ASTM_F_1087_-_02_2009.pdf

Designation:F108702(Reapproved 2009)Standard Test Method forLinear Dimensional Stability of a Gasket Material toMoisture1This standard is issued under the fixed designation F1087;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 a procedure to determine thestability of a gasket material to linear dimensional change dueto hygroscopic expansion and contraction.It subjects a sampleto extremes,that is,oven drying and complete immersion inwater,that have shown good correlation to low and highrelative humidities.21.2 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 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.Summary of Test Method2.1 A series of samples are preconditioned to a stablestarting point,measured,and then conditioned to a secondexposure condition,either wet or dry.These changes are thendetermined and recorded,and the results presented as percentchange.3.Significance and Use3.1 Gasket materials undergo several processing steps frompoint of manufacture to installation in a flange.Many applica-tions require close control of dimensional change.An accuratetest method for determining the relative stability of variousmaterials is needed for design and quality assurance purposes.This test method is useful towards that end.It simulates theextreme storage conditions that a material may undergo prior toinstallation.Samples are allowed unrestricted expansion orcontraction,and so this test method should not be used topredict behavior clamped in a flange or other applications,orduring specific processing steps.3.2 This test method measures linear change,and may needto be modified if the test specimen is not flat,homogeneous,orfree of voids.4.Apparatus4.1 This test method allows individual laboratories to selectmeasuring devices of their own choice,but requires that thedevice be able to measure with a precision of 60.025 mm(0.001 in.).5.Sampling5.1 At least six test specimens should be taken for eachsample material,three for the high humidity and three for thelow humidity tests.The samples should be cut 2.54 cm(1.00in.)wide,and between 20 and 30 cm(8 and 12 in.)in length.The long direction should be in the direction that experiencesthe greatest dimensional change,generally the cross machineor against the grain direction.If there is doubt,both directionsshould be sampled,and the results of the direction with thegreatest change reported.6.Conditioning6.1 Test specimens should be preconditioned at least 20 h ina controlled environment maintained between 21 to 30C(70to 85F)and 50 to 55%relative humidity.7.Procedure7.1 Measure test specimens to 60.025 mm(60.001 in.)andrecord values as initial readings.If the test specimen is markedfor identification or measurement,be certain that the mark iseasily visible and will withstand exposure to heat and immer-sion in water.7.2 Testing for Dimensional Stability to Low HumidityExpose three prepared specimens in a forced hot-air oven set at100 6 2C(212 6 4F)for 5 h.Remove specimens and allowto cool between 21 to 30C(70 to 85F)in a desiccatorcontaining anhydrous-calcium chloride or suitable desiccantmaterial.Remeasure and record measurements as final read-ings.1This test method is under the jurisdiction of ASTM Committee F03 on Gasketsand is the direct responsibility of Subcommittee F03.20 on Mechanical TestMethods.Current edition approved May 1,2009.Published May 2009.Originallyapproved in 1988.Last previous edition approved in 2002 as F1087 02.DOI:10.1520/F1087-02R09.2Since this test method takes a“worst case”approach,actual dimensionalchange due to atmospheric conditions would be expected to be less.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.3 Testing for Dimensional Stability to High HumidityImmerse three prepared specimens into a tray of deionizedwater to a depth of 1.2 cm(0.5 in.)for a 22 h period.Formaterials that are buoyant in water,a supported wire screen orexpanded metal cover should be used with adequate weights tokeep the specimens immersed at the specified depth.Be certainthat the specimens are separated and able to expand in anunrestricted fashion.Remove specimens from water and lightlyblot excess water from the surface of the specimens.Remea-sure and record measurements as final readings.8.Calculation of Results8.1 Report the results as percent change to high or lowhumidity calculated from the following equations:8.1.1 High