1、Designation: D5516 18Standard 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 Th
7、is international 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
8、 (TBT) Committee.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 Pan
9、els in FlexureD4933 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
10、 StandardsE2768 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 Re
11、tardant Impregnated Woodand Fire Retardant Coatings for Building Materials41This 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 June 1, 2018. Published August 2018. Origina
12、llyapproved in 1991 as ES 20 91. Last previous edition approved in 2017 asD5516 17. DOI: 10.1520/D5516-18.2For 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 standa
13、rds 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:/www.nfpa.org.Copyright ASTM Intern
14、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, G
15、uides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Voluntary Product Standard PS1 Structural Plywood5Voluntary Product Standard PS2 Performance Standard forWood-Based Structural Use Panels53. Terminology3.1 DefinitionsDefinitions used in thi
16、s 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 isperpendicular to the span and parallel to the direction in whichthe load is applied.3.2.2 spanthe total dista
17、nce 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. Summary of Test Method4.1 After preconditioning (see 6.5), matched specimens oftreated and untreated pl
18、ywood 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. Flexural strengthresults shall include maximum moment, bending stiffness, andwork to maximum load. Adj
19、ust 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 the plywood andplot the accelerated exposure strength data against exposuretime.5. Significance and Use5
20、.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 environmental conditions on theflexural properties of plywood.5.1.2 Data for use in developing modification
21、 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 Results obtained from tests conducted and analyzed inaccordance with the procedures of this test method a
22、re suitablefor use 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 the cumulative effects of the elevated temperatures andhumidity exposures expected to be encou
23、ntered in service should be takeninto account when recommended roof sheathing spans are established.NOTE 2Practice D6305can be used to extend the laboratory strengthdata obtained by this test method to design value recommendations. Thetest data determined by this test method are used to develop adju
24、stmentfactors 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:6.1.1 Source panels for this test shall be selected from grademarked PS 1 or PS 2 commercially av
25、ailable 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 (as defined in PS 1) is suggested as the testmaterial because it requires higher fire-retardant chemical re
26、tentions toobtain the same flame spread rating compared to other softwood plywoodspecies. Because the bending strength of treated plywood correlates to thechemical retention levels, Southern Pine plywood is believed to representa worst case scenario for the same chemical formulation and treating/red
27、rying procedures. Thus, evaluation of other species of plywood bytesting of that species, rather than by application of southern pine testresults, are considered to be indicative of that species only.6.1.2 Select source panels that provide bending strengthspecimens after cutting with clear essential
28、ly 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 percent latewood along and across the panel faces.Aminimum of six sheets of pl
29、ywood meeting this description isrequired. Alternate 0.61 m (2 ft) long sections to be treated andadjacent untreated 0.61 m (2 ft) sections (see Fig. 1) shall havevisually similar wood quality.6.1.2.1 Specimens shall be inspected and the culling ofspecimens done as necessary in accordance with the c
30、riteria in7.3.4.NOTE 4A minimum of six sheets of plywood is required but cullingof specimens could require more sheets.6.1.3 The specimen cutting pattern and numbering sequenceis shown in Fig. 1. Each panel of plywood is to be labeled witha number from 1 to 6. Cut each sheet crosswise to provide 0.6
31、1by 1.22 m (2 by 4-ft) sections. Each section is labeled with thesheet number and letter A, B, C, or D. The A and C sections of5Available from the U.S. Department of Commerce, 1401 Constitution Ave.,NW Washington, DC 20230, http:/ts.nist.gov/Standards/Conformity/vps.cfm. FIG. 1 Plywood Cutting Patte
32、rnD5516 182each of the six panels is to be treated, while the B and Dsections of the six panels are to remain untreated.6.2 Treatment:6.2.1 For applications requiring conformance to buildingcode requirements for “fire-retardant-treated-wood” based onTest Method E84 test extended to 30 min or Test Me
33、thodE2768, pressure treat the A and C section of each of the sixplywood 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 agency
34、certifying the surface burning characteristics of the treatedplywood. 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
35、, and not allow progression of the flame front beyond adistance of 3.2 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 metho
36、d since this method evaluates theimpact of the fire retardant method 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-
37、mance to AWPA U1, NFPA 703, or similar code requirementsfor “fire-retardant-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
38、 clearly the alternative performance criteria and that thetreatment retention 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 concen
39、tration of chemicals in thesolution. Complete a treating report for each 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
40、 %following the standard redrying procedures established for thetreatment 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 bem
41、inus 3C (5F). There is no upper limit on the redryingtemperature. Sticker 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 als
42、o shall be double stacked rather than stickered indi-vidually.NOTE 5Research 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 requir
43、es that the dry bulb temperature of thekiln not exceed 71C (160F) during 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 cu
44、ring temperatures must notexceed 99C (210F) and the total curing time 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 treatedsoftwo
45、od plywood, the laboratory must redry the test material within asmall 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
46、for evaluating production material that exceedsthe limit, the test material 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
47、at 60C (140F), 10 hat 71C (160F), etc.) is allowed by the standard, provided 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 specifi
48、edby the manufacturer.6.3.2 Monitor the moisture content of the plywood 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 r
49、ecorder chart detailingthe drying cycle and parameters.6.4 Specimen Preparation:6.4.1 After drying, cut the treated and untreated 0.61 by1.22-m (2 by 4-ft) sections into nominal 0.076 by 0.61-m (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 contro
