IEC 60794-1-111:2023

IEC 60794-1-111 ®
Edition 1.0 2023-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-111: Generic specification – Basic optical cable test procedures –
Mechanical tests methods – Bend, method E11

Câbles à fibres optiques –
Partie 1-111: Spécification générique – Procédures fondamentales d'essais des
câbles optiques – Méthodes d'essai mécanique – Courbures, méthode E11
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IEC 60794-1-111 ®
Edition 1.0 2023-09
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-111: Generic specification – Basic optical cable test procedures –

Mechanical tests methods – Bend, method E11

Câbles à fibres optiques –
Partie 1-111: Spécification générique – Procédures fondamentales d'essais des

câbles optiques – Méthodes d'essai mécanique – Courbures, méthode E11

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10  ISBN 978-2-8322-7518-4

– 2 – IEC 60794-1-111:2023 © IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General . 6
4.1 Sample . 6
4.2 Apparatus . 7
4.3 Test methods . 7
4.4 Test conditions . 7
5 Method E11A – Bend as helix . 7
5.1 General . 7
5.2 Single-helix configuration . 8
5.3 Two-helix configuration . 9
5.4 Procedure . 10
6 Method E11B – U bend . 10
7 Requirements . 11
8 Details to be specified . 11
9 Details to be reported . 12
Annex A (informative) Example of a special mandrel for two-helix configuration . 13
Annex B (informative) Rationale for the options of an equal or larger turnaround loop
diameter for the two-helix configuration of method E11A . 14
Bibliography . 19

Figure 1 – Bend test set-up for method E11A: single-helix configuration . 8
Figure 2 – Bend test set-up for method E11A: two-helix configuration . 9
Figure 3 – Bend test set-up for method E11B . 11
Figure A.1 – Example of a special mandrel . 13
Figure B.1 – Options for turnaround loop size for two-helix configuration of
method E11A . 14
Figure B.2 – Difference of change in attenuation for single-mode cable . 17
Figure B.3 – Difference of change in attenuation for multimode cable . 17
Figure B.4 – Worst case difference of change in attenuation . 18

Table B.1 – Used change in attenuation values . 15
Table B.2 – Calculated changes in attenuation of single-mode cable . 15
Table B.3 – Calculated changes in attenuation of multimode cable . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 1-111: Generic specification –
Basic optical cable test procedures –
Mechanical test methods – Bend, method E11

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)
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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 60794-1-111 has been prepared by subcommittee 86A: Fibres and cables, of IEC technical
committee 86: Fibre optics. It is an International Standard.
This document partially cancels and replaces IEC 60794-1-21:2015. This edition constitutes a
technical revision.
This edition includes the following significant technical changes with respect to
IEC 60794-1-21:2015:
a) the nominal sample length was newly specified as 10 m between the cable element fixing
points at both ends, unless otherwise specified;
b) the number of turns on the mandrel in Figure 1 for the single-helix configuration were
corrected to match the number of turns shown in the figure for the two-helix configuration;

– 4 – IEC 60794-1-111:2023 © IEC 2023
c) requirements on the turnaround loop were added for method E11A, two-helix configuration;
d) the turnaround loop with the same diameter as the mandrel was taken into account for
calculation of the number of turns of each helix for method E11A, two-helix configuration;
e) added a formula for calculation of the number of revolutions in each helix for method E11A,
two-helix configuration;
f) added a description for the procedure when the turnaround loop diameter is larger than the
mandrel diameter for method E11A, two-helix configuration;
g) all the figures were updated and the different components labelled;
h) added the attenuation monitoring equipment in 4.2 for the apparatus and the description to
measure the change in attenuation in the test methods E11A and E11B;
i) added Clause 9 for details to be reported;
j) added Annex A showing an example of a special mandrel to perform the bend test according
to method E11A, two-helix configuration;
k) added Annex B providing the rationale for the options of method E11A, two-helix
configuration.
The text of this International Standard is based on the following documents:
Draft Report on voting
86A/2367/FDIS 86A/2373/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/standardsdev/publications.
A list of all 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 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.
IMPORTANT – The "colour inside" logo on the cover page of this document 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.

