ISO 13931:2013

Carbon fibre - Determination of volume resistivity

ISO 13931:2013 specifies two methods (i.e. method A and method B) for the determination of the volume resistivity of carbon fibre.

Fibres de carbone — Détermination de la résistivité transversale

General Information

• Status: Published
• Publication Date: 21-Jul-2013
• ICS: 59.100.20 - Carbon materials
• Technical Committee: ISO/TC 61/SC 13 - Composites and reinforcement fibres
• Drafting Committee: ISO/TC 61/SC 13/WG 1 - Reinforcements and reinforcement products
• Current Stage: 9093 - International Standard confirmed
• Start Date: 11-Jun-2024
• Completion Date: 13-Dec-2025

Overview

ISO 13931:2013 specifies laboratory procedures for determining the volume resistivity of carbon fibre. The standard defines two test methods: Method A (single filament) and Method B (strand), including required apparatus, specimen preparation, measurement procedures and reporting. ISO 13931 is intended for producers, test laboratories and users who need reliable, comparable measurements of carbon fibre electrical resistivity for quality control, R&D and specification compliance.

Key topics and requirements

• Two test methods
  • Method A (single filament): measures resistance of individual filaments. Assumes circular filament cross‑section and calculates volume resistivity from measured resistance, filament diameter and gauge length.
  • Method B (strand): measures resistance of a strand. Cross‑sectional area is derived from strand linear density (tex) and density, then used with measured resistance and length to calculate volume resistivity.
• Apparatus and accuracy
  • Length meter accurate to 0.1 mm.
  • DC resistance meter with precision of 0.5% or better.
  • Method B requires flat copper plate electrodes and an insulating board for electrode spacing.
• Specimen preparation
  • Method A: isolate single filaments from a 40–50 mm fibre sample, mount on a thin template with conductive adhesive and attach a copper lead wire.
  • Method B: prepare whole strands; pretreatment (drying or size removal per ISO 10548) if sizing or moisture could affect results.
• Measurement procedure
  • Measure resistance and gauge length; read resistance shortly after powering the meter (example: within ~30 s in Method B).
  • Volume resistivity is computed from the specimen resistance, length and cross‑sectional parameters (diameter for single filaments; linear density and density for strands). Variables used in formulas include S (volume resistivity), R (resistance), L (length), D (diameter), T (linear density), ρ (density).
• Reporting
  • Report must reference ISO 13931, method used, material identification, test conditions (temperature/humidity/conditioning time), specimen dimensions, individual results and mean (if required), number of specimens and date.

Applications and users

• Who uses it: carbon fibre manufacturers, composite fabricators, test laboratories, material engineers and R&D teams.
• Why it matters: volume resistivity is critical for applications where electrical conductivity or insulation matters-antistatic materials, EMI shielding, conductive composites, sensors and certain aerospace, automotive and electronics components where consistent electrical properties are required.

Related standards

Normative references cited in ISO 13931 include:

• ISO 1889 (linear density of reinforcement yarns)
• ISO 10119 (carbon fibre density)
• ISO 10548 (size content / size removal)
• ISO 11567 (filament diameter and cross‑section)

Keywords: ISO 13931, carbon fibre volume resistivity, carbon fiber resistivity testing, volume resistivity test method, Method A single filament, Method B strand.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 13931
First edition
2013-07-01
Carbon fibre — Determination of
volume resistivity
Fibres de carbone — Détermination de la résistivité transversale
Reference number
©
ISO 2013
© ISO 2013
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Health and safety . 1
4 Principle . 1
5 Method A — Test method for single filament . 1
5.1 Apparatus . 1
5.2 Test specimen . 1
5.3 Procedure . 2
6 Method B — Test method for strand . 2
6.1 Apparatus . 2
6.2 Test specimen . 2
6.3 Procedure . 2
7 Test report . 4
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. 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. 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.
The committee responsible for this document is ISO/TC 61, Plastics, Subcommittee SC 13, Composites
and reinforcement fibres.
iv © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 13931:2013(E)
Carbon fibre — Determination of volume resistivity
1 Scope
This International Standard specifies two methods (i.e. method A and method B) for the determination
of the volume resistivity of carbon fibre.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable to its application. For dated references, only the edition cited applies. For
...