IEC 60794-1-124:2025

IEC 60794-1-124 ®
Edition 1.0 2025-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Optical fibre cables –
Part 1-124: Generic specification – Basic optical cable test procedures –
Mechanical tests methods – Installation test for microduct cabling, Method E24

Câbles à fibres optiques –
Partie 1-124: Spécification générique – Procédures fondamentales d’essais des
câbles optiques – Méthodes d’essais mécaniques – Essai d’installation pour un
câblage en microconduits, Méthode E24
ICS 33.180.10  ISBN 978-2-8327-0457-8

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– 2 – IEC 60794-1-124:2025 © IEC 2025
CONTENTS
FOREWORD. 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Sample . 6
5 Apparatus . 7
6 Ambient conditions . 7
7 Procedure . 8
8 Requirements . 8
9 Details to be specified . 9
10 Details to be reported . 9
11 Test track setup . 10
Annex A (informative) Test track – Practical implementation of the blowing route
Method B (Configuration with 3 mandrels) . 12
Annex B (informative) Crash test . 13
Annex C (informative) Blowing out . 14
Bibliography . 15

Figure 1 – Schematic representation of test tracks for Method A – Configuration with 2
mandrels . 11
Figure 2 –Schematic representation of the test track for Method B – Configuration with
3 mandrels . 11
Figure A.1 – Schematic diagram of the practical implementation of the test track for
Method B – Configuration with 3 mandrels . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 1-124: Generic specification – Basic optical cable test procedures –
Mechanical tests methods – Installation test for microduct cabling,
Method E24
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC 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, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60794-1-124 has been prepared by subcommittee 86A: Fibres and cables: of IEC technical
committee 86: Fibre optics. It is an International Standard.
This first edition cancels and replaces Method E24 of the first edition of IEC 60794-1-21
published in 2015 and Amendment 1:2020. This edition constitutes a technical revision.

– 4 – IEC 60794-1-124:2025 © IEC 2025
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of a blowing route (see Figure 2) which includes a change in the direction of
curvature. This was achieved by introducing a third mandrel;
b) addition of Annex A (Figure A.1 which shows a practical implementation of the blowing
route;
c) addition of Annex B which describes the so-called Crash Test;
d) addition of Annex C which describes a cable blowing out procedure.
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2552/FDIS 86A/2577/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60794 series, published under the general title Optical fibre, can be
found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
INTRODUCTION
The national working committee DKE/UK 412.6 "Optical fibres and optical fiber cables" of the
DKE German Commission for Electrical, Electronic & Information Technologies (www.dke.de)
is responsible for this document.
This document was prepared in cooperation with DKE/UK 412.6 "Optical fibres and optical fibre
cables".
A VDE "application rule" was published in Germany [1] .
Two different blowing routes are presented in this document which can be used to characterize
the blowing performance of microduct cables. The first track (Figure 1, Method A) is identical
with the track which has been used in IEC 60794-21 Method E24 for many years. Even though
the creation of the track seemed to be very simple, it was not used by many facilities because
of its excessive length. A 100 m length track requires a lot of space which is not usually
available in facilities. It also seemed to be over simplified because only bends of the same
curvature were included. The second track (Figure 2, Method B) was designed to include the
end-users’ requirements which were to have a more compact set-up (only 45 m between
mandrel centres) and to have a more realistic route including curvature changes in bends.

