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SVENSKAKRAFTNÄTSWED1SH NATIONAL GRID

UNIT, BUSINESS AREA OUR REFERENCENTL, Overhead Transmission Line; Grid Technology TR05-03-2E

DATE29 Januaiy 2020

.0NLB,NLP,NAL TECHNICAL GUIDELINE

REVISION APPROVED4 TD

Overhead transmission linesManufacturing of supports

IntroductionThese guidelines describe the requirements on manufacture of supports for overhead transmission lines and cover manufacture and installation. The guidelines intend to guarantee satisfactory performance of supports during the service lifetime of the overhead line and shall be used at purchasing of supports

TECHNICAL GUIDELINE 29 January 2020 TR05-03-2E rev 4

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Revision Notes Change notes Date

1 TR05-03 har delats upp i två delar och ersatts av TR05-03-2 Tillverkning (denna del) samt TR05-03-1 Konstruktion

2017-07-04

2 Kapitelhänvisningar reviderade. Kapitel 4.3 SS-EN 50341 -2 införd . kapitel 5.4.1. text under tabell 5A omredigerad. Kapitel 5.9.2. 0,14% ändrat till 0,15% för Fe/Zn95

2017-09-05

3 1. Referenser uppdaterade. 5.2 Utförandekrav förtydligade. 5.3.1 Spårbarhetskrav förtydligat. 5.4.1 Tabell uppdaterad och krav på Z-35 förtydligat. 5.5 Hänvisning till EN ISO 13920 införd och toleranser justerade, krav på krokighet flyttad från kap 7. 5.9.2 Tabell 5F justerad. 5,11 Kapitel om kontrollnivå på svetsar infört. 5.11.8 Text justerad. 5.11.9 Text justerad. 7.3 toleranskrav för krokighet flyttad till 5.5

2018-12-03

4 Technical guideline translated to English. 5.2 EXC regarding traceability revised. 5.11.4 Scope of RT and text revised. 5.10.2 Marking bolts revised. 5.11.7 Text revised. OBS! Drawing 404 0000 is withdrawn.

2020-01-29

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Content

1 References ........................................................................................................... 5

2 Scope .................................................................................................................... 7

3 Definitions ........................................................................................................... 7

4 Wooden poles ...................................................................................................... 8

4.1 General 8

4.2 Dimensions 8

Table 4A 8

4.3 Quality requirement 9

4.4 Impregnation 9

4.5 Marking 9

4.6 Glue laminated poles 10

5 Manufacture of support components in steel ................................................. 10

5.1 Quality system 10

5.2 Execution class 10

5.3 Quality documentation 10

5.3.1 Delivery of quality documentation before manufacturing

starts 10

5.3.2 Delivery of quality documentation during manufacture 11

5.4 Material 11

5.4.1 Structural steel 11

5.4.2 Stay wire 12

5.5 Manufacturing tolerances 12

5.6 Machining 14

5.6.1 Cutting 14

5.6.2 Straightening and bending 14

5.6.3 Holes 14

5.7 Welding 14

5.7.1 Welding of structures which are to be hot-dip galvanised 15

5.8 Marking 15

5.8.1 General 15

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5.8.2 Structures with bolted connections 15

5.8.3 Welded structures 15

5.9 Surface treatment 16

5.9.1 Surface quality 16

5.9.2 Hot-dip galvanising when manufacturing 17

5.10 Bolted connections 18

5.10.1 Surface treatment of bolted connections 18

5.10.2 Svenska kraftnät SK bolts 18

5.11 Inspection and testing 19

5.11.1 Materials 19

5.11.2 Dimensions 19

5.11.3 Machining 19

5.11.4 Welding 20

5.11.5 Bolts and nuts 20

5.11.6 Surface treatment 20

5.11.7 Shop assembly 21

5.11.8 Support test 21

6 Delivery ............................................................................................................. 22

6.1 Quality documentation 22

6.2 Transportation and storage 22

6.2.1 Loading and unloading 22

6.2.2 Transport 22

6.2.3 Storage of steel structures 22

6.2.4 Storage of impregnated wood 22

7 Installation ........................................................................................................ 23

7.1 General information 23

7.2 Repair of hot-dip galvanisation 23

7.2.1 Major damage to hot-dip galvanisation 23

7.3 Installation tolerances 24

7.4 Stay 24

7.5 Bolted connections 24

7.6 Tightening torque 25

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1 References NTR Document no. 1:2013 Nordic wood preservation grades and product

requirements for preservative-treated wood Part 1: Pine and other permeable softwoods

NTR Document no. 3:2013 Nordic regulations for quality control of preservative-

treated wood Part 1: Pine and other permeable softwoods ISO 965-4 General purpose metric screw threads – Tolerances –

Part 4: Limits of sizes for hot-dip galvanised external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanising

