IEC 60794-5-20:2014
(Main)Optical fibre cables - Part 5-20: Family specification - Outdoor microduct fibre units, microducts and protected microducts for installation by blowing
Optical fibre cables - Part 5-20: Family specification - Outdoor microduct fibre units, microducts and protected microducts for installation by blowing
IEC 60794-5-20:2014 is a family specification that covers outdoor microduct fibre units and corresponding microducts and protected microducts for installation by blowing. The protected microducts are intended for duct, directly buried or lashed applications. Microduct fibre units differ from microduct optical fibre cables (see IEC 60794-5-10) in that they provide less protection to the fibres that they contain. Specifically, microduct fibre units rely on the structure of the microduct, protected microduct or appropriate housing to support installation and to provide additional mechanical protection for the optical fibre over the lifetime of the product. Systems built with components covered by this standard are subject to the requirements of sectional specification IEC 60794-5 where applicable.
Câbles à fibres optiques - Partie 5-20: Spécification de famille - Eléments fibres en microconduit extérieur, microconduits et microconduits protégés pour installation par soufflage
IEC 60794-5-20:2014 est une spécification de famille qui couvre les éléments fibres en microconduit extérieur, ainsi que les microconduits et microconduits protégés correspondants pour installation par soufflage. Les microconduits protégés sont destinés à des applications de conduits, d'enfouissement direct ou de câbles lacés. Les éléments fibres en microconduit se différencient des câbles à fibres optiques en microconduit (voir l'IEC 60794-5-10) par une protection moindre des fibres contenues. De manière spécifique, les éléments fibres en microconduit reposent sur la structure du microconduit, du microconduit protégé ou du logement approprié pour supporter leur installation et pour fournir une protection mécanique supplémentaire à la fibre optique pendant la durée de vie du produit. Les systèmes intégrant des éléments couverts par la présente norme sont soumis aux exigences de la spécification intermédiaire IEC 60794-5, le cas échéant.
General Information
Standards Content (Sample)
IEC 60794-5-20 ®
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
colour
inside
Optical fibre cables –
Part 5-20: Family specification – Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
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IEC 60794-5-20 ®
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
colour
inside
Optical fibre cables –
Part 5-20: Family specification – Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
V
ICS 33.180.01, 33.180.10 ISBN 978-2-8322-1420-6
– 2 – 60794-5-20 © IEC:2014(E)
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Symbols . 7
4 General requirements . 8
4.1 Construction . 8
4.1.1 General . 8
4.1.2 Microduct fibre units . 9
4.1.3 Microducts . 9
4.1.4 Protected microducts . 9
4.1.5 Microduct fittings . 9
4.1.6 Microduct hardware . 10
4.2 Optical fibres . 10
4.3 Installation performance tests . 10
4.3.1 Installation conditions . 10
4.3.2 Tests applicable . 11
4.3.3 Mechanical and environmental tests . 11
5 Microduct fibre unit . 11
5.1 Tests applicable . 11
5.2 Family requirements and test conditions for microduct fibre unit tests . 12
5.3 Tensile performance . 12
5.4 Crush . 12
5.5 Repeated bending . 13
5.6 Torsion . 13
5.7 Kink . 13
5.8 Bend . 13
5.9 Temperature cycling . 13
5.10 Ageing . 14
5.11 Water immersion . 14
5.12 Buffer removal . 14
6 Microduct . 14
6.1 Tests applicable . 14
6.2 Tensile performance . 15
6.3 Crush . 15
6.4 Impact . 16
6.5 Repeated bending . 16
6.6 Torsion . 16
6.7 Kink . 16
6.8 Bend . 16
6.9 Microduct route verification test . 17
6.10 Microduct pressure withstand . 17
6.11 Ageing . 17
7 Protected microducts . 17
7.1 Tests applicable . 17
7.2 Tensile performance . 18
7.3 Crush . 18
60794-5-20 © IEC:2014(E) – 3 –
7.4 Impact . 19
7.5 Repeated bending . 19
7.6 Kink . 19
7.7 Bend . 19
7.8 Microduct route verification test . 19
7.9 Microduct pressure withstand . 20
7.10 Ageing . 20
Annex A (informative) Examples of microduct fibre units, microducts, and protected
microducts . 21
Annex B (informative) Product descriptions (blank detail specification and minimum
requirements) . 22
Annex C (normative) Product constructions . 25
Annex D (normative) Transmission requirements . 28
D.1 Attenuation of cabled fibre . 28
D.2 Fibre bandwidth requirements . 29
Annex E (normative) IEC 60794-1-21 Method Exx – Microduct inner clearance test . 30
E.1 Object . 30
E.2 General . 30
E.3 Sample . 30
E.4 Test equipment . 30
E.5 Procedure . 30
E.6 Requirements . 30
E.7 Details to be recorded . 31
Figure A.1 – Protected microducts, tight package . 21
Figure A.2 – Microduct fibre units . 21
Table 1 – Tests applicable for installation performance . 11
Table 2 – Tests applicable for mechanical and environmental performance of
microduct fibre unit . 11
Table 3 – Tests applicable for mechanical and environmental performance of microduct . 15
Table 4 – Tests applicable for mechanical and environmental performance of
protected microduct . 18
Table B.1 – Microduct fibre unit description . 22
Table B.2 – Microduct description . 23
Table B.3 – Protected microduct description . 24
Table C.1 – Typical microduct fibre unit construction . 25
Table C.2 – Microduct construction . 26
Table C.3 – Protected microduct construction . 27
Table D.1 – Multimode maximum cable attenuation coefficient (dB/km) . 28
Table D.2 – Single-mode maximum cable attenuation coefficient (dB/km) – Premises
cabling applications . 28
Table D.3 – Single-mode maximum cable attenuation coefficient (dB/km) – All other
applications . 29
Table D.4 – Minimum multimode fibre bandwidth (MHz×km) . 29
– 4 – 60794-5-20 © IEC:2014(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 5-20: Family specification –
Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
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
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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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 60794-5-20 has been prepared by subcommittee 86A: Fibres and
cables,of IEC technical committee 86: Fibre optics.
