ASTM_C_1258_-_08_2013.pdf

Designation:C125808(Reapproved 2013)Standard Test Method forElevated Temperature and Humidity Resistance of VaporRetarders for Insulation1This standard is issued under the fixed designation C1258;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 test method covers the determination of the agingresistance of flexible low permeance vapor retarders forthermal insulation as classified in Specification C1136.Watervapor permeance measurement and visual inspection afterexposure at elevated temperature and humidity are used toassess vapor retarder response.1.2 Typical vapor retarders applicable to this test methodthat are intended for indoor use include foil-scrim-kraftlaminates,metallized polyester-scrim-kraft laminates,treatedfabrics,treated papers,films,foils,or combinations of thesematerials that may comprise a vapor retarder material.This testmethod is not intended for assessment of the liquid-appliedcoatings,sealants,or mastics commonly used with insulationproducts.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 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:2C168 Terminology Relating to Thermal InsulationC1136 Specification for Flexible,Low Permeance VaporRetarders for Thermal InsulationE96/E96M Test Methods for Water Vapor Transmission ofMaterials3.Terminology3.1 Terminology C168 shall be considered as applying tothe terms used in this specification.4.Summary of Test Method4.1 The vapor retarders are subjected to accelerated agingvia elevated temperature and humidity at 120F(49C)and95%relative humidity for a period of 28 days,then visuallyinspected for corrosion(if applicable),delamination,or otherdegradation.Water vapor permeance in accordance with TestMethods E96/E96M is measured after humid aging.5.Significance and Use5.1 On sub-ambient temperature systems,humid ambientconditions cause a vapor driving force toward the insulationwhich,if not retarded,is detrimental to the insulations thermalresistance.Therefore a vapor retarder should resist degrada-tion.Degradation in this test method is induced by elevatedtemperature and humidity conditions.6.Apparatus6.1 Environmental Chamber,capable of maintaining 120 62F(49 6 1C)and 95 6 2%relative humidity,using distilledor deionized water as the humidity source.The chamber shallbe of the air-circulating variety.6.2 Lighted Box in a Darkened RoomA lighted box is anenclosure having five opaque sides with one transparent glassor plastic viewing side.The box is illuminated using anincandescent lightbulb.The viewing area shall be slightlysmaller than the vapor retarder specimen so that holes ordegradation caused by aging are readily visible.6.3 Cotton Gloves.6.4 Cardboard Overhead Transparency Frames or Equiva-lent.6.5 Stainless Steel Staples.6.6 Glass or Stainless Steel Rods.7.Test Specimens7.1 From each sample cut four specimens that are largeenough to acquire water vapor permeance test specimens after1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved Sept.1,2013.Published January 2014.Originallyapproved in 1994.Last previous edition approved in 2008 as C125808.DOI:10.1520/C1258-08R13.2For 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 exposure.The specimens shall be cut in a manner which bestcharacterizes the roll width.Material exhibiting extraneousdamage from mishandling in shipment or during samplepreparation shall be avoided.A fifth specimen shall be cut andretained as a control.An 1134in.(298 mm)by 1034in.(273mm)specimen size is recommended since this is the size of atypical overhead transparency frame,which is useful to supportspecimens in the humidity chamber.In any case,the specimensize shall be at least 6 in.by 6 in.(152 mm by 152 mm).8.Aging Procedure8.1 Use clean cotton gloves during handling to avoidsurface contamination that may be confused with corrosion onfoil or metallized laminates.8.2 Once cut to the desired size,individually s