1、AMERICAN NATIONAL STANDARD O5.6.2010 SOLID SAWN-NATURALLY DURABLE HARDWOOD CROSSARMS producers of treated and untreated wood products; end users of treated wood; engineers, architects and building code officials; government entities, academia, and other groups with a general interest in wood preserv
2、ation. AWPAs Standards are universally specified for wood preservation in the USA, and are recognized worldwide. AWPA standards help ensure that treated wood products perform satisfactorily for their intended use. They are recognized and used by most, if not all, specifiers of treated wood including
3、 electrical utility, marine, road and building construction as well as by local, state and federal governments. For more information visit . AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criter
4、ia for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not
5、necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved the st
6、andards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover
7、, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CA
8、UTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current i
9、nformation on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer Sustainable Forestry Initiative (SFI), Forest Stewardship Council (FSC); Sistema Brazileiro de Certificao Florestal (CERFLOR); as well as others. Complete detailed instructions shall be
10、given to the supplier whenever the requirements of this Standard are modified to meet special conditions. 2 NORMATIVE REFERENCES The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the
11、 editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ANSI O5.6.2010 5 ANSI C2-2007, National Elect
12、rical Safety Code1, or applicable State RegulationsASTM D198-05a, Standard methods of static tests of lumber in structural sizes.1)ASTM D2017-05, Standard Test Method of Accelerated Laboratory Test of Natural Decay Resistance of Woods.3ASTM D2915-03, Standard practice for evaluating allowable proper
13、ties for grades of structural lumber.1)ASTM D9-05, Standard terminology relating to wood and wood-based products.2)AWPA E109, Standard Method for Laboratory Evaluation to Determine Resistance to Subterranean Termites. AWPA E709 Standard Method of Evaluating Wood Preservatives by Field Tests with Sta
14、kes. AWPA M6-07, Brands used on forest products.2)SPIB, Grading Rules 2002 Edition, Southern Pine Inspection Bureau.3) SPIB, Special Product Rules for Structural, Industrial and Railroad Freight Car Lumber (3)WCLIB, Standard Grading Rules No. 17: West Coast Lumber Inspection Bureau4)3 DEFINITIONS Th
15、e following definitions are equivalent to those given in ASTM D9-05, WCLIB Standard Grading Rules No. 17, or SPIB Grading Rules, and shall apply to the terms used in this standard. 3.1 brashness: Commonly, the tendency of the wood to fail suddenly under stress, and to break at relatively small defle
16、ction across the grain, with little or no splintering. It is also called brittleness. Possible causes of brashness include heat degradation or the presence of decay. Three characteristics indicative of the brashness of a piece are: a) Exceptionally low specific gravity or weight, as compared to aver
17、age weight for its species; b) An especially small proportional amount of latewood; and c) Fibers with thin walls. 3.2 check: Lengthwise grain separation, usually occurring across or through the growth rings, as a result of seasoning. This is shown in Figure 1. _1Available from . 2)Available from Am
18、erican Society of Testing and Materials (ASTM), . 3) Available from Southern Pine Inspection Bureau (SPIB), . 4) Available from West Coast Lumber Inspection Bureau (WCLIB), . ANSI O5.6.2010 6 Figure 1 Features observed during grading 3.3 compression failures: Localized buckling of fibers, produced b
19、y the compression of wood along the grain beyond its ultimate capacity. 3.4 crack: A break or fracture across the grain of the wood. 3.5 decay: A disintegration of wood substance due to the action of wood-destroying fungi, resulting in loss of strength. Also called dote or rot. 3.5.1 advanced (typic
