IEC 60794-1-23:2012

IEC 60794-1-23 ®
Edition 1.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-23: Generic specification – Basic optical cable test procedures – Cable
element test methods
Câbles à fibres optiques –
Partie 1-23: Spécification générique – Procédures fondamentales d’essai des
câbles optiques – Méthodes d’essai des éléments de câble

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IEC 60794-1-23 ®
Edition 1.0 2012-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-23: Generic specification – Basic optical cable test procedures – Cable

element test methods
Câbles à fibres optiques –
Partie 1-23: Spécification générique – Procédures fondamentales d’essai des

câbles optiques – Méthodes d’essai des éléments de câble

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10 ISBN 978-2-8322-7193-3

– 2 – IEC 60794-1-23:2012 © IEC 2012

CONTENTS
CONTENTS . 2

FOREWORD . 4

1 Scope and object . 6

2 Normative references . 6

3 Method G1: Bend test for cable elements . 6

3.1 Object . 6

3.2 Sample . 6

3.3 Apparatus . 6
3.4 Procedure . 7
3.5 Requirements . 7
3.6 Details to be specified . 7
4 Method G2: Ribbon dimensions and geometry – Visual method . 7
4.1 Object . 7
4.2 Sample . 7
4.3 Apparatus . 7
4.4 Procedure . 7
4.4.1 General . 7
4.4.2 Method 1 . 7
4.4.3 Method 2 . 8
4.5 Requirements . 8
4.6 Details to be specified . 8
4.7 Definitions of ribbon dimensions and geometry . 8
4.7.1 General . 8
4.7.2 Width and height . 8
4.7.3 Basis line . 8
4.7.4 Fibre alignment . 8
5 Method G3: Ribbon dimensions – Aperture gauge . 9
5.1 Object . 9
5.2 Sample . 9
5.3 Apparatus . 9
5.4 Procedure . 9
5.5 Requirement . 10

5.6 Details to be specified . 10
6 Method G4: Ribbon dimensions – Dial gauge (Test deleted) . 10
7 Method G5: Ribbon tear (separability) . 10
7.1 Object . 10
7.2 Sample . 10
7.3 Apparatus . 10
7.4 Procedure . 11
7.5 Requirements . 11
7.6 Details to be specified . 11
8 Method G6: Ribbon torsion . 12
8.1 Object . 12
8.2 Sample . 12
8.3 Apparatus . 12
8.4 Procedure . 12

8.5 Requirements . 12

8.6 Details to be specified . 12

9 Method G7: Tube kinking . 13

9.1 Object . 13

9.2 Sample . 13

9.3 Apparatus . 13

9.4 Procedure . 14

9.5 Requirements . 14

9.6 Details to be specified . 15

10 Method G8: Ribbon residual twist test . 15
10.1 Object . 15
10.2 Sample . 15
10.3 Apparatus . 15
10.4 Procedure . 16
10.5 Requirements . 16
10.6 Details to be specified . 16

Figure 1 – Cross-sectional drawing illustrating fibre ribbon geometry . 9
Figure 2 – Aperture gauge . 10
Figure 3 – Sample preparation . 11
Figure 4 – Separability procedure . 12
Figure 5 – Torsion test . 13
Figure 6 – Tube kinking test . 15

Table 1 – Examples of test apparatus dimensions: . 14

– 4 – IEC 60794-1-23:2012 © IEC 2012

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
OPTICAL FIBRE CABLES –
Part 1-23: Generic specification –

Basic optical cable test procedures –

Cable element test methods
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60794-1-23 has been prepared by subcommittee 86A: Fibres and
cables, of IEC technical committee 86: Fibre optics.
This bilingual version (2019-07) corresponds to the monolingual English version, published in
2012-08.
This edition of IEC 60794-1-23 cancels and replaces the cable elements tests methods part of
the second edition of IEC 60794-1-2 published in 2003. It constitutes a technical revision.
The main change with respect to the previous edition is that it has been decided to split the
second edition of IEC 60794-1-2 into six new documents:
– IEC 60794-1-2, Optical fibre cables – Part 1-2: Generic specification – Basic optical cable
test procedures
– IEC 60794-1-20, Optical fibre cables – Part 1-20: Generic specification – Basic optical
cable test procedures – General & Definitions

– IEC 60794-1-21, Optical fibre cables – Part 1-21: Generic specification – Basic optical

cable test procedures – Mechanical tests methods

– IEC 60794-1-22, Optical fibre cables – Part 1-22: Generic specification – Basic optical

cable test procedures – Environmental tests methods

– IEC 60794-1-23, Optical fibre cables – Part 1-23: Generic specification – Basic optical
cable test procedures – Cable elements tests methods

