046: 2006
CEB
SPECIFICATION
WOOD POLES
CEYLON ELECTRICITY BOARD
SRI LANKA
Specification
for
WOOD POLES
CEB Specification 046 : 2006
CEYLON ELECTRICITY BOARD
No. 50, Sir Chittampalam A. Gardiner Mawatha, Colombo 2.
Sri Lanka
Telephone: 94-1-2430471, 2421720
Facsimile: 94-1-2430473
Telex : 21368 CE
CEB SPECIFICATION 046: 2006
CONTENTS
Page No.
1.0
Scope
02
2.0
Service Conditions
02
3.0
Applicable Standards
02
4.0
General Requirements
03
5.0
Criteria for Selection
03
6.0
Manufacturing Requirements
03
7.0
Additional Requirements
04
8.0
Preservative Treatment
05
9.0
Information to be Supplied with the Offer
06
10.0
Inspection & Testing
07
11.0
Annexures
09
1
CEB SPECIFICATION 046: 2006
SPECIFICATION FOR WOOD POLES
1.0
SCOPE
This Specification covers the general requirements, selection, fabrication, seasoning,
preservative treatment and testing of Wood Poles intended for overhead distribution
power lines.
2.0
3.0
SERVICE CONDITIONS
a) Maximum ambient temperature
- 40 ºC
b) Maximum annual average
temperature
- 30 ºC
c) Maximum relative humidity
- 90 ºC
d) Environmental conditions
- Humid tropical climate with polluted
atmosphere
e) Operational altitude
- From MSL to 1900 m above MSL
f)
- 90 days
Isokeraunic (Thunder day) level
APPLICABLE STANDARDS
The treated wood poles shall be supplied in accordance with the latest editions of the
standards specified below and amendments thereof.
a) ANSI 05 : 1 1979
- Specifications & Dimensions for Wood Poles
b) ASTM D 1036-58 1990
- Standard Test Methods of Static Tests Wood Poles
c) BS 1990:
- Specification for Wood Poles for overhead lines
(Power & Telecommunication Lines)
Part 1 - 1984
d) BS 144
- Specification for Soft Wood Poles
- Wood Preservation using coal tar creosotes
Part I : (1990)
- Specification for preservative
Part II : (1990)
- Methods for timber treatment
e) SABS 753
- Pine Poles, Cross-Arms and Spacers for Power
Distribution, Telephone Systems and Street Lighting
f)
- Eucalyptus Poles, Cross-Arms and Spacers for
Power Distribution, Telephone Systems
SANS 754:1994
g) AS 2209 – 1994
- Timber – Poles for Overhead Lines
2
CEB SPECIFICATION 046: 2006
4.0
GENERAL REQUIREMENTS
4.1
Species
Species of Wood Poles shall be of Softwood of Pinus varieties or Hardwood of
Eucalyptus varieties as indicated in the schedule of prices.
4.2
Content of Sapwood
The minimum depth of Sapwood measured at the Butt end shall be 30 mm for Pine
wood poles and 15mm for Eucalyptus poles.
4.3
Shape
Poles shall be generally round in shape and shall be free from short crooks. Natural
sweeps and crooks of poles shall not be appreciable as to affect the straightness of
poles. Top of the Pole shall be cut at an angle not less than 30º to prevent
stagnation of water.
4.4
Seasoning
a) All poles, irrespective of species are to be air seasoned. Such air seasoning shall
be sufficient to ensure conformance for preservative treatment.
b) Seasoning is deemed to commence at the time of felling. Poles should be
seasoned for at least two months, and they shall be protected against heavy and
continuous rain.
c) The moisture content of the poles shall be determined prior to treatment by the
oven test method. The use of moisture meter is acceptable but it is to be noted that
when moisture meters are used, any measurements over 25% shall be confirmed
by the oven test method.
d) Preservative treatment shall not be undertaken until the average moisture content
of the batch being treated is reduced to less than 28%. Further no individual pole in
the batch shall have moisture content greater than 30%.
5.0
CRITERIA FOR SELECTION.
The prohibited defects, permitted defects and limited defects in poles which serve as
the criteria for rejection or acceptance of poles shall be as given in relevant standards
and in the Appendix - A (Verification of criteria for selection).
