1、Designation: F2894 12bStandard Test Method forEvaluation of Materials, Protective Clothing and Equipmentfor Heat Resistance Using a Hot Air Circulating Oven1This standard is issued under the fixed designation F2894; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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 quantitative measurements andsubjective observati
3、ons that characterize the performance forevaluating the heat resistance of materials, protective clothingand equipment when exposed in a hot air circulating oven.1.2 This test method is intended to evaluate physicalchanges in materials, protective clothing and equipment at aspecified heat exposure.1
4、.2.1 The specified heat exposure in the hot air circulatingoven is a combination of convective heat and radiant heat.1.3 Materials, protective clothing and equipment are evalu-ated for visible changes or subjected to a material propertymeasurement following a specified heat exposure.1.3.1 This test
5、method is not to be used for the evaluation ofsticking. An acceptable method for evaluating sticking offabrics is described in NFPA 1975, Sections 7.2.1 and 8.3. TheNFPA 1975 test method evaluates the thermal stability ofspecimens by assessing the blocking of folded specimensplaced between glass pla
6、tes, under a specified weight, inside anoven meeting the same characteristics of the oven used in thistest method.1.4 This test method enables the quantitative measurementof dimensional change that occurs as a result of a specified heatexposure in a hot air circulating oven.1.5 The values stated in
7、SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to other units that are commonly used for thermaltesting.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
8、f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1Flame resistant and heat resistant materials are described in arange of different standards and meet a range of different requirements.For materials tes
9、ted in accordance with this test method, the applicablestandard shall be used to establish preconditioning, conditioning andtesting conditions and requirements.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD7571 Sp
10、ecification for Retained Sewn Seam StrengthAfter Exposures to Hot Air and Open FlameE145 Specification for Gravity-Convection and Forced-Ventilation OvensE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Pre
11、cision of a Test MethodF1494 Terminology Relating to Protective Clothing2.2 AATCC Standard:Test Method 135 Dimensional Changes in Automatic HomeLaundering of Woven and Knit Fabrics32.3 NFPA Standards:NFPA 1975 Standard on Station/Work Uniforms for Fireand Emergency Services43. Terminology3.1 Definit
12、ions of Terms3.2 For definitions of terms used in this test method, use thefollowing documents: If the terms are related to textiles refer toTerminology D123; if the terms are related to protectiveclothing refer to Terminology F1494.3.2.1 convective heat, nheat transferred by the motion ofa fluid.3.
13、2.2 degradation, na deleterious change in one or moreproperties of a material.3.2.2.1 DiscussionIn thermal testing of materials, protec-tive clothing and equipment, degradation is a material response1This is under the jurisdiction of ASTM Committee F23 on Personal ProtectiveClothing and Equipment an
14、d is the direct responsibility of Subcommittee F23.80 onFlame and Thermal.Current edition approved July 1, 2012. Published October 2012. Originallyapproved in 2011. Last previous edition approved in 2012 as F2894 - 12a.DOI:10.1520/F2894-12B.2For referenced ASTM standards, visit the ASTM website, www
15、.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.3Available from American Association of Textile Chemists and Colorists(AATCC), P.O. Box 12215, Research Triangle Park, N
16、C 27709, http:/www.aatcc.org.4Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/www.nfpa.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.evidenced by a change in either o
17、r both the visual propertiesand the performance properties of the test specimen.3.2.2.2 DiscussionDegradation generally is associatedwith a chemical composition change that can result in a changein a visual property, for example, color, or it can result in achange in a performance property including
18、 but not limited tostrength, hand, flammability, penetration resistance, waterrepellency and air permeability.Atest specimen that changes inone property does not necessarily change in other properties.Evidence of degradation in performance properties usuallyrequires additional measurements related t
19、o properties ofspecific interest. Discoloration is a visible material responserelated to degradation. When discoloration is observed, it shallbe reported.3.2.3 dimensional change, na generic term for change inlength or width of a specimen subjected to specified conditions3.2.3.1 DiscussionDimensiona