SS-EN 1090-1 Execution of steel structures and aluminium structures

– Part 1: Requirements for conformity assessment of structural components

SS-EN 1090-2 Execution of steel structures and aluminium structures

— Part 2: technical requirement for steel structures SS-EN ISO 1461 Hot-dip galvanised coatings on fabricated iron and steel

articles — Specifications and test methods EN ISO 3166-1 Codes for the representation of names of countries and

their subdivisions – Part 1: Country codes EN ISO 3834-2 Quality requirements for fusion welding of metallic

materials – Part 2: Comprehensive quality requirements EN ISO 4014 Hexagon head bolts – Product grades A and B EN ISO 4032 Hexagon head bolts (style 1) – Product grades A and B EN ISO 4759-3 Tolerances for fasteners – Part 3: Washers for bolts,

screws and nuts – Product grades A and C EN ISO 5817 Welding – Fusion welded joints in steel, nickel, titanium

and their alloys (beam welding excluded) – Quality levels for imperfections (ISO 5817:2014)

EN ISO 7438 Metallic materials – Bend test ISO 8501-1 Preparation of steel substrates before application of

paints and related products – Visual assessment of surface cleanliness – Part 1: Rust grades and preparation grades of uncoated steel substrates and of steel substrates after overall removal of previous coatings

ISO 8501-3 Preparation of steel substrates before application of

paints and related products – Visual assessment of surface cleanliness – Part 3: Preparation grades of welds, cut edges and other areas with surface imperfections

EN ISO 9001 Quality management systems – Requirements

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EN 10025-1 Hot rolled products of structural steels – Part 1: General technical delivery conditions

EN 10025-2 Hot rolled products of structural steels – Part 2:

Technical delivery conditions for non-alloy structural steels


Technical delivery conditions for normalised/normalised rolled weldable fine grain structural steels


Technical delivery conditions for thermomechanical rolled weldable fine grain structural steels

EN 10149-2 Hot rolled flat products made of high yield strength

steels for cold forming – Part 2 Delivery conditions for thermomechanically rolled steels

EN 10204 Metallic products – Types of inspection documents EN 10210-1 Hot finished structural hollow sections of non-alloy and

fine grain steels – Part 1: Technical delivery conditions EN 10219-1 Cold formed welded structural hollow sections of non-

alloy and fine grain steels – Part 1: Technical delivery conditions

EN 10244 Steel wire and wire products – Non-ferrous metallic

coatings on steel wire – Part 2: Zinc or zinc alloy coatings

EN ISO 10684 Fasteners – Hot-dip galvanised coatings EN ISO 12944-2 Paints and varnishes – Corrosion protection of steel

structures by protective paint systems – Part 2: Classification of environments

EN ISO 13920 Welding - General tolerances for welded constructions -

Dimensions for length and angles - Shape and position (ISO 13920:1996)

EN 14229 Structural timber – Wooden poles for overhead lines

EN 14399-3 Fasteners – High-strength structural bolting assemblies

for preloading – Part 3: System HR – Hexagon bolt and nut assemblies

EN ISO 14713-2 Zinc coatings – Guidelines and recommendations for the

protection against corrosion of iron and steel in structures – Part 2: Hot-dip galvanising

EN 15048-1 Fasteners – Non-preloaded structural bolting

assemblies – Part 1: General requirements EN 15048-2 Fasteners – Non-preloaded structural bolting

assemblies – Part 2: Suitability test

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EN ISO 15609 Specification and qualification of welding procedures for

metallic materials – Welding procedure specification (WPS)


metallic materials – Qualification by adoption of a standard welding procedure


metallic materials – Qualification based on pre-production welding test

EN ISO 15614-1 Specification and qualification of welding procedures for

metallic materials – Welding procedure test – Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

EN 50341-1 Overhead electrical lines exceeding AC 1 kV General

requirements – Common specifications

vSS-EN 50341-2-18 Overhead electrical lines exceeding AC 1 kV National

Normative Aspects (NNA) for Sweden

IEC 60652 Loading tests on overhead line structures TR05-04E Svenska kraftnät Technical guidelines - Conductors

2 Scope

These technical guidelines comprise manufacturing regulations for supports in

steel and wood for transmission lines.

3 Definitions

Sleeper

Designation for beams intended to hold rails together for rail traffic. Here it denotes a

horizontally oriented beam in wood, steel, concrete or other material which is buried

under the ground and anchors a structure through covering with a mass of earth which

forms an abutment.

Support

Structure above foundation intended to support overhead line.

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Steel tower

Support made mainly of steel.

Wooden pole

Support where the legs, and in some cases other parts, are made of wood. The support

legs are made out of a whole trunk that is simply cut and debarked.

4 Wooden poles

4.1 General Wooden poles/sleepers are preferably made of pine (Pinus sylvestris) and shall meet

the requirements in SS EN 14229:2010.

4.2 Dimensions Standard measurements and tolerances for wooden poles are set out in table 4A. These

tolerances replace those in SS EN 14229:2010, clause 5.3.

