AATCC Test Method 76-2005Electrical Surface Resistivity of FabricsDeveloped in 1954 by AATCC The radioactive bar emits alpha ra-the -diation which is externally harmless totee RA32; revised 1963, 1968, 1970,1972, 1973, 1982, 1995, 2000 (with tthe human body. The radioactive isotopei-7. Procedurepolonium 210 is toxic and precautiontle change); reaffirmed 1969, 1975,1978, 1989; editorially revised 1974,should be exercised to prevent Calibrate the electrical resistancemeter according to the manufacturer’s1984, 1985, 1997, 2004; editorially re-or inhalation of the solid material. Do notvised and reaffirmed 1987, 2005take the radioactive bar apart or touch therecommendations. This calibration strip under the grid. If thebe repeated periodically (see ).strip is touched or handled, wash Condition the test specimens in a1. Purpose and Scopethoroughly at once. Return the device tosuitable testing chamber or conditioningthe manufacturer when it loses its effec-room at a predetermined relative The purpose of this test method istiveness as a static eliminator or for dis-ity that will reflect the conditions atto determine the electrical surface resis-posal if use is to be discontinued. Do notwhich information on the electrical resis-tivity of fabrics. The surface electrical re-discard as of the fabric is may influence the For most fabrics which require an-of electrostatic charge of a fabric (refer totistatic treatments or whose static propen-AATCC Method 84 for determination of5. Apparatus and Materialssity is critical, measurements at 20% rela-electrical resistance for yarns). Eltive humidity will be most resistance meter (). In less critical situations 40% rel-2. Conditioning and test chamber (seeative humidity may be Specimens at equilibrium ). For special requirements otherspecified atmospheric conditions of Standard resistors (see ).relative humidities may be used. For ex-tive humidity and temperature are Radioactive bar (see ).ample, preconditioning at 50% ± 2% RHsured for electrical resistance Two rectangular flat meat 21 ± 2°C is required for antistatictal surfacesparallel electrodes by means of an electri-sheeting, film and textiles for use in hos-of suitable size to serve as resistance operating rooms (see ). As an alternative, two concentricsurements may be made under other con-ring electrodes of spacing suitable to the3. Terminologyditions or ranges of conditions that arematerial being measured and the purposeapplicable to the end use (such as 65%of the results (see ). electrical resistivity, n.—mat뇪erialힼ럖쿭췸⁷睷穦RH硷 and 24°C).潭 It is preferable to k퇏eep th싔e?property of a substance whose numericaltemperature or humidity consistent for allvalue is equal to the ratio of the voltage6. Test to the current If it is necessary to measure Adjust the size of fabric test speci-NOTE: For the purposes of this method,trical resistivity under a broad range ofmens to suit the electrodes of the particu-surface resistivity is calculated by usingconditions, additional tests may be run atlar equipment being used. When usingthe measured electrical resistance be-65% RH and at 24°C or other settings ap-parallel plate electrodes, the width of thetween superficially positioned parallelplicable to the end use. It is preferable tospecimen must not exceed the width ofplates or concentric rings and their spac-keep the temperature or humidity consis-the electrodes. When using the concentricing and is reported as ohms per for all , any size specimen at least as largeThis test method in effect measures Optionally remove static chargesas the outer ring may be used. Avoid con-resistance of a material to the flow of cur-on the surface of the fabric by passing ataminating the area on which the mea-rent between two bar over both sides of the fab-surement is to be (see ). Specimens for use with instruments4. Safety Place a test specimen in firm con-providing parallel plate electrodes. Pre-tact with the electrodes. The contact withpare 2 sets of 3 test specimens each, 1 setNOTE: These safety precautions arethe electrodes should be such that, wheneach so that the direction of testing is par-for information purposes only. The pre-additional pressure is applied between theallel to the yarns in the length direction ofcautions are ancillary to the testing proce-fabric and the electrodes, the test resultsthe fabric and 1 set with the direction ofdures and are not intended to be all inclu-are not parallel to the width direction ofsive. It is the user’s responsibility to usethe In the case of equipment usingsafe and proper techniques in handlingmaterials in this test method. Test specimens for use with in-parallel plate electrodes, place the testspecimen in contact with the electrodesstruments providing concentric ring elec-turers MUST be consulted for specificdetails such as material safety data sheetstrodes. Prepare 1 set (3 test specimens)with the direction of the test perpendicu-since, wlar to the adjacent edges of the this type instrument, the resis-and other manufacturer’s recommenda-tions. All OSHA standards and rutance is measured in both fabricMeasure the electrical resistance of the lengthlesmust also be consulted and fabric widfabric in both the length and width direc-th directions simulta-neouslytions. Since the charge will follow Good practices shouldpath of least resistance, record only thebe followed. Wear safety glasses in Depending on the fabric con-lower reading by or end-use, it may be The safety recommendations pro-to differentiate between face and For concentric ring electrodes,vided by the manufacturer of the radioac-measurements. Each test specimenthe charge follows the path of least resis-tive bar should be be taken from a different part oftance Technical Manual/2007TM 76-200597Copyright © 2006 American Association of Textile Chemists and ColoristsCPLNirocopet v rynfeiodrspireg rRodhed te=b uTsHycah otIleiHno ,gASn 0 m Kou3oren/ 2nrd4igce/ atr2Pw n0loi c0Alrey7kstn ies0nsco4gehc: 0pnwia7eiictt:rih 5omU 3nAint MtoAievfTD/d 9TC T9weC7xit 6thil8oe0u C3t 1hli0cee0mn isets faronmd CIHoSlorists --‘‘‘‘‘,‘‘‘‘‘‘,,‘‘,‘,,,‘‘‘,,‘‘-‘-‘,,‘,,‘,‘,,‘---
