7 CFR § 1728.201 - Bulletin 1728H–701, Specification for Wood Crossarms (Solid and Laminated), Transmission Timbers and Pole Keys.
(a) Scope.
(1) The specification in this section describes the minimum acceptable quality of wood transmission and distribution crossarms (hereinafter called arms) purchased by or for RUS borrowers. Where there is conflict between the specification in this section and any other specification referred to in this section, the specification in this section shall govern.
(2) The requirements of the specification in this section implement contractual provisions between RUS and borrowers receiving financial assistance from RUS. The contractual agreement between RUS and a RUS borrower requires the borrower to construct its system in accordance with RUS accepted plans and specifications. Each RUS electric and telecommunications borrower shall purchase only arms produced in accordance with the specification in this section. Each RUS electric and telecommunications borrower shall require a written confirmation from their selected contractor that all material utilized shall be produced in accordance with the specifications in this section.
(b) General stipulations.
(1) Conformance of arms to RUS specifications is the responsibility of the producer. A member of the producer's staff shall be designated as quality control supervisor and charged with the responsibility for the exercise of proper quality control procedures throughout the production process. The primary responsibility of third-party inspection agencies is to verify that producers involved in the manufacture of RUS treated wood products have functional in-house quality control systems in place that result in the shipment of materials meeting applicable RUS specification requirements to borrowers.
(2) Treated wood products intended for RUS borrowers shall not be inspected when in the opinion of the inspector, unsafe conditions are present.
(3) Various requirements relating to quality control and inspection that are contained in § 1728.202 and ANSI O5.2 and ANSI O5.3 (both incorporated by reference in § 1728.97) shall be followed exactly and shall not be interpreted or subject to judgment by the producer's quality control personnel or by the third party inspector.
(4) The requirements of AWPA M3 (incorporated by reference in § 1728.97) pertaining to record keeping, pre-treatment storage, analytical laboratories, plant gauges and other plant facilities, shall be followed.
(5) The producer shall maintain its own properly staffed and equipped analytical laboratory or contract with an independent testing laboratory at or near the treating plant to provide the required analytical service. On a case-by-case basis, with written permission from RUS, a producer with more than one treatment facility may be allowed to use a central laboratory.
(6) Arms can be purchased under either of two purchase plans; a RUS approved Quality Assurance Plan or an Independent Inspection Plan. The method of inspection described in this section shall be used no matter which plan timber products are purchased under.
(7) All third-party inspectors involved in the inspection of RUS products shall maintain their impartiality when providing their inspection service. This requires that these individuals and their employers, as well as producers and suppliers involved in providing RUS borrowers with treated wood products, maintain a professional separation during the performance of their respective functions to eliminate any possible conflict of interest.
(8) With the exception of financial agreements for inspection services, inspection agencies shall neither accept nor provide gratuities or free services to suppliers.
(9) Inspection agencies shall not offer product warranties on inspected material.
(10) Arms shall be warranted to conform to this specification. Arms shall meet or exceed their minimum allowable dimensions for at least one year from time of delivery to the borrower. If any arm is determined to be defective or does not conform to this specification within 1 year from the date of delivery to the borrower, it shall be replaced as promptly as possible by the supplier. In the event of failure to do so, the purchaser may make such replacement and the cost of the arm, at destination, shall be recovered from the supplier.
(11) Arm producers shall have and maintain liability insurance in the amount of $1 million. Evidence of compliance to this requirement shall be forwarded to the RUS annually. The evidence shall be in the form of a certificate of insurance or a bond signed by a representative of the insurance company or Surety Bonding company and include a provision that no change in, or cancellation of, will be made without the prior written notice to the Chairman, Technical Standards Committee “A” (Electric), 1400 Independence Ave. SW, Stop 1569, Washington, DC 20250–1569.
(c) Definitions. The following definitions apply to this section:
Agency refers to Rural Utilities Service (RUS), United States Department of Agriculture.
Certificate of compliance is a written certification by an authorized employee of the producer that the material shipped meets the requirements of this specification and any supplemental requirements specified in a purchase order from a borrower or the borrower's contractor.
Crossarm refers to the structural wood member used to support electrical conductors and equipment. The word arm is used interchangeably with crossarm.