Table 4A Grade K L N G E S S + 2

Top diameter min. (mm) 130 140 150 170 190 210 230

Top diameter max. (mm) 150 160 190 210 220 240 260

Length (m) Tolerance -1 / +2 %

Diameter 2 m from root (mm) Tolerance -0 / +40 mm

8 170 190 - - - - -

8.5 170 190 - - - - -

9 180 200 220 240 260 280 -

9.5 180 200 220 240 260 280 -

10 190 210 230 250 270 290 -

10.5 190 210 230 250 270 290 -

11 200 220 240 260 280 300 320

11.5 200 220 240 260 280 300 320

12 210 230 250 270 290 310 330

12.5 - 230 250 270 290 310 330

13 - 240 260 280 300 320 340

13.5 - - 260 280 300 320 340

14 - - 270 290 310 330 350

14.5 - - 270 290 310 330 350

15 - - 280 300 320 340 360

15.5 - - 280 300 320 340 360

16 - - 290 310 330 350 370

16.5 - - 290 310 330 350 370

17 - - 300 320 340 360 380

17.5 - - 300 320 340 360 380

18 - - 310 330 350 370 390

18.5 - - 310 330 350 370 390

19 - - 320 340 360 380 400

19.5 - - - - 360 380 400

20 - - - - 370 390 410

20.5 - - - - 370 390 410

21 - - - - 380 400 420

21.5 - - - - 380 400 420

22 - - - - 390 410 430

22.5 - - - - - - 430

23 - - - - - - 440

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4.3 Quality requirement SS-EN 50341-2-18 (NNA) clause 7.5 and SS-EN 14229 clause 5 apply to the timber’s

quality, with the addition that the core shall be maximum of 2/3 of the pole’s diameter

and that when processing timber for poles, the branches shall be cut off in the direction

from the root towards the top and with flush and flat surfaces. Wooden poles shall in

addition be sawn even at both ends and shall be completely debarked. This means that,

besides all bark, the outermost layer of wood (1 or 2 annual rings) shall be removed.

4.4 Impregnation Wooden poles/sleepers shall be impregnated in accordance with NTR Document

no. 1 and NTR Document no. 3.

Wooden poles /sleepers shall be pressure-treated with MT-creosote oil WEI type B

according to the requirements for Wood preservation grade A in NTR Document

no. 3:2013, with the amendment that AQL = 0.65% shall apply to poles for

overhead lines. This means that no tests with insufficient penetration according to

table 10.4 in NTR Document no. 3:2013 are permitted. Penetration is to be checked

by means of a drilling test and documented in a test record. The record shall be

included in the quality documentation.

4.5 Marking Poles shall be furnished on delivery with a marking which facilitates

identification/classification of each individual pole in connection with inspection, and

also facilitates destruction in the future.

The marking shall be positioned 4 m from the root end and be clear and permanent.

This can be achieved by placing all information on one or a number of signs made of

permanent material that will last for the pole’s expected service life. The sign(s) shall be

attached in such a way that it/they cannot be damaged or fall off when the pole is

handled. All other markings of poles shall be kept well away from the above marking.

The marking shall contain the following:

CE marking according to SS-EN 14229, Annex ZA.

NTR marking according to NTR document.

Pole class and length (for example E14).

Kind of wood and origin in code form. (Kind of wood according to SS-EN 14229, table E.1 and country code according to SS-EN ISO 3166 1.)

Year (two final digits) when the pole was produced, impregnated.

Wood preservative.

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Manufacturer in code form or plain text; name shall

always be in plain text when wood is imported.

4.6 Glue laminated poles SS-EN 50341-2-18, clause 7.8/SE.1.1 applies to glue-laminated wood. Glue-laminated

wood is impregnated according to SS-EN 50341-2-18, clause 7.9.7/SE.1.

5 Manufacture of support components in steel

All manufacturing of components in steel shall be performed according to SS-EN

1090-2, except the amendments in this technical guideline.

5.1 Quality system Manufacturers of support components in steel shall have a management system for

quality based on EN ISO 9001 and a production control system based on SS-EN 1090-1.

A certificate for SS-EN 1090-2 shall be valid for the manufacture of steel structures

according to execution class EXC3 or EXC4.

5.2 Execution class According to SS-EN 1090-2, the execution class shall be EXC2, with the exception to

that EXC3 is applicable to welds. This means that acceptance level B is applicable to the

execution of welds in accordance with EN ISO 5817.

5.3 Quality documentation All quality documentation related to the work shall be available to the client’s

representative until the work is completed. All documentation, including underlying

documents, shall be in Swedish or English.

5.3.1 Delivery of quality documentation before manufacturing starts

Time schedule

Time schedule shall include dates for tests and deliveries. The document shall be

updated and presented to Svenska kraftnät on an ongoing basis.