– IEC 60794-1-24, Optical fibre cables – Part 1-24: Generic specification – Basic optical

cable test procedures – Electrical tests methods

The text of this standard is based on the following documents:

FDIS Report on voting
86A/1451/FDIS 86A/1469/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 60794 series, published under the general title Optical fibre
cables, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60794-1-23:2012 © IEC 2012

OPTICAL FIBRE CABLES –
Part 1-23: Generic specification –
Basic optical cable test procedures –

Cable element test methods
1 Scope and object
This part of IEC 60794 applies to optical fibre cables for use with telecommunication
equipment and devices employing similar techniques, and to cables having a combination of
both optical fibres and electrical conductors.
The object of this part of IEC 60794 is to define test procedures to be used in establishing
uniform requirements for the geometrical, material, mechanical, environmental properties of
optical fibre cable elements.
Throughout the document the wording “optical cable” may also include optical fibre units,
microduct fibre units, etc.
General requirements and definitions are given in IEC 60794-1-20 and a complete reference
guide to test method of all types in the IEC 60794-1-2.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
IEC 60794-3:2001, Optical fibre cables – Part 3: Sectional specification – Outdoor cables
3 Method G1: Bend test for cable elements

3.1 Object
The purpose of this test is to characterize cable elements for splicing purposes by
determining the attenuation increase of an optical (fibre, ribbon, core tube, breakout unit, etc.)
element when bent within a splice closure or similar device.
3.2 Sample
The length of the sample of optical element shall be sufficient to carry out the testing
specified.
3.3 Apparatus
The apparatus consists of:
a) a mandrel having a smooth surface with diameter as stated in the detail specification;

b) an attenuation measuring apparatus (see IEC 60793-1-40).

3.4 Procedure
The element to be tested shall be loosely wound on the mandrel; the number of turns shall be
stated in the detail specification.

In order to measure the attenuation increase caused by bending, allowance should be made
for the intrinsic attenuation of the fibre.

3.5 Requirements
Any increase in attenuation shall comply with the limits shown in the detail specification.
3.6 Details to be specified
The detail specification shall include the following:
a) optical test wavelength;
b) diameter of the mandrel;
c) number of turns;
d) apparatus and attenuation measuring technique;
e) temperature.
4 Method G2: Ribbon dimensions and geometry – Visual method
4.1 Object
The purpose of this test is to determine the geometry of an optical fibre ribbon as defined by
the parameters of width, height and fibre alignment, for the purpose of type testing to assume
proper manufacturing process control. This test is not necessarily suitable for final product
inspection and, unless otherwise specified, shall not be used for that purpose.
4.2 Sample
The number of samples to be tested shall be specified in the detail specification. The selected
samples shall be statistically independent and representative of the ribbon population tested.
4.3 Apparatus
The apparatus consists of a microscope or profile projector with appropriate magnification.

4.4 Procedure
4.4.1 General
Either of the two following procedures may be used.
For the specified number of samples, all dimensions shall be measured as average as well as
maximum and minimum values.
4.4.2 Method 1
The sample is prepared by cutting it perpendicular to the axis of the ribbon and placing it in a
curable resin or in a tool which holds the ribbon. If necessary, the sample shall be ground and
polished to prepare a smooth perpendicular end face. The prepared sample is secured with its
end face perpendicular to the optical path and measured by means of a microscope or profile
projector.
– 8 – IEC 60794-1-23:2012 © IEC 2012

NOTE Care should be taken that the preparation of the sample does not change the structure of the fibre ribbon

and represents an undisturbed image of the fibre cladding and ribbon cross-section.

4.4.3 Method 2
Place the ribbon in a ribbon fibre holder and remove 20 mm to 25 mm of the fibre coating and

matrix material with the ribbon hot sheath stripping tool and wipe the stripped portion of the

fibres clean with an alcohol-moistened pad. Adjust the position of the ribbon in the ribbon fibre

holder and cleave the fibres at a distance of 250 µm to 500 µm from the stripped edge of the

ribbon. Cut and polish the other end of the ribbon, and illuminate it with a collimated light

source. Align and measure the cleaved end of the ribbon under microscope.