Independent inspection refers to examination of material by a trained inspector employed by a commercial inspection agency.
Inspection means an examination of material in sufficient detail to ensure conformity to all requirements of the specification under which it was purchased.
Lot is a certain number of pieces of a given item submitted for inspection at one time.
Producer is the party who manufactures arms. In some cases the producer may also be the treating plant.
Purchaser refers to either the RUS borrower or contractors acting as the borrower's agent, except where a part of the specification in this section specifically refers to only the borrower or the contractor.
Quality control supervisor refers to an employee of the producer designated to be responsible for quality control procedures carried out by said producer.
Reserve treated stock consists of treated material held in storage by a producer for purchase and immediate shipment to a borrower.
Supplier may refer to the producer, the treater, or to a third-party broker or distributorship involved in supplying RUS products to the borrowers.
Treating plant is the facility that applies the preservative treatment to the arms.
(d) Material requirements—(1) Material and grade. All arms furnished under the specification in this section shall be free of brashy wood, decay, and shall meet additional requirements as shown on specific drawings in this section. Arms shall be made of one of the following:
(i) Douglas-fir which conforms to the applicable provisions of paragraphs 170 and 170a, or the applicable transmission arm provisions of paragraphs 169 and 169a of the West Coast Lumber Standard No. 17 (incorporated by reference in § 1728.97). Only coastal origin Douglas-fir shall be used for Douglas-fir arms manufactured under the specification in this section;
(ii) Southern Yellow Pine which conforms to the provisions of Dense Industrial Crossarm 65, as described in Southern Pine Inspection Bureau's Standard Grading Rules for Southern Pine Lumber (incorporated by reference at § 1728.97); or
(iii) Laminated wood arms shall conform to ANSI O5.2 and have at least the same load carrying capacity as the solid sawn arms being replaced. The load carrying capacity of the laminated arms shall be determined by one of the procedures outlined in ANSI O5.2. The testing and inspection of laminated arms shall be in accordance with AITC 200 (incorporated by reference at § 1728.97).
(2) Alternative arms. Borrowers may use alternative arms that are listed in Informational Publication 202–1, List of Materials Acceptable for Use on Systems of USDA Rural Utilities Service Borrowers. For information on the availability of such material, contact the Chairman, Technical Standards Committee “A” (Electric), 1400 Independence Ave. SW, Stop 1569, Washington, DC 20250–1569, or go to: https://www.rd.usda.gov/files/UEP_LoM.pdf.
(3) Knots. Well-spaced sound, firm, and tight knots are permitted.
(i) Slightly decayed knots are permitted, except on the top face, provided the decay extends no more than 3/4 of an inch into the knot and provided the cavities will drain water when the arm is installed. For knots to be considered well-spaced, the sum of the sizes of all knots in any 6 inches of length of a piece shall not exceed twice the size of the largest knot permitted. More than one knot of maximum permissible size shall not be in the same 6 inches of length. Slightly decayed, firm, or sound “pin knots” ( 3/8 of an inch or less) are not considered in size, spacing, or zone considerations.
(ii) Knots are subject to limits on size and location as detailed in Tables 1 and 2 to this paragraph (d)(3)(ii).
Table 1 to Paragraph (d)(3)(ii)—Knot Limits for Distribution Arms (See Figure 1 to This Section)
[All dimensions in inches]
| Class of knot and location | Maximum knot diameter | |
|---|---|---|
| Close grain | Dense grain | |
| Round Knots: | ||
| Single Knot: Maximum Diameter Center Section 1 | ||
| Upper Half |
|
1 |
| Lower Half | 1 | 1
|
| Elsewhere | 1
|
1
|
| Sum of Diameters in 6-Inch Length: Maximum Center Section: | ||
| Upper Half | 1
|
2 |
| Lower Half | 2 | 2
|
| Elsewhere | 2
|
3 |
1 No knot shall be closer than its diameter to the pole mounting hole.
Table 2 to Paragraph (d)(3)(ii)—Knot Limits for Transmission Arms (See Figure 2 to This Section)
[All dimensions in inches]
| Pole mounting hole zone 1 | Maximum diameter for single knot |
|---|---|
| Upper Half (inner zone) |
|
| Upper Half (outer zone) | 1 for close grain. |
| 1
|
| Other locations transmission arm size 2 | Narrow face | Wide face
(two sides) |
|
|---|---|---|---|
| Edge | Along
centerline |
||
| 4
|
1 | 1
|
1
|
| 5
|
1
|
1
|
1
|
| 3
|
|
1
|
2
|
1 No knot shall be closer than its diameter to the pole mounting hole.
2 For cross sections not shown, refer to grading rules.
(iii) Knot clusters shall be prohibited unless the entire cluster, measured on the worst face, is equal to or less than the round knot allowed at the specific location.