Organization plan

Organization plan shall contain name of key persons, their duties and responsibilities

during the project, position, as well as routes for communication between them.

Inspection schedule

An inspection schedule shall be compiled based on manufacturing drawings for each

structure.

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Identification of material and traceability documents

Svenska kraftnät provides a documentation template for presentation of products and

consumables included in the delivery.

The following information shall be summarized in one document:

Profile type

Steel type

Heat/Batch

Certificate number

Quantity (m/kg)

Manufacturer/Country

Type of document

This document shall be enclosed with each individual delivery, and a summarized

document for all deliveries shall be provided when deliveries are completed.

Records for qualification of welding procedures (WPOR)

Records for qualification of welding procedures according to EN ISO 15612, EN ISO

15613 or EN ISO 15614.

Welding procedure specification (WPS)

Welding procedure specification according to EN ISO 15609 for welds in the structures

that are to be delivered.

5.3.2 Delivery of quality documentation during manufacture

Inspection test records

Records from inspections/tests according to inspection plan.

Deviation reports

All deviations shall be detailed in reports.

5.4 Material

5.4.1 Structural steel

Structural steel shall be in accordance with the standards specified in table 5A.

Table 5A

Standard Type of steel

EN 10025-1 EN 10025-2 EN 10025-3 EN 10025-4 EN 10210-1 EN 10219-1 EN 10149-2

General Non-alloy steel Normalised fine grain structural steels Thermomechanical rolled fine grain structural steel Non-alloy steel and fine grain structural steel for heat-treated pipes Non-alloy steel and fine grain structural steel for cold-treated pipes High strength steels for cold forming

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For bars and girders where steel S355N or S355J2+N is specified on the drawing, this

may be replaced by S355J2. Any change in steel grade shall be approved by Svenska

kraftnät.

Z-35 steel shall be supplied with option 4, according to 10025-1 and with a reported

special process in order to achieve improved properties in the thickness direction. Only

the designation S355N+Z35 will be accepted on inspection certificates. Ultrasonic

inspection may only be performed for this steel type by the person who is responsible

for the manufacturing process.

All steel shall be supplied with inspection certificate type 3.1 according to EN 10204.

Steel material shall be suitable for hot-dip galvanising. See clause 5.9.2.

Rust on steel surface shall not extend further than that specified in EN ISO 8501-1

degree of rusting B.

The material shall be marked with a system specified by the manufacturer, consisting of

paint or text, for identification of the material quality.

5.4.2 Stay wire

Stay wire shall be in accordance with Svk TR05-04E.

5.5 Manufacturing tolerances Measurements shall be in strict conformity with the details stated in each specific case.

Measurements that are dependent on the structure’s position and base shall generally

apply when the structure is placed horizontally on a flat and stable surface.

Measurements apply at room temperature prior to surface coating. However,

measurements for threads refer to measurements after hot-dip galvanising. Hot-dip

galvanised external thread shall have measurements according to ISO 965-4 before hot-

dip galvanising.

The following tolerances generally apply unless stated otherwise on the drawing.

Table 5B

Permissible dimensional deviations for linear dimensions for welded structures,

according to EN ISO 13920, tolerance grade A.

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Base dimensions (mm)

Permissible dimensional deviations (mm)

- (30) (120) (400) (1000) (2000) (4000) (8000) (12000) (16000) (20000)

- - - - - - - - - - -

30 120 400 1 000 2000 4000 8000 12000 16000 20000

±1 ±1 ±1 ±2 ±3 ±4 ±5 ±6 ±7 ±8 ±9

Table 5C

Permissible deviations for angle dimensions, according to EN ISO 13920, tolerance

grade A.

If no angle measurement is provided then deviation from right-angled applies.

Reference length (shortest angle leg)

(mm)

Permitted deviations

mm*)

0 (400)

(1000)

- - -

400 1000

± 0,33°(± 20’) ± 0,25°(± 15’) ± 0,17°(± 10’)

±6 ±4.5 ±3

*) Applicable at a measurement length of 1000 mm (mm/m). At other measurement lengths, the dimensional deviation is increased/reduced in proportion to the measurement length. The following tolerances apply to structures with bolted connections: a) Diameter for bolt hole ≤ 30 mm + 0,30 mm

- 0,15 mm

b) Diameter for bolt hole > 30 mm ± 1 mm

c) Bar length ± 2 mm

d) Tolerance for an individual measurement

between two holes ± 1 mm

e) Tolerance for total measurement between holes ≤ 400 mm ± 1 mm

f) Tolerance for total measurement between holes > 400 mm ± 2 mm

g) Distance from hole centre to edge ≤ 50 mm + 1 mm

- 0 mm

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h) Distance from hole centre to edge > 50 mm ± 1 mm

i) Curvature of support legs, girders or individual bars shall not exceed 0,0015 of

the length.

5.6 Machining

5.6.1 Cutting

Cutting shall be performed according to SS-EN 1090-2, clause 6.4. See also 5.9.1 in this

document.

