1、Designation: F955 071Standard Test Method forEvaluating Heat Transfer through Materials for ProtectiveClothing Upon Contact with Molten Substances1This standard is issued under the fixed designation F955; the number immediately following the designation indicates the year of originaladoption or, in
2、the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1NOTEEditorially corrected 11.1.3 and 11.1.4.3 in February 2015.1. Scope1.1 This test method cov
3、ers the evaluation of materialsthermal resistance to molten substance pour by describingmeans of measuring heat transfer.NOTE 1As used in this test method, the term molten substance refersto the three compositions (aluminum, brass, and iron) for which theprocedure was validated. The test design may
4、be adapted for use withother substances not validated as part of the test method.1.2 This test method is applicable to materials from whichfinished protective apparel articles are made.1.3 This test method does not measure the flammability ofmaterials, nor is it intended for use in evaluating materi
5、alsexposed to any other thermal exposure exclusive of the moltensubstance itself (see Note 1).1.4 This test method should be used to measure and describethe properties of materials, products, or assemblies in responseto molten substance pour under controlled laboratory condi-tions and should not be
6、used to describe or appraise the thermalhazard or fire risk of materials, products, or assemblies underactual conditions. However, results of this test may be used aselements of a thermal risk assessment which takes into accountall the factors that are pertinent to an assessment of the thermalhazard
7、 of a particular end use.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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations pri
8、or to use. Specific hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesE457 Test Method for Measuring Heat-Transfer Rate Usinga Thermal Capacitance (Slug) CalorimeterF1494 Terminology Relating to Protective Clothing3. Terminology3.
9、1 Definitions of Terms Specific to This Standard:3.1.1 break-openin testing thermal protective material, aresponse evidenced by the formation of a hole in the materialwhich allows the molten substance to pass through the mate-rial.3.1.2 charringthe formation of carbonaceous residue asthe result of p
10、yrolysis or incomplete combustion.3.1.3 drippinga material response evidenced by flowingof the polymer.3.1.4 embrittlementthe formation of a brittle residue asthe result of pyrolysis or incomplete combustion.3.1.5 heat fluxthe thermal intensity indicated by theamount of energy transmitted divided by
11、 area and time, W/m2(cal/cm2s).3.1.6 human tissue burn tolerance (heat tolerance)in thetesting of thermal protective materials, the amount of thermalenergy predicted to cause a second-degree burn injury inhuman tissue.3.1.7 ignitionthe initiation of combustion.3.1.8 meltinga material response eviden
12、ced by softeningof the polymer.3.1.9 response to molten substance pourin testing thermalprotective material, the observed effect of molten substancecontact on textile properties or deterioration of the material.1This test method is under the jurisdiction ofASTM Committee F23 on PersonalProtective Cl
13、othing and Equipment and is the direct responsibility of SubcommitteeF23.80 on Flame and Thermal.Current edition approved Feb. 1, 2007. Published February 2007. Originallyapproved in 1985. Last previous edition approved in 2003 as F955 03. DOI:10.1520/F0955-07E012For referenced ASTM standards, visit
14、 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
15、. United States13.1.10 shrinkagea decrease in one or more dimensions ofan object or material.3.1.11 thermal end pointin the testing of thermal protec-tive materials, the point where the copper slug calorimetersensor response (heat energy measured) intersects with apredicted skin burn injury model.3.