6.0
MANUFACTURING REQUIREMENTS
6.1
Pole Dimensions and their Load Capability
All the poles supplied are to be of the same species and shall conform to the
dimensional tolerances stipulated in Clauses 6.1.1 and 6.1.2 below.
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CEB SPECIFICATION 046: 2006
6.1.1
Length
Pole length shall be measured between the extreme ends. Poles shall not be more
than 75mm shorter or 150mm longer than the nominal length.
6.1.2
Diameter
The minimum diameter at 1.5m from the butt end of the pole shall be such as to
ensure that the pole would be capable of taking the ultimate Load Specified for that
pole. The minimum diameter at the top of the pole shall be not less than two-thirds
the minimum diameter at 1.5m from the butt end.
6.1.3
Fabrication
The poles shall be provided with holes as indicated in the pole fabrication drawing
(Annex - 5)
6.1.4
Load Capability
a) The length and minimum ultimate breaking load at 0.6 m from top of pole are as follows;
Length of pole
Ultimate Breaking Load
i)
8.3m
2.20 kN
ii)
9.0m
6.20 kN
iii)
10.0m
8.75 kN
b) The Minimum Ultimate Load capability of poles (as mentioned above) shall be verified by
Mechanical Load Tests (The strength of the poles is to be determined by applying a load at
0.6m below the top of a pole whilst the butt end is rigidly supported) indicated in Annex 8
and 9.
7.0
ADDITIONAL REQUIREMENTS
7.1
Marking and Code Letters
7.1.1
Marking
Each pole shall be marked with the following.
a) Supplier's code or trademark
b) Length of pole in meters
c) Class of pole or diameter at 1.5m from butt.
d) Species of timber
e) Year of preservation
f)
Type of preservation
g) Preservative process
h) Country of origin
4
CEB SPECIFICATION 046: 2006
7.1.2
Codes
a) The species code shall be represented by two letters.
eg.
Pinus sylvestris
Pinus radiata
PS
PR
b) The year of preservation shall be represented by its last two digits.
eg.
1995
1996
95
96
c) The preservative used and the mode of preservation thus.
eg.
Coal Tar Creosote
Rueping Process
CTC
RP
d) The country of origin shall be represented by two letters in abbreviated form.
7.1.3
Methods of Marking
a) Each wood pole shall be gauged or branded with markings listed in 7.1.1 and 7.1.2 above
with characters 25mm high, 5mm wide and 3mm deep. Characters shall be 30mm below
each other.
b) Marking shall be done, with all markings contained within 3m and 2m from the butt end of
the pole (Annex 6)
c) Alternatively a non-corrosive metal tag of suitable shape and dimensions shall be securely
fixed to the pole at a distance of 3m from the butt end. Characters in the tag shall be
marked 10mm below each other as shown, and shall be 10mm high 5mm wide and 1mm
deep (Annex 6). The marking shall be die stamped.
d) At the butt of each pole the length, the diameter and the species of the pole shall be die
stamped or hammer stamped or displayed by a securely fixed non-corrosive metal tag for
the purpose of ready identification.
7.2
Storage, Handling and Mechanical Damage
The Storage, Handling and Mechanical damage shall conform to the relevant
standards.
8.0
PRESERVATIVE TREATMENT
8.1
The Preservative
The coal tar creosote used shall comply (Annex 2A) and copper chromium arsenic
salt used shall comply (Annex 2B) and the relevant standards or the Preservation of
Timber.
8.2
Preparation for Treatment
a) All drilling, notching, cutting or other fabrication (Annex 5) and the marking required
shall be carried out before preservative treatment.
5
CEB SPECIFICATION 046: 2006
b) The average moisture content of the seasoned poles immediately prior to treatment
shall not exceed 28 per cent.
c) The surfaces of the poles to be treated shall be free from inner and outer bark as
well as from extraneous water, mud and dirt.
8.3
Penetration
The penetration of the preservative into a pole shall be to the full depth of the
sapwood. It is practicable to achieve full depth penetration of the heartwood in some
species. Bidders are advised to make their offer on that basis when offering such
species.
8.4
Net Retention
a) The net retention is the quantity of preservative remaining in the treatable volume
(Sapwood) of the pole after removal from the cylinder.
b) The average net retention in poles treated in any batch shall not be less than 115kg
per cubic meter where the calculation of the cubic content of timber in the pole is
based on the mean of the top and bottom diameters taken by calliper.