NOTE Care should be taken that the preparation of the sample does not change the structure of the fibre ribbon
and represents an undisturbed image of the fibre cladding and ribbon cross-section.
4.5 Requirements
Unless otherwise specified in the detail specification, the width, height and fibre alignment
shall be in accordance with IEC 60794-3:2001, Table 1.
4.6 Details to be specified
The detail specification shall include the following:
a) permissible maximum and minimum values;
b) average values;
c) number of samples tested.
4.7 Definitions of ribbon dimensions and geometry
4.7.1 General
The following definitions apply to a fibre ribbon cross-section as shown in Figure 1. The figure
illustrates an example for a 4-fibre ribbon, where a is the diameter of a coloured fibre.
NOTE In consideration of the precision of fiber geometric attributes and the relatively larger precision of ribbon
geometry requirements, it is acceptable for glass core/glass cladding fibres to use the edge of the cladding for the
measurements of 4.7.3 and 4.7.4 in lieu of the fibre centres. In this case, the measurements shall be made on the
same side of all fibres (e.g. top or bottom, left or right side).
4.7.2 Width and height
The width w and height h of the ribbon are the dimensions of the minimum rectangular area
enclosing the ribbon cross-section.

4.7.3 Basis line
The basis line is given in the cross-section of an optical fibre ribbon as the straight line
crossing the fibre centres of the first fibre (fibre 1) and the last fibre (fibre n) of the fibre
ribbon.
4.7.4 Fibre alignment
4.7.4.1 Horizontal fibre separation
The horizontal separation of fibres is the distance of the orthogonal projection of two fibre
centres on the basis line in the fibre ribbon cross-section.
Two horizontal separation parameters can be distinguished:
a) centre-centre distance d between adjacent fibres;
b) centre-centre distance b between the extreme fibres;

4.7.4.2 Planarity
The planarity p of the fibre ribbon structure is the sum of the maximum positive and absolute

values of the maximum negative vertical separation of the fibres.

The vertical separation of the fibres is the orthogonal distance from the fibre centre to the

basis line. The vertical separation is positive for fibres “above” the basis line and negative for

fibres “below” the basis line.

Figure 1 – Cross-sectional drawing illustrating fibre ribbon geometry
5 Method G3: Ribbon dimensions – Aperture gauge
5.1 Object
The purpose of this test is to verify the functional performance of a ribbon. In order to ensure
functional performance, the dimensions of edge bonded ribbons may be controlled and
verified for final inspection purposes with an aperture gauge. The intent is to verify that the
end portion of a ribbon can be inserted into and would be reasonably aligned to the guide
slots of commercial stripping tools. This method is under consideration for encapsulated
ribbons.
5.2 Sample
Unless otherwise specified in the detail specification, five representative ribbon samples,
each with a minimum length of 50 mm, shall be taken from the ribbon to be tested.
5.3 Apparatus
An aperture gauge, as shown in Figure 2, having an aperture based on the dimensions shown
in IEC 60794-3:2001, Table 1, may be used to assess the overall dimensions of a ribbon.
5.4 Procedure
The ribbon sample to be tested is held in the middle and a 10 mm end portion is inserted
through the aperture gauge.
– 10 – IEC 60794-1-23:2012 © IEC 2012

5.5 Requirement
It must be possible for the 10 mm ribbon end portion to be freely inserted through the aperture

gauge without mechanical damage to the sample.

5.6 Details to be specified
The detail specification shall include the following:

a) dimensions of the aperture gauge;

b) number of samples to be tested.

Dimensions in micrometers
Figure 2 – Aperture gauge
6 Method G4: Ribbon dimensions – Dial gauge (Test deleted)
7 Method G5: Ribbon tear (separability)
7.1 Object
The purpose of this test is to assure sufficient tear resistance for ribbons where the fibres are
not required to be separable, or to assure sufficient separability of the fibres for ribbons where
the fibres are required to be separated. The intention of this test is to be able to tear by hand
without damage
7.2 Sample
For an n fibre ribbon, n/2 specimens, each with a minimum length of 100 mm, are taken from
lengths of approximately 1 m each from the fibre ribbon.
The fibres to be tested are separated with a knife or other suitable method on a suitable
length for clamping (see Figure 3) for x samples (x, typically 3 to 5, to be specified in the
detail specification). One fibre is separated from the other fibres in the ribbon. For x more
samples, two fibres are separated from the other fibres in the ribbon, etc. up to n/2 fibres.
7.3 Apparatus
The apparatus consists of:
a) a tensile strength measuring apparatus with suitable clamping devices;

b) a microscope with at least 100 × magnification.

7.4 Procedure
The specimen as shown is inserted into the strength measuring apparatus, as shown in
Figure 4, The fibres to be tested are torn at a speed of approximately 100 mm/min. The force
to tear the fibres on a length of 50 mm is continuously recorded.