5.6.2 Straightening and bending

Straightening and bending shall be adapted to the relevant type of steel and executed

with methods which have as little effect on the properties of the material as possible.

Instructions for different types of steel can be found in the relevant standard or

obtained from the steel manufacturer.

For forming in a cold state it is important not to go below the minimum bending radius

stated in the relevant steel standard. If bending with smaller radius in a cold state is

required, then a bend test shall be performed, see clause 5.11.3.

For forming with heating method the temperature shall be adapted to the relevant type

of steel. Instructions and recommendations can be found in the relevant standard or

obtained from the steel manufacturer.

5.6.3 Holes

Holes shall be executed according to SS EN-1090 2, clause 6.6.3, with the following

additions:

Punching is not permitted for material thicknesses in excess of 13 mm. In other cases,

holes shall be drilled or punched that are at least 3 mm smaller than nominal hole

diameter, and then reamed or drilled to the final diameter.

Holes with diameter smaller than 35 mm shall be drilled or punched.

Edges of holes shall be machined so that they meet the requirements for surface finish

in clause 5.9.1.

Incorrectly drilled holes shall neither completely nor partially filled through welding.

5.7 Welding Welds may only occur where specified and shall then be executed and checked in

conformity with clause 7 in SS-EN 1090-2. The quality requirements according to EN

ISO 3834 part 2 “Comprehensive quality requirements” apply to welds. For details, see

clause 5.2.

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5.7.1 Welding of structures which are to be hot-dip galvanised

Pockets and gaps, which can constitute acid traps is not allowed.

5.8 Marking

5.8.1 General

These marking instructions apply unless indicated otherwise on the drawing or in

another construction document.

All steel parts shall be marked. Based on marking designation, each individual part

shall be traceable to its manufacturing drawing. A description of the marking

designation shall be drawn up by the manufacturer and included in the documentation.

Marking prior to surface coating shall be executed through mechanical punching with

10 mm high characters on angle bars, flat rolled steel and plate up to and including 8

mm material thickness. With material thicknesses greater than 8 mm, including U and

HE girders, marking shall be executed with 14-16 mm high characters. Marking shall be

executed and positioned in such a way that there is no risk of fracture indications and at

least 10 mm from the edge.

On bars and girders, marking shall be positioned 100 150 mm from the last hole in the

group of holes at one end of the outwardly turned side. If this area is not suitable for

marking, it shall be placed further in towards the bar’s or the girder’s centre. For main

bar for tower legs, marking shall be positioned in the lower end and for main bar for

crossarm in the connection end or if it is a crossarm without connections at the

arbitrary end. In certain cases the drawing indicates where the marking is to be placed.

Punched designations shall be separated from each other by a point.

If punched marking is indistinct after galvanisation, the text shall be made clear by

means of paint, which provides a good contrast and has good durability (e.g. fast-drying

PVC paint). Marking with alcohol based marker pens is not permitted.

The marking shall be positioned on the side in the structure that is turned outwards and

so that it is visible after assembly.

5.8.2 Structures with bolted connections

Parts for structures which are to be connected with bolted joints shall be marked in

such a way that the individual part can be unambiguously identified on respective

drawing.

5.8.3 Welded structures

Welded units, which are to be fitted together with each other, shall have

designations of make on the outwardly turned side alongside the joint in such a way

that the markings on the different units are positioned central to each other, i.e. in

line with each other.

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5.9 Surface treatment All steel shall be hot-dip galvanised unless indicated otherwise on the drawing or in

another construction document.

5.9.1 Surface quality

The surfaces of the parts included in the structure shall be free of slag, welding spatter,

oxide scale, cracks, drilling and cutting burrs, as well as paint, grease, oil and other

contaminants. Before all surface treatment, the surfaces shall meet the preparation

grade specified in table 5E according to EN ISO 8501-3.

Table 5E

Surface Preparation grade as per EN ISO 8501-3

Cut edges P3 with the amendment that edges shall be rounded with a radius not less than 1.0 mm on material with thickness < 15 mm.

Edges in holes Hole Ø > 26 mm P3. Hole Ø ≤ 26 mm P2. However, all edges, without a radius/bevel exceeding 0.5 mm, shall be machined after the hole to ensure that they are not sharp.

Spatter P3

Other surfaces P2

The contact surfaces on both sides of a bolt hole shall be flat so that the washer/nut and

bolt head achieve a level fit. Elevations or other irregularities around a bolt hole shall be

ground down.

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5.9.2 Hot-dip galvanising when manufacturing

The steel material shall be suitable for hot-dip galvanising. See also SS-EN ISO 1461,

Annex NA.

The instructions in EN ISO 14713-2, clauses 4.2 and 6.2 shall be taken into

consideration for pre-treatment.

Coating thickness

The hot-dip galvanising shall meet the requirements according to SS-EN ISO 1461 with

appendices. Table 5F below replaces table 3 in the standard and applies if the coating

thickness is not specified on the drawing.