9.0
INFORMATION TO BE SUPPLIED WITH THE OFFER
The following information shall be furnished by the Bidder
i)
Schedule of Particulars duly filled in and signed by the Bidder for each length and
associated strength of pole offered (Annex 1)
ii) List of supplies, during the last five years, to other utilities made by the Bidder.
Such lists should include the name of the utility and address, the quantities, the
species and dimensions of the poles supplied.
iii) Drawings, literature about the supplier and his organization, and any other
particulars called for or that would be useful in evaluating his bid.
iv) Test certificates and reports in accordance with the relevant applicable standard, on
different species of different lengths supplied by the Bidder, are to accompany the
offer. It is required that such certificates and reports are issued by a Recognized
Independent Testing Authority on timber who had witnessed the carrying out
of the tests.
Each test certificate shall provide the following information.
a) Species, diameter and length of pole.
b) Type of seasoning of pole.
c) Maximum fibre stress at failure at ground line.
d) Modulus of Elasticity.
6
CEB SPECIFICATION 046: 2006
e) Load deflection curve.
f)
Moisture Content at time of test.
g) Minimum depth of sap wood.
h) Minimum depth of penetration of preservative.
i)
Net retention of preservative in the sapwood.
10.0
INSPECTION AND TESTING
10.1
Inspection
The selected Bidder shall make necessary arrangements for inspection by an
Engineer appointed by the Purchaser during fabrication, during treatment and before
dispatch. Arrangement shall also be made carry out in his presence necessary
acceptance/sample tests in accordance with the standard specified and as indicated
below.
The Bidder shall ensure that all facilities, equipment, gear, instruments, forms etc. are
made readily available to ensure the smooth and expeditious carrying out of all
inspections and tests.
The Bidder Shall Furnish the following before inspection;
a) A certificate stating that all poles to be supplied have been checked to ensure that
they conform strictly to the Criteria of Selection.
b) Certificate confirming the quality of the Creosote used (Annex 2A) or CCA used
(Annex 2B).
c) A Certificate confirming that Treatment Records as per Annex 7 have been
maintained for the Poles to be supplied and that these Records are available for
inspection.
10.2
Testing (Sample/Acceptance Tests)
The following Sample / Acceptance tests shall be witnessed by the Inspector
appointed by the purchaser and copies of the test certificates shall be furnished with
the Wood Poles.
10.3
Sampling
The number of wood poles to be selected for the sample (lot) shall be in accordance
with column 1 and column 2 of Table 1. The lot shall be selected so as to ensure
randomness.
7
CEB SPECIFICATION 046: 2006
TABLE: 1
2
Number of Poles
selected for the lot
3
Acceptance Number
SEE NOTE
4
Sub sample size
SEE NOTE
up to 90
5
0
2
91 to 150
8
0
2
151 to 500
13
1
3
501 to 1200
20
2
3
1201 and above
32
3
5
1
Number of Wood
Poles in the batch
NOTE
The lot is NOT acceptable if more than the number given as the acceptance number
fail the Criteria for Selection requirements, given in Column 3.
If the lot is found to be ACCEPTABLE after the verification of the Criteria for
Selection, the number of poles indicated in column 4 shall be selected from the lot
and subjected to the load tests.
The inspection and tests shall help the establishment of the following.
a) Criteria of Conformity (Appendix A)
b) Verification of the length, diameter, marking, Ultimate Fibre Stress in Bending and
the Modulus of Elasticity etc. (Appendix B)
8
CEB SPECIFICATION 046: 2006
11.0
ANNEXURES
The following are enclosed.
Annex - 1
Schedule of Particulars
Annex – 2 A
Certificate of Creosote
Annex – 2 B
Certificate of Copper Chromium Arsenic
Annex - 3
Permitted Sweep and Crook in one plane
Annex - 4
Permitted Sweep and Crook
Annex - 5
Fabrication of Poles
Annex - 6
Methods of Marking
Annex - 7
Treatment Record
Annex - 8
Schematic Diagram of Wood Pole under Test
Annex - 9
Schematic Diagram of Wood Pole under Test loaded with dead weights
Appendix – A
Criteria of Conformity.
