WOOD POLES
The present technical specification concerns the supply of wood poles intended for the construction of electrical distribution (Medium voltage and low voltage) overhead lines regardless of their rated voltage.
NORMATIVE REFERENCES
The following standards are applicable to the present specification
-NFC 67-100: wood pole for overhead lines-specifications.
-EN 12490: Durability of wood and wood-based products — Preservative-treated solid wood — Determination of the penetration and retention of creosote in treated wood
-EN 12465: Wood poles for overhead lines- Durability requirements
-EN 12479: Wood poles for overhead lines-Sizes- Methods of measurement and permissible deviations
-EN 12510: Wood poles for overhead lines-Strength grading criteria
-EN 50423-1: Overhead electrical lines exceeding AC 1 kV up to and including AC 45 kV – Part 1 : General requirements – Common specifications
-EN 12511: Wood poles for overhead lines- Determination of characteristic values
-EN 60652: Loading tests on overhead line structures
-EN 12509 : Timber poles for overhead lines-Test methods- Determination of modulus of elasticity, bending-strength, density and moisture content
-SABS 754 (latest version): Eucalyptus poles, cross-arms and spacers for power distribution and telephone systems
Any other international standards guaranteeing for this type of material a quality higher or equal to the standards above mentioned are also accepted.
NB: Wood Poles proposed according to SAS Standard shall have at least the minimum pole characteristics required by NFC 67100.
TECHNICAL CHARACTERISTICS
The wood poles are intended for the construction of the distribution (medium and low voltage) overhead lines, they will be installed into simple or reinforced structure (twinned, strutted, or stayed).
Wood characteristics
The wood species of proposed poles shall be selected among those presented in the standard of reference as well as the process of suited preservative treatment. Tenderers shall specify the following:
-The wood species type and quality
-The process and type of preservative treatment
-The ultimate bending stress (shall not be less than 53.8 MPa)
Dimensional specifications of poles
-Poles must have circular cross sections.
-Each pole is characterized by:
-its diameter at the top end(d),
-its diameter at 1m distance (or 1.5 m according to the equivalent standard considered) from the base (D), and
-its overall length (H).
The two diameters abovementioned are measured after shaping and ends cutting of poles.
Weight and volume of wood poles
The following tables indicate the volume and the weight of wood poles, as a rough guide
Wood pole: S100Length of pole (m) / External Diameter
(cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 12 / 17,5 / 195 / 117
10 / 12 / 18,5 / 225 / 135
11 / 12 / 19 / 260 / 156
12 / 12 / 20 / 300 / 180
13 / 13 / 21 / 375 / 225
14 / 13 / 21,5 / 420 / 252
15 / 13 / 22,5 / 470 / 282
Wood pole: S140
Length of pole (m) / External Diameter
(cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 14 / 19 / 245 / 146
10 / 14 / 20 / 285 / 174
11 / 14 / 21 / 325 / 202
12 / 14 / 22 / 370 / 240
13 / 15 / 23 / 460 / 266
14 / 15 / 23,5 / 515 / 300
15 / 15 / 24,5 / 570 / 319
16 / 16 / 25,5 / 700 / 420
17 / 16 / 26 / 790 / 474
18 / 16 / 26,5 / 880 / 528
19 / 16 / 27 / 1000 / 600
20 / 16 / 27,5 / 1100 / 660
21 / 16 / 28,5 / 1200 / 719
Wood pole: S190
Length of pole (m) / External Diameter
(cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 15,5 / 21 / 285 / 189
10 / 15,5 / 22 / 330 / 203
11 / 15,5 / 23 / 375 / 224
12 / 15,5 / 24 / 430 / 301
