ISO 4345:2025

Steel wire ropes - Fibre main cores - Specifications

This document specifies the construction and characteristics of fibre main cores for steel wire ropes using two types of fibre: a) natural fibre; b) man-made fibre. This document is not applicable to ropes for mine hoisting purposes. NOTE Fibre cores are adversely affected by high ambient temperatures. When selecting fibre cores, the limitation of specific fibres, in this respect, must be recognized.

Câbles en acier — Âmes centrales textiles — Spécifications

General Information

• Status: Published
• Publication Date: 03-Feb-2025
• ICS: 77.140.65 - Steel wire, wire ropes and link chains
• Technical Committee: ISO/TC 105 - Steel wire ropes
• Drafting Committee: ISO/TC 105 - Steel wire ropes
• Current Stage: 6060 - International Standard published
• Start Date: 04-Feb-2025
• Due Date: 29-Sep-2025
• Completion Date: 04-Feb-2025

Relations

• Revises: ISO 4345:1988 - Steel wire ropes - Fibre main cores - Specification
• Effective Date: 06-Jun-2022

Overview

ISO 4345:2025 - Steel wire ropes - Fibre main cores - Specifications defines the construction, characteristics and test methods for fibre main cores used in steel wire ropes. It covers both natural fibres (sisal, abaca/manila, jute) and man-made fibres (e.g., polyolefin forms) and specifies materials, tolerances, lubrication, moisture, acidity and salt limits. The standard is not applicable to ropes for mine hoisting purposes and notes that fibre cores are adversely affected by high ambient temperatures.

Key topics and technical requirements

• Materials: Permitted natural fibres (sisal, abaca, jute) and man-made fibre types (fibre‑forming polyolefins or mutually agreed alternatives). Mixed cores may be used if agreed by purchaser and manufacturer.
• Construction & designation: Cores must be laid up from at least three strands, continuous without splices. Core designation includes nominal diameter, nominal linear density, fibre type, construction and direction of twist; linear density must be stated as lubricated or unlubricated.
• Tolerances: The document sets tolerances on length, nominal diameter and nominal linear density that vary by fibre type and core size (see Tables 1–3 in the standard).
• Core lubricants: Lubricants shall be acid‑free and moisture‑free; lubricant content for pre‑lubricated cores is agreed and measured per Annex C.
• Moisture regain: Specified limits for natural fibres (e.g., hard fibres ≤14.0 %, jute ≤13.0 %) with test procedures in Annex C.
• Water‑soluble acids: Acidity limit of not more than 2.0 mL of 0.1 mol/L alkali per 100 g of core (Annex D).
• Salt content: Maximum 0.3 % NaCl by mass, test method in Annex E.
• Packaging & marking: Continuous unspliced coils/reels, protected for transit, labelled with supplier name, nominal diameter, linear density, length and fibre type.

Practical applications and users

ISO 4345:2025 is essential for:

• Steel wire rope manufacturers specifying or sourcing fibre cores
• Fibre core producers and supply-chain quality managers
• Testing laboratories performing dimensional, moisture, acidity and salt analyses
• Procurement engineers and designers who specify rope constructions for lifting, mooring, rigging and general engineering applications (excluding mine hoisting) The standard helps ensure compatibility between core and rope construction, consistent material quality, and reliable test methods for acceptance and quality control.

Related standards

• ISO 139 - Textiles: standard atmospheres for conditioning and testing (referenced)
• ISO 1968 - Fibre ropes and cordage: vocabulary (referenced)
• Prepared by ISO/TC 105 (Steel wire ropes); this edition replaces ISO 4345:1988.

Keywords: ISO 4345:2025, steel wire ropes, fibre main cores, natural fibre cores, man-made fibre cores, moisture regain, core lubricants, core diameter, linear density, salt content, water-soluble acids, testing methods.