Appendix – B
Verification of Length, Diameter. Marking, Ultimate Fibre Stress in
Bending and Modulus of Elasticity.
Appendix – C
Determination of Moisture Content by oven test method
9
CEB SPECIFICATION 046: 2006
ANNEX - 1
SCHEDULE OF PARTICULARS FOR WOOD POLES
(To be filled by the Bidder for each sizes of poles)
DESCRIPTION
UNITS
PARTICULARS
1. Species
-
………….………………
2. Country of Origin
-
………….………………
3. Average Age of Pole
Years
………….………………
4. Growth Rings per cm
No
………….………………
5. Length of Pole
m
………….………………
6. Minimum Diameter at Ground Line
mm
………….………………
7. Minimum Diameter at top
mm
………….………………
8. Ultimate Load at failure at 0.6 from top
kN
………….………………
9. Ultimate Fibre Stress in Bending
N/mm2
………….………………
10. Modulus of Elasticity
N/mm2
………….………………
11. Method of Seasoning
-
………….………………
12. Method of Marking
-
………….………………
13. Average Moisture Content before Treatment
%
………….………………
14. Percentage of Poles tested for Moisture Content %
………….………………
15. Type or Method of Treatment
-
………….………………
16. Minimum depth of Sapwood
mm
………….………………
17. Minimum depth of penetration of preservative
mm
………….………………
18. Minimum Net Retention of Creosote / CCA
kg/m2
………….………………
19. Shape of the pole Top
-
………….………………
20. Whether end capping provided
-
………….………………
21. End Cap material
-
………….………………
……………………………………
Seal and Signature of Bidder
Date:
10
CEB SPECIFICATION 046: 2006
ANNEX - 2 A
CERTIFICATE OF CREOSOTE
(To be furnished by the Bidder)
Supplied by:
Tested by:
Description of Tests
Results
Compliance with ………………
(Standard No)
1.
Density at 38 ºC
2.
Liquidity
4.
yes/no
i.
Becomes completely liquid at 38 ºC
yes/no
yes/no
ii.
Remains completely liquid after
cooling to 32 ºC
yes/no
yes/no
Remains completely liquid after
standing at 32 ºC for 2 hours
yes/no
yes/no
Water Content
i.
Fresh sample supplied
…… % by volume
yes/no
ii.
…… % by volume
yes/no
iii.
3.
g/ml
Sample from treatment plant
Distillation Range
i.
Distillate at 205 ºC
…… % (m/m)
yes/no
ii.
Distillate at 230 ºC
…… % (m/m)
yes/no
iii.
Distillate at 315 ºC
…… % (m/m)
yes/no
iv.
Distillate at 355 ºC
…… % (m/m)
yes/no
…… ml/100
yes/no
5.
Extractable phenol content
6.
Matter insoluble in toluene
i.
Fresh sample supplied
ii.
Sample from treatment plant
…… %mm
…… %mm
yes/no
yes/no
The creosote tested complies/does not comply with ……………… (Standard No)
I/We certify that the above data are true and correct.
…………………………………………………
Seal and Signature of Testing Authority
Date:
11
CEB SPECIFICATION 046: 2006
ANNEX - 2 B
CERTIFICATE OF COPPER CHROMIUM ARSENIC
(To be furnished by the Bidder)
Supplied by:
Tested by:
Description of Tests
Results
Compliance with ………………
(Standard No)
1.
Composition of preservative
a)
Copper
…… % (m/m)
yes/no
b)
Dichromate
…… % (m/m)
yes/no
c)
Arsenic
…… % (m/m)
yes/no
2.
PH value
……
yes/no
3.
Content of insoluble matter
…… % (m/m)
yes/no
4.
Concentration of working solution
…… % (m/m)
yes/no
The copper chrome arsenic preservative tested complies/does not comply with
……………… (Standard No)
I/We certify that the above data are true and correct.
…………………………………………………
Seal and Signature of Testing Authority
Date:
12
CEB SPECIFICATION 046: 2006
APPENDIX - A
VERIFICATION OF CRITERIA FOR SELECTION
Sampling for the above shall be done as set out in Clause 10.3 and the number to be taken
from each batch shall be as given in Column 2 of Table 1.
