1、Designation: D5516 09D5516 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
2、 adoption 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 of exposure to
3、 high temperatures and humidities on the flexureproperties of fire-retardant treated softwood plywood. In this test method, plywood is exposed to a temperature of 77C (170F).1.2 The purpose of the test method is to compare the flexural properties of fire-retardant treated plywood relative to untreat
4、edplywood. The results of tests conducted in accordance with this test method provide a reference point for estimating strengthtemperature relationships. This test method is intended to provide an accelerated test at elevated temperatures and controlledhumidities of plywood sheathing treated with th
5、e same chemical formulation(s) and processing conditions as plywood usedcommercially.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversionsto inch-pound units that are provided for information only and are not considered standar
6、d.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5 This intern
7、ational standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Commi
8、ttee.2. Referenced Documents2.1 ASTM Standards:2D9 Terminology Relating to Wood and Wood-Based ProductsD1165 Nomenclature of Commercial Hardwoods and SoftwoodsD2915 Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based ProductsD3043 Test Methods for Structural Panels in FlexureD
9、4933 Guide for Moisture Conditioning of Wood and Wood-Based MaterialsD6305 Practice for Calculating Bending Strength Design Adjustment Factors for Fire-Retardant-Treated Plywood RoofSheathingE84 Test Method for Surface Burning Characteristics of Building MaterialsE176 Terminology of Fire StandardsE2
10、768 Test Method for Extended Duration Surface Burning Characteristics of Building Materials (30 min Tunnel Test)2.2 Other Standards:AWPA C-27 Plywood-Fire Retardant Treatment by Pressure Processes3AWPA U1 Use Category System: User Specification for Treated Wood3NFPA 703 Standard for Fire Retardant I
11、mpregnated Wood and Fire Retardant Coatings for Building Materials4PS 1 U.S. Product Standard for Structural Plywood51 This test method is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.Current edition approved
12、 May 15, 2009April 15, 2017. Published June 2009June 2017. Originally approved in 1991 as ES 20 91. Last previous edition approved in20032009 as D5516 03.D5516 09. DOI: 10.1520/D5516-09.10.1520/D5516-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Serv
13、ice at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American Wood Protection Association (AWPA), P.O. Box 361784, Birmingham, AL 35236-1784, http:/.4 Available from National Fire Protection Ass
14、ociation (NFPA), 1 Batterymarch Park, Quincy, MA 02169-7471, http:/www.nfpa.org.5 Available from the U.S. Department of Commerce, 1401 Constitution Ave., NW Washington, DC 20230, http:/ts.nist.gov/Standards/Conformity/vps.cfm.This document is not an ASTM standard and is intended only to provide the
15、user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard
16、 as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1PS 2 U.S. Product Standard for Wood-Based Structural Use Panels53. Terminology3.1 DefinitionsDefinitions used in this test
17、 method are in accordance with Terminologies D9 and E176 and NomenclatureD1165.3.2 Definitions of Terms Specific to This Standard:3.2.1 depth of beamthat dimension of the beam which is perpendicular to the span and parallel to the direction in which theload is applied.3.2.2 spanthe total distance be
18、tween the centerline of supports providing the reactions on which a beam is supported toaccommodate a transverse load.3.2.3 span-depth ratiothe numerical ratio of span divided by beam depth.4. Summary of Test Method4.1 After preconditioning (see 6.5), matched specimens of treated and untreated plywo
19、od will be exposed to 77C (170F)temperature and relative humidity equal to or greater than 50 %.4.2 Flexural strength tests are conducted on exposed specimens removed after various time periods. Flexural strength resultsshall include maximum moment, bending stiffness, and work to maximum load. Adjus
20、t the test results to 67 % relative humidity.(See 50 % relative humidity using Practice D6305 procedures (see X1.2X1.1.)4.3 The purpose of this test method is to determine the ratio of the treated mean to the untreated mean for the plywood and plotthe accelerated exposure strength data against expos
