ISO 4345:2025

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
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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
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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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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
...