The text of this standard is based on the following documents:
CDV Report on voting
86A/1497/CDV 86A/1543/RVC
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
60794-5-20 © IEC:2014(E) – 5 –
A list of all parts of 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.
A bilingual version of this publication may be issued at a later date.
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 – 60794-5-20 © IEC:2014(E)
OPTICAL FIBRE CABLES –
Part 5-20: Family specification –
Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
1 Scope
This part of IEC 60794 is a family specification that covers outdoor microduct fibre units and
corresponding microducts and protected microducts for installation by blowing. The protected
microducts are intended for duct, directly buried or lashed applications.
Microduct fibre units differ from microduct optical fibre cables (see IEC 60794-5-10) in that
they provide less protection to the fibres that they contain. Specifically, microduct fibre units
rely on the structure of the microduct, protected microduct or appropriate housing to support
installation and to provide additional mechanical protection for the optical fibre over the
lifetime of the product.
Systems built with components covered by this standard are subject to the requirements of
sectional specification IEC 60794-5 where applicable.
Annex A gives examples of microduct optical fibre units and microducts.
Annex B describes a blank detail specification for outdoor microduct fibre units and the
associated microducts and incorporates some minimum requirements. Detail product
specifications may be prepared on the basis of this family specification using Annex B as a
guide. Annex C provides normative product constructions for microduct optical fibre units,
microducts and protected microducts.
The parameters specified in this standard may be affected by measurement uncertainty
arising either from measurement errors or calibration errors due to lack of suitable standards.
Acceptance criteria should be interpreted with respect to this consideration.
The number of fibres tested is intended to be representative of the microduct fibre unit design
and should be agreed between the customer and supplier.
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 60304, Standard colours for insulation for low-frequency cables and wires
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
IEC 60793-1-53, Optical fibres – Part 1-53: Measurement methods and test procedures –
Water immersion
IEC 60793-2-10, Optical fibres – Part 2-10: Product specifications – Sectional specification for
category A1 multimode fibres
60794-5-20 © IEC:2014(E) – 7 –
IEC 60793-2-50, Optical fibres – Part 2-50: Products specification – Sectional specification for
class B single-mode fibres
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
IEC 60794-1-21, Optical fibre cables – Part 1-21: Generic specification – Basic optical cable
test procedures – Mechanical test methods
IEC 60794-1-22, Optical fibre cables – Part 1-22: Generic specificaiton – Basic optical cable
test procedures – Environmental test methods
IEC 60794-3:2001, Optical fibre cables – Part 3: Sectional specification – Outdoor cables
IEC 60794-5, Optical fibre cables – Part 5: Sectional specification – Microduct cabling for
installation by blowing
IEC 60794-5-10, Optical fibre cables – Part 5-10: Family specification – Outdoor microduct
optical fibre cables, microducts and protected microducts for installation by blowing
IEC 60811-202, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 202: General tests – Measurement of thickness of non-metallic sheath
IEC 60811-203, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 203: General tests – Measurement of overall dimensions
IEC 60811-501, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 501: Mechanical tests – Tests for determining the mechanical properties of insulating and
sheathing compounds
IEC 60811-601, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 601: Physical tests – Measurement of the drop-point of filling compounds
IEC 60811-602, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 602: Physical tests – Separation of oil in filling compounds
IEC 60811-604, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 604: Physical tests – Measurement of absence of corrosive components in filling
compounds
ISO/IEC 11801, Information technology − Generic cabling for customers premises
3 Symbols
For the purposes of this part of IEC 60794 the following symbols apply.
λ Cabled fibre cut-off wavelength
CC
∆D minimum wall thickness
∆D’ Minimum thickness of the outer sheath of the protected microduct
d Nominal outer diameter of the fibre unit
DS Detail specification
ID Nominal inner diameter of the microduct
– 8 – 60794-5-20 © IEC:2014(E)
OD Nominal outer diameter of the microduct
OD’ Nominal outer diameter of the protected microduct
T The acceptable amount of short-term tensile load that can be applied to the fibre unit
M
without permanent degradation of the characteristics of the fibres in the tensile
performance test
T Temperature cycling test low-temperature limit (usage and storage) according to
A1
IEC 60794-1-2, Method F1
T Temperature cycling test secondary low-temperature limit for extended storage
A2
temperature range according to IEC 60794-1-2, Method F1
T Temperature cycling test high-temperature limit (usage and storage) according to
B1
IEC 60794-1-2, Method F1
T Temperature cycling test secondary high-temperature limit for extended storage
B2
temperature range according to IEC 60794-1-2, Method F1
t Temperature cycling dwell time
n × d The product of a variable and the fibre unit outer diameter used for determining
appropriate sizes for bends, mandrels, etc.
n × OD The product of a variable and the outer diameter of the microduct used for
determining appropriate sizes for bends, mandrels, etc.
n × OD’ The product of a variable and the outer diameter of the protected microduct used for
determining appropriate sizes for bends, mandrels, etc.
W Weight of 1 km of microduct, protected microduct or fibre unit
4 General requirements
4.1 Construction
4.1.1 General
In addition to the constructional requirements in IEC 60794-5, where applicable, the following
considerations apply to outdoor microduct fibre units and their corresponding microducts and
protected microducts.
The products covered in this specification should be designed and manufactured for expected
operating lifetimes of at least 20 years.
The microduct fibre units are designed to be installed in microducts or protected microducts
and in appropriate housings. The microducts and protected microducts that are compatible for
use with microduct fibre units are defined in this document. Microduct fibre units are
optimised for installation and operating lifetime in these microducts.
It shall be possible to install or remove the microduct fibre unit from microduct or protected
microduct by blowing during the operational lifetime except under the following conditions:
a) microduct fibre units or microducts are compromised by multiple installation or removal
operations;
b) microducts are fouled with sediment, debris, or other foreign matter due to inadequate
maintenance;
c) microducts are damaged by extrinsic factors such as dig-ups, earth heaves, etc.
In such cases, the affected section of microduct shall be cleared, repaired or replaced prior to
any microduct fibre unit installations.