Table 5F

Thickness

Structures made of rolled steel in air Fe/Zn 95

Wedge-locked structures in rock

Fe/Zn 115

Structures made of rolled steel in the ground

Fe/Zn 215

Local coating thickness (minimum)

µm

Mean value coating

thickness (minimum)

µm

Local coating thickness (minimum)

µm

Mean value coating

thickness (minimum)

µm

Local coating thickness

(minimum) µm

Mean value coating

thickness (minimum)

µm

Steel > 6 mm 85 95 100 115 190 215

Steel 6 mm 70 85

Silicon content in steel, range

0,15% – 0,21% 0,15% – 0,21% 0,29% – 0,35%

Thermally cut surfaces and edges of material for structures where t ≥ 10 mm are also to

be included as a testing area for zinc thickness. Surfaces with a zinc layer of less than

the permissible local value will be regarded as uncoated.

Any repairs to the hot-dip galvanising shall be specified in the inspection plan.

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5.10 Bolted connections

5.10.1 Surface treatment of bolted connections

Bolts shall be hot-dip galvanised according to SS EN ISO 10684.

5.10.2 Svenska kraftnät SK bolts

Svenska kraftnät SK bolts shall be in accordance with EN ISO 4014, product grade A

with the exception of the dimensions ls and lg which shall be according to table 5G. The

thread shall be undercut according to ISO 965-4. Otherwise, the bolts shall meet the

requirements in EN 15048-1 and 2.

Table 5G

l Shank length

M12 M16 M20 M22 M24

Nom. Min. Max. ls +1 –0

lg max.

ls +1 –0

lg max.

ls +1 –0

lg max.

ls +1 –0

lg max.

ls +1 –0

lg max.

30 29.4 30.4 5.0 8.5

35 34.5 35.5 10.0 13.5

40 39.5 40.5 15.0 18.5 10.0 14.0

45 44.5 45.5 20.0 23.5 15.0 19.0 10.0 15.0

50 49.5 50.5 25.0 28.5 20.0 24.0 15.0 20.0 12.0 17.0

55 54.4 55.6 30.0 33.5 25.0 29.0 20.0 25.0 17.0 22.0

60 59.4 60.6 35.0 38.5 30.0 34.0 25.0 30.0 22.0 27.0 19.5 25.5

65 64.4 65.6 40.0 43.5 35.0 39.0 30.0 35.0 27.0 32.0 24.5 30.5

70 69.4 70.6 45.0 48.5 40.0 44.0 35.0 40.0 32.0 37.0 29.5 35.5

75 74.4 75.6 50.0 53.5 45.0 49.0 40.0 45.0 37.0 42.0 34.5 40.5

80 79.4 80.6 55.0 58.5 50.0 54.0 45.0 50.0 42.0 47.0 39.5 45.5

85 84.3 85.7 55.0 59.0 50.0 55.0 47.0 52.0 44.5 50.5

90 89.3 90.7 60.0 64.0 55.0 60.0 52.0 57.0 49.5 55.5

95 94.3 95.7 65.0 69.0 60.0 65.0 57.0 62.0 54.5 60.5

100 99.3 100.7 70.0 74.0 65.0 70.0 62.0 67.0 59.5 65.5

105 104.3 105.7 70.0 75.0 67.0 72.0 64.5 70.5

110 109.3 110.7 75.0 80.0 72.0 77.0 69.5 75.5

115 114.3 115.7 80.0 85.0 77.0 82.0 74.5 80.5

120 119.3 120.7 85.0 90.0 82.0 87.0 79.5 85.5

125 124.2 125.8 84.5 90.5

130 129.2 130.8 89.5 95.5

3135 134.2 135.8 94.5 100.5

140 139.2 140.8 99.5 105.5

145 144.2 145.8 104.5 110.5

150 149.2 150.8 109.5 115.5

Bolts to be marked with strength grade 8.8 u, u for

undercut thread, the manufacturer’s marking (XYZ), SB

for structural bolt and with the designation SK.

19 (25)


Nuts

Nuts shall have strength grade 8 and meet the requirements in EN 15048-1 and 2 as

well as EN ISO 4032.

The threads of the nuts shall be protected so that they can be stored outdoors for 6

months without corrosion appearing on the threads.

Washers SKRB

Washers for Svenska kraftnät SK bolts shall be SKRB and executed according to EN ISO

4759-3 with the exception of the thickness tolerance which shall be ±0.5 mm and the

dimensions which shall be according to table 5H. The hardness shall be at least 200 HV.

Table 5H

Dimensions ø d1 mm

ø d2 mm

M12 M16 M20 M22 M24

13 17 21 23 25

24 30 37 39 44

5.11 Inspection and testing Inspection and testing shall be executed according to applicable parts of clause 12 in SS-

EN 1090-2.

