over a 610-mm(24-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
9、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 mad
10、e 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 50mm (2 in.) in diameter by 150 mm (6 in.) long, with acase-hardened hemispherical head. The mass of th
11、e 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
12、with 1,1,1trichloroethane or xylene in 10.7.3. Trichloroethane and xyleneare toxic and good ventilation should be provided.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 Labora
13、tory 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 t
14、op surfacing. The quantity ofmaterial in each layer of the membrane shall be within 10 % ofthat specified and the entire sample shall be within 5 %.1This test method is under the jurisdiction of ASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.20 on
15、Roofing Membrane Systems.Current edition approved Sept. 27, 1985. Published November 1985. Originallypublished as D 3746 78. Last previous edition D 3746 78.2Annual Book of ASTM Standards, Vol 04.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,
16、United States.8. Test Specimens8.1 Test specimens may be taken directly from an actualroof or cut from a laboratory-prepared sample using a 305 by305-mm (12 by 12-in.) metal template as described in PracticeD 2829 and shall include all of the aggregate and insulation inthe area of the specimen. Any
17、loose aggregate must bedistributed evenly over the surface of the specimen prior totesting.NOTE 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 thei
18、nsulation. The buffer zone should be a “V” type wedge extending to thebottom of the specimen thickness 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
19、 keep it from moving while cutting the “V” wedge.9. Conditioning9.1 Condition the apparatus and all specimens at the desiredtemperature for a minimum of 8 h prior to testing.10. Procedure10.1 Place the test specimen in position beneath the guidetube so the missile will strike the center of one quadr
20、ant.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
21、to fall 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.FIG. 1 Guide Tube, Test Table, and Centering JigFIG. 2 Steel MissileD 3746 85 (2002)210.6 Repeat 10.4 and 10.5 until all f
22、our quadrants of thespecimen have been subjected to impact.10.7 Damage Assessment:10.7.1 Remove 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 the mem-brane, such as dents or fractures, by photograph or
23、sketch andwritten description.10.7.3 Cut the four impact areas from the specimen using ahot knife. 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,
24、use xylene in place of trichloroet-hane.)10.8 Rating of Impact Damage:10.8.1 Rate the impact 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
25、splits10.8.2 After assigning the numbers to all plies within eachquadrant, add up all the numbers 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 roof
26、s,11.1.2 Complete description of the construction tested,11.1.3 Age of the specimens,11.1.4 Test 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
27、damage in the specific system tested, and11.1.7 Date of test and operators signature.12. Precision 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
28、; missile; resistance; roofing systems;temperatureASTM International takes no position respecting 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 right
29、s, and the riskof infringement of such rights, are entirely their own responsibility.This standard 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 r
30、evision of this standard or for additional standardsand should be addressed to ASTM International 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 y
31、ou shouldmake your views known to the ASTM Committee on Standards, at the address shown below.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).D 3746 85 (2002)3
