ASTM D2898-2008 Standard Practice for Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing.pdf

1、Designation: D 2898 08Standard Practice forAccelerated Weathering of Fire-Retardant-Treated Wood forFire Testing1This standard is issued under the fixed designation D 2898; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o

2、f 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 practice covers the durability of a fire-retardanttreatment of wood under exposure to accelerated weathering.Fo

3、ur conditioning methods are described. Methods are suitablefor application to a test specimen prior to subjecting thatspecimen to an appropriate fire test.1.2 This practice is applicable to wood products that havebeen treated with fire-retardant chemicals by pressure impreg-nation.1.3 The test speci

4、mens are to be in the form of, or suitablefor fabrication into, test specimens, such as those described inTest Methods E84, E 108, and E 1354 and other standard testmethods for evaluating the fire performance of fire-retardant-treated wood products.1.4 The text of these methods references notes and

5、footnotesthat provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be consideredas requirements of these test methods.1.5 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversio

6、ns to SI units that are provided for information onlyand are not considered standard.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 an

7、d determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsE84 Test Method for Surface Burning Characteristics ofBuilding MaterialsE 108 Test Methods for Fire Tests of Roof CoveringsE 176 Te

8、rminology of Fire StandardsE 1354 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using an Oxygen Con-sumption Calorimeter2.2 ICC Evaluation Service Guidelines:3EG 107 Classified Wood Roof Systems2.3 UL Standards:4UL 790 Tests for Fire Resistance of Roof Covering Mater

9、ial3. Terminology3.1 DefinitionsDefinition used in this practice are inaccordance with Terminologies D9and E 176, unless other-wise indicated.4. Significance and Use4.1 This practice describes different methods of exposingfire-retardant-treated wood products or assemblies to con-trolled accelerated

10、weathering or conditioning.4.2 The conditioning simulates effects of leaching, drying,temperature, and, in two methods, ultraviolet (UV) light.4.3 Method A is the method normally specified for regula-tory purposes when testing fire-retardant-treated wood that isintended for exterior applications.5.

11、Apparatus5.1 The test apparatus shall be capable of subjecting thespecimen uniformly to the test conditions described in Section7.5.2 No special means of protecting the specimen back andedges are required, but water shall not impinge directly onthose surfaces which are not exposed either to the weat

12、her inthe assembled form, or to fire in the subsequent test. Waterspray nozzles shall be provided and arranged so as to distributewater evenly over the exposed specimen surface.5.3 Accompany drying cycles with heating that is thermo-statically controlled. The controlling temperature shall be theair

13、temperature measured 1 in. (25 mm) above the specimen1These test methods are under the jurisdiction of ASTM Committee D07 onWood and are the direct responsibility of Subcommittee D07.07 on Fire Perfor-mance of Wood.Current edition approved Nov. 1, 2008. Published December 2008. Originallyapproved in

14、 1970. Last previous edition approved in 2007 as D 2898 07.2For 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.3A

15、vailable from ICC Evaluation Service, Inc., 5360 Workman Mill Road,Whittier, CA 90601, http:/icc-es.org.4Available from Underwriters Laboratories, Inc., 333 Pfingsten Road, North-brook, IL 60062, http:/.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-29

16、59, United States.surface. When sunlamps are part of the method, thetemperature-measuring device must be shielded from the UVradiation of the sunlamps. Accompany drying with uniformforced air movement across the surface of the decks at a rate ofat least 25 ft/min (0.125 m/s). Forced air movement sha

17、ll beuniform across the specimen surface, with provisions made foradequate air changes to assure thorough drying.5.4 In Methods B and C, UV light shall be distributed asevenly as possible over the specimen surface. Use sunlamps5providing UV characteristics of 5.0 W/m2/nm irradiance at awavelength of

18、 315 to 400 nm at 1 m directed normal to andmounted 26 6 6 in. (660 6 152 mm) above the specimenmeasured from the bottom of the lamp. One lamp shall be usedfor each 8 ft2(0.74 m2) of specimen, or fraction thereof.5.5 Water Spray Calibrations:5.5.1 Measure the horizontal projected area over which eac