5.11.1 Materials

Materials supplied shall be checked against inspection certificates, testing reports or

declarations of conformity. Material refers to, for example, metal, steel sections and

consumables for welding.

5.11.2 Dimensions

Parts supplied shall be checked against dimensions indicated on drawing with

tolerances according to clause 5.5, unless tolerances are specified on the drawing.

5.11.3 Machining

Hot and cold bending shall be inspected after hot-dip galvanising. Cold-bent parts shall

be free of cracking and visible flattening (contraction) of the outer radius. Hot-bent

parts shall be free of cracks.

Bend test

If a bend test is required, see clause 5.6.2, it shall be performed according to EN ISO

7438 with the method and bending radius which is closest to the intended execution.

The test shall be hot galvanised and examined after galvanisation.

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An approved bend test shall be free of cracking and visible flattening (contraction) of

the outer radius. The test report from the bend test shall be included in the quality

documentation.

5.11.4 Welding

Inspection and testing of welds shall be executed according to clause 12.4 in SS-EN

1090-2.

Weld inspection level and methods

The level of non-destructive testing according to this guideline takes precedence over

instructions in drawings.

The following testing shall be performed on each individual weld:

> General visual inspection (VT)

100% VT of welds and surfaces, before and after hot-dip galvanising.

> Fillet welds

20% MT.

> Butt welds, panels 8mm and thicker (t ≥ 8mm)

100% UT (level 2).

> Butt welds, panels less than 8mm thick (t < 8mm)

20% RT (level 2)

5.11.5 Bolts and nuts

Inspection and testing for manufacture of bolts and nuts shall be performed according

to respective standards EN 15048-1 and 2 as well as EN 14399-3.

Inspection and testing for assembly shall be executed according to clause 12.5 in SS EN

1090-2.

5.11.6 Surface treatment

Before surface treatment, the structure shall be checked against the requirements in

clause 5.9.1. After hot-dip galvanising, the structure shall meet the requirements

specified in clause 5.9.2 as well as in SS-EN ISO 1461.

The structure shall also be checked in accordance with SS-EN ISO 1090-2, clause F.7.4

with respect to formation of cracks. The check shall be performed as a visual inspection

unless directed otherwise.

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5.11.7 Shop assembly

Shop assembly shall be performed of the first steel structure manufactured of each type

that is to be manufactured for each new order, unless indicated otherwise. The client

have to be given the opportunity to be present for the shop assembly well in advance.

Test assembly have to be performed before hot-dip galvanising, unless there are specific

reasons for doing otherwise. Bolts according to drawing have to be used. In order to

thoroughly inspect the shop assembly all bolt connections have to be tightened and the

tower to be assembled levelled and aligned on the ground. Manufacturer shall have

measuring equipment and a complete set of drawings available on assembly site during

inspection.

The following points shall be inspected at the shop assembly:

> That all parts fit together.

> That it is possible to erect the structure with the equipment and personnel that are

available at the site.

> That the structure has sufficient stability and that all parts have sufficient

dimensions that they do not risk being damaged during erection.

> That the structure has the correct dimensions. It is appropriate to check the

structure’s main dimensions. For a steel tower this is the vertical and horizontal

distance from foundation to phase- and earth wire attachments as well as the

foundation level’s dimensions or dimensions for other connected structures.

> That clamp lengths for the bolt connections accord with the bolt dimension

specified.

> That the surface condition is according to clause 5.9.1.

> Visual control that the overall manufacturing quality is according technical

specification.

> All the quality control documents for the assembled tower shall be available for

inspection.

> On completion of shop assembly, bolts, nuts and washers are not to be included in

the delivery.

5.11.8 Support test

If support testing forms part of the order, a complete support with parts shall be given a

full-scale test according to IEC 60652, “Loading tests on overhead line structures”. See

also EN 50341-1:2012, 7.3.9. The test shall be performed as a type test according to IEC

60652, 4.1 b). The supports shall have the same surface treatment as the mass-

produced supports.

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When evaluating the test results, the risk that the steel material in the support tested

has better material values than the towers delivered shall be taken into account. This

can be done through comparing the material values for bars and plates in the supports

tested, which can be obtained from the inspection certificate with the minimum values

according to the material standard.

6 Delivery

6.1 Quality documentation Quality documentation shall be supplied to Svenska kraftnät before and after

manufacture. For description see clause 5.2.

6.2 Transportation and storage All support material shall be packaged in such a way that it is not damaged or soiled

during transportation, construction or storage.

6.2.1 Loading and unloading

When loading and unloading, the material shall not be damaged when lifting and

neither shall it be subject to impacts and knocks. To avoid damage to galvanised steel,

steel lifting implements shall not touch against the galvanised surface. Spacers of wood,

for example, or straps made of fabric shall be used.

6.2.2 Transport

Material is to be stacked on vehicles on a surface that is firm and in such a way that

underlying items are not deformed. Wooden spacers or equivalent shall be used so that

hot-dip galvanised surfaces are not damaged.