The microduct fitness should be verified with dimensional clearance and static pressure
testing of the microduct route.
60794-5-20 © IEC:2014(E) – 9 –
The materials in the microduct fibre unit, microduct or protected microduct shall take into
consideration local regulations.
4.1.2 Microduct fibre units
In general, microduct fibre units are the smallest and most flexible of all optical cable products
for outdoor use and are intended for installation within microducts. The fibre unit structure is
designed to improve blowing performance compared to a bare fibre and to provide mechanical
and environmental protection for the fibres during installation and over the life of the product.
Fibre unit designs are not described in detail but some examples are given in Annex A. The
microduct fibre units are not as mechanically robust as traditional outdoor optical fibre cables
and, therefore, require the use of suitable installation and handling practices to prevent
damage. Ad hoc installation practices could degrade optical performance or reduce the
product’s operating lifetime.
4.1.3 Microducts
A microduct suitable for installation of microduct fibre units is a small, flexible, lightweight
tube with an outer diameter typically 8 mm or less. Compared to microduct optical fibre cables
(see IEC 60794-5-10), microduct fibre units place greater reliance on microducts and
protected microducts or appropriate closures to provide mechanical protection for the optical
fibres. Therefore, a microduct must meet the realistic impact, compression and bending
requirements for an application. A protected microduct may be required (see 4.1.4).
Microducts shall be able to resist pressure differences needed for installation by blowing. The
microducts shall be circular and uniform in cross-section throughout their length, and their
inner surface may have a low coefficient of friction. Inner- and outer-diameters shall be
specified. As an option, a supplier may provide a special lining or lubricating coating on the
interior of the microduct to aid installation. These layers should not reduce the specified
inside diameter of the microduct.
Microducts generally are intended for benign installation within ducts or as components within
a protected microduct as described in 4.1.4. In all cases, it shall be possible to identify each
individual microduct throughout the length. When using colours they shall be a reasonable
match to IEC 60304.
Microducts installed outdoors and not occupied shall be sealed at each end to prevent the
introduction of moisture, debris, insects, or other such foreign contaminants that could
subsequently hinder the successful installation of fibre unit. Microducts installed outdoors and
not immediately occupied shall be tested for obstructions prior to use.
4.1.4 Protected microducts
A protected microduct is one or more microducts surrounded by a protective sheath, a larger
protective duct and/or an integral thick sheath (such that it complies with the requirements of
Clause 7). A protected microduct can provide additional crush and impact protection
compared to a stand-alone microduct. This additional protection may be needed for a specific
operating environment or installation method. The protective sheath may include an
integrated layer of armouring or thicker outer sheath. In all cases it shall be possible to
identify each individual microduct throughout the length. When using colours, they shall be a
match to IEC 60304 using visual inspection.
4.1.5 Microduct fittings
Microduct fittings are components needed to physically align, connect and seal the junction
between two of more sections of microduct, or to connect microduct to hardware, or to seal
the space between a microduct fibre unit and microduct. Multiple microducts may be
connected in series in order to support extended microduct fibre unit installation distances, or
connected in a branch-type configuration with multiple output terminae for a given input,
within the same system. The latter may be employed in campus type local area networks
– 10 – 60794-5-20 © IEC:2014(E)
(LANs) or fibre-to-the-premises (FTTP) applications to allow for additional flexibility that can
support frequent changes to the physical optical distribution system.
Fittings should be appropriate to the microduct construction. Also, mechanical and
environmental performance requirements of fittings may require that such be tested while
attached to sections of ducting (or hardware) to ensure intermateability and operational
compatibility. The specific physical and material attributes of any fittings used should be
agreed between the customer and supplier.
Microduct fittings shall be able to resist pressure differences needed for installing microduct
fibre units by blowing. When attached to microducts the fittings must pass the pressurization
test of 6.10. Fittings shall allow for the smooth transition of microduct fibre units between
successive sections of microduct, or between microducts and hardware, and shall be
constructed and installed to prevent jamming of the microduct fibre unit at splice, branch, or
other connection points under maximum installation pressures.
Successive sections of microduct may also be welded or otherwise secured together along
the same longitudinal axis without the use of mechanical fittings. Such junctions shall meet
the same mechanical and dimensional requirements as for joints made using mechanical
fittings.
Translucent or transparent materials may be used to support the identification of populated
microducts and for troubleshooting installation related issues.
4.1.6 Microduct hardware
Microduct hardware includes the housings and closures that support the termination of
microduct fibre units, including splicing or connectorization. Because microduct fibre units are
generally compatible with traditional outdoor fibre optic cable hardware, accounting for the
relatively small size, no specific requirements for microduct hardware are included herein. In
some applications, it may be appropriate to use hardware that is compatible with the
microducts in order to create a sealed microduct cabling system. One example is when empty
microducts are pre-installed in hardware to support future microduct fibre unit placement.
4.2 Optical fibres
There shall be no fibre splice in a delivered length, unless otherwise agreed by the customer
and supplier.
It shall be possible to identify each individual fibre throughout the length of the microduct fibre
unit.
The transmission performance shall be in accordance with Annex D.
4.3 Installation performance tests
4.3.1 Installation conditions
A test route may be used to verify the field performance of a microduct fibre unit , microduct,
and/or protected microduct as agreed between the customer and supplier. Ambient conditions
can affect installation performance and, therefore should be monitored. Alternatively, the
supplier can provide performance data from a specified test route under specific ambient
conditions using a specified installation method.
Verifying that a microduct fibre unit or microduct can be installed using a blown installation
technique is critical. Any installation performance requirement shall be agreed upon between
the customer and supplier.
60794-5-20 © IEC:2014(E) – 11 –
4.3.2 Tests applicable
Tests that are applicable for installation performance are given in Table 1.