INTRODUCTION
This document cancels and replaces method E11 of IEC 60794-1-21:2015, which will be
withdrawn. It includes an editorial revision, based on the new structure and numbering system
for optical fibre cable test methods. Additionally, technical changes were implemented. The
mechanical tests contained in IEC 60794-1-21:2015 will be individually numbered in the
IEC 60794-1-1xx series. Each test method is now considered to be an individual document
rather than part of a multi-test method compendium. Full cross-reference details are given in
IEC 60794-1-2.
The descriptions and the figures of the test methods in this document have been considerably
changed to improve the procedures, avoid different interpretations and add useful information
such as examples and rationale. However, the intention and procedures of the test methods
were not changed.
– 6 – IEC 60794-1-111:2023 © IEC 2023
OPTICAL FIBRE CABLES –
Part 1-111: Generic specification –
Basic optical cable test procedures –
Mechanical test methods – Bend, method E11

1 Scope
This part of IEC 60794 defines the test procedure to determine the ability of an optical fibre
cable to withstand bending around a test mandrel. The primary purpose of this procedure is to
measure the change in attenuation when the cable is bent around a test mandrel. A secondary
purpose is to assess whether the cable has been physically damaged by bending.
NOTE 1 This test can be utilized at any specified temperature, including the low or high temperature limits for the
cable.
NOTE 2 The bend test procedure for cable elements is specified in IEC 60794-1-301, method G1.
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 60793-1-46, Optical fibres – Part 1-46: Measurement methods and test procedures –
Monitoring of changes in optical transmittance
IEC 60794-1-1, Optical fibre cables – Part 1-1: Generic specification – General
IEC 60794-1-2, Optical fibre cables – Part 1-2: Generic specification – Basic optical cable test
procedures – General guidance
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 terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
4 General
4.1 Sample
The nominal sample length shall be 10 m and the fibres, buffers, sheath(s) and any strength
members shall be clamped, glued or otherwise fixed together at each end so that they do not
move during the bend test, unless otherwise specified in the relevant specification. The actual
sample length should be longer than the nominal sample length to allow for connection to the
optical monitoring equipment. The section in the middle of the nominal sample length shall be
bent.
4.2 Apparatus
A single mandrel shall enable the sample to be wrapped tangentially in a close helix around a
mandrel (see Figure 1, Figure 2 and Figure 3).
If optical monitoring is required, an optical monitoring equipment according to IEC 60793-1-46
shall be used.
4.3 Test methods
As indicated in the relevant specification, one of the methods described in Clause 5 or Clause 6
shall be used.
4.4 Test conditions
The tests shall be carried out at the temperature specified in the relevant detail specification. If
no temperature is specified, the ambient temperature shall be within the standard atmospheric
conditions as specified in IEC 60794-1-2.
5 Method E11A – Bend as helix
5.1 General
The intent of method E11A is to specify the test with the total number of turns on a mandrel of
a specified diameter.
Either test set-up, single-helix or two-helix configuration, may be used for testing according to
method E11A.
– 8 – IEC 60794-1-111:2023 © IEC 2023
5.2 Single-helix configuration
The test set-up with one helix as shown in Figure 1 may be used.

Key
1 mandrel
2 sample
3 wrapped sample in a single helix
D mandrel diameter
NOTE This figure illustrates 4 turns of the sample on the mandrel.
Figure 1 – Bend test set-up for method E11A: single-helix configuration
Torsion should be minimised but cannot be avoided with this configuration. If torsion should be
avoided altogether, the two-helix configuration should be used.