One data sheet as detailed below is to be used for each pole in each lot and the acceptability
of otherwise of each pole as well as for the lot is to be recorded.
DATA SHEET FOR RECORDING
Identifying No.
LOO
POO
Selection Criteria
Observed Defects
1. Bark Inclusions more than 50mm in depth,
measured on the surface of the pole, are not
permitted.
2. The outer 25mm of poles shall be free from
compression wood visible from either end
Any bark inclusions more
than 50mm deep?
3. Cross Breaks are not permitted.
4. Dead Streaks are not permitted.
5. Decay is not permitted except as for decayed
knots Type II
6. Defective butts (Hollowing in the butt)
caused by `splinter pulling' in felling the tree
may be permitted, provided that the area of
such a hollow is less than 10 per cent of the
butt area.
7. Holes shall not be permitted, except holes
that have been made for test purposes and
plugged.
8. (a) Hollow butts shall not be permitted
(b) Hollow tops shall not be permitted.
9. Hollow pith centers: Hollow pith centers in
butts and in knots may be permitted in poles
that are given full length preservative
treatment.
10. Insect damage consisting of holes or surface
scoring or channeling 2mm or less in
diameter shall be permitted. All other forms
of insect damage shall not be permitted.
Any compression wood in the
outer 25mm of the pole visible
from top or butt end?
Any cross break?
Any dead streak?
Any Decay?
Any area of splinter pulling at
butt end more than 10% of the
butt area?
Any holes other than plugged
test holes?
Any hollows in butt?
Any hollows in top?
Diameter of hollow pith center
in butt mm Diameters of hollow
pith centers in knots mm.
Any insect damage over 2
mm in diameter?
13
Yes
No
CEB SPECIFICATION 046: 2006
11. Knots of diameter greater than 75 mm shall
not be permitted.
The sum of the diameter of all knots greater
than 13mm in diameter in any 300 mm length
of pole shall not exceed 200 mm.
In the case of decayed knots, only type II
decayed knots may be permitted subject to
the limits stated.
12. Marine borer damage shall not be
permitted.
13. Nails, spikes and other metals shall not be
permitted.
14. Sap stain that is not accompanied by
softening or other decay or disintegration of
the wood may be permitted.
15. Scars: Poles shall have no scars or
turpentine cat face located within 600 mm of
the ground line.
Turpentine scars need to be trimmed only to
the extent necessary for examination for
evidence of fungus infection and for insect
damage.
Any knots over 75mm in
diameter?
Any 300mm length of pole
having the sum of the
diameters of knots over
13mm exceeding 200mm?
Any decayed knots type 1?
Any Marine borer damage?
Any nails, spikes or other
metal?
Any sap stain accompanied
by decay or disintegration?
Any scars or turpentine cat
face within 600mm above or
below the ground line?
Any signs of fungus infection
in turpentine scars?
Other sound scars shall be permitted
elsewhere on the pole provided they are
smoothly trimmed and do not interfere with
the cutting of any gain, and provided that the:
Are all sound scars properly
trimmed?
Circumference at any point on trimmed
surfaces located between the butt and
600mm below ground line shall be not less
than the minimum circumference specified or
required at the ground line of the particular
pole, and
depth of the trimmed scar shall be not more
than 50mm if the diameter is 250 mm or less,
or 1/5 the pole diameter at the location is the
diameter is more than 250mm.
Is there any point between the
butt and the ground line (1.5m
from the butt) where the
diameter.
16. Scars (turpentine acid face) on the pole
surface may be permitted elsewhere on the
pole surface in the case of Pinus poles only.
(circumference) is less than
that at the ground line?
Is there any trimmed scar of
more than 50mm or of 1/5 of
the diameter at the point of the
scar, whichever is the greater?
If the pole is NOT Pinus are
there any turpentine acid face
scars above or below the
ground line?
14
CEB SPECIFICATION 046: 2006
17. Shakes in the butt surface which are not
closer than 50mm to the side surface shall be
permitted, provided they do not extent to the
ground line.
Are there any shakes in the
butt not closer than 50mm to
the side face that extend
MORE THAN 1.5m from butt.
Shames or a combination of shakes which
are closer than 50 mm to the side surface of
the pole shall be permitted provided they do
not extend more than 600mm from the butt
surface and do not have an opening more
than 3mm.
