ISO 8903:2016

Broadleaved sawn timber - Nominal sizes

ISO 8903:2016 specifies nominal sizes of unplanned, square-edged and unedged, sawn timber.

Sciages de bois feuillus — Dimensions nominales

General Information

• Status: Published
• Publication Date: 17-Feb-2016
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: ISO/TC 218 - Timber
• Drafting Committee: ISO/TC 218/WG 3 - Sawn and processed timber
• Current Stage: 9093 - International Standard confirmed
• Start Date: 26-Jul-2021
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 8903:1994 - Broadleaved sawn timber - Nominal sizes
• Effective Date: 07-Oct-2012

Overview - ISO 8903:2016 (Broadleaved sawn timber - Nominal sizes)

ISO 8903:2016 defines the nominal sizes for broadleaved (hardwood) sawn timber, applying to unplaned, square‑edged and unedged boards and planks. The standard establishes agreed length, thickness and width ranges and intervals to be used in manufacturing, trading and specifying broadleaved sawn timber, and it replaces the first edition (ISO 8903:1994). Measurement and moisture‑content rules referenced in the standard ensure consistent sizing across the wood industry.

Key technical topics and requirements

• Scope: Nominal sizes for unplaned, square‑edged and unedged broadleaved sawn timber.
• Nominal lengths: From 1 m to 6 m, with size intervals of 0.1 m or 0.25 m.
• Nominal thicknesses (mm): 19 (16), 22, 27 (25), 32 (35), 40 (38), 45 (44), 50 (55), 60 (65), 70 (75), 80, 90, 100.
  • Values in parentheses are non‑preferred sizes.
• Nominal widths: Specified minimums and size intervals depending on thickness:
  • For thinner sizes (e.g., 19–40 mm): widths ≥ 60 mm, with 10 mm intervals.
  • For medium sizes (e.g., 45–70 mm): widths ≥ 80 mm, with 10 mm intervals.
  • For thicker sizes (80–100 mm): widths ≥ 100 mm, with 10 mm intervals.
• Unedged timber requirement: The narrower face must be not less than 40 mm at any point along the length.
• Moisture content basis: Nominal sizes apply to timber having an average moisture content of 20% (mlm), determined in accordance with ISO 4470.
• Measurement and vocabulary: Dimensions measured per ISO 8904; terms and definitions per ISO 24294.

Practical applications and users

ISO 8903 is used to ensure consistent sizing and clear communication throughout the timber supply chain:

• Sawmill operators and wood processors use the standard to cut and sort broadleaved sawn timber to marketable nominal sizes.
• Timber merchants, wholesalers and exporters/importers use it for product specification, packing lists and trade contracts.
• Procurement managers, architects and joiners rely on nominal sizes for project specifications and material take‑offs.
• Quality control and inspection teams use the standard in acceptance criteria and conformity checks.
• Standards bodies and regulators reference ISO 8903 for market harmonization and labeling requirements.

Related standards

• ISO 4470 - Determination of average moisture content of a lot.
• ISO 8904 - Broadleaved sawn timber - Sizes - Methods of measurement.
• ISO 24294 - Timber - Vocabulary for round and sawn timber.
• Developed by ISO/TC 218 (Timber).

Keywords: ISO 8903, broadleaved sawn timber, nominal sizes, sawn timber dimensions, timber standards, timber sizing, moisture content, ISO 4470, ISO 8904.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 8903
Second edition
2016-02-15
Broadleaved sawn timber — Nominal
sizes
Sciages de bois feuillus — Dimensions nominales
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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.
ISO copyright office
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Nominal sizes . 1
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. www.iso.org/directives
Attention is drawn to the possibility that some of the
...

DRAFT INTERNATIONAL STANDARD
ISO/DIS 8903
ISO/TC 218 Secretariat: DTR
Voting begins on: Voting terminates on:
2013-12-02 2014-03-02
Broadleaved sawn timber — Nominal sizes
Sciages de bois feuillus — Dimensions nominales
[Revision of first edition (ISO 8903:1994)]
ICS: 79.040
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 8903:2013(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2013

ISO/DIS 8903:2013(E)
Copyright notice
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ii © ISO 2013 – All rights reserved

ISO 8903:20XX(X)
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. 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 he
...