1、 ANSI O5.4-2017 Naturally Durable Hardwood Poles: 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 Associati
2、on (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 role
3、 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 O5 we
4、bsite 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 proces
5、s 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 groups wi
6、th 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 the r
7、equirements 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. Substantial ag
8、reement 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 any
9、 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 an in
10、terpretation 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 sponsor w
11、hose 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. Purchas
12、ers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer distinct from a group of single knots in which each is a unit. A knot cluster shall be considered as a single knot. 3.18 knot diam
13、eter: The diameter of a knot on the surface of the pole measured in a direction at right angles to the lengthwise axis of the pole. The sapwood as well as the heartwood portion of a knot shall be included in the measurement. NOTE For a description of means for defining the limits of knots, see ASTM
14、D9-87. 3.19 sap stain: A discoloration of the sapwood, caused by the action of certain fungi, which is not accompanied by softening or other disintegration of the wood. 3.20 scar: A depression in the surface of the pole resulting from a wound where healing has not reestablished the normal cross sect
15、ion of the pole. 3.21 shake: A separation along the grain. 3.22 shelling: Ring separation extending to the surface of round or sawn timber normally following the growth rings and often associated with limiting defects such as knots, tension wood or shake. Ring separation usually becomes more pronoun
16、ced as the product dries and may be further aggravated by stress developed during horizontal lifting or loading. NOTE The growth rings of most tropical hardwood species are indistinguishable. 3.23 short crook: A localized deviation from straightness that, within any section 5 feet (1.5 m) or less in
17、 length, is more than 1/2 the mean diameter of the crooked section. (See Figure 1, Diagram 3.) 3.24 spiral-grained (twist-grained) wood: Wood in which the fibers take a spiral course about the trunk of a tree instead of a vertical course. The spiral may extend in a right-handed or left-handed direct
18、ion around the tree trunk. Spiral grain is a form of cross grain. 3.25 split: A lengthwise separation of the wood extending completely through the piece from one surface to another. 3.26 sweep: Deviation of a pole from straightness. (See Figure 1, Diagrams 1 and 2.) 3.27 tension wood: Abnormal wood
19、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 mechanism for crown movement in dense forests. It is sometimes distinguished by eccentric cross-sectional growth, but usually requires mic
20、roscopic examination, the use of chemical indicators, or visual observation upon thorough seasoning. Tension wood typically has greater shrinkage and lower strength properties when compared to normal wood. ANSI O5.4-2017 - 4 - 4 Pole classes The naturally durable hardwood dimension tables show the m
21、inimum circumferences at six feet from the butt and at the tip. The minimum circumferences presented are for the heartwood only, unless the sapwood is rated “Highly Resistant” per ASTM D2017-05. Pole circumferences are determined at 20% MC or less. Many naturally durable hardwoods have distinct prop
22、erties such as a very high density and hardness. They are difficult to gaff, and a one-half inch layer of sapwood should be left on the poles if field climbing is required. The sapwood shall have an indicated Class of Resistance of “Resistant” or higher according to ASTM D2017-05. In order to determ
23、ine the heartwood dimensions, four measurements of the sapwood thickness should be taken at the butt of the pole with one measurement at the thickest sapwood point and the other three measurements at 90 degree increments from this point. The average of these four measurements shall be used as an est
24、imate of the sapwood thickness at the ground line and classing location. Similar procedures should be used to determine the sapwood thickness at the top for the determination of the required top circumference. Poles meeting the above requirements are grouped by classes identified in the Dimension ta
25、bles below, which are based on their circumference measured at six feet from the butt. Poles of a given class and length are designed to have approximately the same load-carrying capacity, regardless of species. Annexes A and B provide further information. 5 Material requirements 5.1 General 5.1.1 S
26、pecies and designated fiber strength values Table 1 - Designated fiber strength for wood utility poles1) air dried Species Common Name Scientific Names Fiber Strength Fiber Strength (psi) (kPa) Abiurana Iron2)Chrysophyllum prieuri 15,700 108,500 Mata Mata Black2)Eschweilera truncata 12,600 87,400 NO
27、TES: 1) This designated fiber strength represents a mean, groundline, fiber strength value with a corresponding coefficient of variation equal to 0.18 for Abiurana Iron and 0.24 for Mata Mata Black. 2) The fiber strength shown was determined with the wood species in their Green State or MC of 30% or
28、 higher. The designated fiber strength values are for pole groundline locations given in the Dimension Tables below. 5.1.2 Drying 5.1.2.1 Air drying All naturally durable hardwood species listed in this Standard may be air dried. No other type of drying or seasoning is required. 5.1.2.2 Kiln drying
29、Pole manufacturers may also employ kiln drying methods suitable for the naturally durable hardwood species, following proven kiln drying processes. 5.1.2.3 Fumigation All naturally durable hardwood poles are to be fumigated prior to shipment to North America in accordance with applicable import requ