Are there any shakes - or a
combination of two checks in
the butt - closer than 50mm to
the side face and which have
an opening LESS THAN 3mm
that extend more than 600mm
from the butt surface.
Shakes shall not be permitted in the top
surface of any pole
Are there any shakes in the
top surface of the pole?
18. Spiral grain (twist grain) is permitted as
given below.
Is the spiral or twist grain
requirement satisfied?
9m and under - one complete twist in any 3m
Over 9m and under 15m - one complete twist
in any 4.5m
15m and over - one complete twist in any 6m.
19. Splits and Checks shall not be permitted at
the top of the pole.
A single split at the butt end, or a combination
of two checks both of which terminate at the
pith center and which are separated by not
less than 1/6 of the butt circumference may
be permitted provided they do not extend
more than 600 mm from the butt end along
the pole.
20. Straightness Sweep or crook shall be
permitted to the extent that a straight line
from the center of the top to the center of the
pole 1.5m of the butt remains within the pole
(Annex 3 and 4).
21. The outer 25mm of poles shall be free from
tension wood visible from either end.
Is there a split or a check at
thee top of the pole? is there
more than on split at the butt?
Are there not more than two
checks at the butt end?
Do the two checks terminate
at or before the butt center?
Are the two checks separated
by LESS than 1/6 the butt
circumference?
Is the pole reasonably
straight?
Is the outer 25mm free from
tension wood?
15
CEB SPECIFICATION 046: 2006
APPENDIX - B
If the lot is proved to be acceptable on the basis of Appendix A, then the number indicated in
Column 4 is to be subjected to the tests indicated here.
1. Every pole is to be measured to verify whether it conforms to the requirements of Clause
6.4 above.
2. Whether the Method of Marking is as set out in Clause 7.1 above.
3. Determine the Moisture Content by the Oven Test Method as set out below.
4. Determine the Ultimate Fibre Stress in Bending and the Modulus of Elasticity. Schematic
diagrams of the type of apparatus to be used are given in Annex 8 and Annex 9. The
Method of Testing is detailed in relevant standards.
16
CEB SPECIFICATION 046: 2006
APPENDIX - C
DETERMINATION OF MOISTURE CONTENT BY OVEN TEST METHOD
1.
Sampling
Samples of 75mm or the full depth of the sapwood, whichever is the greater, shall be taken
from the pole, at a point not less than 1.5 m from either end of the pole, by means of a test
borer consisting of a hollow auger and extractor. Poles so bored shall be plugged with durable
or preservative treated plugs, as soon as the samples have been extracted.
2.
Procedure
Weight the sample (m1) immediately after extraction. Dry the sample in an oven at a
temperature of 103 + 2ºC until the mass is constant, and again weigh immediately after
removal from the drying over (m2)
3.
Calculation
The moisture content expressed as a percentage of the oven dry mass is calculated from the
equation;
W
4.
=
m1 - m2 x 100
m2
Recording Results
The length, the diameter at 1.5 m from butt end and at the top as well as the percentage
moisture content shall be recorded.
Lot
No.
Pole
No.
Length m
Diameter 1.5 m
from butt cm
Diameter
at top cm
Marking as
per Annex 6
L 01
P 00
10 m
8.5 cm
5.8 cm
Yes/No
L 02
17
Percentage
Moisture Content
ANNEX - 7
TREATMENT RECORD
Creosoted by :
Creosoted of :
Treatment Process:
Client :
Buyers contract no.
Our contract no.
Initial air pressure
or
No. of poles in the charge
Date
Charge
No.
volume m3
8m
9m
10m
12m
Total
Moisture
content %
Temperature
Final vaccum pressure
Initial vaccum pressure
value
Duration
volue
(kPa)
(Min.)
(kPa)
duration
Net Retension
Max.
Tested
Poles
Min.
Accepted
Poles
kg.
Tested
Accepted
Poles
Poles
kg/m3
(min)
CEYLON
ELECTRICITY
BOARD
Central Drawing Office
Designed :
Checked :
TREATMENT RECORD
Drawn :
Scale :
Traced :
Date :
Chief Eng.
S.D.O.A.
Drawer No.19/2
Drawing No.min/95/7737
General Manager