Table 1 – Tests applicable for installation performance
Characteristics Family requirements Test methods Remarks
General requirements Agreement between
customer and supplier
IEC 60794-1-21 Method E23
Route verification inner Agreement between
clearance test customer and supplier
Installation test Agreement between Agreement between customer
customer and supplier; and supplier; typically, duct
typically a minimum type and size, route terrain,
distance and time of installation device, maximum
installation over a air pressure and ambient air
specified route is required conditions should be specified
or noted with the results
4.3.3 Mechanical and environmental tests
Based on the expected operating conditions over the life of the product, including the
mechanical loads exerted on the product during installation, the following clauses specify
product performance for microduct fibre units, microducts and protected microducts.
5 Microduct fibre unit
5.1 Tests applicable
Tests that are applicable for mechanical and environmental performance are given in Table 2.
Table 2 – Tests applicable for mechanical and
environmental performance of microduct fibre unit
Characteristics Family requirements Test methods Remarks
a
Tensile performance 5.3 IEC 60794-1-21
Method E1
Crush 5.4 IEC 60794-1-21
Method E3
a
Repeated bending 5.5 IEC 60794-1-21
Method E6
a
Torsion 5.6 IEC 60794-1-2
Method E7
Kink 5.7 IEC 60794-1-21
Method E10
Bend 5.8 IEC 60794-1-21
Method E11
Temperature cycling 5.9 IEC 60794-1-22
Method F1
Ageing 5.10 IEC 60794-1-22
Method F9
Water immersion test 5.11 IEC 60793-1-53
Buffer removal 5.12 As agreed with customer
Water penetration test No requirement Suitable means are used
in the microduct cabling
system for water
blocking
a
For small units (eg < 2 mm outer diameter; <100 N tensile rating), it may be more appropriate to omit some
of these tests in favour of an installation test.
– 12 – 60794-5-20 © IEC:2014(E)
The above tests may need to be modified for use with these cables. In particular, special care
needs to be taken when clamping cables in order to avoid end effects. Unacceptable damage
may include rips, tears, splits, delamination or cracks in the microduct fibre unit. However,
damage at the clamping interface does not constitute a failure.
5.2 Family requirements and test conditions for microduct fibre unit tests
Tests shall be selected from the following by the product specification.
5.3 Tensile performance
a) Family requirements
Under short-term tensile load the fibre strain shall not exceed 60 % of the fibre proof
strain. Other criteria may be agreed between the customer and supplier.
b) Test conditions (loads ≥ 100 N)
Method: Generally to IEC 60794-1-21 Method E1, with duration as
stated below
Length under tension: Not less than 10 m. Taking into account the measurement
accuracy and end effects, shorter lengths may be used by
agreement between the customer and supplier.
Fibre length: Finished microduct fibre unit length.
Tensile load: Equivalent to weight of 1 km of fibre unit
Duration of load 1 min
Diameter of test pulleys: As agreed between customer and supplier but not less than
the minimum loaded bending diameter specified for the
microduct fibre unit. A minimum value of 60 mm is
recommended.
Under visual examination without magnification there shall be no damage to the microduct
fibre unit and there shall be no change in attenuation after the test.
c) Test conditions (loads < 100 N)
Apparatus: Vertical tensometer
Length under tension: Approx 250 mm.
Fibre length: Finished microduct fibre unit length.
Tensile load: Equivalent to weight of 1 km of fibre unit
Duration of load 1 min
Under visual examination without magnification there shall be no damage to the microduct
fibre unit.
5.4 Crush
a) Family requirements
After removal of the load, there shall be no change in attenuation compared to before the
application of the load. Under visual examination, there shall be no damage to the
microduct fibre unit . The imprint of the plate on the microduct fibre unit is not considered
mechanical damage.
b) Test conditions
Method: IEC 60794-1-21 Method E3
Load (plate/plate): 100 N
Duration of load: 1 min
60794-5-20 © IEC:2014(E) – 13 –
5.5 Repeated bending
a) Family requirements
Under visual examination without magnification there shall be no damage to the microduct
fibre unit elements.
b) Test conditions
Method: IEC 60794-1-21 Method E6
Bending diameter: 40 × d or 60 mm whichever is greater.
Load: Adequate to assure uniform contact with the mandrel.
Number of cycles: 25
5.6 Torsion
a) Family requirements
Under visual examination without magnification there shall be no damage to the microduct
fibre unit elements.
There shall be no change in attenuation after the test.
b) Test conditions
Method Generally in accordance with IEC 60794-1-21 Method E7
Test length: 300 mm
Load: Adequate to assure test sample is straight at start of test.
5.7 Kink
a) Family requirements
Under visual examination, there shall be no damage to the microduct fibre unit
b) Test conditions
Method: IEC 60794-1-21 Method E10
Minimum diameter: 40 × d or 60 mm whichever is greater
5.8 Bend
a) Family requirements
There shall be no change in attenuation after the test when measured at room
temperature.
b) Test conditions
Method: IEC 60794-1-21 Method E11A
Diameter of mandrel: 40 × d or 60 mm whichever is greater
Number of turns/helix: 4
Number of cycles: 3
5.9 Temperature cycling
a) Family requirements
to T there shall be no change in attenuation as defined in IEC 60794-1-1.
For T
A1 B1
For T to T and T to T , the change in attenuation coefficient shall be:
A1 A2 B1 B2
– ≤ 0,15 dB/km for single-mode fibre and shall be reversible to measurement uncertainty
when measured in the 1 550 nm region;
– ≤ 0,3 dB/km for multimode fibre and shall be reversible to measurement uncertainty
when measured in the 1 300 nm region.
– 14 – 60794-5-20 © IEC:2014(E)
b) Test conditions
Method: IEC 60794-1-22 Method F1.
Sample length under test: Finished microduct fibre unit length of at least 1 000 m.
High temperature, T : +60 °C to +70 °C, depending on customer requirements.
B2
High temperature, T : +30 °C to +60 °C depending on customer requirements.
B1
Low temperature, T : –15 °C.
A1
Low temperature, T : T to –30 °C or –40 °C depending on customer requirements
A2 A1
Note (temperatures): Other temperature values corresponding to specific climate
conditions can be agreed between supplier and customer.