In the case where fibres are required to be separated, the primary coating of the separated
fibre(s) shall be visually inspected by means of a microscope.

7.5 Requirements
The primary requirement is to be able to make the tear without fibre damage (coating damage
or fibre breakage). For ribbons where the fibres are required to be separated the coloured
primary coating of the separated fibre(s) shall be free from ribbon matrix residues.
Any colour coding of fibres shall remain sufficiently intact to enable individual fibres to be
distinguished from each other.
The minimum or maximum and mean tear forces shall be as specified in the detail
specification.
7.6 Details to be specified
The detail specification shall include the following:
a) minimum and mean tear force, in N, when fibres are not required to be separated;
b) maximum and mean tear force, in N, when fibres are required to be separated;
c) number of samples;
d) type of ribbon (separable or non-separable).
Dimensions in millimeters
Figure 3 – Sample preparation
– 12 – IEC 60794-1-23:2012 © IEC 2012

Figure 4 – Separability procedure
8 Method G6: Ribbon torsion
8.1 Object
The purpose of this test is to verify the mechanical and functional integrity of the fibre ribbon
structure. The test determines the capability of the ribbon to withstand torsion without
delamination, whilst maintaining the fibre separability where required.
8.2 Sample
Unless otherwise specified in the detail specification, five representative samples, each with a
minimum length of 120 mm, are obtained from the ribbon to be tested.
8.3 Apparatus
The testing apparatus, an example of which is in Figure 5, consists of two vertically positioned
clamps to hold the sample while it is twisted under a minimum tension of 1 N. The minimum
length to be tested is 100 mm.
8.4 Procedure
The sample is securely fixed in the apparatus and twisted in increments of 180° ± 5° within a
time of 2 s. The minimum dwell time after each twist increment is 5 s. The incremental

twisting is continued to the value(s) agreed upon between the manufacturer and user, as
defined in the detail specification, or until delamination occurs.
8.5 Requirements
The ribbon shall withstand the number of 180° turns until delamination occurs, as given in the
detail specification.
8.6 Details to be specified
The detail specification shall include the following:
a) number of samples;
b) number of turns.
Dimensions in millimeters
Figure 5 – Torsion test
9 Method G7: Tube kinking
9.1 Object
The purpose of this test is to determine the ability of tubes containing optical fibres to
withstand mechanical stresses encountered during cable installation and splicing. The test is
carried out on tubes taken from an optical cable.
9.2 Sample
Tube containing fibres, with a length of at least L + 50 mm, taken from an optical fibre cable.
5 samples shall be tested, unless otherwise specified.
9.3 Apparatus
The apparatus consists of:
a) a testing device (see Figure 6); where:

– 14 – IEC 60794-1-23:2012 © IEC 2012

L = length of tube under test
L = distance between the tube clamping point of the movable clamp and the tube
clamping point of the fixed clamp at the start of the test

L = moving distance (the length of which determines the reduction of the ellipse

dimension)
The dimensions of the apparatus are given in Table 1.

NOTE 1 The minimum diameter of the loop is not fixed by a curvature in the test equipment, but only controlled by

the fixed length L of the specimen and the moving length L.
NOTE 2 The fixed guideway ensures a defined position of the sample. A transparent cover allows the sample to
be kept in the same plane and observed whilst being tested. The distance between the two covers shall be typically
three times the tube diameter. Too great a distance will allow the tube to move sideways during the test and does
not ensure that the test is severe enough.
Table 1 – Examples of test apparatus dimensions:
Nominal tube diameter L L
1 2
350 mm 100 mm
≤ 3,1 mm
≤ 6,1 mm 650 mm 200 mm
≤ 10,1 mm 1 050 mm 300 mm
9.4 Procedure
The test shall be carried out at standard atmospheric conditions.
The sample shall be marked with a length L and mounted in the test device as shown in
Figure 6, with the movable and fixed clamps separated by a distance L .
The moveable clamp shall be moved between positions 1 and 2 over a distance L and
returned to position 1 at a speed approximately 10 mm/s. This movement is one cycle. During
the last cycle, the sample shall remain in position 2 for 60 s.
The values of test parameters L, L , L and the number of cycles (five, unless stated
1 2
otherwise) should simulate the service deployment conditions. They shall be agreed between
user and manufacturer.
NOTE 1 Whilst the loop tends to form an ellipse rather than a perfect circle during the test, it is possible to
simplify the understanding of the test parameters considerably by assuming that a circle is formed. Based on this
assumption, then:-
L = L –(L + π × D) (1)
1 2
Where D= the tube loop diameter (mm)
NOTE 2 As a mechanical test, a typical minimum value for the tube loop diameter is 60 mm, since this aligns with
the minimum specified bend diameter for most classes of fibre and also represents a minimum practical value of
coiled tube loops within a joint or other connectivity plant.
NOTE 3 Using D = 60 mm then L can be calculated (for tubes ≤ 3,1mm) from equation 1, which also yields the
value of 60 mm. Since the loop does form an ellipse, which makes the effective loop diameter in one plane much
more severe, it is recommended that 60 mm is taken as the maximum length specified for the moving length, L.
Lower values may be specified.
NOTE 4 If this test is used to simulate installation of a tube within a joint, then the value for D may be replaced by
the available width within a joint.
9.5 Requirements
During the test no kinking of the sample shall be visible.

