EN ISO 844:2026

Rigid cellular plastics - Determination of compressive properties (ISO 844:2026)

This document specifies methods for determining the compressive strength, the corresponding compressive strain, the compressive stress at 10 % nominal compressive strain, and the compressive modulus of rigid cellular plastics.
Two procedures are specified. Procedure A and Procedure B.
Procedure A utilizes the compression plate displacement for the nominal property determination. It is used to determine:
compressive strength and the corresponding nominal compressive strain;
compressive stress at 10 % nominal compressive strain;
nominal compressive modulus.
Procedure B uses an extensometer and determines the conventional properties. It is used to determine:
compressive strength and the corresponding compressive strain;
compressive modulus.

Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO 844:2026)

Dieses Dokument legt Verfahren zur Bestimmung der Druckfestigkeit, der zugehörigen Stauchung, der Druckspannung bei 10 % nomineller Stauchung und des Druckmoduls für harte Schaumstoffe fest.
Es werden zwei Verfahren festgelegt: Verfahren A und Verfahren B.
Verfahren A nutzt die Druckplattenverschiebung zur Bestimmung der nominellen Eigenschaften. Es wird angewendet, um Folgendes zu bestimmen:
   Druckfestigkeit und die zugehörige nominelle Stauchung;
   Druckspannung bei 10 % nomineller Stauchung;
   nomineller Druckmodul.
Verfahren B verwendet eine Verformungsmesseinrichtung, um die konventionellen Eigenschaften zu bestimmen. Es wird angewendet, um Folgendes zu bestimmen:
   Druckfestigkeit und die zugehörige Stauchung;
   Druckmodul.

Plastiques alvéolaires rigides - Détermination des caractéristiques de compression (ISO 844:2026)

Le présent document spécifie des méthodes permettant de déterminer la résistance à la compression, la déformation en compression correspondante, la contrainte en compression correspondant à 10 % de déformation en compression nominale et le module d’élasticité en compression des plastiques alvéolaires rigides.
Deux modes opératoires sont spécifiés: le Mode opératoire A et le Mode opératoire B.
Le Mode opératoire A utilise le déplacement du plateau de compression pour la détermination de la caractéristique nominale. Il doit être utilisé pour déterminer:
la résistance à la compression et la déformation en compression nominale correspondante;
la contrainte en compression correspondant à 10 % de déformation en compression nominale;
le module d’élasticité en compression nominal.
Le Mode opératoire B utilise un extensomètre et détermine les caractéristiques conventionnelles. Il doit être utilisé pour déterminer:
la résistance à la compression et la déformation en compression correspondante;
le module d’élasticité en compression.

Trdi penjeni polimerni materiali (trde pene) - Ugotavljanje lastnosti stiskanja (ISO/FDIS 844:2026)

General Information

• Status: Not Published
• Publication Date: 07-Jul-2026
• ICS: 83.100 - Cellular materials
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249 - Plastics
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 23-Jun-2026
• Completion Date: 23-Jun-2026
• Ref Project: kSIST FprEN ISO 844:2026 - Rigid cellular plastics - Determination of compressive properties (ISO/FDIS 844:2026)

Relations

• Referred By: EN ISO 5139:2023 - Dentistry - Polymer-based composite machinable blanks (ISO 5139:2023)
• Effective Date: 28-Jan-2026
• Consolidated By: ISO 844:2026 - Rigid cellular plastics — Determination of compressive properties
• Effective Date: 12-Feb-2026
• Revises: EN ISO 844:2021 - Rigid cellular plastics - Determination of compression properties (ISO 844:2021)
• Effective Date: 19-Jan-2023

Overview

EN ISO 844:2026 – Rigid cellular plastics – Determination of compressive properties (ISO 844:2026) is an international standard developed by the European Committee for Standardization (CEN) and ISO. This standard defines precise test methods for measuring the compressive properties of rigid cellular plastics, including compressive strength, compressive strain, compressive stress at 10% nominal compressive strain, and compressive modulus. EN ISO 844:2026 is an essential reference for manufacturers, test laboratories, and quality assurance professionals dealing with cellular plastics, supporting the reliable evaluation and comparison of material performance.

