Optical fibre cables – Part 1-215: Generic specification – Basic optical cable test procedures – Environmental test methods – Cable external freezing test, Method F15

IEC 60794-1-215:2020 defines test procedures to be used in establishing uniform requirements for the environmental performance of
- optical fibre cables for use with telecommunication equipment and devices employing similar techniques, and
- cables having a combination of both optical fibres and electrical conductors.
Throughout this document, the wording "optical cable" can also include optical fibre units, microduct fibre units, etc. This document defines a test standard to determine the ability of a cable to withstand the effects of freezing water that can immediately surround the optical fibre cable sheath by observing any changes in the physical appearance of the sheath, or in the measured cable optical attenuation. Method F15A is a test standard to simulate freezing of the medium surrounding a buried cable, as in wet earth or water. Method F15A is moved from method F15 in IEC 60794-1-22:2017 without any technical changes. Method F15B is a test standard to simulate freezing of the medium surrounding an outside cable in a rigid conduit (duct) which is made of rigid material, for example steel. Method F15B includes the solution to prevent the cable from being crushed when experiencing freezing conditions in a rigid conduit (duct) which are pressure absorber pads and any other suggested means of cable protection. A reference guide to test methods of all types as well as general requirements can be found in IEC 60794-1-2.

Câbles à fibres optiques - Partie 1-215: Spécification générique - Procédures fondamentales d'essais des câbles optiques - Méthodes d’essais d’environnement - Essai de résistance au gel en extérieur des câbles, méthode F15

IEC 60794-1-215:2020 définit les procédures d’essai à utiliser pour définir des exigences harmonisées pour les performances environnementales:
- des câbles à fibres optiques destinés à être utilisés avec les équipements et dispositifs de télécommunications employant des techniques similaires; et
- des câbles combinant fibres optiques et conducteurs électriques.
Dans le présent document, le terme « câble optique » peut également englober les unités de fibres optiques, les unités de fibres en microconduit, etc. Le présent document définit une norme d’essai pour déterminer la capacité d’un câble à résister aux effets de l’eau gelée pouvant se situer au voisinage immédiat de la gaine d’un câble à fibres optiques, en observant les quelconques variations d’aspect physique de la gaine, ou les quelconques variations de l’affaiblissement mesuré sur le câble. La méthode F15A est une norme d’essai pour simuler le gel du milieu entourant un câble enfoui, par exemple de la terre humide ou de l’eau. La méthode F15A est déplacée de la méthode F15 de l’IEC 60794-1-22:2017 sans aucune modification technique. La méthode F15B est une norme d’essai pour simuler le gel du milieu entourant un câble extérieur dans un conduit (gaine) rigide fabriqué dans un matériau rigide, par exemple l’acier. La méthode F15B inclut la solution qui évite l’écrasement du câble lorsqu’il est soumis à des conditions de gel dans un conduit (gaine) rigide, qui consiste en des tampons d’absorption de la pression et les quelconques autres moyens de protection du câble suggérés. Un guide de référence répertoriant les méthodes d’essai de tous types, ainsi que les exigences générales, peut être consulté dans l’IEC 60794-1-2.

General Information

Status
Published
Publication Date
25-Jun-2020
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
26-Jun-2020
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IEC 60794-1-215
Edition 1.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-215: Generic specification – Basic optical cable test procedures –
Environmental test methods – Cable external freezing test, Method F15
Câbles à fibres optiques –
Partie 1-215: Spécification générique – Procédures fondamentales d’essais des
câbles optiques – Méthodes d’essais d’environnement – Essai de résistance au
gel en extérieur des câbles, méthode F15
IEC 60794-1-215:2020-06(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 60794-1-215
Edition 1.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Optical fibre cables –
Part 1-215: Generic specification – Basic optical cable test procedures –
Environmental test methods – Cable external freezing test, Method F15
Câbles à fibres optiques –
Partie 1-215: Spécification générique – Procédures fondamentales d’essais des
câbles optiques – Méthodes d’essais d’environnement – Essai de résistance au
gel en extérieur des câbles, méthode F15
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.180.10 ISBN 978-2-8322-8570-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 60794-1-215:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 Method F15A – Cable external freezing test for a buried cable as in wet earth or

water ............................................................................................................................... 7

4.1 Object ..................................................................................................................... 7

4.2 Sample ................................................................................................................... 7

4.3 Apparatus ............................................................................................................... 7

4.4 Procedure ............................................................................................................... 8

4.5 Requirements ......................................................................................................... 8

4.6 Details to be specified ............................................................................................. 8

5 Method F15B – Cable external freezing test in a rigid conduit (duct) ................................ 8

5.1 Object ..................................................................................................................... 8

5.2 Sample ................................................................................................................... 8

5.3 Apparatus ............................................................................................................... 9

5.4 Procedure ............................................................................................................... 9

5.5 Requirements ....................................................................................................... 10

5.6 Details to be specified ........................................................................................... 10

Annex A (informative) Example of freezing pressure absorber elements .............................. 11

Bibliography .......................................................................................................................... 13

Figure 1 – Example of F15B apparatus of cable external freezing test in a rigid conduit .......... 9

Figure A.1 – Example of freezing pressure absorber elements .............................................. 11

Figure A.2 – Cross section of the rigid conduit with an optical cable and freezing

pressure absorber elements when the water freezing ............................................................ 12

---------------------- Page: 4 ----------------------
IEC 60794-1-215:2020 © IEC 2020 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPTICAL FIBRE CABLES –
Part 1-215: Generic specification –
Basic optical cable test procedures –
Environmental test methods –
Cable external freezing test, Method F15
FOREWORD

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rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60794-1-215 has been prepared by subcommittee 86A: Fibres and

cables, of IEC technical committee 86: Fibre optics.
The text of this International Standard is based on the following documents:
FDIS Report on voting
86A/2008/FDIS 86A/2026/RVD

Full information on the voting for the approval of this International Standard can be found in the

report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

---------------------- Page: 5 ----------------------
– 4 – IEC 60794-1-215:2020 © IEC 2020

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 "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document 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.