Wooden spacers shall be free of contaminants that can damage or discolour the surface

coating.

6.2.3 Storage of steel structures

The storage location shall be level and the ground shall not be made up of cinders, coke,

slag or anything else that can affect the material.

The material shall not come into direct contact with the ground, nor with other

materials that can damage or discolour the surface coating such as non-galvanised steel

or contaminated timber, for example. Neither shall stored galvanised material be

subject to spatter from grinding, welding, cutting or similar as the surface coating can

be damaged and discoloured.

6.2.4 Storage of impregnated wood

Impregnated wood shall be stored in accordance with Svk TR13-04-01.

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7 Installation

7.1 General information Installation shall take place according to drawing or, where appropriate, installation

instructions.

The installation shall be carried out in such a way that damage to surface coating or

deformation of the structure does not arise. The steel shall not come into contact with

the ground underneath the installation. Steel parts shall not be straightened.

There shall not be any dirt, ice, snow or frost on the surfaces between parts that are to

be joined together with bolt joints. In winter weather conditions, snow, ice or frost shall

be removed by heating.

Before tightening bolt connections, the complete support section shall be assembled

and aligned carefully in its entirely using base works and lift jacks so that the tower

leg/crossarm is straight without distortion so that tolerances are achieved in accordance

with 7.3.

The installation shall be included and documented in the contractor’s inspection

programme.

7.2 Repair of hot-dip galvanisation On completion of installation, the size of repaired hot-dip galvanised areas shall not

exceed the areas that the hot-dip galvaniser is permitted to repair in accordance with

SS-EN ISO 1461. The client shall be informed of the intended repair method for

galvanised areas before the start of assembly. Repairs shall be executed and

documented in accordance with clause 7.2.1.

7.2.1 Major damage to hot-dip galvanisation

Parts with uncoated areas larger than is permissible for the hot-dip galvaniser to

repair according to SS-EN ISO 1461 shall be replaced or alternatively re-galvanised.

If replacement is not possible, repair methods shall be proposed and managed as a

deviation. The repair methods shall be implemented by a certified painter.

Deviations shall be approved by the client before repair are implemented.

Deviation with description of measure shall include as a minimum:

Extent of the areas that are to be repaired.

Reason that the repair is necessary.

Description of repair method including pre-treatment and requirements

for external circumstances when work is carried out.

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Safety data sheet (SDS) and technical product sheet in Swedish for all

products that are to be used.

Inspection plan for proposed repair including check of temperature, dew

point, that pre-treated surfaces that are to be coated have the cleanness

and roughness that the repair method requires, and also check of coating

thickness (see SS-EN 1090-2, clauses F.6.1 and F.7).

The product supplier’s approval of proposed repair methodology including

pre-treatment.

Repairs carried out shall meet corrosion grade C4 according to EN-

ISO 12944-2, service life of 50 years and also be UV-resistant and durable.

7.3 Installation tolerances Clause 5.5. i) is applicable to curvature of tower legs, crossarm or individual bars.

Twisting around longitudinal axis of tower and crossarm may amount to 1° per 10

m, though a maximum of 2°.

However, for towers hinged at both ends, twisting around longitudinal axis may

amount to 3° per 10 m, though a maximum of 5°.

7.4 Stay Pre-bending of stay wires may be executed as cold bending and shall be performed

slowly and without impacts. The stay wire’s temperature shall be higher than -10°C

immediately before it is bent.

When bending, a careful check shall be made that individual wires are not

damaged, free of cracks and tightly joint together.

Test bending shall be performed at the client’s request and approved by the client.

Hazard marking consisting of yellow and black stay sleeves are to be mounted on

stays above stay anchor termination device.

Double stays shall be twisted 7 half - turns in the direction of stranding.

Stay ends shall be lashed. The lash shall be executed with 2.0 mm hot-dip

galvanised steel wire (Soft wire with coating according to EN 10244, grade A or

equivalent). The length shall be >3 times the stay wire’s diameter.

7.5 Bolted connections Bolts shall be turned with the nut on the outside in the tower leg and in crossarms

on the underside where practically possible.

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After installation, the nuts in non-pre-stressed connections shall be locked by

punching the threads with two marks on the threading. For bolts in pre-stressed

connections, the pre-stressing is sufficient as locking. Bolts for hinges shall be

secured with split pin through the bolt outside the nut.

7.6 Tightening torque Table 7A below indicates the tightening torque for hot-dip galvanised bolts in non-

pre-stressed connections in 8.8 grade and in delivery condition.

Bolts in pre-stressed connections are to be tighten according to the combined

method as set out in SS-EN 1090-2, clause 8.5.4.

Table 7A

Bolt dimension Tightening torque (Nm)

M12 70

M16 200

M20 350

M22 500

M24 600

M30 1250

M36 2350

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