1、Designation: D5516 17Standard Test Method forEvaluating the Flexural Properties of Fire-Retardant TreatedSoftwood Plywood Exposed to Elevated Temperatures1This standard is issued under the fixed designation D5516; the number immediately following the designation indicates the year oforiginal adoptio
2、n 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 is designed to determine the effect ofexposure to high tem
3、peratures and humidities on the flexureproperties of fire-retardant treated softwood plywood. In thistest method, plywood is exposed to a temperature of 77C(170F).1.2 The purpose of the test method is to compare theflexural properties of fire-retardant treated plywood relative tountreated plywood. T
4、he results of tests conducted in accor-dance with this test method provide a reference point forestimating strength temperature relationships. This test methodis intended to provide an accelerated test at elevated tempera-tures and controlled humidities of plywood sheathing treatedwith the same chem
5、ical formulation(s) and processing condi-tions as plywood used commercially.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.1.4 Thi
6、s 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 regulatory limitations prior to use.1.5 This international
7、 standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee
8、.2. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based Prod-uctsD1165 Nomenclature of Commercial Hardwoods and Soft-woodsD2915 Practice for Sampling and Data-Analysis for Struc-tural Wood and Wood-Based ProductsD3043 Test Methods for Structural Panels in FlexureD4
9、933 Guide for Moisture Conditioning of Wood andWood-Based MaterialsD6305 Practice for Calculating Bending Strength DesignAdjustment Factors for Fire-Retardant-Treated PlywoodRoof SheathingE84 Test Method for Surface Burning Characteristics ofBuilding MaterialsE176 Terminology of Fire StandardsE2768
10、Test Method for Extended Duration Surface BurningCharacteristics of Building Materials (30 min Tunnel Test)2.2 Other Standards:AWPA C-27 Plywood-Fire Retardant Treatment by PressureProcesses3AWPA U1 Use Category System: User Specification forTreated Wood3NFPA 703 Standard for Fire Retardant Impregna
11、ted Woodand Fire Retardant Coatings for Building Materials4PS 1 U.S. Product Standard for Structural Plywood51This test method is under the jurisdiction of ASTM Committee D07 on Woodand is the direct responsibility of Subcommittee D07.07 on Fire Performance ofWood.Current edition approved April 15,
12、2017. Published June 2017. Originallyapproved in 1991 as ES 20 91. Last previous edition approved in 2009 asD5516 09. DOI: 10.1520/D5516-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volum
13、e information, refer to the standards Document Summary page onthe ASTM website.3Available from American Wood Protection Association (AWPA), P.O. Box361784, Birmingham, AL 35236-1784, http:/.4Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02169-7471, http:/
14、www.nfpa.org.5Available from the U.S. Department of Commerce, 1401 Constitution Ave.,NW Washington, DC 20230, http:/ts.nist.gov/Standards/Conformity/vps.cfm.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard wa
15、s developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1PS 2 U.S. Pr
16、oduct Standard for Wood-Based Structural UsePanels53. Terminology3.1 DefinitionsDefinitions used in this test method are inaccordance with Terminologies D9 and E176 and Nomencla-ture D1165.3.2 Definitions of Terms Specific to This Standard:3.2.1 depth of beamthat dimension of the beam which isperpen
17、dicular to the span and parallel to the direction in whichthe load is applied.3.2.2 spanthe total distance between the centerline ofsupports providing the reactions on which a beam is supportedto accommodate a transverse load.3.2.3 span-depth ratiothe numerical ratio of span dividedby beam depth.4.
18、Summary of Test Method4.1 After preconditioning (see 6.5), matched specimens oftreated and untreated plywood will be exposed to 77C (170F)temperature and relative humidity equal to or greater than50 %.4.2 Flexural strength tests are conducted on exposed speci-mens removed after various time periods.
