1、Designation: F2894 14Standard 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.1.3.1 This test m
5、ethod 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 plat
6、es, 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 S
7、I 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 of
8、 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 test
9、ed 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 Spe
10、cification for Retained Sewn Seam StrengthAfterExposures 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 Preci
11、sion 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:NFPA1975 Standard on Station/Work Uniforms for Fire andEmergency Services43. Terminology3.1 Definition
12、s of Terms:3.2 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.1Thi
13、s 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, 2014. Published February 2014. Originallyapproved in 2011. Last previous edition approved in 201
14、2 as F2894 - 12b.DOI:10.1520/F2894-14.2For 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.3Available from America
15、n 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.Copyright ASTM International, 100 Barr Harbor Drive
16、, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.2 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 or b
17、oth 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 bu
18、t 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 to p
19、roperties 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 DiscussionDimensional c
20、hange 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 shap
21、e.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 functio
22、nality, nin thermal testing of protective cloth-ing 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 pot
24、ential 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, iso
25、lating 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, protectiveclothing and equipment, a response evidenced by flowing ofthe polymer and by the formation of droplets from the flowingmaterial.3.3.4 flaking, nin thermal testing of materials, protectiveclothing and
29、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 the
30、rmal 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.) ind
31、iameter 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 equipme
32、nt, 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 equipme
33、nt, 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 evalua
34、tes the heat resistance ofmaterials, protective clothing and equipment using a hot aircirculating 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.F2894 1424.2.1 If no mate
35、rial 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.4.3 Following heat exposure, the test specimen is removedand examined for evi
36、dence 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 resistanc
37、eof 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 material spec
38、imens.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 hot air c
39、irculating 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 mmby 610
40、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 to 1.5m/s at the standard temperature and pressure of 21C at localatmospheric pressure, measured at the geo
41、metric center pointof 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 mountedsample specimen
42、, 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 K, No. 30 AW
43、G 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 has been fou
44、nd 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, Fig. 1, consists of a rigid board, 9.5 6 3mm(38 618in.) thic
45、k, with uniformly spaced pins along the perimeter atintervals of 25 6 3mm(1618 in.) to secure knit materials.The pins shall protrude 19 6 3mm(34 618 in.) from thesurface of the board, shall have a shank diameter of 2.5 6 0.5mm (0.1 6 0.02 in.), and shall be drawn to a sharply pointedtip. Construct t
46、he stretching frame with a length and width atleast large enough to accommodate the test specimen sizespecified in 9.1.1 and 9.1.2 so that the pins are located 38 612.5 mm (1.5 6 0.5 in.) inward from the edges of the testspecimen.6.3.1 The optional stretching frame is permitted to be usedbefore the
47、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 of time after heat exposure in the oven
48、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 harmfulvapors and gases are evacuated from the
49、 laboratory.7.3 Special care shall be exercised when using the optionalstretching frame. The optional stretching frame contains aseries of sharp pins, which have the potential to present apuncture hazard when not handled properly.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 construction of the pro
