1、Designation: F 2178 06Standard Test Method forDetermining the Arc Rating and Standard Specification forFace Protective Products1This standard is issued under the fixed designation F 2178; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method and product specification is used tomeasure the arc rating and specify the requirem
3、ents forproducts intended for use as face protection for workersexposed to electric arcs that would generate heat flux valuesfrom 84 to 25 120 kW/m22 to 600 cal/cm2s. Products aretested as sold.1.2 This test method determines an arc rating for faceprotective products. The faceshield or other applica
4、ble portionsof the complete product must meet ANSI Z87.1. This excludesthe textile or non ANSI Z87.1 testable parts of the hoodassemblies or other tested products. This standard does notmeasure optical and impact properties (see ANSI Z87.1) butdoes specify requirements for optical and impact propert
5、ies.1.3 The materials covered by this standard are in the form offaceshields attached to the head by protective helmets (hardhats), headgear, or hood assemblies. Faceshields are tested withor without other face and head protective products, for ex-ample, sock hoods, balaclavas, sweat shirt hoods or
6、jackethoods.1.3.1 Fabric layers used in hood assemblies or other itemstested under this standard shall meet the requirements ofSpecification F 1506.1.4 This test method shall be used to measure and describethe properties of materials, products, or assemblies in responseto convective and radiant ener
7、gy generated by an electric arcunder controlled laboratory conditions and does not purport topredict damage from light other than the thermal aspectsmeasured.1.5 UnitsThe values stated in SI units shall be regarded asstandard except as noted. Within the text, alternate units areshown in brackets.The
8、 values stated in each system may not beexact equivalents; therefore, alternate systems must be usedindependently of the other. Combining values from the systemsdescribed in the text may result in nonconformance with themethod.1.6 This standard does not purport to describe or appraisethe effect of t
9、he electric arc fragmentation explosion andsubsequent molten metal splatter, which involves the pressurewave containing molten metals and possible fragments of othermaterials except to the extent that heat energy transmission dueto these arc explosion phenomena is reduced by test specimens.1.7 This
10、standard shall not be used to describe or appraisethe fire hazard or fire risk of materials, products, or assembliesunder actual fire conditions. However, results of this test maybe used as elements of a fire assessment which takes intoaccount all of the factors which are pertinent to an assessmento
11、f the fire hazard of a particular end use.1.8 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 regulator
12、y limitations prior to use. For specificprecautions, see Section 7.2. Referenced Documents2.1 ASTM Standards:2C 177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusD 123 Terminology Relating to TextilesD 3776 Test Met
13、hod for Mass Per Unit Area (Weight) ofFabricD 4391 Terminology Relating to The Burning Behavior ofTextilesE 457 Test Method for Measuring Heat-Transfer Rate Usinga Thermal Capacitance (Slug) CalorimeterF 1494 Terminology Relating to Protective Clothing1This test method is under the jurisdiction of A
14、STM Committee F18 onElectrical Protective Equipment for Workers and is the direct responsibility ofSubcommittee F18.65 on Wearing Apparel.Current edition approved Nov. 15, 2006. Published January 2007. Originallyapproved in 2002. Last previous edition approved in 2002 as F 2178 02.2For referenced AS
15、TM 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
16、ocken, PA 19428-2959, United States.F 1506 Performance Specification for Flame Resistant Tex-tile Materials for Wearing Apparel for Use by ElectricalWorkers Exposed to Momentary Electric Arc and RelatedThermal HazardsF 1958/F 1958M Test Method for Determining the Ignit-ability of Non-flame-Resistant
17、 Materials for Clothing byElectric Arc Exposure Method Using MannequinsF 1959/F 1959M Test Method for Determining the ArcRating of Materials for Clothing2.2 ANSI/IEEE Standards:IEEE Standard Dictionary of Electrical and ElectronicsTerms3ANSI Z87.1-2003 Practice for Occupational and Educa-tional Eye
18、and Face Protection43. Terminology3.1 DefinitionsFor definitions of other textile terms usedin this method, refer to terminology in Terminology D 123,D 4391, F 1494 and the IEEE Standard Dictionary of Electricaland Electronics Terms.3.2 Definitions of Terms Specific to This Standard:3.2.1 afterflame
