prEN 18381
(Main)Biological durability of wood and wood-based products - Preparation of wood and wood-based material specimens before leaching testing
General Information
- Abstract
This document specifies a method for preparing treated wood test specimens prior leaching test to obtain water samples from treated wood which has been in conditions designed to simulate treated wood exposed out of ground contact (wood held in the storage yard after treatment and which has been in conditions designed to simulate outdoor, out of ground contact situations, use Class 3), or continuous contact with the ground or with water (use Class 4 or 5). This document is also applicable to untreated wood and modified wood.
NOTE 1 Test methods written in CEN/TC 38 include how to prepare specimens of wood and wood-based materials before leaching tests.
NOTE 2 EN 350 can be considered when using this document for testing untreated wood or modified wood, regarding reference wood species, number of test specimens etc.
- Status
- Not Published
- Publication Date
- 16-Dec-2027
- Technical Committee
- CEN/TC 38 - Durability of wood and derived materials
- Drafting Committee
- CEN/TC 38/WG 27 - Exposure Aspects
- Current Stage
- 4020 - Submission to enquiry - Enquiry
- Start Date
- 13-Aug-2026
- Due Date
- 31-Jul-2026
- Completion Date
- 13-Aug-2026
Overview
prEN 18381 specifies a standardized method for preparing wood and wood-based material specimens prior to leaching tests. Developed by CEN/TC 38, this standard plays a central role in assessing the biological durability of wood and wood products, particularly when evaluating emissions from preservative-treated wood. These emissions can impact water, soil, and air quality, especially when wood is exposed in storage yards or installed outdoors out of ground contact (Use Class 3), or in situations involving continuous contact with ground or water (Use Class 4 or 5). The requirements also apply to untreated and modified wood.
This standard ensures that test specimens are prepared consistently to provide reliable data for environmental risk assessments and regulatory compliance, supporting regulations such as the Biocidal Product Regulation (BPR) and Construction Product Regulation (CPR).
Key Topics
Application Scope:
- Specimen preparation for leaching tests, including treated, untreated, and modified wood.
- Relevant for wood exposed in various use classes (3, 4, and 5 as defined in EN 335).
Specimen Requirements:
- Selection of wood species (e.g., Pinus sylvestris), with specific criteria regarding sapwood content, grain, and absence of knots or resinous areas.
- Accurate marking, measurement, and end-sealing to prevent undesired preservative penetration or leaching.
- Clear identification of preservative products and description of their composition for traceability.
Testing System:
- Use of inert containers (glass or plastic) that permit all specimen faces to be in contact with water.
- Standardized surface area-to-water volume ratios to ensure consistent leaching conditions.
- Conditioning guidelines for post-treatment specimen handling.
Reporting:
- Comprehensive documentation requirements, such as preservative information, treatment method, conditioning process, specimen retention, and any deviations.
- Alignment with related standards to guarantee test reproducibility and comparability.
Applications
prEN 18381 offers significant practical value across several domains:
Environmental Testing: Enables accurate simulation of leaching scenarios to assess potential emissions from wood products to the environment. This is crucial for both regulatory authorities and manufacturers concerned with the environmental impact of wood preservatives.
Product Certification: Forms a fundamental step in evaluating whether treated wood products meet durability and environmental emission standards, supporting claims of compliance for construction and outdoor wood materials.
Research and Quality Control: Research institutions and testing laboratories use this standard to guarantee the consistency and scientific validity of their leaching studies, whether for product development, innovation in wood modification, or biocide efficacy evaluations.
Regulatory Compliance: Ensures that companies can meet the documentation and performance criteria required under BPR, CPR, and related EU directives affecting the trading and use of wood-based materials in Europe.
Related Standards
prEN 18381 references and complements several key standards and regulatory documents in the field of biological durability and environmental safety of wood:
- EN 15119-1 & EN 15119-2: Methods for determining emissions from preservative-treated wood to the environment for various use classes.
- EN 335: Classification of use classes for biological durability of wood.
- EN 350: Testing and classification of wood and wood-based products against biological agents.
