1、Designation: D 6662 09Standard Specification forPolyolefin-Based Plastic Lumber Decking Boards1This standard is issued under the fixed designation D 6662; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 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 specification covers polyolefin-based plastic lum-ber products for use as exterior residential decking boards.1.2 Plastic lumber
3、products are currently made predomi-nantly with recycled polyolefin plastics (in particular high-density polyethylene) where the products are more or lessnon-homogenous in the cross-section. However, this specifica-tion is also potentially applicable to similar manufacturedplastic products made from
4、 other plastic and plastic compositematerials that have non-homogenous cross-sections.1.3 This specification details a procedure to calculate rec-ommended span lengths for spacing of support joists. Thisprocedure was developed using experimental data from atypical unreinforced plastic lumber made pr
5、edominantly fromrecycled high-density polyethylene. The methodology to de-velop span lengths for other types and compositions of plasticlumber is detailed in Appendix X1 of this standard.1.4 The values are stated in inch-pound units, as these arecurrently the most common units used by the constructi
6、onindustry. Equivalent SI units are indicated in parentheses.However, the units stated for irradiance exposure in theweatherability section (6.3) are in SI units as these are the unitscommonly used for testing of this type.1.5 This standard does not purport to address all of thesafety concerns, if a
7、ny, 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.NOTE 1There is no similar or equivalent ISO Standard.2. Referenced Documents2.1 The followin
8、g documents of the issue in effect on thedate of material purchase form a part of this specification to theextent referenced herein:2.2 ASTM Standards:2D 883 Terminology Relating to PlasticsD 2565 Practice for Xenon-Arc Exposure of Plastics In-tended for Outdoor ApplicationsD 2915 Practice for Evalu
9、ating Allowable Properties forGrades of Structural LumberD 4329 Practice for Fluorescent UV Exposure of PlasticsD 5033 Guide for Development of ASTM Standards Relat-ing to Recycling and Use of Recycled Plastics3D 6109 Test Methods for Flexural Properties of Unrein-forced and Reinforced Plastic Lumbe
10、r and Related Prod-uctsD6112 Test Methods for Compressive and Flexural Creepand Creep-Rupture of Plastic Lumber and ShapesD 6341 Test Method for Determination of the Linear Coef-ficient ofThermal Expansion of Plastic Lumber and PlasticLumber Shapes Between 30 and 140F 34.4 and 60CE84 Test Method for
11、 Surface Burning Characteristics ofBuilding MaterialsE 108 Test Methods for Fire Tests of Roof CoveringsG 151 Practice for Exposing Nonmetallic Materials in Ac-celerated Test Devices that Use Laboratory Light SourcesG 154 Practice for Operating Fluorescent Light Apparatusfor UV Exposure of Nonmetall
12、ic MaterialsG 155 Practice for Operating Xenon Arc Light Apparatusfor Exposure of Non-Metallic Materials3. Terminology3.1 Definitions:3.1.1 plastic lumber, na manufactured product composedof more than 50 weight percent resin, and in which the productgenerally is rectangular in cross-section and typi
13、cally suppliedin sizes that correspond to traditional lumber board anddimensional lumber sizes, may be filled or unfilled, and may becomposed of single or commingled resins.3.1.2 resin, na solid or pseudo solid organic materialoften of high molecular weight, which exhibits a tendency toflow when sub
14、jected to stress, usually has a softening ormelting range, and usually fractures conchoidally. (See Termi-nology D 883.)3.1.2.1 DiscussionIn a broad sense, the term is used todesignate any polymer that is a basic material for plastics.(1982)1This specification is under the jurisdiction of ASTM Commi
15、ttee D20 onPlastics and is the direct responsibility of Subcommittee D20.20 on Plastic Products.Current edition approved April 1, 2009. Published April 2009. Originallyapproved in 2001. Last previous edition approved in 2007 as D 6662 - 07.2For referenced ASTM standards, visit the ASTM website, www.
