1、Designation: E2957 15Standard Test Method forResistance to Wildfire Penetration of Eaves, Soffits andOther Projections1This standard is issued under the fixed designation E2957; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 fire-test-response standard prescribes a method forqualitatively assessing the resistance to fire penetrat
3、ion of eaveoverhangs and other projections, such as the soffits of roofeaves and cantilevered floor projections, when exposed todirect flame impingement from a simulated external wildfireexposure, such as encountered in a “Wildland Urban Interface”scenario. This test method provides data suitable fo
4、r comparingthe relative performance of materials, which are used as theexposed underside surfaces of eave overhangs and otherprojections.1.2 This test method measures the ability of eave overhangsand other projections to resist fire penetration from the exteriorinto the wall cavity or unexposed side
5、 of the test specimenunder the conditions of exposure.1.3 This test method is applicable to eave overhangs andother projections such as the soffits of roof eaves and cantile-vered floor projections intended for use with either combustibleor noncombustible building envelopes.1.4 Limitations of the te
6、st method are listed in Section 5.1.5 The values stated in metric units are to be regarded asthe standard. Values in parentheses are for information only.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 t
7、his standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This standard is used to measure and describe theresponse of materials, products, or assemblies to heat andflame under controlled laboratory conditions, but
8、does not byitself incorporate all factors required for fire hazard or fire riskassessment of the materials, products or assemblies underactual fire conditions.1.8 Fire testing is inherently hazardous. Adequate safe-guards for personnel and property shall be employed inconducting these tests.1.9 The
9、text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(including those in tables and figures) shall not be consideredas requirements of the standard.2. Referenced Documents2.1 ASTM Standards:2C1396 Specification for Gypsum BoardD2898 Practic
10、e for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire TestingD4442 Test Methods for Direct Moisture Content Measure-ment of Wood and Wood-Base MaterialsD4444 Test Method for Laboratory Standardization andCalibration of Hand-Held Moisture MetersD6662 Specification for Polyolefin-Based
11、Plastic LumberDecking BoardsD7032 Specification for Establishing Performance Ratingsfor Wood-Plastic Composite Deck Boards and GuardrailSystems (Guards or Handrails)E176 Terminology of Fire StandardsE631 Terminology of Building ConstructionsE2707 Test Method for Determining Fire Penetration ofExteri
12、or Wall Assemblies Using a Direct Flame Impinge-ment ExposureE2912 Test Method for Fire Test of Non-Mechanical FireDampers Used in Vented ConstructionE2886/E2886M Test Method for Evaluating the Ability ofExterior Vents to Resist the Entry of Embers and DirectFlame Impingement2.2 Other Standards:ISO
13、13943 Fire SafetyVocabulary3NFPA 286 Standard Methods of Fire Tests for EvaluatingContribution of Wall and Ceiling Interior Finish to RoomFire Growth41This test method is under the jurisdiction of ASTM Committee E05 on FireStandards and is the direct responsibility of Subcommittee E05.14 on External
14、 FireExposures.Current edition approved July 1, 2015. Published August 2015. DOI: 10.1520/E2957-152For 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 Docu
15、ment Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http:/www.iso.org.4Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/w
16、ww.nfpa.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsFor definitions of terms used in thisstandard, see Terminology E176, E631 and ISO 13943. In caseof conflict between E176 and E631 or ISO 13943, t
17、hedefinitions given in Terminology E176 shall prevail. In case ofconflict between E631 and ISO 13943, the definitions given inTerminology E631 shall prevail.3.2 Definitions of Terms Specific to This Standard:3.2.1 building envelope, nthe boundary or barrier separat-ing different environmental condit
18、ions within a building andfrom the outside environment.3.2.2 eave, na projecting edge of a roof that extendsbeyond the building envelope.3.2.3 glow, nvisible light emitted by a solid undergoingcombustion.3.2.4 holding fixture, napparatus designed to hold the testspecimen and a wall assembly, describ
19、ed in 7.3.3.2.5 projection, nan exterior outcrop of the building,such as a cantilevered room, that protrudes from or overhangsthe building envelope.3.2.5.1 DiscussionExamples include, but are not limitedto, eaves, soffits, enclosed cantilevered balconies, and enclosedcantilevered room bump-outs.3.2.
