1、Designation: D7984 16Standard Test Method forMeasurement of Thermal Effusivity of Fabrics Using aModified Transient Plane Source (MTPS) Instrument1This standard is issued under the fixed designation D7984; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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.INTRODUCTIONThis standard provides a test method for measuring the thermal effusivity of fabric
3、s under still airconditions. Other standards, Test Methods F1868 and D1518, measure the thermal insulation ofmaterials under steady-state conditions; however, this test method is used to measure transient heatexchange between a fabric specimen and a heated surface. It has been established that there
4、 is a strongpositive correlation between the thermal effusivity and the initial perceived coldness between humanskin and different materials.2,31. Scope1.1 This test method covers the quantitative measurement ofthermal effusivity of woven, knitted, or non-woven fabricsusing a guarded modified transi
5、ent plane source (MTPS)instrument.4This test method is applicable to a wide range ofthicknesses; however, the thickness of the specimen must begreater than the penetration depth of the heat flux during themeasurement time.1.2 This test method is comparative since specimens ofknown thermal effusivity
6、 are used to calibrate the apparatus atthe factory level. Thermal effusivity of the calibration speci-mens are confirmed through calculations that use establishedproperties of thermal conductivity, density, and specific heat.1.3 This test method is intended for measuring fabrics in adry state at amb
7、ient conditions.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 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 t
8、o establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:5D123 Terminology Relating to TextilesD1518 Test Method for Thermal Resistance of BattingSystems Using a Hot PlateD1776 Practice for
9、Conditioning and Testing TextilesD4920 Terminology Relating to Conditioning, Chemical,and Thermal PropertiesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsF1868 Test Method for T
10、hermal and Evaporative Resistanceof Clothing Materials Using a Sweating Hot Plate3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 modified transient plane source (MTPS), nan appa-ratus that has a one sided planar heat source and a guard, orguard ring, mounted perpendicular to t
11、he planar heat source,that is put in contact with one side of a test specimen, so thata short duration heat pulse can penetrate into the specimen.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.51 on Conditioning, Chemi
12、caland Thermal Properties.Current edition approved Feb. 15, 2016. Published March 2016. DOI: 10.1520/D7984-16.2Marin, E., “Teaching Thermal Physics by Touching,” Latin-American Journalof Physics Education, Vol 2, No. 1, January 2008, pp. 15-17.3Wongsriruska, S., Howes, P., Conreen, M., Miodownik, M.
13、, “The Use ofPhysical Property Data to Predict the Touch Perception of Materials,” Materials andDesign, Vol 42, 2012, pp. 238-244.4The sole source of supply of the TCi instrument known to the committee at thistime is C-Therm Technologies, Ltd., C/O RPC, 921 College Hill Rd., Fredericton,New Brunswic
14、k, Canada, E3B 6Z9. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.5For referenced ASTM standards, visit the ASTM w
15、ebsite, 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 St
16、ates13.1.1.1 DiscussionThe purpose of the guard (or guardring) is to maintain a consistent unidirectional heat flow acrossthe test specimen.3.1.2 penetration depth, nthe functional depth to whichthe initial radiation applied at the surface travels into thespecimen.3.1.2.1 DiscussionTo ensure that th
17、e heat wave is con-tained within the test specimen, the thickness of the testspecimen must be greater than the penetration depth.3.1.3 thermal effusivity, na material property that de-scribes its ability to exchange thermal energy with anothermaterial with which it is in contact.e 5 =cp (1)where:e =
18、 thermal effusivity, WS/(m2K), = thermal conductivity, W/(mK),cp= specific heat capacity, J/(kgK), and = mass density, kg/m3.3.1.3.1 DiscussionThe thermal effusivity of two materialsthat are in contact determines the temperature at their interfaceas a result of heat energy exchange.3.2 For definitio
19、ns of other textile terms used in this testmethod refer to Terminology D123.3.3 For definitions of other terms related to conditioning,chemical and thermal properties used in this test method, referto Terminology D4920.4. Summary of Test Method4.1 A constant momentary heat pulse is applied to thesur