- EN 16663: Emission determination for outdoor exposed wooden commodities (semi-field method).
- EN 16637 Series: Assessment of the release of hazardous substances from construction products.
- OECD Guidelines: Laboratory methods for emissions assessment from treated wood.
- Biocidal Products Regulation (EU No 528/2012) and Construction Products Regulation (EU 2024/3110): Providing regulatory context for testing.
By standardizing specimen preparation, prEN 18381 supports consistent, credible leaching testing outcomes for all stakeholders involved in the wood protection, environmental safety, and sustainable construction sectors.
Relations
- Effective Date
- 28-Jan-2026
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Frequently Asked Questions
prEN 18381 is a draft published by the European Committee for Standardization (CEN). Its full title is "Biological durability of wood and wood-based products - Preparation of wood and wood-based material specimens before leaching testing". This standard covers: This document specifies a method for preparing treated wood test specimens prior leaching test to obtain water samples from treated wood which has been in conditions designed to simulate treated wood exposed out of ground contact (wood held in the storage yard after treatment and which has been in conditions designed to simulate outdoor, out of ground contact situations, use Class 3), or continuous contact with the ground or with water (use Class 4 or 5). This document is also applicable to untreated wood and modified wood. NOTE 1 Test methods written in CEN/TC 38 include how to prepare specimens of wood and wood-based materials before leaching tests. NOTE 2 EN 350 can be considered when using this document for testing untreated wood or modified wood, regarding reference wood species, number of test specimens etc.
This document specifies a method for preparing treated wood test specimens prior leaching test to obtain water samples from treated wood which has been in conditions designed to simulate treated wood exposed out of ground contact (wood held in the storage yard after treatment and which has been in conditions designed to simulate outdoor, out of ground contact situations, use Class 3), or continuous contact with the ground or with water (use Class 4 or 5). This document is also applicable to untreated wood and modified wood. NOTE 1 Test methods written in CEN/TC 38 include how to prepare specimens of wood and wood-based materials before leaching tests. NOTE 2 EN 350 can be considered when using this document for testing untreated wood or modified wood, regarding reference wood species, number of test specimens etc.
prEN 18381 is classified under the following ICS (International Classification for Standards) categories: 71.100.50 - Wood-protecting chemicals. The ICS classification helps identify the subject area and facilitates finding related standards.
prEN 18381 has the following relationships with other standards: It is inter standard links to EN ISO 23581:2024. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
prEN 18381 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2026
Biološka odpornost lesa in lesnih proizvodov - Priprava vzorcev lesa in lesnih
materialov pred izpiranjem
Biological durability of wood and wood-based products - Preparation of wood and wood-
based material specimens before leaching testing
Biologische Dauerhaftigkeit von Holz und Holzprodukten - Vorbereitung von Prüfkörpern
aus Holz- und Holzprodukten vor der Auswaschprüfung
Durabilité biologique du bois et des matériaux à base de bois - Préparation des
éprouvettes de bois et de matériaux à base de bois avant essai de lixiviation
Ta slovenski standard je istoveten z: prEN 18381
ICS:
71.100.50 Kemikalije za zaščito lesa Wood-protecting chemicals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 71.100.50
English Version
Biological durability of wood and wood-based products -
Preparation of wood and wood-based material specimens
before leaching testing
Durabilité biologique du bois et des matériaux à base Biologische Dauerhaftigkeit von Holz und
de bois - Préparation des éprouvettes de bois et de Holzprodukten - Vorbereitung von Holz- und
matériaux à base de bois avant essai de délavage Holzwerkstoffproben vor der Auswaschprüfung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 38.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Türkiye and
United Kingdom.
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.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 18381:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General considerations . 5
5 Test specimens . 6
5.1 Test system. 6
5.2 Species of wood. 6
5.3 Quality of wood and wood moisture content . 6
5.4 End seal . 6
5.5 Preparation of the treated test specimens . 7
5.6 Conditioning of the test specimens after treatment. 7
5.7 Preparation and selection of test specimens . 7
5.8 Preservative . 7
6 Information to be included in the test report . 7
Bibliography . 9
European foreword
This document (prEN 18381:2026) has been prepared by Technical Committee CEN/TC 38 “Biological
durability of wood and wood-based products”, the secretariat of which is held by SIS.