16、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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM Internatio
17、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2 Definitions of Terms Specific to This Standard:3.2.1 bulgeconvex distortion (away from the center of thecross-section) of the face of the board from a straight linedrawn from edge to edge across the width of
18、 the board.3.2.2 crookdistortion of the board in which there is adeviation in a direction perpendicular to the edge from astraight line from end to end of the board.3.2.3 cupconcave distortion (towards the center of thecross-section) of the face of the board from a straight linedrawn from edge to ed
19、ge across the width of the board.3.2.4 edgethe side of a rectangular-shaped board corre-sponding to the thickness of the board.3.2.5 facethe side of a rectangular-shaped board corre-sponding to the width of the board.3.2.6 thicknessthe lesser dimension of the cross-sectionalprofile of a rectangular-
20、shaped board.3.2.7 widththe greater dimension of the cross-sectionalprofile of a rectangular-shaped board.3.3 Additional definition of terms applying to this specifi-cation appear in Terminology D 883 and D 5033.4. Ordering Information4.1 The information contained in this specification is in-tended
21、to be helpful to producers, distributors, regulatoryagencies and users. The information can also promote under-standing between purchasers and sellers. The purchaser shallstate whether this specification is to be used, select thepreferred options permitted herein, and include the allowabledesign inf
22、ormation in the invitation to bid and purchase orderfrom the following:4.1.1 Title, number and date of this specification,4.1.2 Minimum allowable bending strength and allowablebending stiffness,4.1.3 Percent recycled content (if requested),4.1.4 Flame spread index,4.1.5 Color,4.1.6 Quantity in linea
23、l feet,4.1.7 Cut length,4.1.8 Cross-sectional dimensions,4.1.9 Packing requirements,4.1.10 Palletization, if required,4.1.11 Marking, if other than specified.4.2 If specific mechanical property values are not requiredby the purchaser (for example, when purchasing materials forgeneral retail sales di
24、stribution and not for a specific project),the manufacturer shall provide minimum allowable designinformation, as would be determined under this specification,to aid in the application of the decking board material by theend user.5. Dimensions and Permissible VariationsIt is permissible to produce d
25、ecking boards either in sizesthat are similar to the standard dimensions of the woodindustry, or to proprietary dimensions designed by manufac-turers. This specification does not limit the dimensional rangeof production. For reference, the standards of the woodindustry are as follows:5.1 ThicknessUn
26、less otherwise specified in 4.1.8, boardsshall be:Nominal (in.) Actual (in.) Tolerance (in.)134 611654 1 611621-12 6116Tolerance on thickness of boards thicker than 2 inches(nominal) shall be 6116 inch.5.2 Width of BoardsUnless otherwise specified in para-graph 4.1.8, board widths shall be:Nominal (
27、in.) Actual (in.) Tolerance (in.)32-12 61164312 61166512 611687-14 611610 9-14 611612 11-14 6116Tolerance on width of boards wider than 12 inches (nominal)shall be 6116 inch.5.3 Length of Boardsunless otherwise specified in 4.1.7,boards up to 20 feet shall have tolerances of +12 inch or -116inch. Ov
28、er 20 feet, the tolerances will be +12-inch or -116 inchper 20-ft of length or fraction thereof. Measurement of lengthsto be made at 73 6 2 F and relative humidity of 50 6 5%.5.4 Flatness ToleranceBoard shall be flat with maximumcup or bulge in the board face limited to the tolerances in Table1. Lin
29、ear interpolation of the values is acceptable for dimen-sions other than listed.5.5 SquarenessUnless a specially shaped member isspecified, the cross-section of all boards shall be visuallyrectangular (that is, the face and edge of the board areperpendicular to each other) and suited for the intende
30、dpurpose.5.6 CrookCrook shall conform to the tolerances in Table2. Linear interpolation of the values is acceptable for dimen-sions other than listed.5.7 Tongue and GrooveBoards shall be without tongueand groove unless otherwise specified in 4.1.8. Because of loadtransfer between adjacent boards, th
31、e methodology and equa-tions presented in section 6.1.4 for determining recommendedmaximum span lengths are not applicable to tongue and grooveboards. Manufacturers of tongue and groove decking boardsshall provide recommended span lengths based on soundengineering practice, taking into account some
32、of the issuesdescribed in 6.1.4 below, as well as previous, in-serviceperformance history.6. Performance Requirements6.1 Flexural Properties:6.1.1 Test ProcedureD 6109.6.1.2 Specimens TestedA minimum of 15 specimens shallbe tested.6.1.3 Criteria(1) The mean value of the secant flexuralmodulus at 1 %
33、 outer fiber strain estimated statistically towithin 5 % with 75 % confidence shall equal or exceed 50 000psi. Table 3 shows the number of specimens required toTABLE 1 Cup or Bulge Tolerances Relative to Nominal Width ofthe Board FaceFace Width, in. #4 in. 6 in. 8 in. 10 in. 12 in.Tolerance132 in.11
34、6 in.18 in.316 in.14 in.D6662092establish the mean value at 75 % confidence interval with 65 % error using Practice D 2915.(2) The 5 % lower tolerancelimit at 75 % confidence flexural stress at 3 % outer fiber strainshall equal or exceed 1000 psi. If any specimen fails prior toreaching 3 % strain, t
35、hen the flexural strength at failure for thatspecimen shall equal or exceed 1000 psi. The 5 % lowertolerance limit at 75 % confidence is computed by subtractingK-times the standard deviation from the mean value, where Kis tabulated in statistics handbooks (and in Table 3 of PracticeD 2915) as a fact
36、or for a one-sided tolerance limit for thedistribution. Table 4 shows the value of K for several samplesizes.NOTE 2Many standards require a minimum sample size of approxi-mately 30 to balance testing costs against the large reductions in theallowable values for very small sample sizes.NOTE 3A 16 in.