20、face of a test specimen. The heat pulse elevates thetemperature of the surface as the heat diffuses into the testspecimen in one dimensional heat flow. Thermal effusivity isdetermined from the temperature increase at the surface of thematerial with elapsed time. The temperature increase at thesurfac
21、e is inversely proportional to the thermal effusivity of thesample material.5. Significance and Use5.1 This test method measures the rate of thermal transportbetween a heating element and a fabric specimen. Some of thecomfort properties of a garment relate to initial thermalsensations (that is, cold
22、 or warm feeling upon initial contact),where lower thermal effusivity values indicate sensations ofwarmth and higher values indicate sensations of coolness. Thethermal effusivity of different fabrics and their initial perceivedsurface temperature are important to assist product developerswith fabric
23、 selection.5.2 The sensor and the test specimen being measured shallbe at the same temperature for measurements at standardconditions. This test method may be applied to any fabric witha thermal effusivity in the range of 35 to 1700 Ws/m2K.5.3 Air flow shall be kept at a minimum to ensure tempera-tu
24、re fluctuations do not occur during the measurement.6. Apparatus6.1 Modified Transient Plane Source ApparatusSee Fig.1. The essential instrumentation required to provide the mini-mum transient plane source capability for this test methodincludes:6.1.1 Heater, to provide a heat pulse to one surface o
25、f thetest specimen sufficient to cause the surface temperature of thespecimen to increase 1 to 3C.6.1.2 Temperature sensor, to provide an indication of thesurface temperature of the test specimen readable to within60.01C.6.1.3 Temperature programmer, capable of providing apower pulse of 1 to3stotheh
26、eater resulting in an increase inthe specimen surface temperature of 1 to 3C.6.1.4 Heated guard ring, or other device to ensure aunidirectional heat flow in the test specimen perpendicular tothe heated surface.6.1.5 Data acquisition device, to provide a means ofacquiring, storing, and displaying mea
27、sured or calculatedsignals, or both, with a digital acquisition rate of 20 data points(1) Fabric Specimen(2) Heater and Sensor(3) Controller(4) Data Acquisition System(5) Constant Pressure ApplicatorFIG. 1 Basic Layout of an Effusivity Measurement ApparatusD7984 162per second or greater.The minimum
28、output signals required aretemperature or temperature rise and time.6.1.6 Auxiliary instrumentation considered necessary oruseful for conducting this test method include:6.1.6.1 Data analysis capability, to perform the necessarycalculations to derive the property of thermal effusivity fromthe temper
29、ature and time experimental variables.6.2 Load device, to apply a fixed controlled force of 10 to 50kPa to the specimen to ensure that the test specimen is inintimate contact with the heater and temperature sensor.7. Preparation of Test Specimens7.1 Specimen PreparationCut specimens so that the sen-
30、sor area is covered completely. Take a minimum of fivespecimens from each sample to be tested. Specimens shall bestaggered in such a manner that no two specimens contain thesame yarns. The specimens need to be thicker than 1.0 mm sothat the heat wave does not penetrate beyond its maximum testpenetra
31、tion of 1.0 mm thickness during the sampling period.That thickness ensures that even if the fabric is on the higherend of the thermal effusivity range, the penetration depth of theheat flux during the measurement time is maintained within thefabric.8. Conditioning8.1 Maintain the room condition as d
32、irected in PracticeD1776.8.2 Bring the test specimens to moisture equilibrium fortesting as directed in Practice D1776. It is necessary to equalizethe temperatures of the sensor and the specimen by placingthem in the same location.NOTE 1Arepeat sensor temperature measurement before the test mayverif
33、y the equalization and sensor stabilization.9. Calibration9.1 Prepare the instrument for operation and perform anyinstrument calibrations according to the operations manual.9.2 Select a industry reference material of known thermaleffusivity (er).NOTE 2The instrument operations manual may offer sugge
34、stions forsuitable industry reference materials.9.3 Determine the thermal effusivity of the industry refer-ence material according to Section 10 and confirm measuredvalues are within 65 % of the expected value for the material.10. Procedure10.1 Place sufficient layers of the fabric test specimen ove