19、hnozzle discharges water to the nearest square foot (0.09 m2).Measure the discharge of water for each nozzle for 1 min.5.5.2 Monitor the total water use during the test. A commer-cial water meter is suitable for this purpose.5.5.2.1 For Method A, the water usage shall be 42 6 1gal/ft2(1711 6 41 L/m2

20、) for a four-day cycle or 73 6 1.7gal/ft2(2975 6 71 L/m2) for a seven-day cycle.5.5.3 Each day during the water cycle, visually check thewater flow from each nozzle for obvious water obstruction inthe nozzle and uneven spray patterns. Make adjustments whennecessary.5.5.4 Review the total water flow

21、at the end of each day andat the end of each water cycle. Correct the cause of anyoff-limit conditions.5.5.5 The characteristics or quality of the water shall benoted (see Note 1).NOTE 1Water quality, especially pH and hardness, can impact theaccelerated weathering of the treated specimens and shoul

22、d be noted.6. Test Specimen6.1 The test specimen shall include all parts of the corre-sponding fire test specimen that are subjected to weatherexposure in normal use. Shingles or shakes shall be applied totheir intended sheathing.NOTE 2Specimens may be mounted in sections that can be reas-sembled su

23、bsequently without trimming into the appropriate fire testspecimen.6.2 The specimen surface shall have a slope of 4 in 12 inMethods A, C, and D of this standard. For Method B, thesurface shall have a slope ranging from 4 in 12 minimum to 8in 12 maximum.7. Exposure Cycle7.1 Method A:7.1.1 The total d

24、uration of this method is twelve weeks (84days).7.1.2 Subject the specimens to an exposure cycle consistingof twelve one-week cycles. Each cycle is to consist of 96 h (4days) of water exposure and 72 h (3 days) of drying.7.1.3 Apply water in a moderately fine spray uniformly overthe exposed specimen

25、 surfaces by spray nozzles that deliver anaverage of 0.7 in. of water per hour (0.05 mm/s) or 0.0073gal/minft2(0.30 L/minm2) of specimen surface) at a tempera-ture between 35 and 60F (2 and 16C).7.1.3.1 Recirculation of the water is not permitted.7.1.3.2 For decks intended for testing by Test Method

26、sE 108, nozzles shall be mounted approximately seven feet (2.1m) above the test decks.7.1.4 Dry at a thermostatically controlled temperature of135 to 140F (57 to 60C).7.1.5 At the end of each cycle, change the position of eachspecimen within the apparatus so that each specimen orsegment occupies app

27、roximately an equal number of cycles ineach location used.7.2 Method B:7.2.1 The total duration of this method is 1000 h (41 days,16 h).7.2.2 Subject the specimen to a exposure cycle consisting offorty-two 24-h cycles. Each cycle is to consist of 4 h wetting,4 h drying, 4 h wetting, 4 h drying, and

28、8 h rest. The last cycleis terminated without the 8-h rest period.7.2.3 Apply water in a moderately fine spray uniformly overthe exposed specimen surface at a rate of 0.3 6 0.02 gal/minft2(12.2 6 0.8 L/minm2) of specimen surface. Thetemperature shall not exceed 90F (32C). During the firstthree cycle

29、s, drain all water rather than recirculate it. In eachsubsequent wetting period, circulate a volume of at least 5 gal(18 L) of fresh water through each spray head.7.2.4 Dry at a temperature of 150 6 5F (63 6 3C), withthis temperature attained within 15 min from the start ofdrying. Exposure to the UV

30、 sunlamps shall be continuousthroughout the drying period.7.2.5 At the end of one or more cycles, change the positionof the specimens within the apparatus so that each specimen orsegment occupies approximately an equal number of cycles ineach location used.7.3 Method C:7.3.1 The total duration of th

31、is method is twelve weeks (84days).7.3.2 Subject the specimens to an exposure consisting of252 eight-hour cycles. Each cycle consists of four hours ofwater exposure, followed by four hours of drying.7.3.3 For the water exposure, use spray nozzles that deliveran average of 0.3 6 0.02 gal/min/ft2(0.02

32、7 L/min/m2)atatemperature of 35 to 90F (1.6 to 32.2C) to apply theuniformly distributed water exposure.7.3.3.1 For decks intended for testing by Test MethodsE 108, nozzles shall be mounted approximately two feet abovethe test decks.7.3.3.2 Recirculation of the water is permitted with thefollowing re