5.3 Two-helix configuration
The test set-up with two helixes as shown in Figure 2 may be used.

Key
1 mandrel
2 sample
3 helix with h revolutions on one side of the mandrel
4 turnaround loop (180° or 0,5 turns)
5 helix with h revolutions on the other side of the mandrel
6 transition point between helix and turnaround loop
D mandrel diameter and same size for turnaround loop diameter
NOTE 1 This figure illustrates 4 turns of the sample on the mandrel (0,5 turns in the turnaround loop and 1,75 turns
in each helix).
NOTE 2 Annex A shows an advanced design of a special mandrel to perform the bend test.
Figure 2 – Bend test set-up for method E11A: two-helix configuration
The diameter of the turnaround loop shall be at least the diameter of the mandrel. If the diameter
of the turnaround loop is equal to the diameter of the mandrel, the number of revolutions in
each helix shall be calculated as given in Formula (1).
h np− 2
( ) (1)
where
h is the number of revolutions in each helix (without turnaround loop);
n is the specified number of turns;
p is the number of turns in the turnaround loop (0,5 turns).
EXAMPLE 1 If the number of turns (n) is specified with 4 and the number of turns in the turnaround loop with 0,5,
the number of revolutions in each helix (h) results in 1,75.
EXAMPLE 2 If the number of turns (n) is specified with 6 and the number of turns in the turnaround loop with 0,5,
the number of revolutions in each helix (h) results in 2,75.
=
– 10 – IEC 60794-1-111:2023 © IEC 2023
If the turnaround loop diameter is larger than the mandrel diameter, the turnaround loop shall
not be taken into account for the calculation of the number of revolutions in each helix as given
in Formula (1). In this case, p shall be entered with the value 0 in Formula (1).
NOTE See Annex B for the rationale for the above options.
5.4 Procedure
The attenuation of the sample shall be measured in the unwrapped configuration before the
start of the test. The fibres of the sample and optical monitoring equipment shall remain
connected throughout the test.
The sample shall be wrapped around the mandrel at a uniform rate. Sufficient tension shall be
applied to ensure that there is no gap between the mandrel and the outer surface of the sample.
The number of turns and revolutions in each helix shall be applied correctly. The change in
attenuation shall be measured in the wrapped configuration.
NOTE When using the single-helix configuration (Figure 1), torsion of the cable cannot be avoided.
The sample shall then be unwrapped. The change in attenuation shall be measured in the
unwrapped configuration.
A cycle consists of one wrapping and one unwrapping of the sample on and from the mandrel.
The diameter of the test mandrel, the number of turns and the number of cycles shall be
specified in the relevant specification.
The change in attenuation shall be calculated relative to the initial attenuation measured before
the start of the test.
6 Method E11B – U bend
The attenuation of the sample shall be measured in the straight configuration before the start
of the test.
The sample shall be bent around a mandrel through 180° and kept taut during the bending as
shown in Figure 3 a).
A cycle consists of one U bend of 180° as shown in Figure 3 a) followed by a reverse U bend
of 180° as shown in Figure 3 b), and a return to the straight position.
The two sample sections away from the mandrel (beyond A and B in Figure 3) have to be moved
to achieve the 180° bend and 180° reverse bend. Ensure that the two sample sections have
sufficiently large bending radii. These bending radii shall be significantly larger than that of the
bent sample around the mandrel.
The diameter of the mandrel and the number of cycles shall be stated in the relevant
specification. A minimum of one mandrel is required to perform the test but two mandrels having
the same diameter may be used, as illustrated in Figure 3.

a) 180° bend b) 180° reverse bend

Key
1 mandrel
2 sample
3 180° bend of sample
4 180° reverse bend of sample
A sample section on one side
B sample section on the other side
D mandrel diameter
NOTE This figure uses two mandrels with the same diameter for better illustration.
Figure 3 – Bend test set-up for method E11B
The change in attenuation shall be measured in the bent and straight configuration during and
in the straight configuration after test as required by the relevant specification. The change in
attenuation shall be calculated relative to the initial attenuation before the start of the test.
7 Requirements
The acceptance criteria for the test shall be as stated in the relevant specification. The
requirements include change in attenuation and physical damage to the cable.
8 Details to be specified
The relevant specification shall include the following:
a) method to be used (E11A or E11B);
b) mandrel diameter (or ratio of mandrel diameter to cable diameter);
c) number of turns (for method E11A);
d) number of cycles;
– 12 – IEC 60794-1-111:2023 © IEC 2023
e) maximum allowable change in attenuation at the specified wavelength(s):
– during the test (if applicable);
– after the test (if applicable);
f) physical change to the cable that does not affect the function of the cable;
g) test temperature, for example ambient, low, or high.
9 Details to be reported
The test report shall include all the information given in Clause 8 and, where applicable, the
following:
a) detailed description of sample (cable type);
b) length of sample;
c) type of fixing all cable elements at both ends (glue, clamps, etc.);
d) number of samples;
e) description of the test set-up;
f) description of the optical measurement equipment;
g) preconditioning procedure, if any;
h) used test set-up configuration (single-helix or two-helix for method E11A);
i) turnaround loop considered in the calculation of the number of revolution in each helix (for
method E11A, two-helix configuration);
j) number of revolutions in each helix (for method E11A, two-helix configuration);
k) change in attenuation at the specified wavelength(s) in wrapped and unwrapped situation
during and unwrapped situation after test;
l) any physical damage to the cable;
m) observations during and after test;
n) any deviations from the test procedure.