Standards Content (Sample)

International
Standard
ISO 4345
Third edition
Steel wire ropes — Fibre main cores
2025-02
— Specifications
Câbles en acier — Âmes centrales textiles — Spécifications
Reference number
© ISO 2025
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
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Phone: [phone]
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Material. 2
4.1 Natural fibre cores .2
4.2 Man-made fibre cores .2
5 Construction . 2
6 Core designation . 2
7 Tolerances . 2
7.1 Tolerance on length .2
7.2 Tolerance on nominal diameter .2
7.3 Tolerance on nominal linear density.3
8 Core lubricants . . 3
9 Moisture regain . 3
10 Water soluble acids . 3
11 Salt . 4
12 Packaging and marking . 4
Annex A (normative) Determination of core diameter . 5
Annex B (normative) Determination of core linear density . 6
Annex C (normative) Determination of moisture regain and core lubricant content . 7
Annex D (normative) Determination of water-soluble acids .11
Annex E (normative) Determination of salt content .12

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)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
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 105, Steel wire ropes.
This third edition cancels and replaces the second edition (ISO 4345:1988), which has been technically
revised.
The main changes are as follows:
— the tolerances for length and nominal diameter have been modified;
— the technical indicator and test method of moisture regain have been added;
— the test method and formula of water solution acid have been modified;
— the formula for calculating salt content has been added;
— the term "runnage" has been replaced by "linear density".
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
International Standard ISO 4345:2025(en)
Steel wire ropes — Fibre main cores — Specifications
1 Scope
This document specifies the construction and characteristics of fibre main cores for steel wire ropes using
two types of fibre:
a) natural fibre;
b) man-made fibre.
This document is not applicable to ropes for mine hoisting purposes.
NOTE Fibre cores are adversely affected by high ambient temperatures. When selecting fibre cores, the limitation
of specific fibres, in this respect, must be recognized.
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 139, Textiles — Standard atmospheres for conditioning and testing
ISO 1968, Fibre ropes and cordage — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1968 and the following 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
water soluble acid
amount of soluble acid in water that can be adequately extracted from the fibre cores, expressed as the
volume of sodium hydroxide or potassium hydroxide solution (with a concentration of 0,1 mol/L) that is
used to neutralize the soluble acid extracted from a sample of 100 g
3.2
moisture regain
mass of water in any form in the fibre core material, determined using prescribed methods and expressed as
a percentage of the mass of water to the absolute dry mass of the fibre core material
3.3
lubricant content
mass of lubricant absorbed in the fibre core material, expressed as a percentage of the mass of lubricant to
the absolute dry mass of the fibre core material

4 Material
4.1 Natural fibre cores
Natural fibre cores shall be made from new hard fibres or some specific soft fibres of the following types:
a) Sisal (Agave sisalana);
b) Abaca; Manila hemp (Musa textilis);
c) Jute.
4.2 Man-made fibre cores
Man-made fibre cores shall be made entirely from new fibres of the following types:
a) fibre-forming polyolefines (i.e. monofilament, film or fibrillated film of polyethylene, polypropylene, etc.);
b) any suitable alternative materials agreed between core purchaser and core supplier.
NOTE Mixed fibre cores are produced by mixing natural fibre and man-made fibre agreed between core purchaser
and core manufacturer.
5 Construction
Main cores conforming to this document shall be laid up from at least three strands. Each coil shall be
continuous throughout its length without core splices.
6 Core designation
The core shall be designated by its nominal diameter, nominal linear density, type of fibre main cores,
construction and direction of twist. These shall be agreed between the core manufacturer and the steel wire
rope manufacturer. The core manufacturer shall state whether the linear density is based on the lubricated
or unlubricated core.
7 Tolerances
7.1 Tolerance on length
The length of core supplied shall be equivalent to the specified length subject to the following tolerances as
given in Table 1.
Table 1 — Tolerance on length
Length, L Tolerance
+5 %
L≤400 m
+20 m
400 m< L≤1 000 m
+2 %
L>1 000 m
7.2 Tolerance on nominal diameter
The tolerance on nominal diameter shall be as given in Table 2. Diameter shall be measured in accordance
with the method specified in Annex A.

Table 2 — Tolerance on nominal diameter
Tolerance on nominal diameter
Type of fibre
≤7 mm >7 mm
Hard fibre +5 %
(Sisal or Abaca) 0
Natural fibre
Soft fibre +5 % +4 %
(Jute) 0 0
+4 % +3 %
Man-made fibre
0 0
7.3 Tolerance on nominal linear density
The tolerance on nominal linear density shall be as given in Table 3. Linear density shall be measured in
accordance with the method specified in Annex B.
Table 3 — Tolerance on nominal linear density
Tolerance on nominal linear density
Type of fibre
≤7 mm >7 mm
+5 %
Natural fibre
+4 % +3 %
Man-made fibre
0 0
8 Core lubricants
Lubricants used for cores shall be acid-free and shall not contain moisture.
The lubricant content of pre-lubricated core
...