Key Topics

• Compressive Strength: The maximum compressive force a rigid cellular plastic sample can withstand before failure, measured according to standardized procedures.
• Compressive Strain: The deformation a test specimen undergoes when a compressive force is applied, expressed as a percentage relative to its original dimensions.
• Compressive Stress at 10% Nominal Compressive Strain: A critical property for materials subjected to intermediate loads, used as a reference point in quality control.
• Compressive Modulus: The measure of a material's stiffness under compression, important for structural and load-bearing applications.
• Testing Procedures:
  • Procedure A determines nominal compressive properties using the displacement of the compression plates, suitable for quality assurance and general material comparison.
  • Procedure B uses an extensometer to measure conventional compressive properties, offering more precise strain data for engineering and research purposes.
• Specimen Preparation and Conditioning: The standard details requirements for specimen shape, size, preparation technique, and environmental conditioning to ensure test consistency.

Applications

EN ISO 844:2026 is widely used across industries that manufacture or utilize rigid cellular plastics, such as:

• Building and Construction: Evaluating insulation boards, foam panels, and other structural components where compressive properties are critical for mechanical performance and safety.
• Furniture and Packaging: Ensuring that foam products like cushioning, protective packaging, or load-support elements can withstand required compressive stresses over time.
• Automotive and Aerospace: Testing lightweight, cellular plastic parts used in vehicle interiors, energy absorbers, and structural supports, optimizing for both strength and weight.
• Product Development and Quality Control: Manufacturers rely on this standard for material verification, supplier comparison, and ongoing batch testing to maintain consistent product quality and regulatory compliance.
• Research and Certification: Laboratories and research institutes use EN ISO 844:2026 as the benchmark for reporting and certifying compressive properties of new or modified rigid foam formulations.

Related Standards

For comprehensive material testing and standardization of plastics, consider these related standards:

• ISO 291: Plastics – Standard atmospheres for conditioning and testing.
• ISO 1923: Cellular plastics and rubbers – Determination of linear dimensions.
• ISO 7500-1: Metallic materials – Calibration and verification of static uniaxial testing machines – Part 1: Tension/compression testing machines.
• ISO 9513: Metallic materials – Calibration of extensometer systems used in uniaxial testing.
• ISO 5725-2: Accuracy (trueness and precision) of measurement methods and results – Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method.

By following EN ISO 844:2026, organizations can ensure reliable, repeatable, and comparable compressive property data for rigid cellular plastics, supporting innovation, product safety, and market access within the plastics industry.

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 844:2025
01-april-2025
Trdi penjeni polimerni materiali (trde pene) - Ugotavljanje lastnosti stiskanja
(ISO/DIS 844:2025)
Rigid cellular plastics - Determination of compressive properties (ISO/DIS 844:2025)
Harte Schaumstoffe - Bestimmung der Druckeigenschaften (ISO/DIS 844:2025)
Plastiques alvéolaires rigides - Détermination des caractéristiques de compression
(ISO/DIS 844:2025)
Ta slovenski standard je istoveten z: prEN ISO 844
ICS:
83.100 Penjeni polimeri Cellular materials
oSIST prEN ISO 844:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 844:2025
oSIST prEN ISO 844:2025
DRAFT
International
Standard
ISO/DIS 844
ISO/TC 61/SC 10
Rigid cellular plastics —
Secretariat: SCC
Determination of compressive
Voting begins on:
properties
2025-02-04
Plastiques alvéolaires rigides — Détermination des
Voting terminates on:
caractéristiques de compression
2025-04-29
ICS: 83.100
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
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.
Reference number
ISO/DIS 844:2025(en)
oSIST prEN ISO 844:2025
DRAFT
ISO/DIS 844:2025(en)
International
Standard
ISO/DIS 844
ISO/TC 61/SC 10
Rigid cellular plastics —
Secretariat: SCC
Determination of compressive
Voting begins on:
properties
Plastiques alvéolaires rigides — Détermination des
Voting terminates on:
caractéristiques de compression
ICS: 83.100
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 844:2025(en)
ii
oSIST prEN ISO 844:2025
ISO/DIS 844:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
5 Principle . 3
6 Apparatus . 3
6.1 Testing machine .3
6.2 Devices for measuring displacement and force .4
6.2.1 Displacement .4
6.2.2 Force .4
6.2.3 Calibration . . .4
6.3 Devices for measuring the dimensions of the test specimens .4
7 Test specimens . 4
7.1 Dimensions .4
7.2 Preparation .5
7.3 Number .5
7.4 Conditioning.5
8 Procedure . 5
9 Expression of results . 6
9.1 General .6
9.2 Compressive strength and compressive strains .7
9.2.1 Compressive strength .7
9.2.2 Nominal compressive strain (procedure A) .7
9.2.3 Compressive strain (procedure B) .8
9.3 Compressive stress at 10 % nominal compressive strain (procedure A) .8
9.4 Nominal compressive modulus (procedure A) .8
9.5 Compressive modulus (procedure B) .8
10 Precision . 8
10.1 Procedure A .8
10.2 Procedure B .9
11 Test report . 10
Annex A (Informative) Remarks about the determination of the compressive modulus.11
Bibliography .13

