EN ISO 8970:2020

SLOVENSKI STANDARD
01-julij-2020
Nadomešča:
SIST EN ISO 8970:2010
Lesene konstrukcije - Preskušanje zvez s kovinskimi veznimi sredstvi - Zahteve za
gostoto lesa (ISO 8970:2020)
Timber structures - Testing of joints made with mechanical fasteners - Requirements for
timber density (ISO 8970:2020)
Holzbauwerke - Prüfung von mechanischen Verbindungen - Anforderungen an die
Rohdichte des Holzes (ISO 8970:2020)
Structures en bois - Essai sur assemblages réalisés par organes mécaniques -
Exigences concernant la masse volumique du bois (ISO 8970:2020)
Ta slovenski standard je istoveten z: EN ISO 8970:2020
ICS:
91.080.20 Lesene konstrukcije Timber structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 8970
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2020
EUROPÄISCHE NORM
ICS 91.080.20 Supersedes EN ISO 8970:2010
English Version
Timber structures - Testing of joints made with
mechanical fasteners - Requirements for timber density
(ISO 8970:2020)
Structures en bois - Essai sur assemblages réalisés par Holzbauwerke - Prüfung von mechanischen
organes mécaniques - Exigences concernant la masse Verbindungen - Anforderungen an die Rohdichte des
volumique du bois (ISO 8970:2020) Holzes (ISO 8970:2020)
This European Standard was approved by CEN on 13 March 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8970:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8970:2020) has been prepared by Technical Committee ISO/TC 165 "Timber
structures" in collaboration with Technical Committee CEN/TC 124 “Timber structures” the secretariat
of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2020, and conflicting national standards shall
be withdrawn at the latest by October 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8970:2010.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8970:2020 has been approved by CEN as EN ISO 8970:2020 without any modification.

INTERNATIONAL ISO
STANDARD 8970
Third edition
2020-03
Timber structures — Testing of joints
made with mechanical fasteners —
Requirements for timber density
Structures en bois — Essai sur assemblages réalisés par organes
mécaniques — Exigences concernant la masse volumique du bois
Reference number
ISO 8970:2020(E)
©
ISO 2020
ISO 8970:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
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Email: copyright@iso.org
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Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 8970:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Wood sampling method and requirements . 1
5.1 General . 1
5.2 Sampling method and requirements . 2
6 Test report . 2
Annex A (normative) Corrections to target conditions . 4
Annex B (informative) Background information . 6
Bibliography . 9
ISO 8970:2020(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 165, Timber structures, in collaboration
with the European Committee for Standardization (CEN) Technical Committee CEN/TC 124, Timber
structures, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This third edition cancels and replaces the second edition (ISO 8970:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
In this edition the sampling method aims not only at ensuring that the selected pieces have a mean
[1]
density comparable to the wood to which the test result is intended to be applied , but also requiring
the coefficient of variation of the density to be reflected. Only then the characteristic value of the
[2]
strength determined by the test can be used directly .
If it is not possible to obtain wood with the target mean value and variation of the wood density, the
normative Annex A provides a correction method. The informative Annex B provides background to the
correction procedure.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

ISO 8970:2020(E)
Introduction
The sampling method given aims at ensuring that the selected pieces have a density distribution
comparable to the timber to which the test result is intended to be applied. When this is fulfilled, the
results can be used directly to determine the characteristic value of the strength parameter.
As it is often difficult to obtain a variation of the density similar to that allowed in a strength class, a
correction method is given to obtain a corrected coefficient of variation for the strength parameter.
It should be kept in mind that the effect of density on the load-bearing capacity of connections is in
many cases less significant than expected, and that many other parameters influence it.
INTERNATIONAL STANDARD ISO 8970:2020(E)
Timber structures — Testing of joints made with
mechanical fasteners — Requirements for timber density
1 Scope
This document specifies a method based on density, for the selection of pieces of wood used in
determining the strength and stiffness properties of joints between members of structural timber
made with mechanical fasteners. It is intended to be used in conjunction with a test standard specifying
a test method.
It is assumed that the wood pieces are conditioned to the relevant conditions, that the wood density is
normally distributed and that any deviations are reported.
This document is applicable only to specimens of structural timber.
NOTE It is emphasized that the wood density is only one of the properties that can influence the strength of
a joint. Other relevant properties are, for example, growth-ring size and orientation, toughness and hardness.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 13061-2, Physical and mechanical properties of wood — Test methods for small clear wood specimens —
Part 2: Determination of density for physical and mechanical tests
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Symbols
...