Dyestuff Reporter, Vol. 40, 1951, pp Measure the electrical resistance of9. Reportthe test specimen according to the Other resistance testers also may Report the following information:ing instruction and procedures for thesatisfactory for this The Log R for each sample andparticular resistance meter being A conditioning and testing chamber isfor the the current to pass through the testrequired capable of providing relative the number of specimens control of ± 2% (preferably effective over aspecimen for 1 min or until a The relative humidity and tem-range of 20-65% RH) and temperature controlreading is obtained. The criterion for con-of ± 1°C (± 2°F) with circulating air. Sinceperature electrical resistivity is a change inequilibration of a test specimen from the The direction of testing if parallelthe value of Log R of less than unitsversus the wet condition relative to the humid-plate electrodes were minute. The time to reach a constantity of the test chamber may show hysteresis,reading may vary with the applied volt-itis recommended that specimens approachage and with the resistance of the testequilibrium from the dry side relative to the10. Precision and Biassample. High voltages for prolonged pe-humidity in the test chamber whenever pos-riods of time may damage the Precision. Precision for this For referee purposes, 80-100 National Fire Protection Association,method has not been established. Until aat 25 mm electrode separation for 1 minStandard NFPA Code #56 A-1973 Sectionprecision statement is generated for be used for the parallel plate con-test method, use standard statistical tech-figuration, and a similar voltage Standard resistors suitable for calibra-niques in making any comparisons of testtion of the electrical resistance meter are avail-for the concentric ring case (see ).results for either within-laboratory orable from Victoreen LLC, 6000 Cochran Rd., Avoid the use of any electricallybetween-laboratory averages. ExperienceCleveland OH 44139-3395; tel: 440/248-conductive liquids on either the fabrichas shown that, with care, reproducibility9300; fax: 440/ specimens or the be ± ≤ 2% average Log The following radioactive bar, Bias. Electrical resistivity can bemaster Ionizing Unit, Model 2 U 500, has8. Evaluationdefined only in terms of a test found to be suitable for the removal ofThere is no independent method for de-electrostatic charges from fabrics and Compute the resistivity to the near-termining the true value. As a means ofavailable from NRD Inc., 2937 Alt. ohms per square as follows:North, Grand Island NY 14072; tel: 716/773-estimating this property, the method For the parallel electrode case: known Accumulation of static electricity gen-R = O × W/Derally is greater the lower the relative humid-11ity (and vice versa). Fabrics which show a low. Noteswhere:degree of static accumulation of 40% RH mayR=resistivity in ohms per The resistance meter in conjunctionexhibit severe static accumulation of 20-25%O=measured resistance in ohmswith the electrode system should be capable ofRH, while fabrics which exhibit static prob-815W=width of specimenmeasuring values in the range of 10-10 forlems at 40% RH may exhibit a low degree ofany critical uses. Equipment that is capable ofD=distance between electrodes뇪ힼ럖쿭췸⁷睷static accumulation of 65% RH. The relation-813measuring values in the range of 10-10ship between the tendency for static accumu-ohms is suitable for work where the穦硷潭퇏싔? productlation and relative humidity varies with For the concentric ring case:performance is known to be acceptable if re-specific antistatic agent, fiber, fabric construc-13sistance is < 10 , surface character, etc. Therefore, 40%R = (O)/log r/ A concentric ring instrument comRH may not provide significant information as-plete with adequate shielding, capable of meato the probable antistatic performance proper--where:815ties of a fabric unless the tests are also run atsuring values in the range of 10-10 ohms, isR=resistivity in ohms per square20-25% RH, an atmospheric condition not un-available from Keithley Instruments Inc.,O=measured resistance in ohmsusual in modern heated and air-conditioned28775 Aurora Rd., Cleveland OH 44139; tel:r=outer electrodes radiusobuildings. Complete information may also re-440/=inner electrodes radiusiquire information of resistivity at the Instruments capable of measuring813level of 65% in the range of 10-10 ohms are Calculate the average resistivity forable from Teradyne Inc., 600 River Park Dr., For more detailed information regard-each sample and for the Reading MA 61864; tel: 978/ the measurement of resistances, Determine the logarithm (base 10) A description of an instrument thatASTM Test D 257, Tests for D-C Resistance13of the resistivity (Log R) for each samplewill not allow measurements > 10 ohms isor Conductance of Insulating Materialsand for the by Hayek & Chromey in American(ASTM Committee D-20).98TM 76-2005AATCC Technical Manual/2007Copyright © 2006 American Association of Textile Chemists and ColoristsCPLNirocopet v rynfeiodrspireg rRodhed te=b uTsHycah otIleiHno ,gASn 0 m Kou3oren/ 2nrd4igce/ atr2Pw n0loi c0Alrey7kstn ies0nsco4gehc: 0pnwia7eiictt:rih 5omU 3nAint MtoAievfTD/d 9TC T9weC7xit 6thil8oe0u C3t 1hli0cee0mn isets faronmd CIHoSlorists --‘‘‘‘‘,‘‘‘‘‘‘,,‘‘,‘,,,‘‘‘,,‘‘-‘-‘,,‘,,‘,‘,,‘---
