ASTM_D_7635_-_D_7635M_-_10.pdf

Designation:D7635/D7635M10Standard Test Method forMeasurement of Thickness of Coatings Over FabricReinforcement1This standard is issued under the fixed designation D7635/D7635M;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 measuring the thickness of thecoating over fiber backing or reinforcing fabric.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.1.3 This standard may involve hazardous materials,operations,and equipment.This standard does not purport toaddress all of the safety concerns,if any,associated with itsuse.It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D4434 Specification for Poly(Vinyl Chloride)Sheet RoofingE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodMEASUREMENT METHOD3.Principle3.1 The thickness of coating material over fiber,fabric,orscrim can be measured with a standard or digital optical orreflectance microscope.Measurement is made with a calibratedviewing device.4.Apparatus4.1 Microscope,30 to 100 magnification capability.4.1.1 Light SourceIf the light source on the microscope isnot adequate,use a small high-intensity lamp.4.1.2 Stage Micrometer,25 m 0.001 in.divisions.4.2 Calibrated Viewing DeviceA digital or analog devicedesigned to provide an enlarged electronic image with calibra-tions to provide measurements.5.Calibration Procedure5.1Place a standard reflectance stage micrometer or cali-brated sample blocks in place of the specimen.5.2 Turn on the light source.5.3 Position the viewing device(calibrated reticule or cam-era)such that the scales are superimposed.For electronicimaging,place the calibrated scale marker on the microscopestage.Focus the viewing device on the specimen.5.4 Calibrate using micrometer or calibrated sample blocksto nearest 10 m.5.5 If using digital image for calibration step,record reso-lution and magnification of calibration image.6.Specimen Preparation6.1Make a clean cut perpendicular to the plane of thespecimen,normal to one of the thread intersections,completelythrough the sheet exposing the area to be measured(see Fig.1).6.2 Remove the razor-cut section and mount with the cutsurface(analytical plane)facing downward into a sample clip.Secure sample clip in 3.175-cm 1.25-in.sample cup with cap.Use a piece of double-sided tape to securely attach clip to thecap part of the cup.Record sample orientation and positionwithin cup.Multiclips can be used for mounting multiplesamples per mount.Assure all that all samples are orientednormal to the plane of the sample cup cap.6.3 Mixed long-cure epoxy at a ratio of 6.3 parts resin to onepart hardener,per volume.A 3.175-cm 1.25-in.mountrequires 19 ml of epoxy.6.4 The mounts are allowed to cure for at least 24 h atambient temperature and humidity.6.5 After curing(24 hours),polish using the procedureexhibited in Table 1.Clean and dry mounts after each step to1This test method is under the jurisdiction ofASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.18 onNonbituminous Organic Roof Coverings.Current edition approved June 1,2010.Published July 2010.DOI:10.1520/D7635_D7635M10.2For 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 States1 insure that all lubricant and polishing compound are removedto prevent contamination in subsequent polishing steps.7.Specimen Analysis7.1 During analyses use the same image resolution andmagnification used for calibration.7.2 Observe the cut surface.Measure the thickness of thecoating over three of the Machine direction threads,and threeof the cross-machine direction threads(ignore tie yarn scrim ifpresent)(see Fig.2 and Fig.3).7.3 Average all the results.7.4 If using electronic imaging technology,save all of theimage files generated for archiving.8.Calculation and Report8.1 Report the average results from all areas measured asstatistically representative of overall film thickness of the filmto the nearest 10 m 0.0005 in.and the estimated orca