This document is currently submitted to the CEN Enquiry.
CEN/TC 38 has leaching standards for estimating environmental emissions from preservative treated
wood. These standards describe the preparation of wood-based specimens that are specific and perfectly
suited to anisotropic materials. Other Technical Committees such as CEN/TC 351 also have leaching
standards for the assessment of release of dangerous substances.
This document aims to describe precisely how to prepare specimens of wood and wood-based materials
before leaching tests for the needs of the CEN/TC 38 standards and if other leaching standards other than
those of CEN/TC 38 are used.
The wood preservative rules request the preparation of specimen then the immersion brings dimensions
considerations at laboratory scales. The immersion regime will be determined by use class (EN 335):
• EN 15119 Part 1: Wood held in the storage yard after treatment and wooden commodities
exposed in Use Class 3 (not covered, not in contact with the ground) — Laboratory method
• EN 15119 Part 2: Wooden commodities exposed in Use Class 4 or 5 (in contact with the ground,
fresh water or sea water) — Laboratory method
• EN 16663 Biological durability of wood and wood-based products — Determination of emissions
from preservative treated wood to the environment — Wooden commodities exposed in Use
Class 3 (Not covered, not in contact with the ground) — Semi-field method
Introduction
For the need of regulations such as Biocidal Product Regulation (BPR), the emissions from preservative
treated wood to the environment need to be quantified to enable an environmental risk assessment of
the treated wood.
For the need of Construction Product Regulation (CPR), the emissions from untreated wood or modified
wood can be evaluated.
As wood is an anisotropic material, an appropriate procedure to prepare the wooden test specimens prior
leaching test can be defined.
This document describes a method for the preparation of the treated test specimens for the estimation
of emissions from preservative treated wood in the case where:
— the preservative treated wood is not covered and not in contact with the ground or the water;
— the preservative treated wood is in contact with the ground, fresh water or seawater.
There are five situations in this case where emissions could enter the environment:
a) emissions from preservative treated wood stored outside in the storage yard of a preservative
treatment site. Rain falling on the treated wood could produce emissions that run off into surface
water and / or soil (see EN15119-1).
b) emissions from treated wood used in commodities exposed in Use Class 3. This is the situation in
which the wood or wood-based product is not covered and not in contact with the ground. It is either
continually exposed to the weather or is protected from the weather but subject to frequent wetting.
Use classes are specified in EN 335 and categorize the biological hazard to which the treated
commodity will be subjected. The Use Classes also specify the situation in which the treated
commodity is used and determine the environmental compartments (air, water, soil) which are
potentially at risk from the preservative treated wood. Rain falling on treated wood in Use Class 3
could produce emissions that run off into surface water and/ or soil (see EN 15119-1 and EN 16663).
c) emissions from treated wood in contact with the ground. Use Class 4. Emissions from the surface of
the treated wood could enter the soil via the soil water (see EN 15119-2).
d) emissions from treated wood in contact with fresh water. Use Class 4. Emissions from the surface of
the treated wood could enter the water (see EN 15119-2).
e) emissions from treated wood in contact with sea water. Use Class 5. Emissions from the surface of the
treated wood could enter the sea (see EN 15119-2).
1 Scope
This document specifies a method for preparing treated wood test specimens prior leaching test to obtain
water samples from treated wood which has been in conditions designed to simulate treated wood
exposed out of ground contact (wood held in the storage yard after treatment and which has been in
conditions designed to simulate outdoor, out of ground contact situations, use Class 3), or continuous
contact with the ground or with water (use Class 4 or 5). This document is also applicable to untreated
wood and modified wood.
NOTE 1 Test methods written in CEN/TC 38 include how to prepare specimens of wood and wood-based
materials before leaching tests.
NOTE 2 EN 350 can be considered when using this document for testing untreated wood or modified wood,
regarding reference wood species, number of test specimens etc.
2 Normative references
The following documents are referr
...



