oSIST prEN 204:2026

• Abstract:

  This European Standard classifies thermoplastic resin based wood adhesives for non-structural applications into durability; classes D1 to D4 based on the dry and wet strengths of bond-lines measured under specified conditions after various; conditioning treatments.; For special applications, further tests that do not fall within the scope of this European standard can be applicable.; The adhesives specified in this European standard are suitable for the bonding of furniture and interior structures,; panelling, doors, windows, stairs etc. made of wood or derived timber products.; This European Standard does not specify the temperature resistance of bond-lines

• Status: Not Published
• Public Enquiry End Date: 30-Oct-2026
• ICS: 83.180 - Adhesives
• Technical Committee: IPMA - Polimer materials and products
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 20-Aug-2026
• Due Date: 07-Jan-2027
• Ref Project: prEN 204 - Classification of thermoplastic wood adhesives for non-structural applications

• Revised: SIST EN 204:2016 - Classification of thermoplastic wood adhesives for non-structural applications
• Effective Date: 19-Jan-2023

oSIST prEN 204:2026 is the Slovenian adoption of draft European Standard prEN 204:2026 from CEN. It classifies thermoplastic resin-based wood adhesives for non-structural applications into durability classes D1 to D4 based on bond-line strength after defined conditioning. It is meant for manufacturers, laboratories, and specifiers who need to match an adhesive to furniture, interior joinery, and similar wood products.

What does oSIST prEN 204:2026 specify?

oSIST prEN 204:2026 sets a durability classification for thermoplastic wood adhesives used in non-structural applications. The classification is based on dry and wet bond-line strength measured after conditioning, so the result tells users how an adhesive performs under service-relevant moisture exposure.

The scope covers furniture, interior structures, panelling, doors, windows, stairs, and similar products made of wood or derived timber products. The document also states that special applications may need additional tests, and it does not specify temperature resistance of bond-lines.

The document is organized into Clause 1 Scope, Clause 2 Normative references, Clause 3 Terms and definitions, Clause 4 Classification, Clause 5 Test method, Clause 6 Requirements, and a bibliography. That structure matters in practice because Clause 4 assigns the class, Clause 5 describes how to test it, and Clause 6 states the acceptance criteria.

What are the key requirements of oSIST prEN 204:2026?

• Clause 4 links each durability class to use conditions described in Table 1. D1 to D4 cover different moisture and exposure situations, from interior use to exterior use with protection by an adequate surface coating. In practice, the class chosen must fit the intended service environment.

• Clause 4 says classification is based on tests on thin bond-lines as defined in prEN 205:2026 (Adhesives - Wood adhesives for non-structural applications - Determination of tensile shear strength of lap joints). This keeps the classification tied to a repeatable lap-joint test method.

• Clause 5 requires testing according to prEN 205:2026 and the conditioning sequence appropriate to the assigned class. Table 2 connects each class to the sequence or sequences that must be completed, so the same adhesive may need more than one sequence for classification.

• Clause 5 requires testing in a standard climate, either 20/65 or 23/50, and says specimen transfers between steps must be immediate. Where water or boiling water is specified, the specimens must be submerged. This controls the moisture history before the strength test.

• Clause 5 requires the individual strength values and the mean value of the 20 test pieces to be recorded for each conditioning sequence. Invalid results still have to be reported, together with the reason. For a buyer or quality manager, that means the full test record matters, not only the final average.

• Clause 6 uses Table 2 to set the minimum mean adhesive strength for each durability class after the relevant conditioning sequence. The requirements are mean values without taking measurement uncertainty into account, and D4 is classified using sequences 1, 3 and 5.

• Clause 5 notes that some sequences are tested in wet state after removal from water, and one sequence allows a short buffer phase after cold-water immersion. That detail matters because it affects how the laboratory handles specimens before the shear test.

What terms does oSIST prEN 2026 define?

• Thermoplastic resin - a polymer or copolymer that softens when heated and hardens when cooled.

• Thermoplastic wood adhesive - an adhesive whose main constituent is a thermoplastic resin and which is formulated for bonding wood.