21、ure time.5. Significance and Use5.1 The flexural properties evaluated by this test method are intended to provide any one or all of the following:5.1.1 Data on the comparative effects of fire-retardant chemical formulations and environmental conditions on the flexuralproperties of plywood.5.1.2 Data
22、 for use in developing modification factors for the allowable design properties of treated plywood when exposed toelevated temperatures and humidities.5.1.3 Data comparing variables, such as other plywood species and dimensions.5.2 Results obtained from tests conducted and analyzed in accordance wit
23、h the procedures of this test method may be used withother information to establish recommended roof sheathing spans for fire-retardant treated plywood.NOTE 1Temperatures lower than the test temperature specified in this test method and the cumulative effects of the elevated temperatures andhumidity
24、 exposures expected to be encountered in service should be taken into account when recommended roof sheathing spans are established.NOTE 2Practice D6305 can be used to extend the laboratory strength data obtained by this test method to design value recommendations. The testdata determined by this te
25、st method are used to develop adjustment factors for fire-retardant treatments to apply to untreated plywood design values. Thetest data are used in conjunction with climate models and other factors.6. Test Specimens6.1 Material Selection:6.1.1 Source panels for this test shall be selected from grad
26、e marked PS 1 or PS 2 commercially available 3, 4, or 5 ply panelsof a single thickness, grade, construction, and bond durability. The nominal panel thickness shall be between 12 mm (1532 in.) and16 mm (58 in.).NOTE 3Southern Pine is suggested as the test material because it requires higher fire-ret
27、ardant chemical retentions to obtain the same flame spreadrating compared to other softwood plywood species. Because the bending strength of treated plywood correlates to the chemical retention levels, SouthernPine plywood is believed to represent a worst case scenario for the same chemical formulat
28、ion and treating/redrying procedures. Thus, evaluation of otherspecies of plywood by testing of that species, rather than by application of southern pine test results, are considered to be indicative of that species only.6.1.2 Select source panels that provide bending strength specimens after cuttin
29、g with clear essentially straight-grained faces freeof scoring or other manufacturing defects. The inner plies shall be essentially free of voids, core gaps, and core laps (see 7.3.4.2).Panels shall have generally uniform grain orientation and percent latewood along and across the panel faces. A min
30、imum of sixsheets of plywood meeting this description is required. Alternate 610 mm (2 ft) long sections to be treated and adjacent untreated610 mm (2 ft) sections (see Fig. 1) shall have visually similar wood quality.6.1.2.1 Specimens shall be inspected and the culling of specimens done as necessar
31、y in accordance with the criteria in 7.3.4.NOTE 4A minimum of six sheets of plywood is required but culling of specimens may require more sheets.6.1.3 The specimen cutting pattern and numbering sequence is shown in Fig. 1. Each panel of plywood is to be labeled witha number from 1 to 6. Cut each she
32、et crosswise to provide 610 mm by 1220-mm (2 by 4-ft) sections. Each section is labeled withthe sheet number and letterA, B, C, or D. TheAand C sections of each of the six panels is to be treated, while the B and D sectionsof the six panels are to remain untreated.D5516 1726.2 Treatment:6.2.1 Pressu
33、re For applications requiring conformance to building code requirements for “fire-retardant-treated-wood” based onTest Method E84 test extended to 30 min or Test Method E2768, pressure treat the A and C section of each of the six plywoodpanels with the fire-retardant formulation being tested. The ga
34、ge retention level of each charge shall not be less than the valuemidway between the middle of the retention range and the maximum retention as specified by the agency certifying the flamespread indexsurface burning characteristics of the treated plywood. The retention range specified by the certify
35、ing agency shallresult in specimens that provide a flame-spread index of 25 or less when tested in accordance with Test Method and be reportedas showing E84 for 10 min, show no evidence of significant progressionprogressive combustion when the test is continued for anadditional 20-min throughout the
