ISO 19374:2026

Recycled carbon fibres — Designation system for recycled carbon fibres

This document establishes a designation system of recycled carbon fibres, which can be used as the basis for specification. This designation system is applicable to recycled carbon fibres used for polymer composites. The types of recycled carbon fibres are differentiated by a designation system based on appropriate levels of the designatory properties: tensile modulus of elasticity. tensile strength. NOTE One to five designatory property(s) that differentiate recycled carbon fibre types from each other is (are) assigned.

Fibres de carbone recyclées — Système de désignation des fibres de carbone recyclées

General Information

• Status: Published
• Publication Date: 14-Jun-2026
• ICS: 59.100.20 - Carbon materials
• Technical Committee: ISO/TC 61/SC 13 - Composites and reinforcement fibres
• Drafting Committee: ISO/TC 61/SC 13 - Composites and reinforcement fibres
• Current Stage: 6060 - International Standard published
• Start Date: 15-Jun-2026
• Due Date: 05-Dec-2026
• Completion Date: 15-Jun-2026

Overview

ISO 19374:2026 defines a comprehensive designation system for recycled carbon fibres (rCF), focusing on their identification and classification. Developed by ISO, this standard is essential for manufacturers, suppliers, and users of recycled carbon fibres used in polymer composites. By providing a systematic approach to designating rCF based on key properties and attributes, this standard supports consistent communication, facilitates material selection, and enhances traceability across global supply chains.

This designation system differentiates various types of recycled carbon fibres primarily by their tensile modulus of elasticity and tensile strength. These mechanical properties are vital for determining the suitability of rCF for specific composite applications. The standard also enables the inclusion of additional data such as source, physical form, sizing, and optional end-use requirements, offering a robust foundation for tailored specifications.

Key Topics

• Standardized Designation Format: ISO 19374:2026 introduces a clear structure for recycled carbon fibre identification, consisting of up to five modular data blocks. Each block addresses key characteristics-including source material, matrix type, recovery process, product form, fibre length, sizing information, and mechanical properties.

• Mechanical Properties: Emphasis is placed on defining rCF types by their ranges of tensile modulus and tensile strength, standardized in accordance with established ISO methods. This supports accuracy and repeatability in performance assessments.

• Data Blocks Explained:

  • Block 1: Origin of recycled fibre (e.g., dry rCF, post-industrial, post-consumer) and matrix type (thermoplastic, thermoset, or none)
  • Block 2: Recovery process, fibre form (milled, chopped, long, continuous), and fibre length
  • Block 3: Sizing information and compatibility (thermoplastic, thermoset, or unspecified)
  • Block 4: Ranges of tensile modulus and tensile strength
  • Block 5 (Optional): Extra requirements or specifications as agreed by parties

• Customizability and Traceability: The system allows for additional property specification, enabling designers and suppliers to communicate unique requirements and trace rCF back to source characteristics.

Applications

The ISO 19374:2026 designation system is crucial in diverse sectors utilizing recycled carbon fibres in composites, such as:

• Automotive manufacturing: For lightweight, durable components
• Aerospace and aviation: Where performance-critical composite parts benefit from rCF
• Construction and infrastructure: Reinforcement in polymer concrete and structural materials
• Sporting goods: Sustainable, high-strength fibres in equipment
• Electrical applications: Overhead conductors and insulative components

The designation system enables efficient specification and sourcing of recycled carbon fibres that meet necessary mechanical and physical requirements for each use-case, aiding in compliance with corporate sustainability initiatives and circular economy goals.

Related Standards

ISO 19374:2026 references and is complemented by various other international standards, including:

• ISO 6989: Textile fibres - Determination of length and length distribution of staple fibres
• ISO 11566:1996: Carbon fibre - Determination of the tensile properties of single-filament specimens
• ISO 19350: Recycled carbon fibre - Determination of tensile strength distribution and interfacial shear strength of single filament embedded in matrix polymer

These related standards offer test methods for the accurate characterization of recycled carbon fibres, ensuring that properties stated in the designation system are reliable and globally consistent.

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Recycled carbon fibre designation standards like ISO 19374:2026 are indispensable for advancing the use of sustainable composite materials worldwide, supporting industry partners in traceability, material performance, and environmental objectives.

Standards Content (Sample)

International
Standard
ISO 19374
First edition
Recycled carbon fibres —
2026-06
Designation system for recycled
carbon fibres
Fibres de carbone recyclées — Système de désignation des fibres
de carbone recyclées
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designation system . 2
4.1 General .2
4.2 Data block 1 (Identification).3
4.3 Data block 2 (Product physical information) .4
4.4 Data block 3 (Sizing information) .4
4.5 Data block 4 (Mechanical properties of the product) .5
4.5.1 Tensile modulus of elasticity .5
4.5.2 Tensile strength .6
4.6 Data block 5 (Optional block) .6
5 Example of a designation . 7
5.1 Designation with four data blocks .7
5.2 Designation with five data blocks .7
Annex A (informative) Illustration of the source of carbon fibre recyclates . 8

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
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www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 13, Composites
and reinforcement fibres.
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
Introduction
Carbon fibres are applied for the reinforcement of polymers or other materials. In particular, the recycled
carbon fibres are being highly durable and have limited degradation through recycling, their reuse for
adaption to circular economy is of much value. This designation system of recycled carbon fibres is necessary
to clearly specify the identification of essential characteristics of recycled carbon fibres.

v
International Standard ISO 19374:2026(en)
Recycled carbon fibres — Designation system for recycled
carbon fibres
1 Scope
1.1 This document establishes a designation system of recycled carbon fibres, which can be used as the
basis for specification.
1.2 This designation system is applicable to recycled carbon fibres used for polymer composites.
1.3 The types of recycled carbon fibres are differentiated by a designation system based on appropriate
levels of the designatory properties:
a) tensile modulus of elasticity.
b) tensile strength.
NOTE One to five designatory property(s) that differentiate recycled carbon fibre types from each other is (are)
assigned.
1.4 It is not intended to imply that recycled carbon fibres having the same designation will give the same
performance. This document does not provide engineering data or data on processing conditions that can be
required to specify materials for a particular and/or method of processing.
1.5 In order to specify recycled carbon fibres for a particular application, additional requirements are
given in optional data block 5 (see 4.6).
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 6989, Textile fibres — Determination of length and length distribution of staple fibres (by measurement of
single fibres)
ISO 11566:1996, Carbon fibre — Determination of the tensile properties of single-filament specimens
ISO 19350, Recycled carbon fibre — Determination of tensile strength distribution and interfacial shear strength
of single filament embedded in matrix polymer
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology 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
recycled carbon fibre
rCF
carbon fibres recovered through a recycling process that retains usable properties
3.2
dry rCF
DrCF
waste from pre-consumer carbon fibres and from a part of woven and non-woven fabric (without uncured
or cured matrix, only fibres)
Note 1 to entry: See Figure A.1
3.3
post-industrial carbon fibre recyclate
PIR
carbon fibres reclaimed after their intended use by industries
No
...