(iv) Spike knots shall be prohibited in deadend arms. Any spike knot across the top face shall be limited to the equivalent displacement of a knot 3/8 of an inch deep on one face and the maximum round knot for its particular location on the worst face, with a maximum width of 1 inch measured at the midpoint of the spiked section. Elsewhere across the bottom or side faces, spike knots shall not exceed 1/2 the equivalent displacement of a round knot permitted at that location, provided that the depth of the knot on the worst face shall not exceed the maximum round knot allowed at that location.
(v) Loose knots shall be prohibited in deadend arms. Loose knots and knot holes shall be permitted only if they allow water to drain when the arm is installed in its normal position. In the center section, upper half, loose knots shall not be greater than 1/2 the dimensions of round knots. Elsewhere, loose knots shall not be greater than the round knot dimension.
(vi) All knots except those “spike” knots intersecting a corner shall be measured on the least diameter of the knot.
(vii) A knot shall be considered to occupy a specific zone or section if the center of the knot (i.e., pith of knot) is within the zone or on the zone's boundary.
(viii) If a round or oval knot appears on two faces and is in two zones, each face shall be judged independently. When this does not occur, average the least dimension showing on both faces. Knots which occur on only one face of a free of heart center (FOHC) arm shall be permitted to be 25 percent larger than the stated size.
(ix) Two or more knots opposite each other on any face shall be limited by a sum not to exceed the size of a maximum single knot permitted for the location. On all four faces, all knots shall be well spaced.
(x) No knot over 5/8 inch in diameter may intersect pin holes in the center section. One-inch diameter knots may intersect insulator pin holes elsewhere.
(e) Miscellaneous characteristics, features and requirements.
(1) The top face of distribution arms shall not have more than four medium pitch and bark pockets in 8-foot arms, and not more than five pitch and bark pockets in 10-foot arms. Elsewhere a maximum of six medium pitch and bark pockets in 8-foot arms and eight in 10-foot arms shall be permitted. Equivalent smaller pockets shall be permissible. An occasional large pocket is permissible.
(2) Shakes shall be prohibited.
(3) Prior to treatment on properly seasoned arms, single face checks shall not exceed an average penetration of 1/4 the depth from any face and shall be limited to 10 inches long on the top face, and 1/3 the arm length on the other faces. Checks shall not be repeated in the same line of grain in adjacent pin holes. The sum of the average depths of checks occurring in the same plane on opposite faces shall be limited to 1/4 the face depth.
(4) Compression wood shall be prohibited on any face. Compression wood is permitted if wholly enclosed in the arm, more than six annual rings from the surface, and not over 3/8 of an inch in width.
(5) Insect holes 3/32 of an inch and larger shall be prohibited. Insect pin holes (i.e., holes not over 1/16 of an inch diameter) shall be allowed if scattered and not exceeding 10 percent of the arm girth.
(6) Wane shall be allowed on one edge, limited to approximately 1 inch measured across the corner. Outside of the top center section, an aggregate length not to exceed 2 feet may have wane up to 1 1/2 inches on an occasional piece on one or both edges. Bark shall be removed.
(7) Prior to and after preservative treatment, crook, bow, or twist shall not exceed 1/2 of an inch in 8-foot arms and 5/8 of an inch in 10-foot arms.
(f) Manufacturing—(1) Quality of work. All arms shall be of the highest quality production. Arms shall be dressed on all four sides, although “hit and miss skips” may occur on two adjacent faces on occasional pieces.