20、al) decay: The older stage of decay in which the disintegration is readily recognized because hardness and other strength properties are reduced. Decided discoloration or bleaching of the rotted wood may be apparent. Unsound red heart is a typical example of advanced decay. 3.5.2 firm red heart: A s
21、tage of incipient decay, characterized by a reddish color in the heartwood. 3.5.3 incipient decay: The early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. Although the wood is invaded and some of its properties may have deteriora
22、ted, no visible change has occurred, with perhaps the exception of minor discoloration. Incipient decay can occur in living trees. ANSI O5.6.2010 7 3.6 density: Mass (weight) of wood per unit volume. Strength is related to density. Higher working strengths can be assigned to wood when lightweight pi
23、eces are eliminated, by specifying limits for rate of growth and minimum percentages of summerwood. 3.7 dote: See decay. 3.8 equilibrium moisture content (EMC): Moisture content at which the wood is neither gaining nor losing moisture at a given temperature and relative humidity. 3.9 heart center: T
24、he pith or center core of the tree. “Free of heart centers” (FOHC) means “without pith” (side-cut). 3.10 heartwood: The inner portion of wood between the pith and the sapwood, composed entirely of nonliving cells. It is usually darker in color and more durable than the sapwood. Heartwood and sapwood
25、 are comparable in strength. 3.11 hit and miss: An area with a series of skips that are not over 1.6 mm (1/16 inch) deep and with surfaced areas between individual skips is called “hit and miss dressing.” 3.12 latewood: That portion of the annual growth ring that is formed during the latter part of
26、the yearly growth period. It is usually denser, darker in color, and stronger mechanically than earlywood. This term is preferred to summerwood. 3.13 nail plate: A galvanized metal plate placed on the end-surfaces to prevent split-widening. 3.14 pitch pocket: An opening between growth rings that usu
27、ally contains, or has contained, resin. 3.15 pith: The small core in the structural center of a log. See heart center. 3.16 rate of growth: The amount of tree growth each year, expressed as the number of growth rings per inch (2.5cm) (see Figure 1). Growth rings in naturally durable hardwoods may no
28、t be discernable under 10X magnification. In such cases a minimum density of 60 lbs/ft3, measured in the green state, must be observed. 3.17 red heart: See decay. 3.18 rot: See decay. 3.19 sapwood: The outer portion of wood next to the bark, usually lighter in color than the heartwood, and containin
29、g some living cells while the tree is alive. If left untreated, sapwood is as strong as heartwood, but is not naturally durable. 3.20 sections: For ease of description, crossarms are divided into sections as shown in Figure 2. Figure 2 - Crossarm sections 3.21 shake: A lengthwise separation along th
30、e grain, the greater part of which occurs between, or through, the growth rings. This is shown in Figure 1. ANSI O5.6.2010 8 3.22 skip: An unsurfaced, rough area on dressed lumber. 3.23 slope of grain: The deviation of the line of fibers from a straight line parallel to the sides of a piece. 3.24 sp
31、lit: A lengthwise separation of the wood from one surface to the other. This is shown in Figure 1. 3.25 tension wood: Abnormal wood which forms on the upper side of branches or inclined trunks of hardwood trees. In tropical hardwoods, tension wood is sometimes formed in non-leaning trees as a mechan
32、ism for crown movement in dense forests. It is sometimes distinguished by eccentric cross-sectional growth, but usually requires microscopic examination, the use of chemical indicators, or visual observation upon thorough seasoning. Tension wood typically has greater shrinkage and lower strength pro
33、perties when compared to normal wood. 3.26 wane: Bark, or the lack of wood from any cause, on the surface of lumber. 3.27 warp: Any variation from a true or plane surface, including bows, crooks, twists, cups, or any combination thereof, as these terms are defined in WCLIB Standard Grading Rules No.
