ASTM_C_483_-_95.pdf

Designation:C 483 95Standard Test Method forElectrical Resistance of Conductive Ceramic Tile1This standard is issued under the fixed designation C 483;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the elec-trical resistance of conductive ceramic tile prior to installation.1.2 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.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.Referenced Documents2.1 ASTM Standards:C 242 Terminology of Ceramic Whitewares and RelatedProducts2D 2240 Test Method for Rubber PropertyDurometerHardness33.Terminology3.1 Definitions:3.1.1 conductive ceramic tiletile made from special bodycompositions or by methods that result in specific properties ofelectrical conductivity while retaining other normal physicalproperties of ceramic tile.3.1.2 tilefor the definition of the term“tile”,refer toTerminology C 242.4.Summary of Test Method4.1 This test method consists of measuring the electricalresistance between an electrode resting upon the tile to betested and a bed of iron filings on a stainless steel plate.5.Significance and Use5.1 This test method provides a means for determiningwhether conductive ceramic tile meets electrical resistancerequirements to prevent the accumulation of dangerous elec-trostatic charges which,in the presence of flammable gases,may cause possible explosions through spark discharges.Suchelectrical resistance requirements are specifically called for inhospital operating rooms and for floors of other rooms whereflammable agents are stored or handled.46.Apparatus6.1 OhmmeterA suitably calibrated d-c ohmmeter with anominal open-circuit output voltage of 500 V and a short-circuit current of 2.5 to 10 mA,having wire leads and alligatorclamps.6.2 ElectrodesTwo electrodes weighing 5.0 lb(2.2 kg)each and having a dry,flat circular contact area 2.5 in.(63.5mm)in diameter.The contact area shall comprise a surface ofaluminum or tin foil 0.0005 to 0.0010 in.(0.013 to 0.025 mm)thick,in electrical contact with the electrode and backed by alayer of rubber 0.25 in.(6.4 mm)thick and having a hardnessof 50 6 10 as determined with a Shore Type A durometer asdescribed in Test Method D 2240.6.3 Iron Filings,dry clean,reasonably free of oxidation,andapproximately 50-mesh size(0.297-mm opening).6.4 Stainless Steel Plate,16 gage(1.29 mm)or heavier and15 by 15 in.(380 by 380 mm)in size.7.Sampling7.1 Size of SampleSufficient individual conductive ce-ramic tile to cover a minimum area of 3 by 3 in.(76 by 76 mm)shall constitute a sample.If mounted,all the tile for one sampleshall be taken from the same sheet.7.2 Selection of SampleOne sample shall be taken fromeach 200 ft2(approximately 19 m2)of tile,but in no case shallless than five samples be tested from a lot.In the case ofpatterns using a combination of conductive and nonconductivetile,only the conductive tile shall be sampled.7.3 Preparation of SampleThe tile shall be dry and,ifpreviously mounted,shall be thoroughly cleaned to remove allmounted material and adhesive.They shall then be dried at200F(95C)to constant weight and cooled to room tempera-ture before testing.8.Procedure8.1 GroupPlace two 1.0-in.(25.4-mm)wide and 0.0625-in.(1.6-mm)thick metal strips parallel to each other on onehalf side of the steel plate.The length of these strips and the1This test method is under the jurisdiction of ASTM Committee C-21 onCeramic Whitewares and Related Products and is the direct responsibility ofSubcommittee C21.06 on Ceramic Tile.Current edition approved Sept.10,1995.Published November 1995.Originallypublished as C 483 61 T.Last previous edition C 483 66(1990).2Annual Book of ASTM Standards,Vol 15.02.3Annual Book of ASTM Standards,Vol 09.01.4See the National Fire Protection Association Pamphlet No.56,Ch.25(June1959).1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMdistance between them depends upon the size of the sample tobe tested.Fill the space between the metal strips with ironfilings and use a straight-edge to level the layer.The thicknessof the metal strips assure a uniform thickness of 0.0625-in.(1.6mm).Any other apparatus that can be devised that assures theuniform 0.0625-inch(1.6-mm)layer of iron filings in contactwith the stainless plate is acceptable.Place the tile to be testedon the filings so that they are in contact with ea