13 / 16,5 / 25 / 525 / 343
14 / 16,5 / 26 / 585 / 399
15 / 16,5 / 27 / 650 / 451
16 / 17 / 27,5 / 760 / 467
17 / 17 / 28 / 850 / 505
18 / 17 / 28,5 / 960 / 620
19 / 18 / 29,5 / 1120 / 723
20 / 18 / 30 / 1260 / 814
Wood pole: S255
Length of pole (m) / External Diameter (cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 17 / 23 / 330 / 198
10 / 17 / 24 / 380 / 228
11 / 17 / 25 / 435 / 261
12 / 17 / 26 / 500 / 300
13 / 18 / 27 / 600 / 360
14 / 18 / 28 / 665 / 399
15 / 18 / 29 / 735 / 441
16 / 19 / 30 / 920 / 552
17 / 19 / 30,5 / 1010 / 606
18 / 19 / 31 / 1120 / 672
19 / 20 / 32 / 1280 / 768
20 / 20 / 33 / 1440 / 864
21 / 20 / 33,5 / 1570 / 942
22 / 20 / 34 / 1700 / 1020
Wood pole: bois: S325
Length of pole (m) / External Diameter (cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 19 / 25 / 395 / 215
10 / 19 / 26 / 450 / 265
11 / 19 / 27 / 515 / 310
12 / 19 / 28 / 590 / 370
13 / 20 / 29 / 700 / 410
14 / 20 / 30 / 780 / 430
15 / 20 / 31 / 860 / 555
16 / 21 / 32 / 1070 / 580
17 / 21 / 33 / 1220 / 630
18 / 22 / 33,5 / 1370 / 792
Wood pole: bois: S430
Length of pole (m) / External Diameter
(cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 21 / 27 / 465 / 270
10 / 21 / 28,5 / 545 / 316
11 / 21 / 29,5 / 625 / 363
12 / 21 / 30,5 / 715 / 415
13 / 22 / 31,5 / 810 / 470
14 / 22 / 32,5 / 910 / 528
15 / 22 / 33,5 / 1010 / 586
Wood pole:: S550
Length of pole (m) / External Diameter
(cm) / Volume
(dm3) / Weight
(kg)
At the TOP end / At 1m from the Butt end
9 / 23 / 29 / 540 / 313
10 / 23 / 30,5 / 630 / 365
11 / 23,5 / 32 / 750 / 435
12 / 23,5 / 33 / 850 / 493
13 / 24,5 / 34 / 960 / 557
14 / 24,5 / 35 / 1070 / 621
15 / 25 / 36,5 / 1230 / 713
REQUIREMENTS
The trees used must have all qualities of adult wood, i.e. the number of rings at the top after planing must be at least equal to the minimal diameter at the top (in cm) characterizing the pole. This number is however reduced by 20% for Douglas type poles.
The quality of wood shall meet the following requirements:
Required structure
Straightness
The straight line between the centre of the top and the centre of the cross section located 1.5 m from the butt end shall not stray from the surface of the wood pole.
Knot
-At any cross section along the length of the pole, no knot with a diameter measured at right angle to the length of the pole greater than one-fifth of the circumference shall be found.
-The sum of knot diameters at the cross section shall not exceed one-forth of the circumference.
-The knot shall be assessed in accordance with the clause 5.4.5 of EN 12510.
Cracks (“Fentes latérales”)
Cracks across the pole and the grain shall not be permitted.
Fissure
Fissures shall not have a depth greater than half the diameter at one point along the pole. A single continuous fissure shall not exceed 50 % of the length of the pole.
Slope of grain
-Spiral grain shall not exceed a slope of 1 in 6.
-The slop of grain shall be determined in compliance with the § 5.4.2 of EN 12510.
Bark pockets and Rindgalls (“entre-écorces et excroissance”)
Bark pockets and rindgalls shall be permitted in the first 1 m of length from the butt. Above the first 1 m length from the butt, depth, position and number of bark pockets and rindgalls shall not exceed those given for mechanical damage.
Decay and insects
Poles shall be sound and free from decay and attack by insects. Minor insect holes are acceptable providing these are, either, not larger than 1.5 mm in diameter and do not exceed 5 in number, or, not larger than 1.0 mm in diameter and do not exceed 20 in number, evenly distributed in any 100 mm length of the pole.
