1、Designation: D2898 10Standard Practice forAccelerated Weathering of Fire-Retardant-Treated Wood forFire Testing1This standard is issued under the fixed designation D2898; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、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 addresses the durability of a fire-retardanttreatment of wood products by exposure to accelerated cycles
3、of wetting, drying, or ultraviolet (UV) exposure, or combina-tion thereof, prior to evaluation by a fire response test. Fourconditioning methods are described.1.2 This practice is applicable to wood products that havebeen treated with fire-retardant chemicals by pressure impreg-nation.1.3 The test s
4、pecimens are to be in the form of, or suitablefor fabrication into, test specimens, such as those described inTest Methods E84, E108, and E1354 and other standard testmethods for evaluating the fire performance of fire-retardant-treated wood products.1.4 The text of these methods references notes an
5、d 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 mathematicalconvers
6、ions 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
7、and 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 MaterialsE108 Test Methods for Fire Tests of Roof CoveringsE176 Te
8、rminology of Fire StandardsE1354 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using an Oxygen Con-sumption Calorimeter2.2 ICC Evaluation Service Acceptance Criteria:3AC 107 Classified Wood Roof Systems2.3 UL Standards:4UL 790 Tests for Fire Resistance of Roof Coveri
9、ng Material3. Terminology3.1 DefinitionsDefinition used in this practice are inaccordance with Terminologies D9 and E176, unless otherwiseindicated.4. Significance and Use4.1 This practice describes different methods of exposingfire-retardant-treated wood products or assemblies to con-trolled accele
10、rated weathering or conditioning.4.2 The conditioning simulates effects of leaching, drying,temperature, and, in two methods, 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. Apparatu
11、s5.1 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 weather inth
12、e 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 temperat
13、ure measured 1 in. (25 mm) above the specimen1This practice is under the jurisdiction of ASTM Committee D07 on Wood andare the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.Current edition approved March 1, 2010. Published March 2010. Originallyapproved in 1970. Last previ
14、ous edition approved in 2009 as D2898 09. DOI:10.1520/D2898-10.2For 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 websit
15、e.3Available 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 1942
16、8-2959, 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 (0.127 m/s). Forced air movement
17、 shall 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/m2irradiance 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 69 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 1Note water quality, especially pH and hardness, as it canimpact the accelerated weathering of the treated specimen
22、s.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 2It is acceptable to mount specimens in sections that can bereassembled 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 (0.005 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 Metho
26、dsE108, 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 one or more cycles, change the positionof the specimens within the apparatus so that each specimenoccupies every
27、location within the apparatus for an approxi-mately equal number of cycles.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,
28、 4 h drying, and 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
29、 firstthree cycles, drain all water rather than recirculate it. In eachsubsequent wetting period, circulate a volume of at least 5 gal(19 L) of fresh water through each spray head.7.2.4 Dry at a temperature of 150 6 5F (66 6 3C), withthis temperature attained within 15 min from the start ofdrying. E
30、xposure to the UV 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 specimenoccupies every location within the apparatus for an approxi-mately equal number of cycles.7.3 Method C:7.3.
31、1 The total duration of this 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
32、.3 6 0.02 gal/min/ft2(12.2 6 0.8 L/min/m2)ata temperature 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 MethodsE108, nozzles shall be mounted approximately two feet abovethe test decks.7.3.3.2 Recirculation of the water is
33、 permitted with thefollowing restrictions. 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 be5General Electric Type H275 RUV (275
34、 W) or Osram Ultra-Vitalox (300 W), orequivalent, is suitable. General Electric no longer manufactures the Type H275 bulb.If you are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the
35、responsible technical committee,1which you may attend.D2898 102introduced at a rate that provides a minimum of 5 gal (19 L) offresh water per nozzle, per cycle.7.3.4 Drying shall utilize sunlamps for both heat and UVexposure, with supplemental heaters as required to maintain atemperature of 145F to
36、155F (63C to 68C) with thistemperature attained within 15 min from the start of drying.7.3.5 At the end of one or more cycles, change the positionof the specimens within the apparatus so that each specimenoccupies every location within the apparatus for an approxi-mately equal number of cycles.7.4 M
37、ethod 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 (sevendays) of water exposure, 48 h (two days) of rest for drainingand 120 h (five days) of drying. The water exposure of thesev
38、enth 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 per hour (0.005 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
39、.4.3.1 Recirculation of the water is not permitted.7.4.3.2 For decks intended for testing by Test MethodsE108, nozzles shall be mounted approximately seven feet (2.1m) above 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 one or mor
40、e cycles, change the positionof the specimens within the apparatus so that each specimenoccupies every location within the apparatus for an approxi-mately equal number of cycles.8. Conditioning8.1 Upon completion of the prescribed exposure, the speci-men shall be conditioned in accordance with the a
41、pplicable firetest standard.8.2 For decks intended for testing by Test Methods E108,control the final drying cycle temperature so the moisturecontent of the deck lumber is from 8 % to 12 %. For plywooddeck, the moisture content shall not exceed 8 %.9. Report9.1 Report the following information:9.1.1
42、 The accelerated weathering method (A, B, C, or D)used.9.1.2 Description of the specimens.9.1.2.1 Include information about the fire-retardant treat-ment including any surface coating and any identifying marks.9.1.2.2 Visual observations of the specimens before andafter the accelerated weathering.9.
43、1.3 Description of the weathering apparatus or chamber:9.1.3.1 The horizontal projected area over which eachnozzle discharges water to the nearest square foot (0.09 m2).9.1.3.2 The slope of the test specimen (see 6.2).9.1.3.3 Information on the UV lamps used, if used.9.1.3.4 Any deviations from the
44、specifications in the stan-dard.9.1.4 Describe any means used to protect surfaces that arenot exposed to weather in the assembled form or fire in thesubsequent test (see 5.2).9.1.5 Results of the water spray calibration (see 5.5).9.1.6 The characteristics or quality of the water, includingpH and har
45、dness (see 5.5.5 and Note 1).9.1.7 The quantity of water that was re-circulated (see7.1.3.1, 7.2.3, 7.3.3.2,or7.4.3.1).9.1.8 Rate of flow of forced air movement across the surfaceof the specimens (see 5.3).10. Keywords10.1 fire retardant; fire retardant-treated wood; fire testing;weatheringAPPENDIX(
46、Nonmandatory Information)X1. COMMENTARYX1.1 Method A was devised for larger specimens, andMethod B for smaller ones.X1.2 Method B was developed by the USDA, ForestService, Forest Products Laboratory. The method and theexposure chamber commonly associated with Method B aredescribed in various publica
47、tions of that laboratory.X1.3 A research study showed that the two exposuremethods, A and B, were equivalent in leaching effect asdemonstrated by the flame-spread results obtained on speci-mens exposed by either method when tested for flame spread.6X1.4 Method C is part of the acceptance criteria fo
48、rclassified wood roof systems of the ICC Evaluation Service.The option of successful fire tests after the exposure of the“amended rain test” was developed as an alternative to theirrequirement for successful fire tests of specimens exposed to6“Correlation of ASTM Exposure Tests for Evaluating Durabi
49、lity of Fire-Retardant Treatment of Wood,” by C.A. Holmes, Forest Products Laboratory,Research Paper FPL 194, U.S.D.A. Forest Service, 1973.D2898 103the 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 E108).X1.5 Method D is an alternative test cycle for the Rain Testspecified in Test Methods E108.X1.6 This practice discusses methods for acceleratedweathering of fire-retardant-treated wood for fire
