1、TECHNICAL REPORT O5.TR.01.2009 PHOTOGRAPHIC MANUAL OF WOOD POLE CHARACTERISTICS (BASED ON ANSI O5.1.2008) Founded in 1904, the American Wood Protection Association (AWPA) is a non-profit organization which is responsible for promulgating voluntary wood preservation standards. AWPA Standards are deve
2、loped by its technical committees in an open, consensus-based process 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 buildin
3、g code officials; government entities, academia, and other groups with a general interest in wood preservation. 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 t
4、heir intended use. They are recognized and used by most, if not all, specifiers of treated wood including 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 Nat
5、ional Standard requires review by ANSI that the 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
6、and materially affected interests. Substantial 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 comp
7、letely voluntary; their existence does not in 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
8、standards and will in no circumstances give an 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 sh
9、ould be addressed to the secretariat or sponsor 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 rea
10、ffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer Type II decayed knots are simply decayed knot fibers that do not extend deep into
11、 the pole and are not a cause for concern. Type I decayed knots are prohibited and are cause for rejection of a pole. Here is an example of a decayed knot that is associated with heart rot, causing this pole to be rejected. This Type II knot does have decayed fibers, but they do not extend into the
12、poles center, and is therefore permitted. O5.TR.01.2009 10 3.9 Defective Butt (O5.1, Section 5.4.4) Defective butts are limited by ANSI O5.1.2008 in 5.4.4. This Western red cedar pole contains decay in the heartwood, but is accepted because the cross-sectional area of the defect is less than 10% of
13、the total area of the butt surface. Here is an example of splinter pulling in Southern pine. It is also accepted, as the void area makes up less than 10% of the total area of the butt surface. O5.TR.01.2009 11 3.10 Hollow Heart (O5.1, Sections 3.14, 5.2, and 5.4.4) Hollow heart is generally a type o
14、f heartwood decay; it is frequently called heart rot. In Southern pines, hollow heart is often the same as red heart. Here is an example of hollow heart in Southern pine. Hollow heart is prohibited in all species except Western red cedar as permitted under Defective Butts. 3.11 Hollow pith center (O
15、5.1, Sections 3.15 and 5.3.2) Hollow pith centers are sometimes found in utility poles. It is important to note that these are permitted, but by definition, only the pith can be hollow. If the hollow pith center is more than one-eighth inch (3mm) across, the void needs to be probed to ensure that de
16、cay has not affected the surrounding heartwood. Here is a true hollow pith center, which is one-eighth inch (3mm) in diameter and within the original pith of this Southern pine. Therefore, this hollow pith center is normal and permitted. O5.TR.01.2009 12 This defect only appears to be a hollow pith
17、center in Southern pine. However, it is inch (6mm) across, of irregular shape, is lined with loose wood fibers, and when probed, was determined to be associated with hollow heart. Therefore, this is not hollow pith center - rather, it is hollow heart and is grounds for rejection. 3.12 Insect Damage
18、(O5.1, Sections 3.16 and 5.4.5) Insect damage is self-explanatory. Insects and their larvae attack wood, leaving visible holes or channels. Only holes that penetrate the pole and are greater than one-sixteenth inch (2mm) are prohibited by ANSI O5.1.2008. Channeling of the surface is considered an ac
19、ceptable defect. This is an O5.TR.01.2009 13 example of ambrosia beetle damage in Western red cedar. Since the holes are all less than one-sixteenth inch (2mm) in diameter, this would be accepted. This bark beetle damage in Western red cedar (below) is acceptable as long as there are no holes extend
20、ing into the pole. These are flathead borer holes in Southern pine. Since these holes are greater than one-sixteenth inch (2mm) in diameter, this pole must be rejected. O5.TR.01.2009 14 3.13 Knot Cluster (O5.1, Sections 3.18 and 5.4.6) When two or more knots are in such close proximity that the grai
21、n is deflected around the group of knots, they are to be considered as one knot. These two Western red cedar knots are almost touching and therefore must be measured as one knot. Because the grain deviates all the way around this Western red cedar knot cluster, they must be measured as if they were
22、a single knot across the widest dimension. O5.TR.01.2009 15 3.14 Knot Diameter (O5.1, Sections 3.19, 5.4.6, and Table 2) The measurement of knots is confusing to many people. In the softwood species, it is very easy to distinguish the heartwood portion of a knot from the sapwood portion. However, AN
23、SI O5.1.2008 requires that the width of all of the knot fiber perpendicular to the pole axis be measured. In the example below, the “Total Knot Width“ measurement below is perpendicular to the axis of the pole. O5.TR.01.2009 16 ANSI O5.1.2008 limits the sum of the widths of all knots greater than on