Number of cycles: 2
5.10 Ageing
a) Family requirements: as per IEC 60794-1-22, Method F9
b) Test conditions:
Method: IEC 60794-1-22, Method F9
5.11 Water immersion
a) Family requirements
Attenuation coefficient change at room temperature:
– ≤ 0,05 dB/km at 1 550 nm for single-mode fibre;
– ≤ 0,2 dB/km at 850 nm and 1 300 nm for multimode fibre.
The attenuation shall be monitored throughout the test at least once every 24 h.
b) Test conditions
Method: IEC 60793-1-53
Water: Distilled, demineralized or de-ionized water which has a PH
of between 5,0 and 8,0
Dwell time: 30 days
5.12 Buffer removal
a) Family requirements
The buffer materials shall be removable such that primary coated fibres or fibre ribbons
shall be free from fibre unit sheathing and/or buffer materials and free from damage
following the test.
b) Test conditions
The method for buffer removal shall be defined by the supplier.
6 Microduct
6.1 Tests applicable
Tests shall be selected from the following Table 3, in accordance with the relevant product
specification. If the microduct is only to be used in a protected microduct, some tests may not
be relevant.
60794-5-20 © IEC:2014(E) – 15 –
Table 3 – Tests applicable for mechanical and environmental performance of microduct
Characteristics Family requirements Test methods Remarks
Tensile performance 6.2 Under consideration,
IEC 60794-1-21
Method E1
Crush 6.3 IEC 60794-1-21
Method E3A
Impact 6.4 Under consideration,
IEC 60794-1-21
Method E4
Repeated bending 6.5 IEC 60794-1-21
Method E6
Torsion 6.6 IEC 60794-1-21
Method E7
Kink 6.7 IEC 60794-1-21
Method E10
Bend 6.8 IEC 60794-1-21
Method E11B
Microduct route 6.9 IEC 60794-1-21
verification test Method E23
Microduct pressure 6.10 IEC 60794-1-22
withstand Method F13
Ageing 6.11 Under consideration
The above tests may need to be modified for use with microducts. In particular, special care
needs to be taken when clamping in order to avoid end effects. Unacceptable damage may
include rips, tears, splits or cracks in the microduct. However, damage at the clamping
interface does not constitute a failure.
6.2 Tensile performance
a) Family requirements
Under visual examination, without magnification, there shall be no damage after the test
and shall pass the inner clearance test (Annex E).
b) Test conditions
Method: Generally to IEC 60794-1-21, Method E1
(note: use of IEC 60811-501 is under consideration)
Microduct length under tension: >1 m
Tensile load on microduct: 1 W
Duration of load: 10 min
6.3 Crush
a) Family requirements
Under visual examination, without magnification, the
...
IEC 60794-5-20 ®
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 5-20: Family specification – Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
Câbles à fibres optiques –
Partie 5-20: Spécification de famille – Eléments fibres en microconduit extérieur,
microconduits et microconduits protégés pour installation par soufflage
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IEC 60794-5-20 ®
Edition 1.0 2014-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 5-20: Family specification – Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
Câbles à fibres optiques –
Partie 5-20: Spécification de famille – Eléments fibres en microconduit extérieur,
microconduits et microconduits protégés pour installation par soufflage
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.01; 33.180.10 ISBN 978-2-8322-4959-8
– 2 – IEC 60794-5-20:2014 © IEC 2014
CONTENTS
CONTENTS . 2
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Symbols . 7
4 General requirements . 8
4.1 Construction . 8
4.1.1 General . 8
4.1.2 Microduct fibre units . 9
4.1.3 Microducts . 9
4.1.4 Protected microducts . 9
4.1.5 Microduct fittings . 9
4.1.6 Microduct hardware . 10
4.2 Optical fibres . 10
4.3 Installation performance tests . 10
4.3.1 Installation conditions . 10
4.3.2 Tests applicable . 11
4.3.3 Mechanical and environmental tests . 11
5 Microduct fibre unit . 11
5.1 Tests applicable . 11
5.2 Family requirements and test conditions for microduct fibre unit tests . 12
5.3 Tensile performance . 12
5.4 Crush . 12
5.5 Repeated bending . 13
5.6 Torsion . 13
5.7 Kink . 13
5.8 Bend . 13
5.9 Temperature cycling . 13
5.10 Ageing . 14
5.11 Water immersion . 14
5.12 Buffer removal . 14
6 Microduct . 14
6.1 Tests applicable . 14
6.2 Tensile performance . 15
6.3 Crush . 15
6.4 Impact . 16
6.5 Repeated bending . 16
6.6 Torsion . 16
6.7 Kink . 16
6.8 Bend . 16
6.9 Microduct route verification test . 17
6.10 Microduct pressure withstand . 17
6.11 Ageing . 17
7 Protected microducts . 17
7.1 Tests applicable . 17
7.2 Tensile performance . 18
7.3 Crush . 18
7.4 Impact . 19
7.5 Repeated bending . 19
7.6 Kink . 19
7.7 Bend . 19
7.8 Microduct route verification test . 19
7.9 Microduct pressure withstand . 20
7.10 Ageing . 20
Annex A (informative) Examples of microduct fibre units, microducts, and protected
microducts . 21
Annex B (informative) Product descriptions (blank detail specification and minimum
requirements) . 22
Annex C (normative) Product constructions . 25
Annex D (normative) Transmission requirements . 28
D.1 Attenuation of cabled fibre . 28
D.2 Fibre bandwidth requirements . 29
Annex E (normative) IEC 60794-1-21 Method Exx – Microduct inner clearance test . 30
E.1 Object . 30
E.2 General . 30
E.3 Sample . 30
E.4 Test equipment . 30
E.5 Procedure . 30
E.6 Requirements . 30
E.7 Details to be recorded . 31
Figure A.1 – Protected microducts, tight package . 21
Figure A.2 – Microduct fibre units . 21
Table 1 – Tests applicable for installation performance . 11
Table 2 – Tests applicable for mechanical and environmental performance of
microduct fibre unit . 11
Table 3 – Tests applicable for mechanical and environmental performance of microduct . 15
Table 4 – Tests applicable for mechanical and environmental performance of
protected microduct . 18
Table B.1 – Microduct fibre unit description . 22
Table B.2 – Microduct description . 23
Table B.3 – Protected microduct description . 24
Table C.1 – Typical microduct fibre unit construction . 25
Table C.2 – Microduct construction . 26
Table C.3 – Protected microduct construction . 27
Table D.1 – Multimode maximum cable attenuation coefficient (dB/km) . 28
Table D.2 – Single-mode maximum cable attenuation coefficient (dB/km) – Premises
cabling applications . 28
Table D.3 – Single-mode maximum cable attenuation coefficient (dB/km) – All other
applications . 29
Table D.4 – Minimum multimode fibre bandwidth (MHz×km) . 29
– 4 – IEC 60794-5-20:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 5-20: Family specification –
Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
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
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 60794-5-20 has been prepared by subcommittee 86A: Fibres and
cables,of IEC technical committee 86: Fibre optics.