Annex A
(informative)
Example of a special mandrel for two-helix configuration
Figure A.1 shows an advanced design of a special mandrel to perform the bend test according
to method E11A with a two-helix configuration. The diameter of the mandrel and short peg
should be the same.
Key
1 mandrel
2 peg
D mandrel and peg diameter
Figure A.1 – Example of a special mandrel

– 14 – IEC 60794-1-111:2023 © IEC 2023
Annex B
(informative)
Rationale for the options of an equal or larger turnaround loop
diameter for the two-helix configuration of method E11A
The options of the two-helix configuration using an equal or a larger turnaround loop diameter
than the one from the mandrel was considered as useful to allow flexibility in different
implementations of the turnaround loop in test laboratories. If the difference of the change in
attenuation between the two options is small, both options can be announced as equal and can
be allowed. The two options given in 5.3 are illustrated in Figure B.1 a) and b).

a) Option 1: Turnaround loop diameter b) Option 2: Turnaround loop diameter
equal to mandrel diameter larger than mandrel diameter

Key
D mandrel diameter
D turnaround loop diameter of option 1, equal to D
D turnaround loop diameter of option 2, larger than D
NOTE The diameter D in Figure B.1 b) is drawn twice as large as the diameters D and D for illustration purposes.
2 1
Figure B.1 – Options for turnaround loop size for two-helix
configuration of method E11A
To evaluate the difference, a few case examples were calculated with the changes in
attenuation for the two options, using the maximum bend performance limits for B-657.A1 and
B-652.D fibres at 1 550 nm and A1-OMxb (x = 2, 3, 4 or 5) fibres at 850 nm given in the optical
fibre product specifications IEC 60793-2-50:2018, Table A.5 (B-652) and Table F.3 (B-657),
and IEC 60793-2-10:2019 and IEC 60793-2-10:2019/AMD1:2022, Table A.3 (A1-OM2b to
A1-OM5b), and used as cable performance. If no bend performance specification was available
for a given bend diameter, the maximum change in attenuation was estimated. Table B.1 gives
the used change in attenuation values. Typical real values of change in attenuation of bent
fibres are lower than the maximum values used for the case examples.

Table B.1 – Used change in attenuation values
Fibre type Mandrel Maximum change Wavelength Source
diameter in attenuation
per one turn
mm dB nm
Single-mode, B-657.A1 20 0,750 1 550 IEC 60793-2-50
Single-mode, B-657.A1 30 0,025 1 550 IEC 60793-2-50
Single-mode, B-657.A1 40 0,010 1 550 Estimated
Single-mode, B-657.A1 50 0,005 1 550 Estimated
Single-mode, B-652.D 60 0,001 1 550 IEC 60793-2-50
Multimode, A1-OM2b to A1-OM5b 15 0,100 850 IEC 60793-2-10
Multimode, A1-OM2b to A1-OM5b 30 0,050 850 IEC 60793-2-10
Multimode, A1-OM2b to A1-OM5b 40 0,020 850 Estimated
Multimode, A1-OM2b to A1-OM5b 60 0,005 850 Estimated

The parameters and the calculated changes in attenuation are given in Table B.2 for
single-mode cable at 1 550 nm and Table B.3 for multimode cable at 850 nm.
Table B.2 – Calculated changes in attenuation of single-mode cable
Parameter Option 1 (D = D) Option 2 (D > D)
1 2
a
D, D D n p 2*h ∆A ∆A ∆A p 2*h ∆A ∆A
∆A
1 2 p 2*h t 2*h t
p
mm mm - - - dB dB dB - - dB dB dB
20 30 4 0,5 3,5 0,375 2,625 3,000 0 4 0,013 3,000 3,013
20 30 6 0,5 5,5 0,375 4,125 4,500 0 6 0,013 4,500 4,513
20 30 10 0,5 9,5 0,375 7,125 7,500 0 10 0,013 7,500 7,513
30 50 4 0,5 3,5 0,013 0,088 0,100 0 4 0,003 0,100 0,103
30 50 6 0,5 5,5 0,013 0,138 0,150 0 6 0,003 0,150 0,153
30 50 10 0,5 9,5 0,013 0,238 0,250 0 10 0,003 0,250 0,253
40 60 4 0,5 3,5 0,005 0,035 0,040 0 4 0,001 0,040 0,041
40 60 6 0,5 5,5 0,005 0,055 0,060 0 6 0,001 0,060 0,061
40 60 10 0,5 9,5 0,005 0,095 0,100 0 10 0,001 0,100 0,101
Key
D mandrel diameter
D turnaround loop diameter of option 1 (D = D)

