ANSI ASC O5 O5.3-2015 SOLID SAWN-WOOD CROSSARMS & BRACES C SPECIFICATIONS & DIMENSIONS.pdf

1、 ANSI O5.3-2015 Solid Sawn Wood Crossarms and Braces: Specifications and Dimensions AMERICAN NATIONAL STANDARD FOR WOOD UTILITY PRODUCTS Accredited Standards Committee O5 was first organized in 1924 by the Bell Telephone System and the U.S. Independent Telephone Associations American Standards Assoc

2、iation (ASA) Telephone Group. The Exchange Carrier Standards Association (ECSA), which later became the Alliance for Telecommunications Industry Solutions (ATIS), accepted sponsorship and Secretariat responsibility for ASC O5 in 1985. The American Wood Protection Association (AWPA) then assumed the

3、role of Secretariat, effective January 1, 2011. ASC O5 is jointly accredited with its Secretariat by the American National Standards Institute. This committee develops standards for wood poles, crossarms, braces, and glue laminated timber for utility structures. For more information, visit the ASC O

4、5 website at www.asco5.org. Founded in 1904, the American Wood Protection Association (AWPA) is a non-profit organization that promulgates voluntary standards for technologies which protect wood from degradation. AWPA Standards are developed by its technical committees in an open, consensus-based pr

5、ocess that involves individuals from all facets of wood preservation: Producers of preservatives and preservative components; producers of treated and untreated wood products; end users of treated wood; engineers, architects and building code officials; government entities, academia, and other group

6、s with a general interest in wood preservation. AWPAs Standards are universally specified for wood protection in the USA, and are recognized worldwide. For more information visit the AWPA website at . AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that t

7、he requirements for due process, consensus, and other criteria 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. Substantia

8、l agreement means much more than a simple majority, but not 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

9、 any respect preclude anyone, whether he has approved the standards 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 a

10、n interpretation of any American National Standard. Moreover, 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 spons

11、or whose name appears on the title page of this standard. CAUTION 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. Pur

12、chasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer and from dense Southern pine of the following species: longleaf pine (Pinus palustris), shortleaf pine (Pinus echinata), loblo

13、lly pine (Pinus taeda), and slash pine (Pinus elliottii). The specifications are intended to cover communications crossarms, power crossarms, heavy-duty crossarms, and heavy-duty braces. Crossarms are intended primarily for use as beams. Heavy-duty crossarms may also be used as struts or columns in

14、braced H-frames. Braces are used for tension, compression-bracing, or both. 1.2 General organization of the standard This standard is divided into three parts: (1) Part I: General requirements and options that are applicable to all crossarms and braces covered in this standard are specified in Part

15、I; (2) Part II: Specific requirements and options relating to crossarms and braces manufactured from Douglas-fir are specified in Part II; and (3) Part III: Specific requirements and options relating to crossarms and braces manufactured from dense Southern pine are specified in Part III. 2 Normative

16、 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 editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Americ

17、an National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. ASTM D9-12, Standard terminology relating to wood and wood-based products.1) ASTM D198-09, Standard methods of static tests of lumber in structural sizes.1) ASTM

18、D2915-10, Standard practice for evaluating allowable properties for grades of structural lumber.1) AWPA U1-14, User specification for treated wood.2) AWPA M6-13, Brands used on forest products.2) 1) Available from ASTM International . 2) Available from American Wood Protection Association (AWPA) . A

19、NSI O5.3-2015 - 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 The following definitions are a

20、ligned with those used in ASTM D9-12, WCLIB Standard Grading Rules No. 17, or SPIB Grading Rules, and shall apply to the terms used in this standard. 3.1 brashness: The tendency of the wood to fail suddenly under stress, and to break at relatively small deflection across the grain, with little or no

21、 splintering. It is also called brittleness. Possible causes of brashness include heat degradation or the presence of decay. The following three characteristics are particularly indicative of brashness of a piece: a) Low specific gravity or density, as compared to average density of the species; b)

22、A small proportion (e.g. less than 10%) 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. 3.3 close grain grade: A Douglas-fir grade (WCLIB Standard Grading Ru

23、les No. 17, paragraph 204-b) requiring an average of approximately 6, but not more than approximately 30 annual growth rings per inch (2.5 cm) on either one end or the other of a piece, measured as shown in Figure 1, Rate of growth, as shown in WCLIB Standard Grading Rules No. 17, paragraph 204-d. P

24、ieces averaging 5 rings or more but not more than 30 rings per inch (2.5 cm) are accepted as close grain if they average 1/3 or more latewood (summerwood). 3.4 compression failures: Localized buckling of fibers, produced by the compression of wood along the grain beyond its ultimate capacity. 3.5 co

25、mpression wood: Abnormal wood growth that frequently occurs on the underside of leaning coniferous trees. It is denser and harder than normal wood, and is characterized by relatively wide growth rings, usually eccentric, and includes what appears to be an exceptional proportion of latewood. In compr

26、ession wood, the contrast in color between earlywood and latewood is usually less than in normal wood. Compression wood is low in strength for its weight and shrinks excessively along the grain compared to normal wood. 3.6 cross break: A break or fracture across the grain of the wood. 3.7 crossgrain

27、: Fibers in wood that are not parallel with the long axis of the piece. 3.8 decay: A disintegration of wood substance due to the action of wood-destroying fungi, resulting in loss of strength. Also called dote or rot. 3.8.1 advanced (typical) decay: The older stage of decay in which the disintegrati

28、on 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. 3.8.2 firm red heart: A stage of incipient decay, characterized by a reddish color in

29、the heartwood. 3.8.3 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 deteriorated, no visible change has occurred, with perhaps the excepti