This bilingual version (2017-10) corresponds to the monolingual English version, published in
2014-02.
The text of this standard is based on the following documents:
CDV Report on voting
86A/1497/CDV 86A/1543/RVC
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 parts of 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 60794-5-20:2014 © IEC 2014
OPTICAL FIBRE CABLES –
Part 5-20: Family specification –
Outdoor microduct fibre units, microducts and
protected microducts for installation by blowing
1 Scope
This part of IEC 60794 is a family specification that covers outdoor microduct fibre units and
corresponding microducts and protected microducts for installation by blowing. The protected
microducts are intended for duct, directly buried or lashed applications.
Microduct fibre units differ from microduct optical fibre cables (see IEC 60794-5-10) in that
they provide less protection to the fibres that they contain. Specifically, microduct fibre units
rely on the structure of the microduct, protected microduct or appropriate housing to support
installation and to provide additional mechanical protection for the optical fibre over the
lifetime of the product.
Systems built with components covered by this standard are subject to the requirements of
sectional specification IEC 60794-5 where applicable.
Annex A gives examples of microduct optical fibre units and microducts.
Annex B describes a blank detail specification for outdoor microduct fibre units and the
associated microducts and incorporates some minimum requirements. Detail product
specifications may be prepared on the basis of this family specification using Annex B as a
guide. Annex C provides normative product constructions for microduct optical fibre units,
microducts and protected microducts.
The parameters specified in this standard may be affected by measurement uncertainty
arising either from measurement errors or calibration errors due to lack of suitable standards.
Acceptance criteria should be interpreted with respect to this consideration.
The number of fibres tested is intended to be representative of the microduct fibre unit design
and should be agreed between the customer and supplier.
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 60304, Standard colours for insulation for low-frequency cables and wires
IEC 60793-1-40, Optical fibres – Part 1-40: Measurement methods and test procedures –
Attenuation
IEC 60793-1-53, Optical fibres – Part 1-53: Measurement methods and test procedures –
Water immersion
IEC 60793-2-10, Optical fibres – Part 2-10: Product specifications – Sectional specification for
category A1 multimode fibres
IEC 60793-2-50, Optical fibres – Part 2-50: Products specification – Sectional specification for
class B single-mode fibres
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
IEC 60794-1-21, Optical fibre cables – Part 1-21: Generic specification – Basic optical cable
test procedures – Mechanical test methods
IEC 60794-1-22, Optical fibre cables – Part 1-22: Generic specificaiton – Basic optical cable
test procedures – Environmental test methods
IEC 60794-3:2001, Optical fibre cables – Part 3: Sectional specification – Outdoor cables
IEC 60794-5, Optical fibre cables – Part 5: Sectional specification – Microduct cabling for
installation by blowing
IEC 60794-5-10, Optical fibre cables – Part 5-10: Family specification – Outdoor microduct
optical fibre cables, microducts and protected microducts for installation by blowing
IEC 60811-202, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 202: General tests – Measurement of thickness of non-metallic sheath
IEC 60811-203, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 203: General tests – Measurement of overall dimensions
IEC 60811-501, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 501: Mechanical tests – Tests for determining the mechanical properties of insulating and
sheathing compounds
IEC 60811-601, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 601: Physical tests – Measurement of the drop-point of filling compounds
IEC 60811-602, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 602: Physical tests – Separation of oil in filling compounds
IEC 60811-604, Electric and optical fibre cables – Test methods for non-metallic materials –
Part 604: Physical tests – Measurement of absence of corrosive components in filling
compounds
ISO/IEC 11801, Information technology − Generic cabling for customers premises
3 Symbols
For the purposes of this part of IEC 60794 the following symbols apply.
λ Cabled fibre cut-off wavelength
CC
∆D minimum wall thickness
∆D’ Minimum thickness of the outer sheath of the protected microduct
d Nominal outer diameter of the fibre unit
DS Detail specification
ID Nominal inner diameter of the microduct
– 8 – IEC 60794-5-20:2014 © IEC 2014
OD Nominal outer diameter of the microduct
OD’ Nominal outer diameter of the protected microduct
T The acceptable amount of short-term tensile load that can be applied to the fibre unit
M
without permanent degradation of the characteristics of the fibres in the tensile
performance test
T Temperature cycling test low-temperature limit (usage and storage) according to
A1
IEC 60794-1-2, Method F1
T Temperature cycling test secondary low-temperature limit for extended storage
A2
temperature range according to IEC 60794-1-2, Method F1
T Temperature cycling test high-temperature limit (usage and storage) according to
B1
IEC 60794-1-2, Method F1
T Temperature cycling test secondary high-temperature limit for extended storage
B2
temperature range according to IEC 60794-1-2, Method F1
t Temperature cycling dwell time
n × d The product of a variable and the fibre unit outer diameter used for determining
appropriate sizes for bends, mandrels, etc.
n × OD The product of a variable and the outer diameter of the microduct used for
determining appropriate sizes for bends, mandrels, etc.
n × OD’ The product of a variable and the outer diameter of the protected microduct used for
determining appropriate sizes for bends, mandrels, etc.