1 1
D turnaround loop diameter of option 2 (D > D)
2 2
n specified number of turns, see Formula (1)
p number of turns in the turnaround loop, see Formula (1)
2*h number of revolutions in both helixes (without turnaround loop), see Formula (1)
∆A change in attenuation of turnaround loop

p
∆A change in attenuation of both helixes

2*h
∆A total change in attenuation (turnaround loop and both helixes)
t
NOTE The values of change in attenuation in the table were rounded to three digits after the comma.
a
The change in attenuation of the turnaround loop is added for the calculation of the total change in attenuation
of option 2, although the turnaround loop is not considered (p = 0) in the calculation of the number of
revolutions in each helix in Formula (1) but may contribute more or less to the measured total change in
attenuation.
– 16 – IEC 60794-1-111:2023 © IEC 2023
Table B.3 – Calculated changes in attenuation of multimode cable
Parameter Option 1 (D = D) Option 2 (D > D)
1 2
a
D, D D n p 2*h ∆A ∆A ∆A p 2*h ∆A ∆A
∆A
1 2 p 2*h t 2*h t
p
mm mm - - - dB dB dB - - dB dB dB
15 30 4 0,5 3,5 0,050 0,350 0,400 0 4 0,025 0,400 0,425
15 30 6 0,5 5,5 0,050 0,550 0,600 0 6 0,025 0,600 0,625
15 30 10 0,5 9,5 0,050 0,950 1,000 0 10 0,025 1,000 1,025
30 40 4 0,5 3,5 0,025 0,175 0,200 0 4 0,010 0,200 0,210
30 40 6 0,5 5,5 0,025 0,275 0,300 0 6 0,010 0,300 0,310
30 40 10 0,5 9,5 0,025 0,475 0,500 0 10 0,010 0,500 0,510
40 60 4 0,5 3,5 0,010 0,070 0,080 0 4 0,003 0,080 0,083
40 60 6 0,5 5,5 0,010 0,110 0,120 0 6 0,003 0,120 0,123
40 60 10 0,5 9,5 0,010 0,190 0,200 0 10 0,003 0,200 0,203
Key
D mandrel diameter
D turnaround loop diameter of option 1 (D = D)

1 1
D turnaround loop diameter of option 2 (D > D)

2 2
n specified number of turns, see Formula (1)
p number of turns in the turnaround loop, see Formula (1)
2*h number of revolutions in both helixes (without turnaround loop), see Formula (1)
∆A change in attenuation of turnaround loop

p
∆A change in attenuation of both helixes

2*h
∆A total change in attenuation (turnaround loop and both helixes)
t
NOTE The values of change in attenuation in the table were rounded to three digits after the comma.
a
The change in attenuation of the turnaround loop is added for the calculation of the total change in attenuation
of option 2, although the turnaround loop is not considered (p = 0) in the calculation of the number of
revolutions in each helix in Formula (1) but may contribute more or less to the measured total change in
attenuation.
For a better overview, the total attenuation changes of option 2 and option 1 calculated in
Table B.2 and Table B.3 were put into relation and the relative increases in attenuation of
option 2 compared to option 1 were determined in percent.
For example for a single-mode cable, D = D = 30 mm versus D = 30 mm/D = 50 mm and
1 2
6 turns, the increased change in attenuation is calculated by subtracting the total change in
attenuation of option 2 (0,153 dB) with the total change in attenuation of option 1 (0,15 dB) and
its result divided by the total change in attenuation of option 1 (0,15 dB). That results in an
increased change in attenuation of 2 % (see Figure B.2, orange bar in the centre of the figure).
Figure B.2 for single-mode fibre and Figure B.3 for multimode cable show the relative increase
of attenuation of option 2.
NOTE The descriptions of the letters used are given in Table B.2.
Figure B.2 – Difference of change in attenuation for single-mode cable

NOTE The descriptions of the letters used are given in Table B.3.
Figure B.3 – Difference of change in attenuation for multimode cable
A general observation is that the higher the number of turns (n), the relative increase of change
in attenuation of option 2 compared to option 1 decreases.
In addition, the worst case of the changes in attenuation for the two options was calculated.
The worst case is when the diameter of the turnaround loop is only slightly larger than the
diameter of the mandrel. For the calculation, D was defined as equal to D. In that case, the
change in attenuation caused by the turnaround loop adds to the overall result but is not
considered (p = 0) in the calculation of the number of revolutions in each helix in Formula (1).