19、 Flexural strengthresults shall include maximum moment, bending stiffness, andwork to maximum load. Adjust the test results to 50 % relativehumidity using Practice D6305 procedures (see X1.1.)4.3 The purpose of this test method is to determine the ratioof the treated mean to the untreated mean for t
20、he plywood andplot the accelerated exposure strength data against exposuretime.5. Significance and Use5.1 The flexural properties evaluated by this test method areintended to provide any one or all of the following:5.1.1 Data on the comparative effects of fire-retardantchemical formulations and envi
21、ronmental conditions on theflexural properties of plywood.5.1.2 Data for use in developing modification factors for theallowable design properties of treated plywood when exposedto elevated temperatures and humidities.5.1.3 Data comparing variables, such as other plywoodspecies and dimensions.5.2 Re
22、sults obtained from tests conducted and analyzed inaccordance with the procedures of this test method may beused with other information to establish recommended roofsheathing spans for fire-retardant treated plywood.NOTE 1Temperatures lower than the test temperature specified in thistest method and
23、the cumulative effects of the elevated temperatures andhumidity exposures expected to be encountered in service should be takeninto account when recommended roof sheathing spans are established.NOTE 2Practice D6305 can be used to extend the laboratory strengthdata obtained by this test method to des
24、ign value recommendations. Thetest data determined by this test method are used to develop adjustmentfactors for fire-retardant treatments to apply to untreated plywood designvalues. The test data are used in conjunction with climate models andother factors.6. Test Specimens6.1 Material Selection:6.
25、1.1 Source panels for this test shall be selected from grademarked PS 1 or PS 2 commercially available 3, 4, or 5 plypanels of a single thickness, grade, construction, and bonddurability. The nominal panel thickness shall be between 12mm (1532 in.) and 16 mm (58 in.).NOTE 3Southern Pine is suggested
26、 as the test material because itrequires higher fire-retardant chemical retentions to obtain the same flamespread rating compared to other softwood plywood species. Because thebending strength of treated plywood correlates to the chemical retentionlevels, Southern Pine plywood is believed to represe
27、nt a worst casescenario for the same chemical formulation and treating/redrying proce-dures. Thus, evaluation of other species of plywood by testing of thatspecies, rather than by application of southern pine test results, areconsidered to be indicative of that species only.6.1.2 Select source panel
28、s that provide bending strengthspecimens after cutting with clear essentially straight-grainedfaces free of scoring or other manufacturing defects. The innerplies shall be essentially free of voids, core gaps, and core laps(see 7.3.4.2). Panels shall have generally uniform grain orien-tation and per
29、cent latewood along and across the panel faces.Aminimum of six sheets of plywood meeting this description isrequired. Alternate 610 mm (2 ft) long sections to be treatedand adjacent untreated 610 mm (2 ft) sections (see Fig. 1) shallhave visually similar wood quality.6.1.2.1 Specimens shall be inspe
30、cted and the culling ofspecimens done as necessary in accordance with the criteria in7.3.4.NOTE 4A minimum of six sheets of plywood is required but cullingof specimens may require more sheets.6.1.3 The specimen cutting pattern and numbering sequenceis shown in Fig. 1. Each panel of plywood is to be
31、labeled witha number from 1 to 6. Cut each sheet crosswise to provide 610mm by 1220-mm (2 by 4-ft) sections. Each section is labeledwith the sheet number and letter A, B, C, or D. The A and Csections of each of the six panels is to be treated, while the Band D sections of the six panels are to remai
32、n untreated.6.2 Treatment:6.2.1 For applications requiring conformance to buildingcode requirements for “fire-retardant-treated-wood” based onFIG. 1 Plywood Cutting PatternD5516 172Test Method E84 test extended to 30 min or Test MethodE2768, pressure treat the A and C section of each of the sixplywo
33、od panels with the fire-retardant formulation beingtested. The gage retention level of each charge shall not be lessthan the value midway between the middle of the retentionrange and the maximum retention as specified by the agencycertifying the surface burning characteristics of the treatedplywood.
34、 The retention range specified by the certifyingagency shall result in specimens that provide a flame-spreadindex of 25 or less and be reported as showing no evidence ofsignificant progressive combustion throughout the 30-minperiod, and not allow progression of the flame front beyond adistance of 3.