19、, npersistent flaming of a material afterthe ignition source has been removed.3.2.2 afterflame time, nthe length of time for which amaterial continues to flame after the ignition source has beenremoved.3.2.3 arc duration, ntime duration of the arc, s.3.2.4 arc energy, vi dt, nsum of the instantaneou
20、s arcvoltage values multiplied by the instantaneous arc currentvalues multiplied by the incremental time values during thearc, J.3.2.5 arc gap, ndistance between the arc electrodes, cmin.3.2.6 arc rating, nvalue attributed to materials that de-scribes their performance to exposure to an electric arc
21、discharge, J/cm2(cal/cm2).3.2.6.1 DiscussionThe arc rating is expressed inJ/cm2(cal/cm2) and is derived from the determined value ofATPV or EBT(should a material system exhibit a breakopenresponse below the ATPV value).3.2.7 arc thermal performance value (ATPV), nin arctesting, the incident energy o
22、f a fabric or material that resultsin 50 % probability that sufficient heat transfer through thespecimen is predicted to cause the onset of a second-degreeskin burn injury based on the Stoll curve.53.2.8 arc voltage, nvoltage across the gap caused by thecurrent flowing through the resistance created
23、 by the arc gap(V).3.2.9 asymmetrical arc current, nthe total arc currentproduced during closure; it includes a direct component and asymmetrical component, A.3.2.10 blowout, nthe extinguishing of the arc caused by amagnetic field.3.2.11 breakopen, nin electric arc testing, a materialresponse eviden
24、ced by the formation of one or more holes inthe material which may allow thermal energy to pass throughmaterial.3.2.11.1 DiscussionThe specimen is considered to exhibitbreakopen when any hole in the material or fabric is at least 1.6cm20.5 in.2 in area or at least 2.5 cm 1.0 in. in anydimension. For
25、 textile materials, single threads across theopening or hole do not reduce the size of the hole for thepurposes of this test method. In multiple layer specimens, ifsome of the layers are ignitable, breakopen occurs when theselayers are exposed.3.2.12 breakopen threshold energy (EBT), nthe incidenten
26、ergy on a fabric or material that results in a 50 % probabilityof breakopen.3.2.12.1 DiscussionThis is the value in J/cm2cal/cm2determined by use of logistic regression analysis representingthe energy at which breakopen of the layer occurred.3.2.13 deformation, nfor electric arc testing of face pro-
27、tective products, the sagging of material greater than 7.6 cm 3in. or melting in any manner that the faceshield/windowtouches any part of the body.3.2.14 delta peak temperature, ndifference between themaximum temperature and the initial temperature of the sensorduring the test, C.3.2.15 dripping, ni
28、n electric arc testing, a material re-sponse evidenced by flowing of a specimens material ofcomposition.3.2.15.1 DiscussionDripping is exhibited by either thefabric material or faceshield material of face protective prod-ucts.3.2.16 electric arc ignition, nin electric arc testing of faceprotective p
29、roducts, the initiation of combustion as related toelectric arc exposure, a response that causes the ignition oftextile test specimen material which is accompanied by heatand light, and then subsequent burning for at least 5 s, andconsumption of at least 25 % of the test specimen area.3.2.16.1 Discu
30、ssionFor multilayer specimens, consump-tion of the innermost FR layer must be at least 25 %.3.2.17 faceshield, na protective device commonly in-tended to shield the wearers face, or portions thereof, inaddition to the eyes, from certain hazards.3.2.18 heat attenuation factor, HAF, nin electric arcte
31、sting, the average of the percent of the incident energy that isblocked by a material.3.2.18.1 DiscussionIn arc testing of face protective prod-ucts, HAF (face) is based on the highest sensor reading amongthe four head sensors for each head exposure.3.2.19 heat flux, nthe thermal intensity indicated
32、 by theamount of energy transmitted per area and time W/m2cal/cm2s.3Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331, http:/www.ieee.org.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4t
33、h Floor, New York, NY 10036, http:/www.ansi.org.5Derived from Stoll,A. M., and Chianta, M.A., “Method and Rating System forEvaluations of Thermal Protection,” Aerospace Medicine , Vol 40, 1969, pp.1232-1238 and Stoll, A. M., and Chianta, M. A., “Heat Transfer through Fabrics asRelated to Thermal Inj
34、ury,” TransactionsNew York Academy of Sciences, Vol 33(7), Nov. 1971, pp. 649-670.F21780623.2.20 i2t, nsum of the instantaneous arc current valuessquared multiplied by the incremental time values during thearc, A2/s.3.2.21 incident energy monitoring sensors, nsensorsmounted on each side of each head