36、 30-min period, and not allow progression of the flame front beyond a distance of 3.2 m (10.5ft) beyond the centerline of the burners anytime during the 30-min extended test.6.2.1.1 Alternate methods or processes of imparting fire-retardant properties can be substituted for pressure treatment forpur
37、poses of this test method since this method evaluates the impact of the fire retardant method on the properties of the underlyingplywood.6.2.1.2 The provisions of 6.2.1 are not intended to prevent use of this test method when the fire-retardant treatments beingcertified are for applications other th
38、an those requiring conformance to AWPA C-27,AWPA U1, NFPA 703, or similar buildingcode requirements for “fire-retardant-treated wood” that require the Test Method E2768 or Test Method E84 test extended to 30min. When alternative performance criteria for the treatment are being certified, the test re
39、port on specimens of that treatment shallstate clearly the alternative performance criteria and that the treatment retention was limited to that required for the alternativeperformance criteria.6.2.2 Weigh all plywood sections before and immediately after treatment to determine the chemical retentio
40、n based on thesolution retained and the concentration of chemicals in the solution. Complete a treating report for each charge of material todocument the treating cycle, times, pressures, and plywood retentions.6.3 Post-Treatment Drying:6.3.1 After pressure treatment, kiln dry the twelve treated ply
41、wood sections to a maximum moisture content of 15 % followingthe standard redrying procedures established for the treatment by the manufacturer. Redry the sections at the manufacturersmaximum specified dry bulb temperature with a minus 2C (4F) tolerance for 21 h of the first 24-h period. For the rem
42、ainder ofthe drying period, the tolerance shall be minus 3C (5F). There is no upper limit on the redrying temperature. Sticker all plywoodsections to obtain proper air flow across the panels and to provide even drying. If the manufacturers procedures permit doublestacking of panels intended for stru
43、ctural application, treated plywood test sections also shall be double stacked rather thanstickered individually.NOTE 5Research has shown that high kiln drying temperatures can adversely affect the structural properties of wood products. TheAWPAand NFPAstandards for fire retardant treated wood produ
44、cts limit kiln dry bulb temperatures. AWPA C-27 requires that the dry bulb temperature of the kiln notexceed 70C71C (160F) during any kiln drying of plywood treated with fire retardants. In the case of exterior fire retardants that require curing at highertemperatures, curing after the moisture cont
45、ent is 15 % or less is permitted. However, such elevated curing temperatures must not exceed 99C (210F)and the total curing time must not exceed 48 h. In NFPA 703, the dry bulb temperature must not exceed 70C71C (160F) until the average moisturecontent of the wood has dropped to 25 % or less.NOTE 6T
46、o establish the worst-case flexural properties of treated softwood plywood, the laboratory must redry the test material within a small negativetolerance of the maximum temperature used by the manufacturer. Therefore, there is no upper limit for the temperature used in the tests. If a manufacturerdes
47、ires to establish conservative property values or provide a basis for evaluating production material that exceeds the limit, the test material can beredried at that temperature. A manufacturer then is allowed to determine the necessary production schedule for their treatment and equipment orconditio
48、ns. Thus, a stepped schedule (for example, 10 h at 54C (130F), 10 h at 60C (140F), 10 h at 71C (160F), etc.) is allowed by the standard,provided the maximum temperature tolerance requirement is met. These provisions provide for air-drying production material provided the redryconditions for the test
49、 materials are within the tolerance of the maximum temperature specified by the manufacturer.FIG. 1 Plywood Cutting PatternD5516 1736.3.2 Monitor the moisture content of the plywood sections during the drying cycle by individually weighing the sections.Reduce as much as possible damage or warp during the drying process by adequately supporting the sections. Keep awell-documented kiln charge report and kiln recorder chart detailing the drying cycle and parameters.6.4 Specimen Preparation:6.4.1 After drying, cut the treated an
