SIST EN 321:2026
(Main)Wood-based panels - Determination of moisture resistance under cyclic test conditions
Wood-based panels - Determination of moisture resistance under cyclic test conditions
This document specifies a test method for the determination of the moisture resistance of wood-based panels under cyclic test conditions.
Holzwerkstoffe - Bestimmung der Feuchtebeständigkeit durch Zyklustest
Dieses Dokument legt ein Prüfverfahren zur Bestimmung der Feuchtebeständigkeit von Holzwerkstoffen durch Zyklustest fest.
Panneaux à base de bois - Détermination de la résistance à l'humidité selon essais cycliques
Le présent document décrit une méthode d’essai en milieu humide pour la détermination du comportement des panneaux à base de bois dans les conditions d’un essai cyclique.
Lesne plošče - Ugotavljanje odpornosti proti vlagi pri cikličnih pogojih
Ta dokument določa preskusno metodo za določanje odpornosti plošč na osnovi lesa proti vlagi v cikličnih preskusnih pogojih.
General Information
- Status
- Published
- Public Enquiry End Date
- 29-Jun-2024
- Publication Date
- 08-Apr-2026
- Technical Committee
- LLZ - Les, lesni izdelki in zaščita lesa
- Current Stage
- 6060 - National Implementation/Publication (Adopted Project)
- Start Date
- 07-Apr-2026
- Due Date
- 12-Jun-2026
- Completion Date
- 09-Apr-2026
Relations
- Effective Date
- 08-Apr-2026
- Effective Date
- 08-Apr-2026
- Effective Date
- 08-Apr-2026
- Effective Date
- 08-Apr-2026
- Effective Date
- 08-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Effective Date
- 01-Apr-2026
- Referred By
SIST EN 300:2006 - Oriented Strand Boards (OSB) - Definitions, classification and specifications - Effective Date
- 01-Apr-2026
- Effective Date
- 27-Dec-2023
Overview
kSIST FprEN 321:2025:2024 is a European standard developed by CEN/TC 112 that specifies a test method for evaluating the moisture resistance of wood-based panels under cyclic test conditions. This updated standard supersedes EN 321:2001 and introduces refined wording to eliminate misinterpretations, ensuring accurate and reliable testing procedures.
The standard focuses on simulating real-life moisture exposure by subjecting wood-based panels to repeated cycles of water immersion, freezing, and drying. The results provide critical information on the durability and structural integrity of these materials when exposed to varying moisture levels, which is essential for manufacturers, quality control labs, and product developers dealing with wood-based panels.
Key Topics
- Scope: Defines methods for determining the moisture resistance of wood-based panels through cyclic wetting, freezing, and drying cycles.
- Apparatus Requirements:
- Water bath maintaining 20 ± 1 °C
- Freezing cabinet with temperatures between −12 °C and −25 °C
- Drying cabinet at 70 ± 2 °C with controlled air exchanges
- Test Pieces:
- Sampling and sizing according to EN 326-1 and EN 310/317/319 respectively
- Conditioning to a constant mass at 65 ± 5 % relative humidity and 20 ± 2 °C before testing
- Cyclic Test Procedure:
- Three complete cycles each including immersion in neutral pH water, freezing, drying, and reconditioning
- Immersion time per cycle: 70 ± 1 hours
- Freezing time per cycle: 24 ± 1 hours
- Drying time per cycle: 70 ± 1 hours
- Measurement Parameters:
- Swelling in thickness post-treatment (according to EN 317)
- Tensile strength perpendicular to the board plane (EN 319)
- Bending strength (EN 310)
- Result Reporting: Includes detailed expression of swelling and strength changes, following EN 326-1 guidelines for test reports
Applications
kSIST FprEN 321:2025:2024 is crucial for assessing the performance and durability of various wood-based panels such as particleboards, fibreboards, and oriented strand boards (OSB) used in both internal and external environments. Its practical applications include:
- Product Development: Enables manufacturers to improve moisture-resistant properties of wood panels.
- Quality Assurance: Provides a reproducible testing method for verifying compliance with moisture performance specifications.
- Construction Industry: Assists specifiers and builders in selecting wood-based panels suitable for cyclic moisture exposure, reducing failure risks.
- Research and Innovation: Facilitates investigation of new adhesives, treatments, and panel compositions for enhanced moisture durability.
By simulating realistic environmental cycling, the standard provides actionable data to support material optimization and regulatory compliance in building, furniture, and packaging industries involving wood-based panels.