24、e-half inch (13 mm) in any 1-foot (30 cm) section. Here is an example of a marked knot section. Refer to O5.1.2008, Table 2, for applicable limitations. 3.15 Mechanical Damage (O5.1, Section 8.3) Mechanical damage is typically caused during handling or machining of a pole. Here is an example of punc
25、ture by a forklift. This pole shall be rejected if the depth of the injury is one-tenth the pole diameter at this point or one inch (2.5cm), whichever is less. Consideration may be taken if the section is oversized for the specified class of the pole. O5.TR.01.2009 17 Mechanical damage also includes
26、 unnecessary chain saw cuts, such as in this pole. Since this cut is greater than one inch (2.5cm), it shall be rejected. 3.16 Rate of Growth (O5.1, Section 5.1.4) Rate of growth is determined by counting the number of rings in the outer two (5cm) or three inches (7.5cm) of a pole, depending on the
27、size pole measured. If there are less than four rings per inch (2.5cm), the pole must be rejected. If there are four or five rings per inch (2.5cm), they must consist of at least 50% summerwood. Six rings per inch (2.5cm) or more are always accepted. This photograph has eight rings in the outer two
28、inches, but contains less than 50% summerwood. Therefore, this pole shall be rejected. O5.TR.01.2009 18 Summerwood (also known as latewood) is characterized by the darker, more dense portion of a growth ring, whereas springwood (also known as earlywood) is generally lighter in color and slightly les
29、s dense. The following photograph shows the difference in coloration between the two types of wood in a typical growth ring. When measuring rate of growth, each annual ring consists of an inner springwood band and an outer summerwood band. O5.TR.01.2009 19 3.17 Red Heart (O5.1, Sections 3.20 and 5.3
30、.1) Red heart is caused by the fungus Fomes pini, which darkens the heartwood to a reddish-brown color and destroys the heartwood. Here is an extreme example of red heart in Southern pine. This pole shall be rejected. 3.18 Sap Stain (O5.1, Sections 3.21 and 5.3.3) Sap stain can be caused by many dif
31、ferent types of stain fungi. While it does increase the permeability of the wood, and does allow other types of fungi and bacteria to more readily attack the wood, stain fungi does not appreciably affect the strength of the wood. The following photograph is an example of sap stain in Ponderosa pine
32、and is permitted. O5.TR.01.2009 20 3.19 Scar (O5.1, Sections 3.22, 3.23, 3.24, and 5.4.7) Scars are typically caused by the destruction of or trauma to the cambium of a living tree. The tree then grows new wood to cover the scar. Scars are not permitted within two feet (61 cm) of the groundline of t
33、he pole. Here is an example of a cat-face scar in Western red cedar. This is a typical cat-face scar in Southern pine. O5.TR.01.2009 21 3.20 Shake (O5.1, Sections 3.25 and 5.4.8) A shake is a longitudinal separation between the annual rings of a tree, as is shown in this Southern pine pole. Since th
34、is shake is closer than two inches (5cm) to the surface of the pole, it must have an opening less than one-eighth inch (3mm) wide to be accepted. If it is less than one-eighth inch (3mm) wide, it cannot extend farther than two feet (61cm) from the butt of the pole. 3.21 Shelling (O5.1, Sections 3.26
35、 and 5.4.12) Shelling occurs when growth rings separate at or near the surface, and is often associated with knots, compression wood, and shake. The following photograph depicts shelling on the surface of this CCA O5.TR.01.2009 22 treated Southern pine pole caused by compression wood on the surface.
36、 Shelling is limited to one inch in depth. The Southern pine pole below shows the effects of shelling where the growth rings extend from an inner growth ring to the surface of the pole around a knot. O5.TR.01.2009 23 3.22 Short Crook (O5.1, Sections 3.27, 5.4.9, and Figure 1) A short crook is a shar
37、p deviation in the axis of the pole, and is different from a long, gradual bend as in sweep. Here is an example of short crook in Southern pine. The red line is parallel to the axis of the lower portion of the pole (the pole in the photograph below is viewed from the tip, with the butt end at the to
38、p of the picture). To measure short crook in this instance, one would mark the point where the line begins to deviate from the center of the pole, then measure upward five feet (1.5m) and mark this point at the center of the pole. The distance between that mark and the line shall not exceed two inch
39、es (51mm). This photograph of the lower two-thirds of a Southern pine pole most resembles the example as shown in Figure 1 of O5.1.2008, Diagram 3, Case 3. O5.TR.01.2009 24 3.23 Spiral grained wood (O5.1, Sections 3.28 and 5.4.10) In many trees, the fibers are “wound” around the axis of the pole. Th
40、is is limited in all species. The photograph below is an extreme example of spiral grain in Douglas-fir. Refer to section 5.4.10 for limitation. The following photograph is of a short section of a Southern pine pole rejected because of spiral grain. Note the way in which the check is at a severe ang
41、le compared to the upper surface of the pole. O5.TR.01.2009 25 3.24 Split (O5.1, Sections 3.29 and 5.4.11) Splits are caused by mechanical stresses imposed upon a pole. However, in some cases, splits are indicated when two deep checks intersect near the center of the pole. Here is a photograph of a pole with a split top. The limitation of splits depends upon the location of the split in relation to the bolt hole, but in no case can extend down the pole more than 12 inches (31cm). Refer to 5.4.11 for more information.