W Weight of 1 km of microduct, protected microduct or fibre unit
4 General requirements
4.1 Construction
4.1.1 General
In addition to the constructional requirements in IEC 60794-5, where applicable, the following
considerations apply to outdoor microduct fibre units and their corresponding microducts and
protected microducts.
The products covered in this specification should be designed and manufactured for expected
operating lifetimes of at least 20 years.
The microduct fibre units are designed to be installed in microducts or protected microducts
and in appropriate housings. The microducts and protected microducts that are compatible for
use with microduct fibre units are defined in this document. Microduct fibre units are
optimised for installation and operating lifetime in these microducts.
It shall be possible to install or remove the microduct fibre unit from microduct or protected
microduct by blowing during the operational lifetime except under the following conditions:
a) microduct fibre units or microducts are compromised by multiple installation or removal
operations;
b) microducts are fouled with sediment, debris, or other foreign matter due to inadequate
maintenance;
c) microducts are damaged by extrinsic factors such as dig-ups, earth heaves, etc.
In such cases, the affected section of microduct shall be cleared, repaired or replaced prior to
any microduct fibre unit installations.
The microduct fitness should be verified with dimensional clearance and static pressure
testing of the microduct route.
The materials in the microduct fibre unit, microduct or protected microduct shall take into
consideration local regulations.
4.1.2 Microduct fibre units
In general, microduct fibre units are the smallest and most flexible of all optical cable products
for outdoor use and are intended for installation within microducts. The fibre unit structure is
designed to improve blowing performance compared to a bare fibre and to provide mechanical
and environmental protection for the fibres during installation and over the life of the product.
Fibre unit designs are not described in detail but some examples are given in Annex A. The
microduct fibre units are not as mechanically robust as traditional outdoor optical fibre cables
and, therefore, require the use of suitable installation and handling practices to prevent
damage. Ad hoc installation practices could degrade optical performance or reduce the
product’s operating lifetime.
4.1.3 Microducts
A microduct suitable for installation of microduct fibre units is a small, flexible, lightweight
tube with an outer diameter typically 8 mm or less. Compared to microduct optical fibre cables
(see IEC 60794-5-10), microduct fibre units place greater reliance on microducts and
protected microducts or appropriate closures to provide mechanical protection for the optical
fibres. Therefore, a microduct must meet the realistic impact, compression and bending
requirements for an application. A protected microduct may be required (see 4.1.4).
Microducts shall be able to resist pressure differences needed for installation by blowing. The
microducts shall be circular and uniform in cross-section throughout their length, and their
inner surface may have a low coefficient of friction. Inner- and outer-diameters shall be
specified. As an option, a supplier may provide a special lining or lubricating coating on the
interior of the microduct to aid installation. These layers should not reduce the specified
inside diameter of the microduct.
Microducts generally are intended for benign installation within ducts or as components within
a protected microduct as described in 4.1.4. In all cases, it shall be possible to identify each
individual microduct throughout the length. When using colours they shall be a reasonable
match to IEC 60304.
Microducts installed outdoors and not occupied shall be sealed at each end to prevent the
introduction of moisture, debris, insects, or other such foreign contaminants that could
subsequently hinder the successful installation of fibre unit. Microducts installed outdoors and
not immediately occupied shall be tested for obstructions prior to use.
4.1.4 Protected microducts
A protected microduct is one or more microducts surrounded by a protective sheath, a larger
protective duct and/or an integral thick sheath (such that it complies with the requirements of
Clause 7). A protected microduct can provide additional crush and impact protection
compared to a stand-alone microduct. This additional protection may be needed for a specific
operating environment or installation method. The protective sheath may include an
integrated layer of armouring or thicker outer sheath. In all cases it shall be possible to
identify each individual microduct throughout the length. When using colours, they shall be a
match to IEC 60304 using visual inspection.
4.1.5 Microduct fittings
Microduct fittings are components needed to physically align, connect and seal the junction
between two of more sections of microduct, or to connect microduct to hardware, or to seal
the space between a microduct fibre unit and microduct. Multiple microducts may be
connected in series in order to support extended microduct fibre unit installation distances, or
connected in a branch-type configuration with multiple output terminae for a given input,
within the same system. The latter may be employed in campus type local area networks
– 10 – IEC 60794-5-20:2014 © IEC 2014
(LANs) or fibre-to-the-premises (FTTP) applications to allow for additional flexibility that can
support frequent changes to the physical optical distribution system.
Fittings should be appropriate to the microduct construction. Also, mechanical and
environmental performance requirements of fittings may require that such be tested while
attached to sections of ducting (or hardware) to ensure intermateability and operational
compatibility. The specific physical and material attributes of any fittings used should be
agreed between the customer and supplier.
Microduct fittings shall be able to resist pressure differences needed for installing microduct
fibre units by blowing. When attached to microducts the fittings must pass the pressurization
test of 6.10. Fittings shall allow for the smooth transition of microduct fibre units between
successive sections of microduct, or between microducts and hardware, and shall be
constructed and installed to prevent jamming of the microduct fibre unit at splice, branch, or
other connection points under maximum installation pressures.
Successive sections of microduct may also be welded or otherwise secured together along
the same longitudinal axis without the use of mechanical fittings. Such junctions shall meet
the same mechanical and dimensional requirements as for joints made using mechanical
fittings.
Translucent or transparent materials may be used to support the identification of populated
microducts and for troubleshooting installation related issues.
4.1.6 Microduct hardware
Microduct hardware includes the housings and closures that support the termination of
microduct fibre units, including splicing or connectorization. Because microduct fibre units are
generally compatible with traditional outdoor fibre optic cable hardware, accounting for the
relatively small size, no specific requirements for microduct hardware are included herein. In
some applications, it may be appropriate to use hardware that is compatible with the
microducts in order to create a sealed microduct cabling system. One example is when empty
microducts are pre-installed in hardware to support future microduct fibre unit placement.
4.2 Optical fibres
There shall be no fibre splice in a delivered length, unless otherwise agreed by the customer
and supplier.
It shall be possible to identify each individual fibre throughout the length of the microduct fibre
unit.