16、2 For definitions of other textile terms used in this testmethod, refer to Terminology D123.4. Summary of Test Method4.1 Amaterial specimen is mounted on a vertical incline andis exposed to a molten substance pour of prescribed minimumtemperature, volume, pour rate, and vertical height.4.2 The amoun
17、t of heat energy that is transmitted throughthe test specimen during and after the molten substanceexposure is measured using two copper slug calorimeters. Theheat transport response is assessed versus the Stoll curve, anapproximate human tissue tolerance predictive model thatprojects the onset of a
18、 second-degree skin burn injury asmanifested by a blister (See 12.2).4.3 A specific set of subjective evaluations is performed onthe test specimen response to the molten substance exposureusing a standardized rating scale for appraisal (found in TableX.1).5. Significance and Use5.1 Workers may be ex
19、posed to contact with molten sub-stances. The clothing used should provide some protection.Whether personal injury results from such contact depends onthe resistance of the material from which the clothing is madeto molten substance contact and the amount of heat transferredthrough the material to t
20、he wearer.5.2 This test method rates materials, that are intended forprotective clothing against potential molten substance contact,for their thermal insulating properties and their reaction to thetest exposure.5.3 The protective performance, as determined by this testmethod, will relate to the actu
21、al end-use performance only tothe degree that the end-use exposure is identical to theexposure used in the test method.5.4 Visual inspection of the specimen subjectively notes thematerials resistance to molten substance contact.6. Apparatus6.1 The test apparatus consists of four major components asf
22、ollows:6.1.1 An inclined specimen mounting and exposure boardwith two copper slug calorimeter thermal sensors and supports,6.1.2 A pouring crucible and pouring mechanism,6.1.3 A furnace for melting the test metal, and6.1.4 Instruments for measuring test conditions and testresults.6.2 Sensor Construc
23、tion6.2.1 Each copper slug calorimeter shall be 18 6 1g,40mm diameter and 1.6 mm thick and shall be constructed fromelectrical grade copper with a single 30 gage, iron/constantanthermocouple wire and shall be installed as identified in Fig. 1.6.2.2 The exposed surface of each copper slug calorimeter
24、shall be painted with a thin coating of a flat black hightemperature spray paint with an emissivity of 0.9. The paintedsensor shall be dried before use and present a uniformlyapplied coating (no visual thick spots or surface irregularities).Note that an external heat source, for example, an external
25、 heatNOTE 1Sensor ConstructionPlace a straight, bare tip thermocouplewire into the hole located in the center of the copper disk. Place a short“copper plug” into the center hole with the thermocouple junction byclipping a section of bare copper wire of appropriate diameter that, whencombined with th
26、e thermocouple wire, will just fit into the center hole.Use a center punch to mechanically wedge the wire bundle into place.Peen around the hole to further secure the thermocouple into the copperdisk. Take care not to cut the thermocouple wire during this assemblyprocess. Check the electrical contin
27、uity and thermal response prior tousing the completed copper slug calorimeter.FIG. 1 Sensor ConstructionF955 0712lamp, has been used to completely drive off any remainingorganic carriers on a freshly painted surface.6.3 Specimen/Sensor Board6.3.1 The specimen/sensor board shall be nominally 250mm by
28、 406 mm 10 in. by 16 in. and fabricated of a flame andheat resistant material with a thermal conductivity value of 0.15 W/mK, high temperature stability, and resistance tothermal shock. The board shall be nominally 13 mm 0.5 in. orgreater in thickness.6.3.2 The copper slug calorimeters shall be loca
29、ted in thecenterline of the sensor board and mounted as shown in Fig. 1.The calorimeters shall be located 101 mm and 203 mm 4 in.and 8 in. respectively, from the top of the board to thecalorimeter centers as indicated in Fig. 2.6.3.3 An attachment method shall be provided that affixesthe test specim
30、en to the board such that it covers both sensorsand extends at least 25 mm 1 in. beyond all edges.6.3.4 The sensor board shall be inclined at an angle of 70from horizontal.6.3.5 The sensor board shall be located so that it meets thepour geometry illustrated in Fig. 2, where the molten substanceis in
31、troduced at the centerline of the board.6.4 Pouring CrucibleThe pouring crucible shall be suit-able for the substance being poured and for handling tempera-tures up to at least 56C 100F above the pouring tempera-ture. Crucible sizes appropriate for specific substances areshown in Table 1. The crucib
32、le shall be attached to a tiltingmechanism capable of turning the ladle at the rate of onerevolution per 4.7 6 0.2 s. The crucible shall be pivoted at apoint 25 mm 1 in. below the top of the crucible on thevertical. When tilted, the tilted action shall be stopped me-chanically after a rotation of 10