Damage
Mechanical damage shall not extend to a depth that will reduce the diameter by more than 5% of the diameter at any cross section when measured in accordance with §5.4.6 of EN 12510.
No more than two occurrences of mechanical damage shall be permitted and no part of these shall be less than 500 mm apart.
Moisture content
-The average moisture content of each batch of the wood poles shall not exceed 28 %.
-The moisture content of the individual pole in batch shall not exceed 30 %.
-The method to determine moisture content shall comply with EN 12509.
Mechanical characteristics
Wood poles are defined by their:
-Ultimate load or “Rated force’, available at (25cm or 60 cm or other distance to be specified according to the standard used) from the top end, which is the maximum temporary stress likely to be applied by the conductors to the pole, (wind pressure on the support being taken equal to 400 Pa for rated value).
-Force of permanent deformity, available at (25cm or 60 cm or other distance to be specified according to the standard used) from the top end, which is likely to be applied to the pole in a permanent way by the conductors.
-Cantilever load or “Load of test”: it is the load specified for the mechanical resistance test and which will be applied at (25cm or 60 cm or other distance to be specified according to the standard used) from the top end. It is defined as the minimum required force to cause a fibre stress of 55 MPa (or 75 MPa if otherwise specified).
The modulus of elasticity of the wood pole shall not be less than 10.480 N/mm²
The following tables give a standard pole size range (to NFC 67100) with length less or equal to 15 m for the first table and longer than 15 m for the second. Characteristics of poles indicated in the tables below shall be considered as minimum requirements.
H≤ 15 m
Poles / Characteristics / Total length (m)9 / 10 / 11 / 12 / 13 / 14 / 15
S 100 / Minimum diameter of the top end (cm) / 12 / 12 / 12 / 12 / 13 / 13 / 13
Minimum diameter at 1m from the butt end (cm) / 17,5 / 18,5 / 19 / 20 / 21 / 21,5 / 22,5
Testing load (Cantilever load) (daN) / 315 / 330 / 330 / 345 / 360 / 360 / 375
Available load (‘Effort disponible’) F 400 (daN) normal wind / 100
Permanent deformity load (Effort de déformation permanente) (daN) / 35
S 140 / Minimum diameter of the top end (cm) / 14 / 14 / 14 / 14 / 15 / 15 / 15
Minimum diameter at 1m from the butt end (cm) / 19 / 20 / 21 / 22 / 23 / 23,5 / 24,5
Testing load (daN) / 425 / 435 / 445 / 460 / 475 / 475 / 495
Available load (‘Effort disponible’) F 400 (daN) normal wind / 140
Permanent deformity load (Effort de déformation permanente) (daN) / 45
S 190 / Minimum diameter of the top end (cm) / 15,5 / 15,5 / 15,5 / 15,5 / 16,5 / 16,5 / 16,5
Minimum diameter at 1m from the butt end (cm) / 21 / 22 / 23 / 24 / 25 / 26 / 27
Testing load (daN) / 570 / 580 / 590 / 605 / 625 / 645 / 665
Available load (‘Effort disponible’) F 400 (daN) normal wind / 190
Permanent deformity load (Effort de déformation permanente) (daN) / 65
S 255 / Minimum diameter of the top end (cm) / 17 / 17 / 17 / 17 / 18 / 18 / 18
Minimum diameter at 1m from the butt end (cm) / 23 / 24 / 25 / 26 / 27 / 28 / 29
Testing load (daN) / 750 / 750 / 760 / 770 / 790 / 810 / 825
Available load (‘Effort disponible’) F 400 (daN) normal wind / 255
Permanent deformity load (Effort de déformation permanente) (daN) / 85
S 325 / Minimum diameter of the top end (cm) / 19 / 19 / 19 / 19 / 20 / 20 / 20
Minimum diameter at 1m from the butt end (cm) / 25 / 26 / 27 / 28 / 29 / 30 / 31
Testing load (daN) / 960 / 960 / 960 / 960 / 980 / 1000 / 1015
Available load (‘Effort disponible’) F 400 (daN) normal wind / 325
Permanent deformity load (Effort de déformation permanente) (daN) / 110
S 430 / Minimum diameter of the top end (cm) / 21 / 21 / 21 / 21 / 22 / 22 / 22
Minimum diameter at 1m from the butt end (cm) / 27 / 28,5 / 29,5 / 30,5 / 31,5 / 32,5 / 33,5
Testing load (daN) / 1220 / 1250 / 1250 / 1250 / 1250 / 1275 / 1290
Available load (‘Effort disponible’) F 400 (daN) normal wind / 430
Permanent deformity load (Effort de déformation permanente) (daN) / 150
PRESERVATIVE TREATMENT
Wood specie and preservative treatment:
The adopted treatment process shall be compatible with the proposed wood specie, in accordance with NFC 67100 standard or equivalent. The supplier shall indicate the proposed specie and adapted preservative treatment in its offer.