33、strictions. At the end of each of the first threewetting cycles, and before each of last three wetting cycles, allwater shall be drained from the system and replaced with freshwater. For all other wetting cycles, fresh water shall beintroduced at a rate that provides a minimum of 5 gal (19 L) offres

34、h water per nozzle, per cycle.5General Electric Type H275 RUV (275 W) or Osram Ultra-Vitalox (300 W), orequivalent, is suitable. General Electric no longer manufactures the Type H275 bulb.D28980827.3.4 Drying shall utilize sunlamps for both heat and UVexposure, with supplemental heaters as required

35、to maintain atemperature of 145F to 155F (63C to 68C) with thistemperature attained within 15 min from the start of drying.7.4 Method D:7.4.1 The total duration of this method is 97 days.7.4.2 Subject the specimens to an exposure consisting ofseven two-week cycles. Each cycle is to consist of 168 h

36、(sevendays) of water exposure, 14 h (two days) of rest for drainingand 120 h (five days) of drying. The water exposure of theseventh cycle is six days.7.4.3 Apply water in a moderating fine spray uniformly overthe exposed specimen surfaces by spray nozzles that deliver anaverage of 0.7 in. of water

37、per hour (0.05 mm/s) or 0.0073gal/min-ft2(0.30 L/min-m2) of specimen surface at a tempera-ture between 35 and 60F (2 and 16C).7.4.3.1 Recirculation of the water is not permitted.7.4.3.2 For decks intended for testing by Test MethodsE 108, nozzles shall be mounted approximately seven feet (2.1m) abov

38、e the test decks.7.4.4 Dry at a thermostatically controlled temperature of135 to 140F (57 to 60C).7.4.5 At the end of each cycle, change the position of eachspecimen within the apparatus so that each specimen orsegment occupies approximately an equal number of cycles ineach location used.8. Conditio

39、ning8.1 Upon completion of the prescribed exposure, the speci-men shall be conditioned in accordance with the applicable firetest standard.8.2 For decks intended for testing by Test Methods E 108,control the final drying cycle temperature so the moisturecontent of the deck lumber is from 8 % to 12 %

40、. For plywooddeck, the moisture content shall not exceed 8 %.9. Keywords9.1 fire retardant; fire retardant-treated wood; fire testing;weatheringAPPENDIX(Nonmandatory Information)X1. COMMENTARYX1.1 Method A was devised for larger specimens, andMethod B for smaller ones.X1.2 Method B was developed by

41、the USDA, ForestService, Forest Products Laboratory. The method and theexposure chamber commonly associated with Method B aredescribed in various publications of that laboratory.X1.3 A research study showed that the two exposuremethods, A and B, were equivalent in leaching effect asdemonstrated by t

42、he flame-spread results obtained on speci-mens exposed by either method when tested for flame spread.6X1.4 Method C is part of the evaluation guidelines forclassified wood roof systems of the ICC Evaluation Service.The option of successful fire tests after the exposure of the“amended rain test” was

43、developed as an alternative to theirrequirement for successful fire tests of specimens exposed tothe rain test of Method A of this standard and additionalspecimens subjected to three years of the natural weatheringtests described in the fire test standard for roof coverings(UL 790 and Test Methods E

44、 108).X1.5 Method D is an alternative test cycle for the Rain Testspecified in Test Methods E 108.X1.6 This practice discusses methods for acceleratedweathering of fire-retardant-treated wood for fire testing. InTest Methods E 108 and in EG 107, such accelerated methodsare referred to as “rain” test

45、s. The term “weathering” refers toexposing the specimens to actual outdoor exposures for speci-fied periods of time. For the outdoor exposures, the test decksare mounted facing south at an incline of 0.5 in. per horizontalfoot (416 mm per horizontal metre). Decks are tested after eachof one, three,

46、five, and ten years of exposure.6“Correlation of ASTM Exposure Tests for Evaluating Durability of Fire-Retardant Treatment of Wood,” by C.A. Holmes, Forest Products Laboratory,Research Paper FPL 194, U.S.D.A. Forest Service, 1973.D2898083ASTM International takes no position respecting the validity o

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