oSIST prEN 18381:2026

• 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
• Public Enquiry End Date: 30-Oct-2026
• ICS: 71.100.50 - Wood-protecting chemicals
• Technical Committee: LLZ - Les, lesni izdelki in zaščita lesa
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 21-Aug-2026
• Due Date: 08-Jan-2027
• Ref Project: prEN 18381 - Biological durability of wood and wood-based products - Preparation of wood and wood-based material specimens before leaching testing

• Referred By: SIST EN ISO 23581:2024 - Petroleum products and related products - Determination of kinematic viscosity - Method by Stabinger type viscometer (ISO 23581:2024)
• Effective Date: 28-Jan-2026

Overview

oSIST prEN 18381:2026 specifies the standardized method for preparing wood and wood-based material specimens before leaching testing, crucial for assessing the biological durability and environmental impact of treated, untreated, or modified wood products. Developed by SIST and aligned with CEN/TC 38, this standard sets clear guidance for specimen preparation simulating real-life exposure scenarios, such as outdoor, above-ground, and continuous ground or water contact (Use Classes 3, 4, and 5 as defined in EN 335).

Leaching tests help quantify emissions from wood products, aiding environmental risk assessments required by regulations like the Biocidal Product Regulation (BPR) and the Construction Product Regulation (CPR). Accurate specimen preparation per this standard is critical for reliable laboratory or semi-field results, supporting regulatory compliance and the safe use of wood-protecting chemicals.

Key Topics

• Scope and Applicability
  • Covers preparation of treated, untreated, and modified wood specimens before leaching tests.
  • Relevant for wood exposed out of ground contact (Use Class 3), or in continuous contact with ground, fresh, or sea water (Use Classes 4, 5).
• Test Specimen Requirements
  • Specifies species, quality, and conditioning of wood, following wood preservative manufacturers’ guidance.
  • Calls for plain sawn wood, 100% sapwood, typical of commercially used species like Scots pine (Pinus sylvestris).
  • Outlines marking and traceability of specimens to ensure representativity.
• End-Sealing Procedures
  • Details when and how to end-seal specimens using suitable, non-water-permeable substances (e.g., silicone sealant, epoxy-resin).
  • Differentiates procedures for superficial versus penetration treatments, ensuring valid leaching data.
• Testing Container and Ratios
  • Requires inert containers (glass or plastic) with correct specimen surface-to-water volume ratios to ensure standard exposure during testing.
• Preservative Documentation
  • Mandates detailed reporting of preservative type, treatment process, composition, and retention to ensure transparency and repeatability.
• Reporting Requirements
  • Specifies critical information for test reports, including specimen details, preservative data, conditioning procedures, end-sealant details, and any deviations.

Applications

• Environmental Impact Assessment
  • Provides the basis for estimating environmental emissions from wood preservatives, vital for product approval processes under BPR.
• Construction and Outdoor Wood Protection
  • Supports reliable evaluation of treated wood products used in outdoor structures, landscaping, and marine applications, ensuring compliance with CPR.
• Research and Development
  • Offers laboratories and manufacturers a clear, harmonized protocol for preparing specimens for leaching tests, streamlining new product validation.
• Regulatory Compliance
  • Assists regulatory bodies and organizations in standardizing methods for emission measurement prior to market authorization of wood-protecting chemicals.

Related Standards

The following standards provide further context and should be referenced alongside oSIST prEN 18381:2026 for a comprehensive approach to testing and classification:

• EN 335: Durability of wood and wood-based products - Use classes, definitions, relevant for categorizing exposure conditions.
• EN 350: Durability of wood and wood-based products - Testing and classification of biological durability.
• EN 15119-1 & EN 15119-2: Determination of emissions from preservative treated wood in different use classes (laboratory methods for yard storage, ground, and water contact).
• EN 16663: Semi-field methods for emissions assessment in Use Class 3 scenarios.
• EN 16637 (Parts 1-3): Guidance and methods for assessing release of dangerous substances from construction products.
• OECD Guidelines: International methods for estimating emissions from preservative treated wood.
• Biocidal Product Regulation (EU) No 528/2012: Legal framework for authorizing and marketing biocidal products in the EU.

By following oSIST prEN 18381:2026 and associated standards, organizations can confidently assess the biological durability and environmental safety of wood and wood-based products, ensuring high performance and regulatory compliance.

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
...