33、 6 5 from the vertical (Fig. 2).See also Appendix X2.6.5 FurnaceAsuitable furnace for melting and heating thetest substance is needed. The furnace and lining must be of atype that the chemistry of the substance is not changed duringcontact with the furnace nor throughout the term of the testseries.6
34、.6 Pouring height shall be 305 mm 12 in. (See Fig. 2).6.7 Data Acquisition SystemThe system shall be capableof recording the calorimeter outputs as required by the test.6.7.1 The temperature data (calorimeter outputs) shall beacquired at a minimum sampling rate of four samples persecond per calorime
35、ter. The acquisition system shall be able torecord temperatures to 150C 300F, have at least a resolu-tion of 0.1C 0.2F, and measuring accuracy of 60.75C61.4F.7. Materials7.1 Description of standard substances for test purposes isincluded in Table 1.8. Hazards8.1 Perform the test in a ventilated area
36、 to carry awaycombustion products, smoke, and fumes. Care shall be exer-cised in handling the hot substance. A full fire extinguisher,preferably of the carbon dioxide type, shall be readily avail-able. Use normal safety practices for the handling of the moltensubstance and potentially flammable mate
37、rials. Place a catchpan filled with dry sand under the assembly. Extreme care shallbe taken to prevent contact between the molten substance andwater because explosive quantities of steam can result.8.2 The sensor board and calorimeter assembly becomeheated during prolonged testing. Use protective gl
38、oves whenhandling these hot objects and during the pour.9. Sampling and Specimen Preparation9.1 Lot SizeFor acceptance sampling purposes, a lot isdefined as 4572 m 5000 yd or a single shipment of a singlestyle of material, whichever is smaller. A lot may constitute allor part of a single customer or
39、der.9.2 Lot SampleAs a lot sample, takea2m2.2 ydfull-width piece of material from both the beginning and end ofthe lot.9.3 Test SpecimensCut and identify three test specimensfrom each sample. Make each test specimen at least 305 6 2mm by 460 6 2 mm 12 6116 by 18 6116 in. Do not cutsamples closer tha
40、n 10 % of the material width from the edgeand arrange the specimens across the sample swatch so as toget as representative a sampling as possible.9.4 Sensor Care:9.4.1 Initial TemperatureCool the sensor after a pourexposure with a jet of air to approximately 21C 70F justprior to positioning the test
41、 specimen.9.4.2 Surface ReconditioningWipe the sensor face with anonabrasive material immediately after each run, while it ishot, to remove any decomposition products which condense,since these could be a source of error. If there is a deposit onthe surface of the sensor that appears to be thicker t
42、han a thinlayer of paint, or is irregular, the sensor surface requiresreconditioning. Carefully clean the cooled sensor with acetoneFIG. 2 Schematic of Test ApparatusF955 0713or petroleum solvent, making certain there is no ignition sourcenearby. Repaint the surface, if bare copper is showing, with
43、athin layer of flat black spray paint as identified in 6.2.2 above.10. Procedure10.1 Specimen MountingA piece of the test material,prepared in accordance with 9.3, against the sensor board withthe sample material hung over the sensor board, centeredhorizontally over the calorimeters with the top of
44、the materialabout 130 mm 5 in. above the top of the upper sensor. Attachthe test material to the sensor board by an appropriate means.10.1.1 Multiple Layer SamplesFor the standard tests tomeasure the protective property of multiple layer samples,place the surface of the material to be used as the ou
45、tside of thegarment facing out. Place the subsequent layer(s) underneath inthe order used in wearing with the surface to be worn towardthe skin facing the calorimeters.10.2 Pour MethodMolten substance of sufficient quantityfor the test series is first heated in a furnace. When the sampleis mounted a
46、nd all is in readiness, the test substance shall bebrought to about 56C 100F above the pour temperature.Make molten substance temperature measurements with anappropriate device such as an optical pyrometer or other heatmeasuring device with an accuracy of at least 614C 625F.Use a preheated crucible
47、appropriate to the substance beingused, as shown in Table 1. Put a quantity of substance, 610 %of the weight shown in Table 1 in the test crucible, and thentransfer it into the pouring rig. Align the assembly holding thepouring crucible so that the main part of the molten substancestream impacts on
48、the material specimen directly above thecenter of the top calorimeter.10.2.1 The data acquisition system is started several sec-onds before the actual molten material pour is initiated. Thisestablishes the average starting copper slug calorimeter tem-peratures for the heat energy determination.10.2.
49、2 When the temperature of the molten substance dropsto the appropriate pour temperature, tilt the crucible and pourthe substance onto the material specimen set on the inclinedsensor panel board for the test. (Take extreme care to avoidbeing splashed by the hot substance.) Continue the exposurefor 45 s then stop data acquisition.10.2.3 Observe the specimen during and immediately afterthe pour.10.2.4 Expose two specimens for each sample tested.10.2.5 If the temperature rise of the two tests differ