30、on of minor discoloration. Incipient decay can occur in living trees. 3) Available from Southern Pine Inspection Bureau (SPIB) . 4) Available from West Coast Lumber Inspection Bureau (WCLIB), . ANSI O5.3-2015 - 3 - Figure 1 - Features observed during grading 3.9 dense material grade: 3.9.1 Douglas-f

31、ir: (see WCLIB Standard Grading Rules No. 17, paragraph 204-c) requiring an average of approximately 6 or more annual growth rings per inch (2.5cm) and, in addition, 1/3 or more latewood (summerwood) on either one end or the other of a piece, measured as shown in Figure 1, Rate of growth, in WCLIB S

32、tandard Grading Rule No. 17, paragraph 204-d. The contrast in color between the latewood (summerwood) and earlywood (springwood) must be distinct. Pieces averaging less than 6 annual rings per inch (2.5 cm) but not less than 4 are accepted as dense if averaging 1/2 or more latewood (summerwood). 3.9

33、.2 Dense Southern Pine: Southern pine crossarm stock purchased by crossarm producers shall meet the requirements of Dense Industrial 65, 72, or 86 grades in the SPIB Special Product Rules for Structural, Industrial, and Railroad-Freightcar Lumber. See Annex A. ANSI O5.3-2015 - 4 - 3.10 density: Mass

34、 (weight) of wood per unit volume. Strength is related to density. Higher working strengths can be assigned to wood when lightweight pieces are eliminated, by specifying limits for rate of growth and minimum percentages of summerwood. See rate of growth. See close grain grade and dense material grad

35、e. 3.11 dote: See decay. 3.12 earlywood: That portion of the growth ring that is formed during the early part of the seasons growth. It is usually less dense, lighter in color, and weaker mechanically than latewood. The term is preferred to springwood. 3.13 equilibrium moisture content (EMC): Moistu

36、re content at which the wood is neither gaining nor losing moisture at a given temperature and relative humidity. 3.14 heart center: The pith or center core of the tree. “Free of heart centers” (FOHC) means “without pith” (side-cut). 3.15 heartwood: The inner portion of wood between the pith and the

37、 sapwood, composed entirely of nonliving cells. It is usually darker in color and more durable than the sapwood. Heartwood and sapwood are comparable in strength. 3.16 knot: A portion of a branch or limb that has become incorporated in a piece of lumber. The shape of the knot depends on the angle th

38、rough which the branch was cut. Least diameters determine the size unless otherwise stated. Terms used to describe knots include: 3.16.1 decayed knot: A knot that is softer than the surrounding wood, containing advanced decay. 3.16.2 firm knot: A knot that is solid across its face, containing incipi

39、ent decay. 3.16.3 fixed knot: A knot that will hold its place in dry lumber under ordinary conditions, but can be moved by pressure, not easily pushed out. 3.16.4 intergrown knot: A knot whose growth rings are partially or completely intergrown on one or more faces with the growth rings of the surro

40、unding wood. 3.16.5 knot cluster: Two or more knots grouped together as a unit with the fibers of the wood deflected around the entire unit. A knot cluster is distinct from a group of single knots, in which each is a unit. 3.16.6 loose knot: A knot not held firmly in place by growth or position, tha

41、t cannot be relied upon to remain in place. 3.16.7 sound knot: A knot that is solid across its face, is as hard as the surrounding wood, and shows no indications of decay. It may vary in color from the natural color of the wood to reddish brown or black. 3.16.8 spike knot: A knot cut lengthwise or d

42、iagonally through the long axis of the branch. In a crossarm, the cross-sectional view of the knot appears on one surface of the arm, and the longitudinal view appears on an adjacent surface. The size of a spike knot is considered to be the distance across the end-grain of the knot, between the edge

43、 of the arm and a line parallel to the edge. 3.16.9 tight knot: A knot that is so fixed by growth, shape, or position that it will firmly retain its place in the piece. 3.17 latewood: That portion of the annual growth ring that is formed during the latter part of the yearly growth period. It is usua

44、lly denser, darker in color, and stronger mechanically than earlywood. This term is preferred to summerwood. 3.18 intentionally left blank. 3.19 nail plate: A galvanized metal plate placed on the end-surfaces to prevent split-widening. 3.20 pitch pocket: An opening between growth rings that usually

45、contains, or has contained, resin. 3.21 pith: The small core in the structural center of a log. See heart center. 3.22 rate of growth: The amount of tree growth each year, expressed as the number of growth rings per inch (2.5 cm) (see Figure 1). 3.23 red heart: See decay. ANSI O5.3-2015 - 5 - 3.24 r

46、ot: See decay. 3.25 sapwood: The outer portion of wood next to the bark, usually lighter in color than the heartwood, and containing some living cells while the tree is alive. If left untreated, sapwood is as strong as heartwood, but is not naturally durable. 3.26 sections: For ease of description,

47、crossarms are divided into sections as shown in Figure 2. Figure 2 - Crossarm sections 3.27 shake: A lengthwise separation along the grain, the greater part of which occurs essentially between, or through, the growth rings. This is shown in Figure 1. 3.28 skip: An unsurfaced area on dressed lumber.

48、3.29 split: A lengthwise separation of the wood from one surface to the other. This is shown in Figure 1. 3.30 springwood: See earlywood. 3.31 summerwood: See latewood. 3.32 torn grain: Consists of parts of the wood being torn out during sawing, planing, or other processing operations. These effects

49、 are most often found around areas with knots, spiral, or diagonal grain. 3.33 wane: Bark, or the lack of wood from any cause, on the surface of lumber. 3.34 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. 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 (1 cm) or larger. Marking or branding shall not be deepe