30、irements. An Official Governments Certificate of Fumigation, from the country of origin, must be provided to the user prior to shipping the poles to North America. ANSI O5.4-2017 - 5 - 5.1.3 Rate of growth Most tropical hardwoods do not have discernable growth rings. Other than first growth tropical
31、 hardwoods, all tropical hardwoods must have records of evidence showing a minimum age of 40 years. 5.2 Prohibited defects 1) Cross breaks. 2) Decay, except as permitted for defective butts in 5.4.3, and decayed knots in 5.4.5. 3) Dead streaks, except as permitted in 5.4.2. 4) Holes, open or plugged
32、, are prohibited, except for those deliberately placed holes for explicit use as framing or inspection holes. 5) Hollow butts or tops, except as permitted under hollow pith centers and defective butts. 6) Marine borer damage. 7) Nails, spikes, and other metal not specifically authorized by the purch
33、aser. 8) Tension wood presence upon thorough seasoning. 5.3 Permitted defects Sap stain that is not accompanied by softening or other disintegration (decay) of the wood is permitted. 5.4 Limited defects 5.4.1 Bark inclusions Depressions containing bark inclusions shall be not more than 2 inches (50
34、mm) in depth, measured from the surface of the pole. 5.4.2 Dead streaks A single, sound dead streak is permitted, provided the greatest width of the streak is less than 1/4 of the circumference of the pole at the point of measurement. 5.4.3 Defective butts Hollowing in the butt caused by “splinter p
35、ulling“ in felling the tree is permitted, provided that the area of such a hollow is less than 10% of the butt area. Hollow heart or decay, or both, is permitted, provided the aggregate area of the hollow heart or decay, or both, does not exceed 10% of the entire butt area and does not occur closer
36、than 2 inches (50 mm) to the side surface and provided that the depth of the hollow does not exceed 2 feet (0.61 m), as probed and measured from the butt surface. 5.4.4 Insect damage Insect damage, consisting of holes 1/16 inch (2 mm) or less in diameter, or surface scoring or channeling is permitte
37、d. All other forms of insect damage are prohibited, except those associated with hollow heart. 5.4.5 Knot The diameter of any single knot and the sum of knot diameters in any 1-foot (0.31 m) section shall not exceed the limits of Table 2. In determining the sum of the knot diameters in any 1-foot (0
38、.31 m) section, only those knots with diameters over 0.5 inch (13 mm) whose pith centers fall within the section shall be included in the sum, and the 1-foot (0.31 m) section shall be located so as to include the maximum number of knots (i.e., the most severe condition). Type II “decayed knots” are
39、permitted. 5.4.6 Scars (cat face) No pole shall have a scar located within 2 feet (0.61 m) of the groundline. Sound scars are permitted elsewhere on the pole surface, provided they are smoothly trimmed and do not interfere with the cutting of any gain, and provided that: 1) The circumference at any
40、point on trimmed surfaces located between the butt and 2 feet (0.61 mm) below the groundline is not less than the minimum circumference specified at 6 feet (1.8 m) from the butt for the class and length of the pole. ANSI O5.4-2017 - 6 - 2) The depth of the trimmed scar is not more than 2 inches (50
41、mm), if the diameter is 10 inches (0.25 m) or less, or 1/5 the pole diameter at the location of the scar if the diameter is more than 10 inches (0.25 m). 5.4.7 Shakes Shakes in the butt surface that are not closer than 2 inches (50 mm) to the side surface of the pole are permitted, provided they do
42、not extend to the groundline. Shakes or a combination of connected shakes that are closer than 2 inches (50 mm) to the side surface of the pole are permitted, provided they do not extend farther than 2 feet (0.61 m) from the butt surface and do not have an opening wider than 1/8 inch (3 mm). Shakes
43、in the pole top are permitted, provided that the shake is not closer to the surface of the pole than the midpoint of a line extending from the pith to the surface (i.e., the shake is permitted if it is closer to the pith than to the surface of the pole). 5.4.8 Shape Poles shall be free from short cr
44、ooks. A pole may have sweep subject to the following limitations: 1) Where sweep is in one plane and one direction only: For poles of all species, a straight line joining the surface of the pole at the groundline and the edge of the pole at the top shall not be distant from the surface of the pole a
45、t any point by more than 1 inch (25 mm) for each 10 feet (3 m) in length. (See Figure 1, Diagram 1.) 2) Where sweep is in two planes (double sweep) or in two directions in one plane (reverse sweep): A straight line connecting the midpoint at the groundline with the midpoint at the top shall not at a
46、ny intermediate point pass through the surface of the pole. (See Figure 1, Diagram 2.) 5.4.9 Spiral grain Spiral grain (twist grain) is permitted as follows: Length of pole (feet) Maximum twist of grain permitted 30 (9.1 m) and shorter 1 complete twist in any 10 feet (3 m) 35 (10.7 m)-45 (13.7 m), i
47、nclusive 1 complete twist in any 16 feet (5 m) 50 (15.2 m) and longer 1 complete twist in any 20 feet (6 m) 5.4.10 Splits and checks 5.4.10.1 In the top A split or a combination of two single checks (each check terminating at the pith center and separated by not less than 1/6 of the circumference) h
48、aving one or both portions located in a vertical plane within 30 degrees of the top bolt hole shall not extend downward along the pole more than 6 inches (0.15 m). All other combinations of checks or a split shall not extend downward along the pole more than 12 inches (0.31 m). 5.4.10.2 In the butt
49、A split or a combination of two single checks, as defined above shall not extend upward along the pole more than 2 feet (0.61 m). 5.4.11 Tension wood The outer 1-inch (25 mm) of all poles shall be free from tension wood on either end. 6 Dimensions For dimensions of particular naturally durable hardwood species of poles, see Dimension Tables 3 through 4M. 6.1 Length Poles less than 50 feet (15.2 m) in length shall be not more than 3 inches (80 mm) shorter or 6 inches (0.15 m) longer than nominal length. Poles 50 feet (15.2 m) or more in length shall be not more than 6 inch