___________
Numbers in square brackets refer to the Bibliography

– 6 – IEC 60794-1-124:2025 © IEC 2025
OPTICAL FIBRE CABLES –
Part 1-124: Generic specification – Basic optical cable test procedures –
Mechanical tests methods – Installation test for microduct cabling,
Method E24
1 Scope
This part of IEC 60794 contains test procedures, referred to as Method E24, for evaluating the
behaviour of microduct cabling (microduct optical cable, fibre unit or hybrid cable etc.) when
blown into a microduct or protected microduct.
This document describes two blowing track layouts: Method A consists of two mandrels and two
long straight sections in between (same curvature). Method B consists of 3 mandrels. The
middle mandrel forces the cable to experience both left- and right-hand bending, which is a
feature of any realistic blowing route.
In addition, this document describes an optional procedure to check the capability of blowing
out an installed cable.
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.
IEC 60794-1-21, Optical fibre cables – Part 1-21: Generic specification – Basic optical cable
test procedures – Mechanical test methods
IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60794-1-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
4 Sample
The sample consists of a microduct (or microduct assembly) and microduct cabling which is
longer than the microduct.
5 Apparatus
The apparatus consists of:
– a microduct system (see Clause 11 Method A, Method B and Annex A);
– a cable pay-off;
– a blowing machine which shall be selected according to the desired blowing length and to
the cable type, size and weight;
– a blowing machine with continuous, electronic recording of air pressure, speed, push-force,
blowing length and blowing time at smaller intervals (1 m to 25 m) is preferred. If data have
to be recorded manually, intervals up to 100 m can be used;
– the blowing machine can trigger an alarm (optional) in case of cable slipping at the
mechanical drive and automatically switch off if necessary (slip monitoring);
– the blowing machine settings shall be adjustable to set a defined push force resulting from
the crash test;
– a compressor with
• constant air pressure up to 1,5 MPa ± 0,05 MPa for microduct fibre optical cables;
• an airflow adapted to the microduct inner diameter. For a typical microduct this value is
3 3
1 m /min up to 2 m /min;
– a unit for calibrating the inner diameter of the microduct;
– an ambient temperature measuring device;
– an ambient moisture measuring device;
– a timer.
The pipe system consists of the cable conduit (microduct or microduct assembly) as described
in Clause 11. In preparation for the test, the facility shall be equipped with the microducts of
the specified lengths agreed between the customer and the supplier. To obtain the desired test
length, the microduct is laid multiple times in continuation according to the test track layouts
described in Clause 11. Since the location of the blowing equipment and the test route typically
are a few meters apart, ducts have to be installed between the blowing equipment and the test
route (inlet pipe and outlet pipe). To ensure comparable results across different testing facilities,
a new microduct shall be used for each test.
For personal protection as well as for the protection of the cables, microducts and equipment
used during the test, the maximum blowing speed shall be adjustable and set to comply with
the limits specified by the blowing machine supplier and cable manufacturer. Currently blowing
speeds up to 100 m/min are assumed to be safe and do not require special safety precautions
to be taken as regards equipment (e.g. cable pay-off).
6 Ambient conditions
The test is carried out under ambient conditions, usually at temperatures between 0°°C and
+40°°C. The specified installation temperature of the cable shall be taken into account.
NOTE Lower temperatures can lead the duct to be obstructed by ice. Temperatures higher than 40°°C can degrade
the blowing performance due to an increase in the coefficient of friction of the cable jacket and microduct.