20、6 sofft, nthe enclosed underside of any exterior over-hanging section of a roof eave.3.2.7 sustained flaming, nflame on or over the surface ofa test specimen that lasts longer than a period of 4 s.3.2.8 wall assembly, nframed vertical section simulatingan exterior wall below an eave overhang or proj
21、ection used inthe evaluation of test specimen.3.2.8.1 DiscussionParagraph 7.2 describes the wall as-sembly used in this test method.4. Summary of Test Method4.1 This test method provides for the direct flame exposureof eave overhang and other projections.4.2 This test method employs a gas burner to
22、produce adiffusion flame in contact with the test specimen.4.3 The flame source is centered left to right and below thetest specimen.4.4 The gas burner produces a prescribed net rate of heatoutput during the flame exposure period, after which the flameexposure is terminated.4.5 The test method monit
23、ors the fire characteristics and theability of the test specimen to resist fire penetration during theflame exposure period and a subsequent observation period.4.6 Observations are made for the appearance of sustainedflaming and glow on the unexposed side during the 10-minflame exposure period and a
24、 subsequent 30-min observationperiod.5. Significance and Use5.1 The test method described herein monitors the firecharacteristics and the ability of eave overhangs and otherprojections to resist exterior fire penetration from underneathunder the specified fire exposure conditions.5.2 Representative
25、joints and other characteristics of theeave overhang or projection shall be included in the testspecimen when these details are representative of the end-useconstruction.5.3 The test method does not apply to vents or perforatedmaterials used to enclose or cap eaves, soffits, and otherprojections.NOT
26、E 1Test Methods E2912 and E2886/E2886M are methods used totest vents or perforated materials to resist direct flame impingement andflame penetration into the building.5.4 The test method is devised for eave overhangs and otherprojections independent of the materials covering the buildingenvelope.NOT
27、E 2Heat contribution from burning materials covering the build-ing envelope beyond the prescribed fire exposure is not considered in thistest method.5.5 The test method does not necessarily represent theexpected performance of eave overhang and projections underall actual fire conditions, but it doe
28、s provide a basis forcomparing eave overhang and projections materials whensubjected to the test procedure described herein.5.6 In this procedure, the test specimen is subjected tospecific laboratory fire test conditions. If different test condi-tions are substituted or the anticipated end-use condi
29、tions arechanged, it is not known whether it is possible by use of thistest to predict changes in the performance characteristicsmeasured. Therefore, the results are strictly valid only for thefire test conditions and construction tested.5.7 The test method does not provide any basis for deter-minin
30、g the fire resistance characteristics of eave overhangs orprojections when exposed to a fire originating in the building.5.8 The test method does not address interior or exteriorflame spread.6. Safety Precautions6.1 The test procedure involves high temperatures andcombustion processes. Therefore, th
31、e potential exists for burns,ignition of extraneous objects or clothing, and for inhalation ofcombustion products.7. Apparatus7.1 Unless otherwise noted, dimensions in the followingdescriptions shall be followed with a tolerance of 613 mm (0.5in.).7.2 Wall AssemblyFramed assembly made up of standard
32、38 by 89 by 2440 mm (2 by 4 in. by 8 ft) standard wood wallstuds (metal studs optional) at 406 mm (16 in.) o.c. overlaidwith 16 mm (58 in.) Type “X” gypsum board complying withSpecification C1396, or a noncombustible board material ofnominal thickness of 12 mm (12 in.) or greater.7.2.1 The wall asse
33、mbly dimensions shall be 1220 mm (4 ft)wide and 2440 mm (8 ft) high.7.3 Holding FixtureThe assembly shown in Figs. 1 and 2is designed to permit rapid installation and removal of the testE2957 152specimen and the wall assembly, and to prevent edge penetra-tion of fire at the margins of the wall assem
34、bly. The holdingfixture includes a sturdy frame assembly to mount the testspecimen and the wall assembly. The holding fixture permits aprefabricated wall assembly with an attached test specimen tobe inserted from the rear and to seal in such a way that protectsthe wall assembly edges from fire. Side
