Publishing and copyright information

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© The British Standards Institution 2024

Published by BSI Standards Limited 2024

ISBN 978 0 539 22842 7

ICS 71.100.50; 79.020

The following BSI references relate to the work on this document:
Committee reference B/515
Draft for comment 23/30457821 DC

Foreword

Publishing information

This British Standard is published by BSI Standards Limited, under licence from The British Standards Institution, and came into effect on 31 August 2024. It was prepared by Technical Committee B/515, Wood Preservation. A list of organizations represented on this committee can be obtained on request to the committee manager.

Supersession

This British Standard supersedes BS 8417:2011+A1:2014, which is withdrawn.

Relationship with other publications

This British Standard is one of a group of documents dealing with the preservative treatment of wood. It is based on the principles given in BS EN 599‑1, BS EN 351‑1 and BS EN 335, developed to support product standards mandated in England, Scotland and Wales (Great Britain) by The Construction Products (Amendment etc.) (EU Exit) Regulations 2019 [1] and in the EU (including Northern Ireland) by the Construction Products Regulation [2]. This British Standard is the national interpretative document for BS EN 599‑1 and BS EN 351‑1, and is intended to provide complementary information relevant to the wood treater and to the specifier or purchaser of treated wood for use in the United Kingdom.

Information about this document

This is a full revision of the document, and introduces the following principal changes:

Table 2 has been updated, with most changes made to the “Need for preservation” column;
Annex A and Annex B have been introduced on the performance of wood products in service and the natural durability recommendations for timber components;
a note has been added in 5.2 on warranties in response to criticism that desired service life does not guarantee a service life;
Figure 1 has been added to Clause 7 to illustrate a penetration pattern conforming to NP7;
Table 3 has been updated to include the drying characteristics of small section wood in use class 3; cross-laminated timber is omitted from the treatment recommendations and is replaced with a note; treatment recommendations for cooling tower material are omitted; and
Table 5 in BS 8417:2011+A1:2014 has been removed as no such preservatives appear to be in commercial use.

This publication can be withdrawn, revised, partially superseded or superseded. Information regarding the status of this publication can be found in the Standards Catalogue on the BSI website at knowledge.bsigroup.com, or by contacting the Customer Services team.

Where websites and webpages have been cited, they are provided for ease of reference and are correct at the time of publication. The location of a webpage or website, or its contents, cannot be guaranteed.

Use of this document

As a code of practice, this British Standard takes the form of recommendations and guidance. It is not to be quoted as if it were a specification. Users are expected to ensure that claims of compliance are not misleading.

Users may substitute any of the recommendations in this British Standard with practices of equivalent or better outcome. Any user claiming compliance with this British Standard is expected to be able to justify any course of action that deviates from its recommendations.

Presentational conventions

The provisions of this document are presented in roman (i.e. upright) type. Its recommendations are expressed in sentences in which the principal auxiliary verb is “should”.

Commentary, explanation and general informative material is presented in smaller italic type, and does not constitute a normative element.

Where words have alternative spellings, the preferred spelling of the Shorter Oxford English Dictionary is used (e.g. “organization” rather than “organisation”).

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

1 Scope

This British Standard gives recommendations and guidance for the preservative treatment of wood to provide protection against biodeterioration in end-use situations. It gives recommendations for determining the need for treatment and for specifying the type of treatment.

This British Standard also recommends levels for the penetration and retention requirements of preservatives tested to BS EN 599‑1 and creosote preservatives, using the terminology in BS EN 351‑1, for different timber components. It also takes into account the natural durability and treatability of the wood employed, the use class as defined in BS EN 335 and the desired service life. It also provides guidance on establishing whether a specified level of treatment has been achieved.

This British Standard does not include precise treatment parameters to achieve the recommended penetrations and retentions.

NOTE 1 It is the responsibility of the treater to use wood in an appropriate condition and to use an appropriate treatment schedule to achieve the recommended values of penetration and retention.

This British Standard applies to solid wood and glued laminated wood (Glulam).

This British Standard does not apply to:

wood-based panel products;
NOTE 2 Guidance on treatment is given in the Wood Protection Association Guidance note TW 15 [3].
wood that has been modified by physical, biological or non-biocidal chemical techniques in order to enhance its performance; or
NOTE 3 Guidance on cross-laminated timber (CLT) is given in Annex A.
curative treatments.

NOTE 4 Only preservatives approved under the Control of Pesticides Regulations 1986 (as amended) [4] or authorized in Great Britain under The Chemicals (Health and Safety) and Genetically Modified Organisms (Contained Use) (Amendment etc.) (EU Exit) Regulations 2020 [5] or (in Northern Ireland) under the Biocidal Products Regulation [6] are permitted for the treatment of wood in the United Kingdom.

2 Normative references

3 Terms and definitions

4 Determining the need for treatment

4.1 General

4.2 Use class

4.3 Likelihood and consequence of failure related to use class

4.4 Natural durability of wood

5 Specifying treatment of wood

5.1 General

5.2 Desired service life

5.3 Preservative type

6 Preservative treatment of wood

6.1 General

6.2 Preservatives where the performance has been tested in accordance with BS EN 599‑1

6.3 Preservatives involving creosote

6.4 Achieving the penetration and retention requirements

7 Sampling and testing

Bibliography

BS 8417:2024

Preservation of wood. Code of practice

Current

Published:

15 Aug 2024