(2) Dimensions and tolerances. All dimensions and tolerances shall conform to those shown on the drawings in this section or drawings supplied with the purchase order. Arms supplied shall meet or exceed minimum dimensions shown on the drawings in this section. Cross-sectional dimensions shall be measured and judged at about 1/4 the arm length, except when the defects of “skip dressing” or “machine bite or offset” are involved.
(3) Shape. The shape of the arms at any cross section, except for permissible wane, shall be as shown on the respective drawings in this section or supplied with the order. The two top edges may be either chamfered or rounded 3/8 of an inch radius. The two bottom edges shall be slightly eased 1/8 of an inch radius for the entire length.
(4) Lamination techniques. Lamination techniques shall comply with ANSI O5.2.
(5) Pin and bolt holes. Pin and bolt holes shall be smoothly bored without undue splintering where drill bits break through the surface. The center of any hole shall be within 1/8 of an inch of the center-line locations on the face in which it appears. Holes shall be perpendicular to the starting and finishing faces.
(6) Incising. The lengthwise surfaces of Douglas-fir arms shall be incised a minimum of 1/4 of an inch deep. The incision shall be reasonably clean cut with a spacing pattern that ensures uniform penetration of preservative.
(g) Conditioning prior to treatment. AWPA T1 (incorporated by reference at § 1728.97) shall be followed.
(1) All solid sawn arms shall be made of lumber which has been kiln-dried. Douglas-fir arms shall have an average moisture content of 19 percent or less, with a maximum not to exceed 22 percent in a single arm. Southern Yellow Pine arms shall have an average moisture content of 22 percent or less, with a maximum not to exceed 30 percent in a single arm.
(2) Moisture content levels shall be measured at about 1/4 the length and at a depth of about 1/5 the arm's thickness. Additionally, the moisture content gradient between the shell (i.e.,1/4 of an inch deep) and the core (i.e., about 1 inch deep) shall not exceed 5 percentage points.
(3) A minimum of at least 20 solid sawn arms per treating charge shall be measured and the individual results recorded by the producer to verify moisture content.
(4) The moisture content of lumber used in laminating shall, at the time of gluing, be within the range of 8 to 12 percent, inclusive.
(h) Preservatives.
(1) Creosote, water-borne preservatives, pentachlorophenol, DCOI, and copper naphthenate shall conform to the requirements of AWPA U1 (incorporated by reference at § 1728.97). Oxide formulations of waterborne preservatives shall be supplied. If CCA is the selected preservative, CCA–C shall be the type required.
(2) Douglas-fir arms shall not be treated with CCA.
(i) Preservative treatment.
(1) All timber products manufactured under the specification in this section shall be pressure treated. AWPA T1 shall be followed.
(2) These materials may be further conditioned by steaming, or by heating in hot oil (Douglas-fir), within the following time and temperature limits:
| Max. time
(hours) |
Temperature | |
|---|---|---|
| (i) Steam | 3 | 220 °F |
| (ii) Heating in Preservative | 3 | 210 °F |
(3) A final steam or hot oil bath may be used only to meet cleanliness requirements. Total duration of the final steam bath shall not exceed 2 hours and the temperature shall not exceed 240 °F.
(j) Results of treatment—(1) Penetration and retention. The quality control supervisor shall test or supervise the testing of each treated charge for penetration and retention.
(2) Method of sampling. When testing penetration and retention, a borer core shall be taken from a minimum of 20 arms in each treating charge. The borings shall be taken from any face except the top face at a point as close to the end as possible, being at least 3 inches from the end of the arm and no closer than 3 inches from the edge of the holes. The bored holes shall be plugged with treated plugs. Borings from laminated arms shall not be taken from the same laminate unless there is an end joint separation.
(3) Preservative penetration. All of the sapwood present in Douglas-fir and southern yellow pine arms shall be completely penetrated with preservative. Preservative penetration in the heartwood of Douglas-fir arms shall be not less than 3 inches longitudinally from the edge of holes and ends, and at least 3/16 inch from the surface of any face.
(4) Preservative retention. Preservative retention in the outer 0.6 inch for Douglas-fir arms and in the outer one inch of southern yellow pine arms shall be not less than the following:
| Preservative | Retention
(pcf) |
|---|---|
| (i) Creosote | 8.0 |
| (ii) Pentachlorophenol | 1 0.4/0.36 |
| (iii) ACA, ACZA, or CCA–C | 0.4 |
| (iv) Copper Naphthenate | 0.04 |
| (v) DCOI | 0.13 |
1 If the copper pyridine method is used when timbers may have been in contact with salt water, a penta retention of 0.36 pcf is required for all species native to the Pacific Coast region.