– 8 – IEC 60794-1-124:2025 © IEC 2025
7 Procedure
The micro duct system sealing shall be checked, either by checking the pressure drop when
the microduct system is pressurized or by checking for sufficient airflow at the end of the
microduct.
Since the microduct length can change due to temperature changes, the straightness of the
microducts and the specified bending radii shall be verified before the test is started.
Before starting the blowing tests, the microduct route shall be verified by test method E23 of
IEC 60794-1-21 with an air pressure of 0,1 MPa to 0,5 MPa.
Before each blowing test on a microduct cable, if no maximum push-force has been specified
by the cable manufacturer, a "crash test" shall be carried out to determine the max. push-force
that can be exerted on the cable without causing damage to the cable (see Annex B).
Before blowing in, the inserted cable end shall be equipped with a cable end cap (preferably
with the same diameter as the cable). If agreed between the customer and the supplier, the
microducts or the cable may be lubricated by suitable lubricants. A one-time lubrication is
carried out by applying the lubricant using a sponge. A lubricator can also be used to achieve
continuous lubrication on the cable. The lubricator is integrated into the injection head where
the cable is fed into the microduct and where the compressed air is applied.
The cable is fed directly from its delivery reel into the blowing machine by means of a suitable
cable pay-off. Alternate feeding methods can be used such as from a cable laid in a figure-8
pattern on the ground. Safety requirements shall be implemented to avoid any pollution on the
cable surface.
One option to begin the installation process is to insert approximately 20 m to 50 m only by
mechanically pushing by the blowing machine. Then the compressed air is turned on and the
flow increased until the desired blowing speed is reached. The maximum blowing speed is
determined by the mechanical drive. The installation time, installation speed and maximum push
force shall be recorded at regular intervals (see Clause 5).
The blowing machine shall be adjusted to maintain a blowing speed within the permissible range
(see Clause 8), typically between a minimum of 20 m/min and a maximum of 100 m/min.
After the cable arrives at the end of the microduct section and the pressure drops to the ambient
pressure, the blowing test is finished.
Blowing out can be required to replace a cable with another cable of higher transmission
capacity (higher fibre count). Annex C provides guidance on the Blowing out procedure.
8 Requirements
The blowing test is considered as passed if:
– the maximum acceptable installation time, agreed between customer and supplier, has not
been exceeded;
– the minimum acceptable installation distance, agreed between customer and supplier, has
been reached.
9 Details to be specified
The test specification shall specify the following details:
– the cable to be tested;
– the inner diameter and outer diameter of the microduct;
– the presence of grooves on the inner duct surface (with grooves or without grooves);
– the loop length L ("Method A", approximately 200 m, "Method B", approximately 100 m);
– the total length (minimum 1 000 m);
– the bend radius at the entry and at the exit according to Clause 10;
– lubricant (if applicable);
– blowing pressure: 1,3 MPa to 1,5 MPa for microduct fibre optical cables and 0,9 MPa to
1,0 MPa for microduct fibre units (unless otherwise specified);
– installation speed range: typically, from a minimum of 20 m/min to a maximum of 100 m/min
(unless otherwise specified by the customer);
– installation time;
– mandrel (bend) diameter.
10 Details to be reported
The following parameters shall be defined or recorded once at the start of the test:
– test method to be used;
– test location and test date
– description of the cable to be tested;
– cable manufacturer;
– reel number and batch number;
– cable type designation (data sheet);
– cable diameter D and cable ovality (D -D );
c cmax cmin
– cable weight per meter;
– number of fibres;
– cable sheath material (PE, PA, etc.);
– outer diameter of the cable end cap (if required);
– description of the microducts used, including the manufacturer name and indication of the
underlying standards;
– microduct inner diameter and outer diameter (nominal value and measured value);
– microduct ovality (d -d );
max min
– tube inside surface condition (e.g. smooth or longitudinally grooved);
– loop length L of the section;
– total length of the test track;
– bend radius of the microduct at the entry (see Figure A.1 entry “In”) and at the exit (see
Figure A.1 exit ”Out”)
– pressure test details:
• test pressure;
• test duration;
• pressure drop;
– 10 – IEC 60794-1-124:2025 © IEC 2025
– diameter of the cable end cap
– calibration procedure details:
• the test object (calibre) used to verify the microduct route (type, diameter and length);
• lubricant used for calibration (product name and manufacturer name);
• sponge used for calibration (dimensions, product name and manufacturer name);
• calibration result (pass or fail; if pass: calibre running time);
– lubricant procedure (prelubrication, continuous lubrication):
• prelubrication details:
• size, type and number of sponges used for lubrication and their running time;
• lubricant quantity per length and lubrication equipment used (type and
manufacturer);
– type of cable pay-off (mechanism, product name and manufacturer name);
– ambient temperature and humidity;
– cable sheath temperature (measured at the cable surface in direct contact (e.g.
thermocouple) or contact less (e.g. pyrometer).
– microduct temperature (measured somewhere along the installed length, by positioning a
T-sensor close to the microducts) ;
– maximum push-force (see crash test in Annex B).
The following parameters shall be recorded continuously during the test:
– injection pressure (tube pressure);
– push-force on the microduct optical fibre cable;
– blowing speed;
– slipping (alarm, automatic stop or other);
– blown air temperature;
The following parameters shall be recorded after test completion:
– maximum installation speed;
– minimum installation speed;
– test start and end time;
– net blowing time;
– blowing length.
Attenuation measurements on the optical fibres before and after the blowing test shall be
performed if required.
11 Test track setup
This document specifies two different blowing routes which can be used to characterize the
blowing performance of microduct cables: Method A: Configuration with 2 mandrels (see
Figure 1), Method B: Configuration with 3 mandrels (see Figure 2).