The transmission performance shall be in accordance with Annex D.
4.3 Installation performance tests
4.3.1 Installation conditions
A test route may be used to verify the field performance of a microduct fibre unit , microduct,
and/or protected microduct as agreed between the customer and supplier. Ambient conditions
can affect installation performance and, therefore should be monitored. Alternatively, the
supplier can provide performance data from a specified test route under specific ambient
conditions using a specified installation method.
Verifying that a microduct fibre unit or microduct can be installed using a blown installation
technique is critical. Any installation performance requirement shall be agreed upon between
the customer and supplier.
4.3.2 Tests applicable
Tests that are applicable for installation performance are given in Table 1.
Table 1 – Tests applicable for installation performance
Characteristics Family requirements Test methods Remarks
General requirements Agreement between
customer and supplier
IEC 60794-1-21 Method E23
Route verification inner Agreement between
clearance test customer and supplier
Installation test Agreement between Agreement between customer
customer and supplier; and supplier; typically, duct
typically a minimum type and size, route terrain,
distance and time of installation device, maximum
installation over a air pressure and ambient air
specified route is required conditions should be specified
or noted with the results
4.3.3 Mechanical and environmental tests
Based on the expected operating conditions over the life of the product, including the
mechanical loads exerted on the product during installation, the following clauses specify
product performance for microduct fibre units, microducts and protected microducts.
5 Microduct fibre unit
5.1 Tests applicable
Tests that are applicable for mechanical and environmental performance are given in Table 2.
Table 2 – Tests applicable for mechanical and
environmental performance of microduct fibre unit
Characteristics Family requirements Test methods Remarks
a
Tensile performance 5.3 IEC 60794-1-21
Method E1
Crush 5.4 IEC 60794-1-21
Method E3
a
Repeated bending 5.5 IEC 60794-1-21
Method E6
a
Torsion 5.6 IEC 60794-1-2
Method E7
Kink 5.7 IEC 60794-1-21
Method E10
Bend 5.8 IEC 60794-1-21
Method E11
Temperature cycling 5.9 IEC 60794-1-22
Method F1
Ageing 5.10 IEC 60794-1-22
Method F9
Water immersion test 5.11 IEC 60793-1-53
Buffer removal 5.12 As agreed with customer
Water penetration test No requirement Suitable means are used
in the microduct cabling
system for water
blocking
a
For small units (eg < 2 mm outer diameter; <100 N tensile rating), it may be more appropriate to omit some
of these tests in favour of an installation test.
– 12 – IEC 60794-5-20:2014 © IEC 2014
The above tests may need to be modified for use with these cables. In particular, special care
needs to be taken when clamping cables in order to avoid end effects. Unacceptable damage
may include rips, tears, splits, delamination or cracks in the microduct fibre unit. However,
damage at the clamping interface does not constitute a failure.
5.2 Family requirements and test conditions for microduct fibre unit tests
Tests shall be selected from the following by the product specification.
5.3 Tensile performance
a) Family requirements
Under short-term tensile load the fibre strain shall not exceed 60 % of the fibre proof
strain. Other criteria may be agreed between the customer and supplier.
b) Test conditions (loads ≥ 100 N)
Method: Generally to IEC 60794-1-21 Method E1, with duration as
stated below
Length under tension: Not less than 10 m. Taking into account the measurement
accuracy and end effects, shorter lengths may be used by
agreement between the customer and supplier.
Fibre length: Finished microduct fibre unit length.
Tensile load: Equivalent to weight of 1 km of fibre unit
Duration of load 1 min
Diameter of test pulleys: As agreed between customer and supplier but not less than
the minimum loaded bending diameter specified for the
microduct fibre unit. A minimum value of 60 mm is
recommended.
Under visual examination without magnification there shall be no damage to the microduct
fibre unit and there shall be no change in attenuation after the test.
c) Test conditions (loads < 100 N)
Apparatus: Vertical tensometer
Length under tension: Approx 250 mm.
Fibre length: Finished microduct fibre unit length.
Tensile load: Equivalent to weight of 1 km of fibre unit
Duration of load 1 min
Under visual examination without magnification there shall be no damage to the microduct
fibre unit.
5.4 Crush
a) Family requirements
After removal of the load, there shall be no change in attenuation compared to before the
application of the load. Under visual examination, there shall be no damage to the
microduct fibre unit . The imprint of the plate on the microduct fibre unit is not considered
mechanical damage.
b) Test conditions
Method: IEC 60794-1-21 Method E3
Load (plate/plate): 100 N
Duration of load: 1 min
5.5 Repeated bending
a) Family requirements
Under visual examination without magnification there shall be no damage to the microduct
fibre unit elements.
b) Test conditions
Method: IEC 60794-1-21 Method E6
Bending diameter: 40 × d or 60 mm whichever is greater.
Load: Adequate to assure uniform contact with the mandrel.
Number of cycles: 25
5.6 Torsion
a) Family requirements
Under visual examination without magnification there shall be no damage to the microduct
fibre unit elements.
There shall be no change in attenuation after the test.
b) Test conditions
Method Generally in accordance with IEC 60794-1-21 Method E7
Test length: 300 mm
Load: Adequate to assure test sample is straight at start of test.
5.7 Kink
a) Family requirements
Under visual examination, there shall be no damage to the microduct fibre unit
b) Test conditions
Method: IEC 60794-1-21 Method E10
Minimum diameter: 40 × d or 60 mm whichever is greater
5.8 Bend
a) Family requirements
There shall be no change in attenuation after the test when measured at room
temperature.
b) Test conditions
Method: IEC 60794-1-21 Method E11A
Diameter of mandrel: 40 × d or 60 mm whichever is greater
Number of turns/helix: 4
Number of cycles: 3
5.9 Temperature cycling
a) Family requirements
to T there shall be no change in attenuation as defined in IEC 60794-1-1.
For T
A1 B1
For T to T and T to T , the change in attenuation coefficient shall be:
A1 A2 B1 B2
– ≤ 0,15 dB/km for single-mode fibre and shall be reversible to
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