20、l change is usually ex-pressed as a percentage of the original dimension. Positivevalues for dimensional change indicate growth while negativevalues for dimensional change indicate shrinkage.3.2.4 distortion, nthermal testing of equipment, a speci-men response evidenced by a change in its original s
21、hape.3.2.4.1 DiscussionThis type of observation is generallyapplied to equipment items such as protective helmets and isbased on the placement of the item on a specific holding deviceplaced in the oven, such as a head form, and the measurementof the specimen relative to the holding device.3.2.5 func
22、tionality, nin thermal testing of protectiveclothing and equipment, the continued utility of the test item asdetermined by an assessment of its capability to function afterthe heat exposure in the same manner as before its exposure toheat.3.2.5.1 DiscussionThis type of assessment is generallyapplied
23、 to items of hardware or to portions of or completeprotective clothing and equipment items.3.2.6 ignition, nthe initiation of combustion.3.2.7 protective clothing, nan item of clothing that isspecifically designed and constructed for the intended purposeof isolating all or part of the body from a po
24、tential hazard; or,isolating the external environment from contamination by thewearer of the clothing.3.2.8 protective equipment, na non-clothing item ofequipment that is specifically designed and constructed for theintended purpose of isolating all or part of the body from apotential hazard; or, is
25、olating the external environment fromcontamination by the user of the equipment.3.2.9 radiant heat, nheat communicated by energy propa-gated through space and transmitted by electromagnetic waves.3.3 Definitions of Terms Related to Thermal Testing ofMaterials, Protective Clothing and Equipment:3.3.1
26、 deformation, nin thermal testing of materials, pro-tective clothing and equipment, a material response evidencedby a change in shape of the test specimen that is irreversible atroom temperature.3.3.1.1 DiscussionA change in shape caused by the speci-fied heat exposure such as distortion of woven or
27、 non wovenfabrics or curling of knit fabrics shall not be identified asdeformation as long as these changes are reversible at roomtemperature.3.3.2 delamination, nin thermal testing of materials, pro-tective clothing and equipment, a material response evidencedby the separation of two of more layers
28、 of the test specimen inwhole or in part.3.3.3 dripping, nin thermal testing of materials, protec-tive clothing and equipment, a response evidenced by flowingof the polymer and by the formation of droplets from theflowing material.3.3.4 flaking, nin thermal testing of materials, protectiveclothing a
29、nd equipment, a material response evidenced by theunassisted loss of visible particles of material from the testspecimen when the test specimen is removed from the oven forinspection.3.3.4.1 DiscussionThe specimen shall not be abraded,flexed or impacted to generate flaking.3.3.5 hole formation, nin
30、thermal testing of materials,protective clothing and equipment, the appearance of a visibleaperture during the test exposure.3.3.5.1 DiscussionThe specimen is considered to exhibithole formation when a visible hole is produced as a result ofthe thermal exposure that is approximately 3 mm (0.12 in.)
31、indiameter or greater, or if the hole is rectangular in shapeapproximately 3 mm (0.12 in.) in width and length or greater.Single threads across the hole do not reduce the size of the holefor the purposes of this test method.3.3.6 melting, nin thermal testing of materials, protectiveclothing and equi
32、pment, the liquefaction of material under theinfluence of heat.3.3.6.1 DiscussionMelting is determined visually by achange in the material physical appearance such as fusing offibers or the evidence of material flowing.3.3.7 separation, nin thermal testing of materials, protec-tive clothing and equi
33、pment, a material response evidenced bysplitting or delaminating.3.3.8 splitting, nin thermal testing of materials, protectiveclothing and equipment, a material response evidenced by thetest specimen breaking into two or more pieces in whole or inpart.4. Summary of Test Method4.1 The test method eva
34、luates the heat resistance of mate-rials, protective clothing and equipment using a hot air circu-lating oven.4.2 Specimens shall be exposed in the test oven at aspecified temperature for a specified oven exposure time asrequired by the applicable material or product specification.4.2.1 If no materi