Freshly felled poles are accepted as well as dried poles. The preservative treatment process shall be adapted to each of both cases, in accordance with NFC 67100 or equivalent.
For dry poles, drying minimum period of time shall be at least 6 months for the smallest poles.
Treatment process of wood poles
According to NFC 67100 Standard
PROCESS / ALLOWED SPECIES / PRESERVATIVE PRDUCTS (1) / COMPLEMENTARY TREATMENT OF THE BASE END (2)A - Freshly felled wood poles
Boucherie / All resinous species / Copper sulfate / Heavy Creosote, or puncture (injection) with water-soluble products
B - Treatment of dry wood poles (3)
Bréhant-Béthell / Pine, larch (mélèze) / - Copper sulfate
- Fluid creosote
- water-soluble salts admitted to the C.T.B.F. brand / - Heavy Creosote
- No complementary treatment
- Heavy Creosote, or without any complementary treatment according to C.T.B.F. label prescription
Rüping / Pine, larch (mélèze) / - Fluid creosote / - No complementary treatment
Estrade / Fir tree (sapin), spruce (épicéa), larch, cedar (cèdre), Douglas / - Fluid creosote / - No complementary treatment
Drying and or fissuration (fendillement) / Fir tree (sapin), spruce (épicéa), larch, cedar (cèdre), Douglas / - Fluid creosote
- water-soluble salts admitted to the C.T.B.F. brand / - No complementary treatment
- Heavy Creosote
(1) Preservation of wood in implementation works (Standard NF X 40-500), published by the French Association of standardization
(2) Complementary treatment of the base with creosote is carried out, preferably, in tilting (tipping out) autoclave (combined treatment described in § 4.4)
(3) The treatment of dry wood poles is carried out in autoclave
Dried Eucalyptus poles shall be treated using creosote pressure according to SABS 754 Standard or equivalent.
All species with a fiber stress not less than 41 N/mm² are accepted.
Other preservative treatments than creosote (Pentachlorophenol, Ammoniacal Cupric Arsenate, Chromated Copper Arsenate, ...), giving at least the same efficiency, and processed according to a given standard at least equivalent to NF C 76100 (or SBS 754 Standards for Eucalyptus poles) are also accepted.
Treatment process and preservative type shall fit with the proposed species of wood poles.
MARKING
Each pole shall have a nameplate indicating, in legible and indelible characters, in accordance with the requirements of the standard of reference, the following inscriptions:
-Name of the manufacturer
-Country of origin
-Name or logo of --
-Species code in conformity with the standard of reference.
-Process and type of preservative treatment, with codification in conformity with the standard of reference.
-Year of manufacturing/ preservation
-The length of the pole in meters
-Rated available force
The nameplate shall be located at 3.5 m from the base level for pole with less than 15 m length, and 4m for the other lengths
The poles will be delivered with a metal belt of protection or device against cracking (fissure) in butt end, and a waterproof covering cap at the top of the pole.