35、2 m (10.5 ft) beyond the centerline of the burnersanytime during the 30-min test.6.2.1.1 Alternate methods or processes of imparting fire-retardant properties can be substituted for pressure treatmentfor purposes of this test method since this method evaluates theimpact of the fire retardant method
36、on the properties of theunderlying plywood.6.2.1.2 The provisions of 6.2.1 are not intended to preventuse of this test method when the fire-retardant treatments beingcertified are for applications other than those requiring confor-mance to AWPA U1, NFPA 703, or similar code requirementsfor “fire-ret
37、ardant-treated wood” that require the Test MethodE2768 or Test Method E84 test extended to 30 min. Whenalternative performance criteria for the treatment are beingcertified, the test report on specimens of that treatment shallstate clearly the alternative performance criteria and that thetreatment r
38、etention was limited to that required for the alter-native performance criteria.6.2.2 Weigh all plywood sections before and immediatelyafter treatment to determine the chemical retention based onthe solution retained and the concentration of chemicals in thesolution. Complete a treating report for e
39、ach charge of materialto document the treating cycle, times, pressures, and plywoodretentions.6.3 Post-Treatment Drying:6.3.1 After pressure treatment, kiln dry the twelve treatedplywood sections to a maximum moisture content of 15 %following the standard redrying procedures established for thetreat
40、ment by the manufacturer. Redry the sections at themanufacturers maximum specified dry bulb temperature witha minus 2C (4F) tolerance for 21 h of the first 24-h period.For the remainder of the drying period, the tolerance shall beminus 3C (5F). There is no upper limit on the redryingtemperature. Sti
41、cker all plywood sections to obtain proper airflow across the panels and to provide even drying. If themanufacturers procedures permit double stacking of panelsintended for structural application, treated plywood test sec-tions also shall be double stacked rather than stickered indi-vidually.NOTE 5R
42、esearch has shown that high kiln drying temperatures canadversely affect the structural properties of wood products. TheAWPAandNFPAstandards for fire retardant treated wood products limit kiln dry bulbtemperatures. AWPA C-27 requires that the dry bulb temperature of thekiln not exceed 71C (160F) dur
43、ing any kiln drying of plywood treatedwith fire retardants. In the case of exterior fire retardants that requirecuring at higher temperatures, curing after the moisture content is 15 % orless is permitted. However, such elevated curing temperatures must notexceed 99C (210F) and the total curing time
44、 must not exceed 48 h. InNFPA 703, the dry bulb temperature must not exceed 71C (160F) untilthe average moisture content of the wood has dropped to 25 % or less.NOTE 6To establish the worst-case flexural properties of treatedsoftwood plywood, the laboratory must redry the test material within asmall
45、 negative tolerance of the maximum temperature used by themanufacturer. Therefore, there is no upper limit for the temperature usedin the tests. If a manufacturer desires to establish conservative propertyvalues or provide a basis for evaluating production material that exceedsthe limit, the test ma
46、terial can be redried at that temperature. Amanufacturer then is allowed to determine the necessary productionschedule for their treatment and equipment or conditions. Thus, a steppedschedule (for example, 10 h at 54C (130F), 10 h at 60C (140F), 10 hat 71C (160F), etc.) is allowed by the standard, p
47、rovided the maximumtemperature tolerance requirement is met. These provisions provide forair-drying production material provided the redry conditions for the testmaterials are within the tolerance of the maximum temperature specifiedby the manufacturer.6.3.2 Monitor the moisture content of the plywo
48、od sectionsduring the drying cycle by individually weighing the sections.Reduce as much as possible damage or warp during the dryingprocess by adequately supporting the sections. Keep a well-documented kiln charge report and kiln recorder chart detailingthe drying cycle and parameters.6.4 Specimen P
49、reparation:6.4.1 After drying, cut the treated and untreated 610 by1220-mm (2 by 4-ft) sections into nominal 75 by 610-mm (3 by24-in.) test specimens as shown on Fig. 1. Alternatively,specimen sizes in accordance with Test Methods D3043, TestMethod A shall be used instead of this size. Number thesespecimens consecutively from 1 to 14, creating 168 treated and168 untreated specimens. Randomly select 20 of the 168untreated and treated specimens as unexposed controls. Theremaining 148 treated and 148 untreated specimens shall