37、 on center joist spacing is considered typical standardspacing for residential deck construction. While 50 000 psi is given as aminimum flexural modulus, a modulus greater than 50 000 psi ispotentially required for some decking board sizes in order to meet thisspacing when determining span lengths p
38、er the guidance presented in6.1.4 below. Alternatively, use span lengths less than 16 in. on center asneeded.NOTE 4Concurrent to the development of this specification for PlasticLumber Decking, a Standard Guide for the Design and Construction ofPlastic Lumber Decking is being developed by Section D2
39、0.20.01 (underthe Subcommittee D20.20 on Plastic Products). This Standard Guide isexpected to be available sometime after this Specification has beenapproved and in use.6.1.4 Span LengthsRecommended maximum spanlengths shall be determined using the following equations:For concentrated loads on board
40、s which are continuous overa minimum of two spans (such as decking boards) as shown inFig. 1, the maximum recommended span shall be limited byeither the stress or the deflection formula as follow, whicheverprovides the lesser span:Stress Formula:L 5 64SFb8!/13P! (1)Deflection Formula:L 5 67E8I!/Pka!
41、#12 (2)For distributed (or uniform) loads on boards which arecontinuous over a minimum of two spans (such as deckingboards) as shown in Fig. 2, the maximum span shall be limitedby either the stress or the deflection formula as follow,whichever provides the lesser span:Stress Formula:L 5 8SFb8!144!/q
42、b!#12 (3)Deflection Formula:L 5 185E8I!144!/qb ka!#13 (4)where:L = computed span length, in.,S = section modulus, in.3,Fb8 = allowable flexural stress as computed in 6.1.4.1, psi,P = concentrated load, lb,E8 = effective modulus of elasticity as computed in6.1.4.2, psi,I = moment of inertia, in.4,k =
43、 factor used to limit deflection to L/k (for exampleL/360 with k = 360; or L/120 with k = 120),q = uniformly distributed load, lb/sq-ft,b = actual board width, in., anda = Creep Adjustment Factor = 1.5.NOTE 5The attached commentary in Appendix X1 provides a ratio-nale for the Creep Adjustment Factor
44、, a.TABLE 2 Crook Tolerances Relative to Nominal Length andWidth of the BoardLength in Feet #4 in. Width 6 in. Width 8 in. Width 10 in. Width 12 in. Width4638 in.14 in.316 in.18 in.18 in.812 in.12 in.38 in.14 in.316 in.1034 in.58 in.12 in.716 in.38 in.12 1 in.78 in.1316 in.34 in.916 in.14 114 in. 11
45、8 in. 1 in.78 in.34 in.16 112 in. 138 in. 118 in. 1 in.78 in.TABLE 3 Number of Specimens Required to Establish the MeanValue with an Error of 6 5 % with 75 % Confidence for VariousCoefficients of Variation (COV) in the Data SetCOV Range, % 1015 1520 2025 25No. of Specimens, N 15 23 34 60TABLE 4 Valu
46、e of K for Establishing the Lower 5 % LowerTolerance Limit with 75 % Confidence for Various Sample SizesNo. of Specimens, N 15 30 InfiniteValue of K 1.991 1.869 1.645FIG. 1 Schematic of Concentrated Load on Boards that areContinuous Over Two SpansFIG. 2 Schematic of Distributed Load on Boards that a
47、reContinuous Over Two SpansD66620936.1.4.1 Allowable Flexural StressThe allowable flexuralstress, Fb8, of the decking board is given as follows:Fb8 5 Fb/FS! CD CT(5)where:Fb= the base flexural stress value for plastic lumber madeof HDPE-type polyolefins for normal duration load-ing (10 yr. duration)
48、, psi,FS = Factor of Safety = 1.5,CD= Load Duration Factor for flexural stress, presented inFig. 3 and Table 5, depends on the shortest-durationload in combination, applied either cumulatively orcontinuously, andCT= Temperature Factor, Table 6.Fb, the base flexural stress value for plastic lumber ma
49、de ofHDPE type polyolefins, is determined as follows:Fb5 Fbt 0.3 (6)where:Fbt= the 5 % lower tolerance limit at 75 % confidence ofthe flexural stress at 3 % outer fiber strain determinedfrom flexure tests conducted in accordance with TestMethod D 6109, and0.3 = factor to convert the 3 minute test value to a ten yearnormal duration value (that is, a flexural stress equalto 30 % of Fbtwill induce a 3 % outer fiber strain inten years).NOTE 6The attached commentary in Appendix