• Durability class - the D1 to D4 classification used in this standard to relate an adhesive to service conditions and test sequences.

• Standard climate - the controlled conditioning atmosphere used before testing, either 20/65 or 23/50.

Who uses oSIST prEN 204:2026?

oSIST prEN 204:2026 is used by adhesive manufacturers, test laboratories, furniture makers, and producers of interior wood products such as doors, windows, stairs, and panelling. It is also useful to quality managers and buyers who need to specify or check the durability class of a thermoplastic wood adhesive for a particular application.

What changed in oSIST prEN 204:2026 from the previous edition?

oSIST prEN 204:2026 will supersede EN 204:2016. Compared with EN 204:2016, the foreword states these changes: Clause 5 a) and b) were modified; the last sentence in Clause 5 was changed by deleting “atmosphere used as a control”; Table 2 was edited and note d was added; and the water temperature range in Table 2 was modified.

Which standards are used with oSIST prEN 2026?

The document makes two standards normative. prEN 205:2026 provides the tensile shear strength test for lap joints, and EN 923 provides the general terms and definitions for adhesives.

The introduction also places this document in a wider family of adhesive classifications. EN 12765 covers thermosetting wood adhesives for non-structural applications, and EN 17619 covers wood adhesives for non-structural timber products for exterior use.

What does the oSIST prEN 204:2026 document contain?

The document contains a classification scheme, a test method, and acceptance criteria for thermoplastic wood adhesives. Table 1 describes the durability classes and gives examples of climatic conditions and fields of application.

Clause 5 sets out the test conditions, including the standard climates, handling of specimens, and the reporting of valid and invalid results. Table 2 gives the conditioning sequences and the minimum mean strengths required for each class.

The bibliography points to related classification standards for thermosetting adhesives and exterior-use wood adhesives. That helps users place D classes alongside other adhesive classification systems when they choose or compare products.

SLOVENSKI STANDARD
01-oktober-2026
Razvrstitev plastomernih lepil za les za nekonstrukcijsko uporabo
Classification of thermoplastic wood adhesives for non-structural applications
Klassifizierung von thermoplastischen Holzklebstoffen für nichttragende Anwendungen
Classification des colles thermoplastiques pour bois à usages non structuraux
Ta slovenski standard je istoveten z: prEN 204
ICS:
83.180 Lepila Adhesives
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 83.180 Will supersede EN 204:2016
English Version
Classification of thermoplastic wood adhesives for non-
structural applications
Classification des colles thermoplastiques pour bois à Klassifizierung von thermoplastischen Holzklebstoffen
usages non structuraux für nichttragende Anwendungen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 193.
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 204:2026 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 Classification. 5
5 Test method . 6
6 Requirements . 6
Bibliography . 8

European foreword
This document (prEN 204:2026) has been prepared by Technical Committee CEN/TC 193 “Adhesives”,
the secretariat of which is held by UNE.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 204:2016.
Compared to EN 204:2016 the following modifications have been made:
a) In Clause 5, a) and b) the sentences have been modified;
b) In Clause 5, the last sentence has been modified deleting “atmosphere used as a control”;
c) Table 2 modified editorially and adding note d;
d) Table 2: modified water temperature range.
Introduction
European Standards giving a common classification with respect to durability classes for wood adhesives
will allow considerable improvement in consumer protection in any future product liability system with
regard to properties guaranteed by the adhesive manufacturer.
Wood adhesives for non-structural applications can be classified according to D class, C class and XT class.
D class is relevant for thermoplastic adhesives, such as PVAc, whereas C class (EN 12765) is relevant for
thermosetting adhesives, such as UF and MUF.
Adhesives that can be considered as thermoplastic or thermosetting, such as PU and EPI, according to
manufacturer instructions, can be classified according to D, C or both classes.
XT class (EN 17619) is relevant for all wood adhesives for exterior use.
This document is giving classification with respect to durability classes for thermoplastic wood
adhesives.
1 Scope
This document classifies ther
...