a) Schematic representation of the test track: protected microduct, with leg-length L (= 100 m) and
mandrel radius R (R = 20 × OD, where OD is the duct outer diameter)

b) Schematic representation of the test track: unprotected microduct, with leg-length L (= 100 m) and
mandrel radius R (R = 20 × OD, where OD is the duct outer diameter)

Figure 1 – Schematic representation of test tracks for Method A –
Configuration with 2 mandrels
Dimensions in metres
Key
A: Diameter A: typically same as D
B: Diameter B: typically same as D
C: Diameter C: typically same as D
D: Diameter D: D = 6 m
Test track details:
– Loop length: approximately 100 m
– Maximum total length: 2 000 m
– Tolerance radii: ± 5 %
Figure 2 –Schematic representation of the test track for Method B –
Configuration with 3 mandrels
– 12 – IEC 60794-1-124:2025 © IEC 2025
Annex A
(informative)
Test track – Practical implementation of the blowing route Method B
(Configuration with 3 mandrels)
For information, a practical embodiment of a test section according to Clause 11 is shown in
Figure A.1.
Dimensions in metres
Key
In Microduct entry
Out Microduct exit
R3 = 6 m
R10 > 6 m
Test track details:
– Loop length: approximately 100 m
– Maximum total length: 2 000 m
– Tolerance radii: ± 5 %
– Radii as specified in the key in Figure A.1
Figure A.1 – Schematic diagram of the practical implementation of the test track for
Method B – Configuration with 3 mandrels
To consider thermal stresses to which the duct system is subjected to and to facilitate
maintenance, the installer implemented the layout shown in Figure A.1 which resulted in
deviations to the ideal setup given in Clause 11, Figure 2.

Annex B
(informative)
Crash test
Prior to any blown cable installation trial or live cable installation, it is crucial that a 'crash test'
is undertaken to determine the maximum push-force that can be applied to the cable from the
blowing head. This test involves using the blowing head to drive the cable (at the recommended
cable installation speed) through a length of the microduct (typically 2 m to 10 m). To perform
the test, the microduct should be replaced with a transparent polymeric tube of the same inner
diameter as the microduct. The other end of the microduct (or of the transparent polymeric tube
as recommended) is closed with an end stop. When the cable hits the end stop the blowing
head should stop the cable in a manner that does not cause any damage to the cable. This is
then repeated with an increase in push-force until cable damage (jacket abrasion, cable kink)
is witnessed. The maximum push-force retained value is the highest push-force value at which
the cable remains undamaged when it hits the end stop. This procedure ensures that the cable
will not be damaged if it encounters an obstacle in the microduct during the installation process.
The maximum push-force determined by this crash test shall be recorded.
The push-force determined in this way can be used for blowing in until one of the following
parameters changes:
– cable (manufacturer, cable type);
– microduct inner diameter;
– ambient temperature – a value of ± 8 °C should be taken as a guide value for the permissible
temperature change.
NOTE If the maximum permissible push-force is specified by the cable manufacturer for the different microducts
and across the whole installation temperature range, then the crash test is no longer required.

– 14 – IEC 60794-1-124:2025 © IEC 2025
Annex C
(informative)
Blowing out
Often, in FTTx networks, installed optical fibre cables shall be removed from the duct. This
should be preferably done by blowing out the cable in one single piece. The following difficulties
shall be overcome:
– effect of static friction along the entire cable;
– applied lubrication which would be no longer effective.
In general, it can be assumed that if the blowing speed drops below 20 m/min when blowing in
a cable at a pressure of up to 1,5 MPa, blowing out in one piece is not guaranteed. Thus the
blowing in test is rated as “unsuccessful”.
After a waiting time of 30 min for the cable and tube to relax, the cable is blown out at a
maximum pressure of 1,5 MPa. Sometimes the blowing out process can be supported by a
pulsed application of the blowing pressure.
The blowing out of the optical fibre cable can be either done in the blowing in direction or in the
opposite direction.
It shall also be decided whether the cable should be rewound onto a reel or whether the cable
should be blown out into the free space and laid in coils or directly into a container for disposal.
This depends on whether the optical fibre cable is to be reused afterwards.
The cable can be pulled to facilitate the blowing out process. The maximum permissible tensile
force for this cable design shall not be excee
...