35、, using calorimeters, notcovered by specimens, used to measure incident energy.3.2.22 incident exposure energy (Ei), nin arc testing, thetotal incident energy delivered to monitor calorimeter sensorsas a result of the arc exposure, J/cm2cal/cm2.3.2.22.1 DiscussionIn an arc test exposure, incident ex
36、-posure energy for a specimen is determined from the averageof the measured incident energy from the respective twomonitor sensors adjacent to the test specimen.3.2.23 material response, nmaterial response to an elec-tric arc is indicated by the following terms: breakopen, melting,dripping, deformat
37、ion, afterflame time, shrinkage, and electricarc ignition.3.2.24 melting, nin arc testing, a material response evi-denced by softening of the material.3.2.25 peak arc current, nmaximum value of the AC arccurrent, A.3.2.26 RMS arc current, nroot mean square of theAC arccurrent, A.3.2.27 shrinkage, ni
38、n testing face protective products,amaterial response evidenced by reduction in specimen size.3.2.28 Stoll curve, nan empirical predicted second-degreeskin burn injury model, also commonly referred to as the StollResponse.3.2.29 time to delta peak temperature, nthe time frombeginning of the initiati
39、on of the arc to the time the delta peaktemperature is reached, s.3.2.30 X/R ratio, nthe ratio of system inductive reactanceto resistance. It is proportional to the L/R ratio of time constant,and is, therefore, indicative of the rate of decay of any DCoffset. A large X/R ratio corresponds to a large
40、 time constantand a slow rate of decay.4. Summary of Test Method4.1 This test method determines the heat transport responseacross a material, fabric, or fabric system when exposed to theheat energy from an electric arc. This heat transport response isassessed versus the Stoll curve, an approximate h
41、uman tissuetolerance predictive model that projects the onset of a second-degree burn injury.4.1.1 Products are mounted on the standard mannequin headcontaining copper slug calorimeters inserted in the eyes,mouth, and chin positions. During this procedure, the amountof heat energy transferred by the
42、 specimen face protectiveproducts is measured during and after exposure to an electricarc.4.1.2 The thermal energy exposure and heat transport re-sponse of the test specimen(s) are measured with copper slugcalorimeters. The change in temperature versus time is used,along with the known thermo-physic
43、al properties of copper todetermine the respective thermal energies delivered to andthrough the specimen(s).4.2 This procedure incorporates incident energy monitoringsensors.4.3 Product and material performance for this procedure aredetermined by comparing the amount of thermal energygenerated by th
44、e arc flash on monitor sensors with the energytransferred by or through the test specimen(s) and measured bysensors on the mannequin head.4.4 Product and material responses shall be further de-scribed by recording the observed effects of the electric arcexposure on the specimens using the terms in t
45、he Reportsection.5. Significance and Use5.1 This test method is intended for the determination of thearc rating of a product/design, intended for use as faceprotection for workers exposed to electric arcs.5.1.1 Because of the variability of the arc exposure, differ-ent heat transmission values may b
46、e observed at individualsensors. The results of each sensor are evaluated in accordancewith Section 12.5.2 This test method maintains the specimen in a static,vertical position and does not involve movement except thatresulting from the exposure.5.3 This test method specifies a standard set of expos
47、ureconditions. Different exposure conditions may produce differ-ent results.5.4 This specification covers the minimum performancecriteria for arc resistance and other requirements for faceprotective products used by workers who may be exposed tothermal hazards of momentary electric arcs or flame.5.5
48、 The purchaser has the option to perform or haveperformed any of these tests in order to verify the performanceof the face protective product. Claims for failure to meet thespecification are subject to verification by the manufacturer.NOTE 1In addition to the standard set of exposure conditions, oth
49、erconditions representative of the expected hazard may be used and shall bereported should this data be cited.6. Apparatus6.1 General Arrangement for Determining Rating UsingSensor Heads and Monitor SensorsThe test apparatus shallconsist of supply bus, arc controller, recorder, arc electrodes,two (or optionally three) four-sensor heads, and four (oroptionally six) incident energy monitoring sensors. The arcexposure shall be monitored with two incident energy-monitoring sensors for each sensored head.6.1.1 Arrangement of t