35、al or end product specification require-ments for the oven temperature and oven exposure time areprovided, the oven temperature shall be 260 +8/-0C (500+14/-0F) and the oven exposure time shall be 5 minutes+15/-0 seconds.F2894 12b24.3 Following heat exposure, the test specimen is removedand examined
36、 for evidence of one or more of the followingphenomena: ignition, melting, dripping, separation, etc., see11.5.4.4 If specified, test specimens are evaluated for dimen-sional change as a result of the convective heat exposure.5. Significance and Use5.1 This test method is used to evaluate the heat r
37、esistanceof materials, clothing and equipment when exposed to heat ina hot air circulating oven. The principal findings of this testmethod are observations of the specimen response to the heatexposure.5.1.1 The majority of procedures specified in this testmethod apply to the evaluation of flat mater
38、ial specimens.5.1.2 When evaluating non-flat materials, alternative proce-dures are required for mounting specimens and interpreting theeffects of the heat exposure.5.2 If specified, this test method is used for the measurementof material dimensional change following a convective heatexposure in a h
39、ot air circulating oven.5.3 This test method is not intended to simulate the actualexposure of material, clothing or equipment in high heatconditions such as a fire environment.6. Apparatus6.1 Test OvenThe test oven shall be a horizontal-flowcirculating oven with minimum interior dimensions of 610 m
40、mby 610 mm by 610 mm such that a specimen can be suspendedand be positioned at least 50 mm (2 in.) from any interior ovensurface or other specimen.6.1.1 The test oven shall have an air velocity of 0.5 m/s to1.5 m/s at the standard temperature and pressure of 21C atlocal atmospheric pressure, measure
41、d at the geometric centerpoint of the oven.6.1.2 The test oven shall be equipped with an oven sensingthermocouple which is used as part of the oven temperaturecontrol mechanism.6.1.2.1 The oven sensing thermocouple shall be positionedso that it is level with the horizontal centerline of a mountedsam
42、ple specimen, and the oven sensing thermocouple shall beequidistant between the vertical centerline of a mountedspecimen positioned in the middle of the oven and the ovenwall where the airflow enters the oven test chamber.6.1.2.2 The oven sensing thermocouple shall be an exposedbead, Type J or Type
43、K, No. 30 AWG thermocouple.6.2 Specimen MountingMetal hooks or clamps shall beused to suspend the specimens in the oven.6.2.1 If the specimens are too large to be suspended, asuitable insulating form shall be placed in the center of theoven and the specimen shall rest on the insulating form.Ceramic
44、has been found to be an effective material for thisform.6.2.2 In the testing of some items, such as individual piecesof hardware, loops of heat-resistant thread are used to suspendthe specimen.6.3 Optional Stretching FrameThe optional stretchingframe consists of a board with uniformly spaced pins al
45、ong theperimeter at intervals of 25 mm (1 in.) to secure knit materials.Construct the stretching frame to accommodate the test speci-men size specified in 9.1.1 and 9.1.2 so that the pins are locatedapproximately 50 mm (2 in.) inward from the edges of the testspecimen.6.3.1 The optional stretching f
46、rame is permitted to be usedbefore the knit specimen is placed in the oven for marking thespecimen for dimensional change determination. The stretch-ing frame is not used while the knit specimen is exposed in theoven. The optional stretching frame is also permitted to be usedfor a specified period o
47、f time after heat exposure in the oven toreturn knit specimens to their original dimensions. See 9.3.1and 11.6.1.7. Hazards7.1 Normal precautions shall be taken for working aroundhot surfaces and flaming, melting or dripping test specimens.7.2 The oven shall be properly vented to ensure that harmful
48、vapors and gases are evacuated from the laboratory.8. Preconditioning of Test Samples8.1 Material samples not obtained from garments for pre-conditioning shall be at least 1 m2(1.2 yd2) to ensure sufficientmaterial for the test specimen size requirements in 9.1.1 and9.1.2. The material sample shall
49、be representative of thematerial utilized in the construction of the protective clothingend product.8.1.1 If the material width is less than 1 m (1.1 yd), thesample shall be the full width of the material and the length ofthe sample shall be sufficient to meet the test specimen sizerequirements of 9.1.1 or 9.1.2.8.1.2 Precondition samples of protective clothing as com-plete items.8.1.3 Precondition samples of protective equipment as com-plete items.8.2 Precondition samples as required by the applicablematerial or end product specification.8.2.1 If no
