ISO 15206:2010

INTERNATIONAL ISO
STANDARD 15206
First edition
2010-04-01
Timber poles — Basic requirements and
test methods
Poteaux en bois — Exigences de base et méthodes d'essai

Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Symbols and abbreviated terms .6
5 General requirements .7
5.1 Marking.7
5.2 Tree felling and wood preparation.7
5.3 Requirements for pole sizes, tolerances, permissible deviations and damage .7
5.4 Characteristic values .7
5.5 Strength-reducing characteristics.8
5.6 Other characteristics.10
5.7 Untreated wood poles.10
5.8 Preservative-treated wood poles .10
6 Test methods .11
6.1 Length and diameter .11
6.2 Knots and knot clusters.11
6.3 Slope of grain.11
6.4 Rate of growth .11
6.5 Bark pockets and rind galls .12
6.6 Mechanical damage.12
6.7 Fissures, splits and checks.12
6.8 Determination of moisture content.12
7 Evaluation of conformity .12
7.1 General .12
7.2 Initial type testing .12
7.3 Product assessment .13
8 Marking and declarations .13
8.1 Marking (mandatory) .13
8.2 Specific marking and declarations .13
8.3 Marking (optional) .14
Annex A (informative) Commonly used sizes for wood poles .15
Annex B (normative) Scheme for sampling preservative-treated wood poles by taking borings .16
Annex C (normative) Test method for bending properties — Cantilever method .17
Annex D (normative) Test method for bending properties — Four-point method.22
Annex E (normative) Test method for bending properties — Three-point method proof test .28
Annex F (normative) Determination of characteristic values.33
Bibliography.37

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15206 was prepared by Technical Committee ISO/TC 165, Timber structures.

iv © ISO 2010 – All rights reserved

Introduction
This International Standard covers the requirements for grading and assignment of characteristic values that
can be used for the design of timber poles used as cantilevers and/or in compression.
It is the responsibility of the supplier to always ensure that all products supplied are in conformity with the
requirements of this International Standard and any other specification with which they are provided. This
International Standard is intended for the initial determination of the characteristic values for a given
population of poles and additional determination when there is a reason to suspect that the characteristics of a
population have changed.
This International Standard recognizes that there are many different visual strength-grading rules for timber in
use internationally. These have come into existence to allow for
⎯ different species or groups of species,
⎯ geographic origin,
⎯ different dimensional requirements,
⎯ varying requirements for different uses,
⎯ the quality of material available, and
⎯ historical influences or traditions.
Because of the diversity of existing standards for wood poles for overhead lines in use in different countries, it
is impossible to lay down a single set of acceptable visual grading rules.
This International Standard therefore gives the basic principles to be followed when drawing up regional,
national, local or buyer requirements for some characteristics and sets limits for others.
In laying down visual grading rules, two main factors are relevant:
⎯ they shall clearly define and limit the strength-affecting characteristics in poles, such that there is very
high confidence that poles supplied meet the required characteristic strength value;
⎯ the rules and the text are such that they can be easily understood and be suitable for implementation by
grading personnel.
This International Standard is also concerned with the durability characteristics of wood poles for overhead
power and telecommunication lines. It assumes that all such poles are constructed from round timber in which
the finished product comprises either a central core of heartwood surrounded by a zone of sapwood or the
heartwood only. Such assumptions dictate that where sapwood is present, preservative treatment is normally
required in order to provide the poles with sufficient enhanced durability, unless the amount of sapwood
present is such that its loss would not compromise the integrity of the pole during its service life and the
heartwood has sufficient natural durability as required by this International Standard.
Some timber species do not allow an easy differentiation between heartwood and sapwood. Various
standards provide recommendations to address this problem; for example, EN 351-1 and AS 2209:1994
(Appendix D) specify the method of treatment of such timber when preservation is required.

INTERNATIONAL STANDARD ISO 15206:2010(E)

Timber poles — Basic requirements and test methods
1 Scope
This International Standard specifies the requirements for grading, test methods, determination of
characteristic values, methods of specifying durability and sizes of single poles manufactured from solid
timber for telecommunications and electrical distribution purposes, either preservative treated or untreated,
under cantilever or compression loading.
It specifies the:
⎯ methods of measuring the sizes of solid wood poles for overhead transmission and telecommunication
lines and permissible deviations that are taken into account for the acceptance of the poles;
⎯ requirements for handling and the characteristics for visual strength grading of softwood and hardwood
poles, as well as the marking requirements;
⎯ methods of test to determine characteristic values for modulus of elasticity and bending strength of any
population of wood poles and moisture content of solid wood poles;
⎯ requirements for durability and preservative treatment of wood poles.
This International Standard is applicable to both softwood and hardwood poles.
This International Standard does not quantify the service life that can be expected from a pole.
NOTE This depends on its geographical location, the associated climate of its service environment and either the
natural durability of the heartwood of the species selected or the combination between selection of species, preservative
type, and requirements of retention and any incised zones.
It is not applicable to poles used as beams.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1: Country
codes
ISO 21887:2007, Durability of wood and wood-based products — Use classes
AS/NZS 1604.1, Specification for preservative treatment — Part 1: Sawn and round timber
AS 2209:1994, Timber — Poles for overhead lines
AS 2209:1994/Amd.1:1997, Timber — Poles for overhead lines
EN 252, Field test method for determining the relative protective effectiveness of a wood preservative in
ground contact
EN 351-1, Durability of wood and wood-based products — Preservative-treated solid wood — Part 1:
Classification of preservative penetration and retention
EN 599-1, Durability of wood and wood-based products — Efficacy of preventive wood preservatives as
determined by biological tests — Part 1: Specification according to use class
EN 13183-1, Moisture cont
...