35、rthe heater surface so that the heater is completely covered andthat a total specimen thickness of more than 1.0 mm isachieved. Rotate each fabric layer by about 30 from thoseabove and below so that no layer is aligned with the adjacentone.10.2 Select and apply a fixed load of between 10-50 kPa toth
36、e fabric layers on the side opposite to the heater to ensureintimate contact with the heater.10.3 Initiate the experiment. Provide a constant momentarypower pulse to the heater and guard ring so that a temperaturerise of 1 to 3C occurs at the surface of the test specimen within1to3s.NOTE 3The temper
37、ature increase at the surface is inversely propor-tional to the thermal effusivity of the sample material.Ascouting run maybe used to determine the optimal power and timing perimeters.Alternatively, instrument operations manual may recommend specificpower levels.10.4 Record the thermal effusivity (e
38、o).610.5 Allow the test specimen and apparatus to cool toambient temperature.NOTE 4This normally takes less than 1 min.10.6 Repeat the thermal effusivity measurement accordingto steps 10.3 10.5 on each specimen two additional times.10.7 Repeat steps 10.1 10.6 for the additional fourspecimens.11. Cal
39、culation11.1 Average data from all five specimens to determine theaverage thermal effusivity values and standard deviation for thefabric samples.12. Report12.1 Report the following information:12.1.1 Identification of the material tested,12.1.2 Identification of the calibration materials and timingp
40、erimeters employed in the calibration (test time, calculatedstart time, cooling period, frequency, power level, andtemperature),12.1.3 Temperature and relative humidity of the testenvironment,12.1.4 Sensor temperature,12.1.5 The side of each specimen that was applied againstthe sensor,12.1.6 The the
41、rmal effusivity of each specimen, the averagethermal effusivity, and standard deviation of all specimens ofone fabric type,12.1.7 The test time applied to the measurement pulse,12.1.8 Applied force used with the compression test acces-sory and sample thickness.13. Precision and Bias13.1 The precisio
42、n of this test method is based on anintralaboratory study (ILS) of ASTM WK43374, New Stan-dard Test Method for Measuremetn of Thermal Effusivity ofFabrics Using a Modified Transient Plane Source (MTPS)Instrument, conducted in 2014.Asingle laboratory participatedin this study, testing five fabrics. E
43、very “test result” representsan individual determination, and is an average of five measure-ments in a given location. The laboratory reported threereplicate test results for each material. Except for the use of6“Thermal Conductivity 28/Thermal Expansion 16, with R. Dinwiddie, M. A.White, and D. L.
44、McElroy, eds., DEStech Publishing, Lancaster PA, 2005, pp.256-268.D7984 163only one laboratory, Practice E691 was followed for the designand analysis of the data; the details are given in a ResearchReport.713.1.1 Repeatability (r)The difference between repetitiveresults obtained by the same operator
45、 in a given laboratoryapplying the same test method with the same apparatus underconstant operating conditions on identical test material withinshort intervals of time would in the long run, in the normal andcorrect operation of the test method, exceed the followingvalues only in one case in 20.13.1
46、.1.1 Repeatability can be interpreted as maximum dif-ference between two results, obtained under repeatabilityconditions, that is accepted as plausible due to random causesunder normal and correct operation of the test method.13.1.1.2 Repeatability limits are listed in Table 1.13.1.2 Reproducibility
47、 (R)The difference between twosingle and independent results obtained by different operatorsapplying the same test method in different laboratories usingdifferent apparatus on identical test material would, in the longrun, in the normal and correct operation of the test method,exceed the following v
48、alues only in one case in 20.13.1.2.1 Reproducibility can be interpreted as maximumdifference between two results, obtained under reproducibilityconditions, that is accepted as plausible due to random causesunder normal and correct operation of the test method.13.1.2.2 Reproducibility limits cannot
49、be calculated from asingle laboratorys results.13.1.3 The preceding terms (repeatability limit and repro-ducibility limit) are used as specified in Practice E177.13.1.4 Any judgment in accordance with 13.1.1 wouldnormally have an approximate 95 % probability of beingcorrect, however the precision statistics obtained in this ILSmust not be treated as exact mathematical quantities which areapplicable to all circumstances and uses. The limited numberof laboratories reporting replicate results essentially guaranteesthat there will be times when diffe