35、 shields are situatednear the vertical edges of the holding fixture and extend fromthe holding fixtures base to within 305 mm (12 in.) of the topof the wall assembly as shown in Figs. 1 and 2 to aid inminimizing extraneous drafts to the surface of the test speci-men.7.3.1 The side shields shall cons
36、ist of nominal 16 mm (58in.) Type “X” gypsum board complying with SpecificationC1396 or a noncombustible board material of 12 mm (12 in.)nominal thickness or greater mounted on a sturdy frame.7.3.2 The side shield dimensions shall be 609 mm (28 in.)wide and 2134 mm (84 in.) high.FIG. 1 Holding Fixtu
37、re Loaded With Eave Test Specimen and Wall AssemblyE2957 153NOTE 3The holding fixture used in this test method is the same as theWall Assembly Holding Fixture described in Paragraph 7.2, Test MethodE2707 except the simulated noncombustible soffit has been replaced withthe test specimen under investi
38、gation.8. Test Room8.1 The ambient temperature in the test room shall be above15 C (60 F) and the relative humidity shall be less than 75 %.The test room shall be draft-protected and equipped with anexhaust hood system for removal of products of combustionduring testing.8.2 Air velocities in the vic
39、inity of the ignition sourceburner shall not exceed 0.5 m/s (1.64 ft/s) measured at ahorizontal distance of 0.5 m (20 in.) from the edge of the wallassembly.8.3 Air supply shall not be limited during the test.9. Ignition Source and Calibration9.1 Ignition Source Burner:9.1.1 The ignition source shal
40、l be a gas diffusion burnerwith a porous top surface of a refractory material.FIG. 2 Holding Fixture Loaded With Projection Test Specimen and Wall AssemblyE2957 1549.1.1.1 The gas diffusion burner shall have a nominalsurface area 305 by 305 mm (12 by 12 in.), as shown in Fig. 3.9.1.1.2 The gas diffu
41、sion burner shall be supported for anominal height of 152 mm (6 in.) making the total height 3056 6mm(126 0.25 in.).NOTE 4The burner used for testing in this standard is the same asdescribed in Section 4.1, NFPA 286.9.1.2 The refractory material specified in 9.1.1 shall be aminimum 102 mm (4 in.) la
42、yer of white Ottawa sand used toprovide the horizontal surface through which the gas issupplied.9.2 Burner Position:9.2.1 The gas diffusion burner enclosure shall be positionedso that it is centered relative to the width of the wall assembly.9.2.2 The gas diffusion burner shall be located 25 6 6mm(1
43、 6 0.25 in.) from the wall assembly.9.2.3 The distance from the base of the holding fixture inFigs. 1 and 2 to the top surface of the gas diffusion burner shallbe 915 6 6mm(366 0.25 in.). To obtain the required distancefrom the base of the holding fixture in Figs. 1 and 2 to the topsurface of the ga
44、s diffusion burner, the nominal 305 mm (12in.) tall burner shall be placed on top of a nominal 610 mm (24in.) tall metal stand with a nominal top surface area of 610 by610 mm (24 by 24 in). The metal stand is shown in Fig. 4.9.3 The gas diffusion burner shall be supplied with mini-mum 99 % pure prop
45、ane (often described by suppliers as CP or“chemically pure” grade) having a nominal heating value of93.0 MJ/m322.2 kilocalories (thermochemical) per cubicmeter or 2500 Btu (thermochemical) per cubic foot.9.4 The propane shall be supplied to the gas diffusion burnerthrough a metered control system.9.
46、5 The propane supply to the gas diffusion burner shallproduce a net heat output of 300 615 kW (17,060 6 853BTU/min).9.6 The gas diffusion burner shall be ignited by a pilotburner or a remotely controlled spark igniter.9.7 Gas diffusion burner controls shall be provided forautomatic gas supply shut-o
47、ff if flameout occurs.9.8 Gas Diffusion Burner Calibration:9.8.1 The gas supply to the gas diffusion burner shall be thesame as used for testing. The gas shall be metered and keptconstant throughout the calibration test.FIG. 3 Gas Diffusion Burner for TestE2957 1559.8.2 Place the gas diffusion burne
48、r in the configuration tobe used for testing and obtain the heat release rate valueprescribed in 9.5.9.8.3 Take measurements at least once every 6 s and start 1min prior to ignition of the gas diffusion burner. Determine theaverage heat output over a period of at least 1 min by theoxygen consumption
49、 method, or calculate the heat output fromthe gas mass flow and the net heat of combustion.9.9 Frequency of Calibration:9.9.1 Calibrate the gas diffusion burner for heat output priorto each days use.9.9.2 Any indication of off-limit condition such as unusualflame appearance or flame contour, excess turbulence, orunusual noise shall be cause for calibration prior to further use.10. Preparation of Test Specimens10.1 Unless otherwise noted, dimensions in the followingdescriptions, shall be followed with a tolerance of 613 mm(0.5 in.).10.2 Construction