(5) Arms surfaces. The surfaces of all arms shall be free from oil exudation (bleeding) and pentachlorophenol crystallization (blooming), and other surface deposits.
(6) Retreatment of arms. Arms may be retreated no more than twice. Initial treatment steaming time plus re-treatment steaming time, combined, shall not exceed total steaming time allowed.
(k) Marking/branding.
(1) Before treatment, arms shall be legibly branded (hot brand) or die-stamped to a depth of approximately 1/16 of an inch, with the top of the brand oriented to the top of the arm. The brand shall be placed on either of the wide surfaces of the arm, approximately one foot from the midpoint of the piece.
(2) The letters and figures shall be not less than 1/2 of an inch in height.
(3) The brand or die-stamp shall include:
(i) The manufacturer's identification symbol;
(ii) Month and year of manufacture;
(iii) Species (DF for Douglas-fir and SP for southern yellow pine);
(iv) Preservative (C for creosote, DA for DCOI, PA for penta, SK for CCA, SZ for ACZA, N for Copper Naphthenate); and
(v) Required retention. An example of required retention is: M–6–16 Manufacturer—Month—Year and DF–PA–.4 Douglas-fir–penta treated—.40 pcf retention.
(4) Brands and quality assurance/inspection marks shall be removed from arms that do not meet these specifications.
(l) Storage.
(1) Producers may manufacture/treat RUS arms for reserve treated stock under either of the allowable purchase plans. (See paragraph (b)(6) of this section).
(2) Arms treated with creosote or oil-borne preservatives, and which have been held in storage for more than 1 year before purchase and shipment to the borrower shall be re-assayed before shipment. Any such arms found to be nonconforming for retention shall be retreated and reassayed per the requirements of this section of the specification.
(m) Drawings.
(1) The drawings of Figure 3 to this section, Crossarm Drilling Guide, have a type number and show in detail the hole size, shape, and pattern desired for arms ordered under the specification in this section.
(2) Purchase orders shall indicate the type arm required.
(3) Arms shall be furnished in accordance with the details of the drawings in this section or in accordance with drawings attached to the purchase order.
(4) Appropriate drawings for transmission arms are to be specified and included with purchase orders. Technical drawings for transmission arms are published in Bulletin 1728F–811 (incorporated by reference at § 1728.97) and Bulletin 1728F–810 (incorporated by reference at § 1728.97).
(n) Destination inspection. The RUS borrower shall have the prerogative to inspect materials at destination. All provisions of the specification in this section shall apply to material inspected at destination. If a disagreement arises over conformance of materials received at destination, it shall be the responsibility of the supplier to resolve the matter with the purchaser.
(o) Purchase of related specifications and standards.
(1) All ANSI and AWPA standards may be purchased from: American Wood Protection' Association (AWPA), P.O. Box 361784, Birmingham, AL 35236–1784, Telephone (205)733–4077, Web address: http://www.awpa.com.
(2) Standard Grading Rules for Southern Pine Lumber and Special Products Rules for Structural, Industrial, and Railroad Freight Car Lumber may be purchased from: Southern Pine Inspection Bureau, 4709 Scenic Highway, Pensacola, Florida 32504–9094, Telephone (850) 434–2611, Web address: http://www.spib.org.
(3) Standard Grading Rules for West Coast Lumber may be purchased from: West Coast Lumber Inspection Bureau, P.O. Box 23145, Portland, Oregon 97281, Telephone (503) 639–0651, Web address: http://www.wclib.org.
(4) AITC 200 may be purchased from: American Institute of Timber Construction, 7012 S Revere Park Way, Englewood, Colorado 80112, Telephone (303) 792–9559, Web address: http://aitc-glulam.org.
(p) Information to be completed by the borrower. When using the specification in this section, the borrower or borrower's representative should enter into a written agreement with a material supplier by way of a contract or purchase order. This agreement should state that all arms shall be manufactured in strict accordance with the specifications in this section.