– 18 – IEC 60794-1-111:2023 © IEC 2023
For example for a single-mode cable and D = D = D = 30 mm with 6 turns, the increased
1 2
change in attenuation is calculated by subtracting the total change in attenuation of option 2
(two helixes with 6 turns of 0,15 dB plus a turnaround loop of 0,5 turns of 0,012 5 dB results in
total 0,162 5 dB) with the total change in attenuation of option 1 (two helixes and a turnaround
loop with total 6 turns of 0,15 dB) and its result divided by the total change in attenuation of
option 1 (0,15 dB). That results in an increased change in attenuation of 8,3 % (see Figure B.4,
orange bar).
The worst case differences are shown in Figure B.4 that are independent of the mandrel
diameter and are applicable for single-mode and multimode.

NOTE The descriptions of the letters used are given in Table B.2 and Table B.3.
Figure B.4 – Worst case difference of change in attenuation
The maximum change in attenuation in the cable specifications is typically specified as 0,4 dB
or less during the test when the sample is wrapped on the mandrel. The increased changes in
attenuation of option 2 compared to option 1 are therefore very small. The difference of 3 % for
single-mode (maximum in Figure B.2) results in an absolute difference of 0,012 dB; the
difference of 6,3 % for multimode (maximum in Figure B.3) results in an absolute difference of
0,025 dB. Because of these relatively small differences in the change in attenuation of the case
examples and even in the worst case calculations, the two options were allowed and included
in this document.
Bibliography
IEC 60793-2-10:2019, Optical fibres – Part 2-10: Product specifications – Sectional
specification for category A1 multimode fibres
IEC 60793-2-50:2018, Optical fibres – Part 2-50: Product specifications – Sectional
specification for class B single-mode fibres
IEC 60794-1-21:2015, Optical fibre cables – Part 1-21: Generic specification – Basic optical
cable test procedures – Mechanical tests methods
IEC 60794-1-301, Optical fibre cables – Part 1-301: Generic specification – Basic optical cable
test procedures – Cable elements test methods – Bend test, Method G1

____________
___________
Under preparation. Stage at the time of publication: IEC/CFDIS 60794-1-301:2023.

– 20 – IEC 60794-1-111:2023 © IEC 2023
SOMMAIRE
AVANT-PROPOS . 21
INTRODUCTION . 23
1 Domaine d’application . 24
2 Références normatives . 24
3 Termes et définitions . 24
4 Généralités . 24
4.1 Échantillon . 24
4.2 Appareillage . 25
4.3 Méthodes d’essai . 25
4.4 Conditions d’essai . 25
5 Méthode E11A – Courbure en spires . 25
5.1 Généralités . 25
5.2 Configuration à spire simple . 26
5.3 Configuration à deux spires . 27
5.4 Procédure . 28
6 Méthode E11B – Courbure en U . 28
7 Exigences . 29
8 Informations détaillées à spécifier. 29
9 Informations détaillées à consigner . 30
Annexe A (informative) Exemple d'un mandrin spécial pour une configuration à
deux spires . 31
Annexe B (Informative) Justification des options d'un diamètre de boucle
d’enroulement égal ou supérieur pour la configuration à deux spires de la
méthode E11A . 32
Bibliographie . 37

Figure 1 – Montage d'essai de courbure pour la méthode E11A: configuration à spire
simple . 26
Figure 2 – Montage d'essai de courbure pour la méthode E11A: configuration à
deux spires . 27
Figure 3 – Montage d'essai de courbure pour la méthode E11B . 29
Figure A.1 – Exemple d’un mandrin spécial . 31
Figure B.1 – Options pour la taille de la boucle d’enroulement dans la configuration à
deux spires de la méthode E11A . 32
Figure B.2 – Écart de variation de l’affaiblissement pour un câble unimodal . 35
Figure B.3 – Écart de variation de l’affaiblissement pour un câble multimodal . 35
Figure B.4 – Écart de la variation de l’affaiblissement dans le cas le plus défavorable .
...