1、Designation: F2894 12Standard 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 adopti
2、on 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 observatio
3、ns 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.1.4 This test met
5、hod enables the quantitative measurementof shrinkage that occurs as a result of a specified heat exposurein a hot air circulating oven.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to other units that are commonly used fo
6、r 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 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to us
7、e.NOTE 1Flame resistant and heat resistant materials are described in arange of different standards and meet a range of different requirements.For materials tested in accordance with this test method, the applicablestandard shall be used to establish preconditioning, conditioning andtesting conditio
8、ns and requirements.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesE145 Specification for Gravity-Convection and Forced-Ventilation OvensE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691
9、Practice for Conducting an Interlaboratory Study toDetermine the Precision 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/Wo
10、rk Uniforms for Fireand Emergency Services43. Terminology3.1 Definitions 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
11、.3.2.1 convective heat, nheat transferred by the motion ofa fluid.3.2.2 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 responseevidenced by a change in either o
12、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
13、 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
14、o properties of1This is under the jurisdiction of ASTM Committee F23 on Personal ProtectiveClothing and Equipment and is the direct responsibility of Subcommittee F23.80 onFlame and Thermal.Current edition approved Feb. 1, 2012. Published March 2012. Originallyapproved in 2011. Last previous edition
15、 approved in 2011 as F2894 -11 .DOI:10.1520/F2894-12.2For referenced ASTM standards, visit 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.3Availab
16、le from American Association of Textile Chemists and Colorists(AATCC), P.O. Box 12215, Research Triangle Park, NC 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 B
17、arr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.specific interest. Discoloration is a visible material responserelated to degradation. When discoloration is observed, it shallbe reported.3.2.3 ignition, nthe initiation of combustion.3.2.4 protective clothing, nan item
18、of clothing that isspecifically designed and constructed for the intended purposeof isolating all or part of the body from a potential hazard; or,isolating the external environment from contamination by thewearer of the clothing.3.2.5 protective equipment, na non-clothing item ofequipment that is sp
19、ecifically designed and constructed for theintended purpose of isolating all or part of the body from apotential hazard; or, isolating the external environment fromcontamination by the user of the equipment.3.2.6 radiant heat, nheat communicated by energy propa-gated through space and transmitted by
20、 electromagnetic waves.3.2.7 shrinkage, na decrease in one or more dimensionsof an object or material.3.3 Definitions of Terms Related to Thermal Testing ofMaterials, Protective Clothing and Equipment:3.3.1 deformation, nin thermal testing of materials, pro-tective clothing and equipment, a material
21、 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 non wovenfabrics or curling of knit fabrics shall not be identified asdeformation as long as
22、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 of the test specimen inwhole or in part.3.3.3 dripping, nin thermal testing of materials, pro
23、tec-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 and equipment, a material response evidenced by theunassisted loss of visible particles of mate
24、rial 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 thermal testing of materials,protective clothing and equipment, the appearance of a visibleape
25、rture 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.) indiameter or greater, or if the hole is rectangular in shapeapproximately 3 mm (0.12 in.) in
26、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 equipment, the liquefaction of material under theinfluence of heat.3.3.7 separation, nin thermal t
27、esting of materials, protec-tive clothing and equipment, 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 inpar
28、t.3.3.9 sticking, nin thermal testing of materials, protectiveclothing and equipment, a material response evidenced by thetest specimen adhering to itself or to other surfaces.3.3.9.1 DiscussionThis test method is conducted in amanner that avoids the contact of test specimens with ovensurfaces or wi
29、th adjacent test specimens. However, it is stillpossible for test specimens to stick to the mounting hooks orclamps and this observation shall be reported. Another evalu-ation of sticking specific to fabrics is described in 7.2.1 and 8.3of NFPA 1975. The NFPA 1975 test method evaluates thethermal st
30、ability of specimens by assessing the blocking offolded specimens placed between glass plates under weightinside an oven meeting the same characteristics as the ovenused in this test method.4. Summary of Test Method4.1 The test method evaluates the heat resistance of mate-rials, protective clothing
31、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 material or end product specification require-ments for the oven tem
32、perature 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.4.3 Following heat exposure, the test specimen is removedand examined for evidence of one or more of the followingphenomena: ignition, meltin
33、g, dripping, separation, etc., see11.5.4.4 If specified, test specimens are evaluated for shrinkageas a result of the convective heat exposure.5. Significance and Use5.1 This test method is used to evaluate the heat resistanceof materials, clothing and equipment when exposed to combi-nation of conve
34、ctive heat and radiant heat in a hot aircirculating oven. The principal findings of this test method areobservations of the specimen response to the heat exposure.5.1.1 The majority of procedures specified in this testmethod apply to the evaluation of flat material specimens.5.1.2 When evaluating no
35、n-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 shrinkage following a convective heat exposure ina hot air circulating oven.5.3 This test method is
36、 not intended to simulate the actualexposure of material, clothing or equipment in high heatconditions such as a fire environment.F2894 1226. Apparatus6.1 Test OvenThe test oven shall be a horizontal-flowcirculating oven with minimum interior dimensions of 610 mmby 610 mm by 610 mm such that a speci
37、men 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, measured at the geometric centerpoint of the
38、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 mountedsample specimen, and the oven sensing the
39、rmocouple 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 K, No. 30 AWG thermocouple.6.2 Specime
40、n 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 has been found to be an effective mate
41、rial 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 along theperimeter at intervals of 25 mm
42、 (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 frame is permitted to be usedbefore the
43、 knit specimen is placed in the oven for marking thespecimen for shrinkage determination. The stretching frame isnot used while the knit specimen is exposed in the oven. Theoptional stretching frame is also permitted to be used for aspecified period of time after heat exposure in the oven toreturn k
44、nit 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 harmfulvapors and gases are evacuated from the laborator
45、y.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 be representative of thematerial utilized in the
46、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 prote
47、ctive 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 material or end product specification require-ments for preconditioning are provided, precon
48、dition samplesaccording to the temperature, relative humidity and condition-ing time required by Practice D1776.8.2.2 If the test specimen form is not included in PracticeD1776, condition the test specimen at 21 6 1C (70 6 2F)and 65 6 2 % RH for eight hours.9. Preparation of Test Specimens9.1 After
49、preconditioning cut test specimens to the specifiedsize for testing.9.1.1 Cut each material test specimen from the materialsample or from the protective clothing complete item to a sizeof 380 6 13 mm by 380 6 13 mm (15 6 0.5 in. by 15 6 0.5in.).9.1.2 Smaller size material test specimens of 150 6 6mmby 150 6 6mm(66 0.25 in. by 6 6 0.25 in.) shall beacceptable for materials that are not to be subjected toshrinkage measurement.9.1.3 For specimens (such as straps) narrower than 150 mmin one dimension, use specimens at their normal width and cutto 150 mm in
