ASTM_D_7376_-_10a.pdf

Designation:D737610aStandard Practice forOutdoor Evaluation of Wet Stack Storage Conditions onCoil-Coated Metals1This standard is issued under the fixed designation D7376;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice is used to determine the resistance tocorrosion and blistering of coil-coated metal products relativeto one another when stacked outdoors under direct weatheringconditions in which they are wetted by rain and dew.1.2 The coil-coated product variables evaluated may in-clude,but are not limited to,substrates,pretreatments,primers,topcoats,and backers.1.3 This test simulates a stacked building panel bundlestored at a job site in wet outdoor conditions.The results frompanels tested during the same time period at the same physicallocation may be used to compare products as an indicator ofrelative field performance.Environments with higher tempera-ture and moisture levels accelerate corrosion and blistering.1.4 This standard does not endorse the storage of level(thatis,0 from horizontal)building panels stacks in wet outdoorconditions.Level storage of building panels is not recom-mended and is used in this standard for evaluation only.1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.6 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D610 Practice for Evaluating Degree of Rusting on PaintedSteel SurfacesD714 Test Method for Evaluating Degree of Blistering ofPaintsD1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive EnvironmentsG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic Materials3.Summary of Practice3.1 This practice is for the evaluation of relative resistanceto wet stack corrosion and blistering of coil-coated metal.Thetest is to be conducted in an outdoor environment withcoil-coated panels placed on a flat surface while allowingexposure to direct weather conditions including rain,dew,andsolar radiation.3.2 It is necessary to expose negative controls in each testrun,that is,products with known resistance to corrosion andblistering in this location,at the same time as the test productto determine its resistance relative to controls.3.3 Panels are evaluated periodically for corrosion andblistering as specified in 6.7.4.Significance and Use4.1 This practice provides for periodic testing for resistanceto wet conditions during storage to compare the relativeperformance of specific combinations of coatings,substrates,and/or pretreatments used on coil-coated metal.The resultsmust be considered relative and do not indicate absoluteperformance.4.2 When stored improperly,coil-coated building panelstacks can be exposed to rainwater,which flows into gapsbetween panels by capillary action or gravity,and remains inthe gaps because of poor drainage conditions.Such a conditionis known as a“wet stack”and may cause blistering andcorrosion of the painted surfaces.This practice simulates suchimproper storage conditions.4.3 Because the outdoor environment shows year-to-yearseasonal and geographic climate variation,the absolute amountof degradation based on corrosion and blistering may vary(seeAppendix X1).1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1,2010.Published June 2010.Originallyapproved in 2007.Last previous edition approved in 2010 as D7376-10.DOI:10.1520/D7376-10A.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 4.4 Temperature,rain,humidity,and storage practices areimportant factors in wet stack corrosion.Corrosion and blis-tering will accelerate with increased temperature.The pre-ferred test location is south of 27N latitude in Florida.Otherlocations may be used,but differences in temperature andmoisture must be considered,and the amount of corrosion andblistering are expected to vary considerably with climate.Testsites must have the instrumentation to measure and recordambient temperature and rainfall as in Practice G7.4.5 This practice is not meant to support the field s