Related Standards
For comprehensive testing and specification, kSIST FprEN 321:2025:2024 references several interconnected standards:
- EN 310: Wood-based panels - Determination of modulus of elasticity and bending strength
- EN 317: Particleboards and fibreboards - Determination of swelling in thickness after water immersion
- EN 319: Particleboards and fibreboards - Determination of tensile strength perpendicular to the plane of the board
- EN 325: Wood-based panels - Determination of dimensions of test pieces
- EN 326-1: Wood-based panels - Sampling, cutting, inspection, and expression of test results
- EN 300, EN 312, EN 622-5, EN 634-2: Standards detailing product specifications and classifications for different wood-based panel types
Integration of these standards ensures a robust framework for evaluating mechanical and moisture resistance properties, facilitating consistent quality assessment throughout the wood panel industry.
Keywords: kSIST FprEN 321:2025, wood-based panels moisture resistance, cyclic test conditions, moisture resistance test, wood panel durability, EN 321:2024, wood panel testing standards, moisture cycling test, timber panel moisture resistance, quality control wood panels, wood-based panel standards, CEN TC112.
Get Certified
Connect with accredited certification bodies for this standard
Gozdarski inštitut Slovenije
Slovenian Forestry Institute. Forest management certification support, timber testing.
Sponsored listings
Frequently Asked Questions
SIST EN 321:2026 is a standard published by the Slovenian Institute for Standardization (SIST). Its full title is "Wood-based panels - Determination of moisture resistance under cyclic test conditions". This standard covers: This document specifies a test method for the determination of the moisture resistance of wood-based panels under cyclic test conditions.
This document specifies a test method for the determination of the moisture resistance of wood-based panels under cyclic test conditions.
SIST EN 321:2026 is classified under the following ICS (International Classification for Standards) categories: 79.060.01 - Wood-based panels in general. The ICS classification helps identify the subject area and facilitates finding related standards.
SIST EN 321:2026 has the following relationships with other standards: It is inter standard links to SIST EN 325:2026, SIST EN 326-1:1996, SIST EN 317:1996, SIST EN 310:1996, SIST EN 319:1996, SIST EN 622-5:2010, SIST-TS CEN/TS 15534-1:2007, SIST EN 312:2011, SIST EN 13810-1:2004, SIST-TS CEN/TS 15534-3:2007, SIST EN 13986:2005, SIST EN 634-2:2007, SIST EN 13986:2005+A1:2015, SIST EN 300:2006, SIST EN 321:2004. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
SIST EN 321:2026 is associated with the following European legislation: EU Directives/Regulations: 305/2011. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
SIST EN 321:2026 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-maj-2026
Lesne plošče - Ugotavljanje odpornosti proti vlagi pri cikličnih pogojih
Wood-based panels - Determination of moisture resistance under cyclic test conditions
Holzwerkstoffe - Bestimmung der Feuchtebeständigkeit durch Zyklustest
Panneaux à base de bois - Détermination de la résistance à l'humidité selon essais
cycliques
Ta slovenski standard je istoveten z: EN 321:2026
ICS:
79.060.01 Lesne plošče na splošno Wood-based panels in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 321
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2026
EUROPÄISCHE NORM
ICS 79.060.01 Supersedes EN 321:2001
English Version
Wood-based panels - Determination of moisture resistance
under cyclic test conditions
Panneaux à base de bois - Détermination de la Holzwerkstoffe - Bestimmung der
résistance à l'humidité selon essais cycliques Feuchtebeständigkeit durch Zyklustest
This European Standard was approved by CEN on 26 January 2026.
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, Türkiye 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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 321:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Apparatus . 4
5.1 Water bath . 4
5.2 Freezing cabinet . 4
5.3 Drying cabinet . 4
6 Test pieces . 5
6.1 Sampling . 5
6.2 Dimensions of test pieces . 5
6.3 Conditioning . 5
7 Procedure . 5
7.1 Treatment of the test pieces . 5
7.1.1 General. 5
7.1.2 Initial conditioning and measurement . 5
7.1.3 Cyclic treatment . 5
7.1.4 Reconditioning . 7
7.2 Determination of swelling in thickness . 7
7.3 Determination of tensile strength perpendicular to the plane of the board . 7
7.4 Determination of bending strength . 8
8 Expression of results . 8
8.1 Swelling in thickness . 8
8.2 Tensile strength . 8
8.3 Bending strength . 8
9 Test report . 8
Bibliography . 9
European foreword
This document (EN 321:2026) has been prepared by Technical Committee CEN/TC 112 “Wood-based
panels”, the secretariat of which is held by DIN.
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 September 2026, and conflicting national standards shall
be withdrawn at the latest by September 2026.
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 321:2001.
— the wording of 7.2 has been changed to avoid misinterpretations;
— the Bibliography has been updated.
This document is one of a series specifying methods of test for determining the behaviour of wood-based
panels under the influence of moisture.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Türkiye and the United
Kingdom.
1 Scope
This document specifies a test method for the determination of the moisture resistance of wood-based
panels under cyclic test conditions.
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.
EN 310, Wood-based panels — Determination of modulus of elasticity in bending and of bending strength
EN 317, Particleboards and fibreboards — Determination of swelling in thickness after immersi
...




Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...