TOP CUT
The top end of the pole can be cut in conical, slant (slope) or bevel shape («en biseau»). The top shall be covered by a waterproof cap adapted to the top-cut.
TESTS
Qualification tests
The manufacturer must self-control the quality of its products and must be able to constantly justify conformity with the present technical specification of materials entering in the manufacturing of the poles and the good progress of the impregnation operations.
-- reserves the right to check the good quality of supply and the good execution of the operations of impregnation. For this purpose the manufacturer is held to place at the disposal of -- the material and the personnel necessary to this checking.
In any event the guarantee of the manufacturer remains full and whole.
The supplier shall submit in its proposal a qualification test report or a conformity certificate of its products in accordance to reference standards.
The test report shall contain details of the test material, the test procedure and the test results as described below
- Test material
The following information shall be reported:
-species:
-length;
-mass;
-butt nominal diameter;
-nominal diameter 1,5 m from butt, or at the assumed ground line;
-nominal diameter at load point;
-tip nominal diameter;
-assumed ground-line position;
-moisture content;
-density;
-type of preservation, process used and penetration where applicable;
-sampling procedure;
-location and size of strength reducing characteristics within 300 mm either side of the failure zone;
-geographical region of pole population tested;
-maximum growth rate (i.e. minimum number of rings per 25 mm);
-ovality at points of nominal diameter measurement.
- Test procedure
The following information shall be recorded:
-equipment used;
-any other information that can have influenced the test results.
- Test results
The following information shall be recorded:
-maximum load applied;
-bending strength;
-position of section of maximum stress;
-mode of failure;
-modulus of elasticity;
-any other relevant information that can influence the results.
Acceptance tests
Acceptance tests shall be done in factory and will be borne by the supplier. Tests will be sanctioned by statements signed by the present parts.
-- reserves the right to be represented in these tests.
To verify compliance of the pole design with the specifications, acceptance tests shall be carried out in accordance with the related clauses of IEC 60652 and NFC 67100 or equivalent, and the following tests for the wood poles:
Non-Destructive tests
Samplingwill be done in accordance with the stipulations of the standard ISO 2859-1 and on the following basis:
- Level of control: S2
Normal simple control: it is supposed that moving to reduced or reinforced control will be done in accordance with the stipulations of the abovementioned standard.
-Acceptable Level of quality (NQA): 4
-Checking of the marking of the poles
-Visual inspections (according to EN 12510)
- Straightness
- Knot
- Fissure
- Bark pockets and Rindgalls
- Insect hole
- Decay
-Measuring overall dimensions:
-Measuring slop of grain:
Destructive tests
For the mechanical resistance test the number of samples is = 1% for each type of stress.
Destructive testing shall be carried out on 2 per thousand (2/1000) of ordered poles with at least 1 pole, for each item.
The result must be conclusive.
-Ultimate bending stress test:
-Modulus of elasticity test:
-Moisture content test: Appendix B of BS 1990
-Preservative penetration test: Appendix C of BS 1990
DELIVERY
The supplier shall ensure that there is no deterioration of characteristics during the transit to their final destination.
-The wood poles shall not be bent during transportation and storage.
-There shall be neither scratching nor punching on the wood poles during transportation and storage.
-The wood poles shall be carried on the proper transport vehicles.
The supplier shall provide the method of transportation and storageto withstand rough handling during transit and exposure to extreme temperature, salt and precipitation during transit and open storage
WARRANTY
The supplier shall provide a full ten-year limited warranty on all poles supplied.
The warranty shall cover all parts and all costs, which are directly attributable to the supplier. Warranty coverage shall begin on the date that the poles are received.
PRESENTATION OF THE OFFER:
Bids must be written in English.
The values of the performance given by the manufacturer shall be respected.
Information to be provided with the BID :
Technical descriptions, data sheets, catalogues and other information shall be submitted with the BID and those which are submitted shall be sufficient to enable to evaluate thoroughly the proposal as to its compliance with the requirements of this specification.