34、 17, Paragraph 752, and in SPIB Grading Rules, Paragraph 752. 4 MARKING 4.1 All crossarms and braces shall be legibly and permanently marked or branded in characters 3/8 inch (1cm) or larger. Marking or branding shall not be deeper than 1/8 inch (0.3cm) and shall be applied to a wide face. NOTE All
35、crossarms shall be marked to indicate the top of the arm because greater defects are permitted on the bottom than on the top. Upside-down installation may thus result in less strength. Also, rounded edges offer less resistance to insulated wires that may be pulled over the crossarms during installat
36、ion. 4.2 Markings or brandings shall include the following information: a) Manufacturers name or symbol; b) Year of manufacture; c) Wood species (see 5.2.1); 4.2.1 Species Designation Table 1- List of approved species Designation Species (Scientific Names) CA Cupiuba (Goupia glabra.) GU Guajara (Pou
37、teria oppositifolia) PQ Piquia (Caryocar villosum) VE Tauari Vermelho (Cariniana micrantha) TI Timborana (Pseudopiptadenia spp.) ANSI O5.6.2010 9 4.2.2 Example. (This information may be in some other form or order, if authorized by the purchaser.) ABC Co. 01/09 (manufacturer, date and year of manufa
38、cture) VE (species) 5 STORAGE For storage of longer than two months, crossarms and braces shall be stacked above ground with enough room to provide adequate ventilation, on non-decaying skids, in a well-drained area. The stacks should be protected from the sun and weather to minimize checking and ph
39、ysical distortion. 6 QUALITY CONTROL 6.1 Inspection and determination of conformance to requirements shall be performed by the manufacturer at the place of manufacture. Inspection may also be performed by the purchaser (or purchasers representative) at the place of manufacture, or the delivery desti
40、nation. The supplier shall provide to the purchaser, or to the purchasers representative, such access as is reasonable and necessary to determine that the material conforms to all specified requirements, and shall furnish all necessary apparatus, labor, and other facilities for making the tests call
41、ed for without cost to the purchaser. 6.2 Inspection by the purchaser or purchasers representative, or waiving of inspection, shall in no way relieve the supplier of the obligation to furnish material in accordance with all specified requirements. . 7 REJECTION Crossarms and braces determined not to
42、 be in accordance with specified requirements shall be rejected. 8 DESIGNATED FIBER STRENGTH Arms covered by Table 1 Table 2 - Fiber Strength Species Moisture Content Density (Dry State) Adjusted MOR for Green State lb/ft3g/cm3psi kPa Cupiuba 25% 47 0.75 10,100 69,664 Guajara 25% 42 0.67 11,000 75,8
43、72 Piquia 25% 46 0.74 9,730 67,112 Tauari Vermelho 25% 35 0.56 8,710 60,077 Timborana 25% 46 0.74 10,900 75,182 ANSI O5.6.2010 10 Only naturally durable hardwoods with fiber strength above 7800 psi (53800 kPa) will be allowed to be listed in the standard. The fiber strengths are for the loading conf
44、iguration described for the MOR test in Annex A, and may be subject to adjustment (increase or decrease) for other loading configurations. ANSI O5.6.2010 11 Figure 3 - Recommended dimensions for crossarms with arms having 2, 4, 6, and 8 pin holes NOTE: Normal shrinkage allowance shall be considered
45、using the arms current moisture content and actual size. Using the average shrinkage allowances for naturally durable hardwoods, which is very similar to Douglas-fir and Southern Yellow Pine, as one percent size change for each four point moisture content change below the fiber saturation point, cal
46、culations can be made to determine if the arm met the minimum size at time of manufacture, when the arm was to meet the average moisture content. ANSI O5.6.2010 12 Figure 4 - Sample of specification prepared by user NOTES: 1) Holes shall not be more than 1/16 inch (0.2cm) off longitudinal center. 2)
47、 All bolt holes shall pass, without forcing, standard galvanized steel bolts of nominal diameters 1/16 inch (0.2cm) less than the specified hole diameters. Bolt holes shall not admit a “no go-gage” 1/32 inch (0.1cm) larger in diameter than the specified hole diameter. Figure 5 - Crossarm edges NOTES
48、: 1) The two top edges (only) shall be either chamfered or rounded. (The manufacturer may choose the shape preferred.) 2) The two bottom edges may be slightly eased for the entire length, 1/8 in (0.3cm) 1/16 in (0.2cm) radius. ANSI O5.6.2010 13 9 SPECIFICATIONS FOR CROSSARMS The specifications in th
49、is standard are intended to apply to crossarms having cross sections of not more than 4 inches (10.2cm) on one face by not more than 6 inches (15.2cm) on the other face. 9.1 Options 3-1/2 inches (8.9cm) x 4-1/2 inches (11.4cm); 3-1/2 inches (8.9cm) x 5-1/2 inches (14cm); and 3-3/4 inches (9.5cm) x 4-3/4 inches (12.1cm). The crossarms with the 3-1/2 inch (8.9cm) x 4-1/2 inch (11.4cm) cross sections and the 3-1/2 inch (8.9cm) x 5-1/2 inch (14cm) cross sections can be produced from standard ALS (American Lumber Standard) lumber sizes. 9.1.2.