iii
oSIST prEN ISO 844:2025
ISO/DIS 844:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 10, Cellular
plastics, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This eighth edition cancels and replaces the seventh edition (ISO 844:2021), which has been technically
revised. The main changes compared to the previous edition are as follows:
— “Compression” changed to “compressive” throughout the document, including the title.
— The scope changed to include details of Procedure A and Procedure B.
— “Relative deformation” changed “compressive strain.”
— “Nominal relative deformation” changed “nominal compressive strain”.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
oSIST prEN ISO 844:2025
ISO/DIS 844:2025(en)
Introduction
For the determination of compressive stresses, it is common practice to apply an overall deformation to
a standard test specimen, especially for quality assurance. However, the test specimen has a complex
and inhomogeneous deformation state, under compression, which is not subjected to further analysis in
such an evaluation. Measurement results are, therefore not easily transferable to other test specimens or
products. This standard describes this procedure as Procedure A, which determines the nominal properties.
Procedure B, on the other hand, is used to determine conventional properties, as described below.
Procedure A employs relative plate displacement for the determination of compressive properties. It shall be
used to determine:
— compressive strength and the corresponding nominal compressive strain;
— compressive stress at 10 % nominal compressive strain;
— nominal compressive modulus.
Procedure B employs displacement measuring devices directly positioned on the specimen (contact or
optical extensometer) or similar devices that measure the specimen displacement. Procedure B shall be
used to determine:
— compressive strength and the corresponding compressive strain;
— compressive modulus
v
oSIST prEN ISO 844:2025
oSIST prEN ISO 844:2025
DRAFT International Standard ISO/DIS 844:2025(en)
Rigid cellular plastics — Determination of compressive
properties
1 Scope
This document specifies methods for determining the compressive strength, the corresponding compressive
strain, the compressive stress at 10 % nominal compressive strain, and the compressive modulus of rigid
cellular plastics.
Two procedures are specified. Procedure A and Procedure B. Procedure A utilizes the compression plate
displacement for the nominal property determination, while Procedure B uses an extensometer and
determines the conventional properties.
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.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 1923, Cellular plastics and rubbers — Determination of linear dimensions
ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
nominal compressive strain
ε
C
ratio of the reduction (in relation to its initial value) in thickness of the test specimen
Note 1 to entry: It is expressed as a percentage.
Note 2 to entry: ε is the nominal compressive strain at σ (see 3.3).
Cm m
Note 3 to entry: Procedure A applies.
3.2
compressive strain
ε
ratio of the reduction (in relation to its initial value) of extensometer gauge length
Note 1 to entry: It is expressed as a percentage.

oSIST prEN ISO 844:2025
ISO/DIS 844:2025(en)
Note 2 to entry: ε is the compressive strain at σ (see 3.3).
m m
Note 3 t
...