9.6 Details to be specified
The detail specification shall include the following:

a) number of cycles (five, unless otherwise specified);

b) lengths L, L , L ; (use L = 60 mm, L = 350 mm, L = 100 mm, unless otherwise specified,
1 2 1 2
for tubes ≤ 3,1 mm)
Figure 6 – Tube kinking test
10 Method G8: Ribbon residual twist test
10.1 Object
The ribbon residual twist test, or flatness test, evaluates the degree of permanent twist in a
cabled optical fibre ribbon.
10.2 Sample
Ribbon samples shall be taken from a preconditioned (aged) test cable.
The samples shall be of a length sufficient to include the gauge length of 50 cm and additional
length on each end to facilitate attachment of clamps and the test weight.

10.3 Apparatus
The apparatus shall be constructed to have the following characteristics:
– The ribbon shall hang vertically, clamped at the top, with the bottom end free to rotate and
translate as necessary.
– A mass shall be attached to the bottom end of the ribbon sample, with the gauge length
situated between the top clamp and the bottom mass.
– The bottom mass shall be arranged so that it does not impart any twisting or side loading
of the ribbon.
– The gauge length shall be 50 ± 5 cm, unless otherwise specified.
– The mass shall be 100 ± 5 g, unless otherwise specified.
– A method shall be provided to measure the axial rotation of the lower end of the ribbon
gauge length with respect to the upper end.

– 16 – IEC 60794-1-23:2012 © IEC 2012

10.4 Procedure
Perform the following steps, unless otherwise specified:

1) Precondition the ribbon at 85 ± 2 °C, uncontrolled relative humidity, for 30 days in its
cable.
2) Mount one end of the ribbon in the top clamp.

3) Attach the bottom mass.
4) Allow the ribbon to rotate. When the rotation settles out and the ribbon becomes still,

measure the angular rotation of the bottom end of the gauge length with respect to the

upper end of the gauge length.

5) Calculate the residual twist of the sample:
Residual twist = (final angle, top to bottom) / (measured gauge length)
10.5 Requirements
The buffered fibres shall not exceed the maximum residual twist requirements of the detail
specification. In most cases, a maximum residual twist of 8 degrees/cm is adequate.
10.6 Details to be specified
The detail specification shall include the following:
a) the preconditioning conditions, if different from those stated above;
b) the ribbon gauge length, if different from that stated above; and
c) the tension mass, if different from that stated above.

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– 18 – IEC 60794-1-23:2012 © IEC 2012

SOMMAIRE
AVANT-PROPOS . 20

1 Domaine d’application et objet . 22

2 Références normatives . 22

3 Méthode G1: Essai de courbure pour les éléments de câble . 22

3.1 Objet . 22

3.2 Echantillon . 22

3.3 Appareillage . 22

3.4 Procédure . 23
3.5 Exigences . 23
3.6 Détails à spécifier . 23
4 Méthode G2: Dimensions et géométrie du ruban – Méthode visuelle . 23
4.1 Objet . 23
4.2 Echantillon . 23
4.3 Appareillage . 23
4.4 Procédure . 23
4.4.1 Généralités . 23
4.4.2 Méthode 1 . 24
4.4.3 Méthode 2 . 24
4.5 Exigences . 24
4.6 Détails à spécifier . 24
4.7 Définitions des dimensions et de la géométrie du ruban . 24
4.7.1 Généralités . 24
4.7.2 Largeur et hauteur . 24
4.7.3 Ligne de base . 24
4.7.4 Alignement des fibres . 25
5 Méthode G3: Dimensions du ruban – Gabarit d’ouverture . 25
5.1 Objet .
...