---------------------- Page: 6 ----------------------
IEC 60794-1-215:2020 © IEC 2020 – 5 –
INTRODUCTION

This part of IEC 60794 defines a test method to determine the ability of a cable to withstand the

effects of freezing water that can immediately surround the optical fibre cable sheath by

observing any changes in the physical appearance of the sheath, or in the measured cable

optical attenuation. The cable external freezing test in a rigid conduit (duct) is an item of F15

under consideration in IEC 60794-1-22:2017.

This document includes method F15 of IEC 60794-1-22:2017 as F15A: Cable external freezing

test for a buried cable, as in wet earth or water. There is no technical change in F15A. F15B is

a new introduced method. The numbering of these tests continues the F-series numbering

sequence of IEC 60794-1-22:2017.

The number of IEC 60794-1-215 is in line with the new numbering system of test methods as

planned in IEC 60794-1-2 .
___________

Fifth edition under preparation. Stage at the time of publication: IEC/CC 60794-1-2:2020.

---------------------- Page: 7 ----------------------
– 6 – IEC 60794-1-215:2020 © IEC 2020
OPTICAL FIBRE CABLES –
Part 1-215: Generic specification –
Basic optical cable test procedures –
Environmental test methods –
Cable external freezing test, Method F15
1 Scope

This part of IEC 60794-1 defines test procedures to be used in establishing uniform

requirements for the environmental performance of

• optical fibre cables for use with telecommunication equipment and devices employing similar

techniques, and
• cables having a combination of both optical fibres and electrical conductors.

Throughout this document, the wording "optical cable" can also include optical fibre units,

microduct fibre units, etc.

This document defines a test standard to determine the ability of a cable to withstand the effects

of freezing water that can immediately surround the optical fibre cable sheath by observing any

changes in the physical appearance of the sheath, or in the measured cable optical attenuation.

Method F15A is a test standard to simulate freezing of the medium surrounding a buried cable,

as in wet earth or water. Method F15A is moved from method F15 in IEC 60794-1-22:2017

without any technical changes.

Method F15B is a test standard to simulate freezing of the medium surrounding an outside cable

in a rigid conduit (duct) which is made of rigid material, for example steel. Method F15B includes

the solution to prevent the cable from being crushed when experiencing freezing conditions in

a rigid conduit (duct) which are pressure absorber pads and any other suggested means of

cable protection.

A reference guide to test methods of all types as well as general requirements can be found in

IEC 60794-1-2.
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
---------------------- Page: 8 ----------------------
IEC 60794-1-215:2020 © IEC 2020 – 7 –
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 Method F15A – Cable external freezing test for a buried cable as in wet earth
or water
4.1 Object

This test determines the ability of a buried cable, as in wet earth or water, to withstand the

effects of freezing water that can immediately surround the optical fibre cable sheath by

observing any changes in the physical appearance of the sheath, or in the measured cable

optical attenuation.

The external freezing test simulates freezing of the medium surrounding a buried cable, as in

wet earth or water. It is not intended to simulate freezing of a cable in a rigid conduit (duct) or

pipe; refer to F15B for this testing. This external freezing test has little use for evaluating an

outdoor cable, since such cables rarely fail the test. The aggregate of other requirements for

outdoor cables results in a cable that is sufficiently robust to easily withstand this test. For

freezing of microduct cables in microducts, consideration of ITU-T L.108:2018, Appendix II, is

suggested [2] . It can be useful for evaluating cables not normally intended for outdoor

installation. Users are encouraged to refer to national standards in effect in applicable regions.

4.2 Sample

A 50 m minimum length of cable shall be loosely coiled in the water to be frozen. Contact

between the cable coil and the water tank wall shall be random. Additional length sufficient to

make the required optical measurements and to connect the cable from the apparatus to the

measuring equipment shall be provided.
4.3 Apparatus

The apparatus shall be a water tank suitable to contain the sample gauge length covered with

water.

The water shall be common tap water. This procedure is written in view of the use of tap water.

Other types of water, such as sea water or the like, shall be as specified by the detail

specification. In these cases, the detail specification can prescribe temperatures other than

those specified herein.

The water tank shall be positioned in an apparatus suitable for freezing the water and

maintaining it at the specified temperature ±3 °C. An environmental chamber is a common

example. Optionally, a temperature monitoring device may be used to monitor the cable

temperature. In this case, the device shall be in close proximity to the sample under test.

___________
Numbers in square brackets refer to the Bibliography.
---------------------- Page: 9 ----------------------
– 8 – IEC 60794-1-215:2020 © IEC 2020
4.4 Procedure

1) Place the cable gauge length in the water tank, either as a coil or by coiling it into the tank.

Cover the cable with water.

2) Perform initial attenuation measurements as indicated by the detail specification.

3) If the optional temperature monitoring device is used, the chamber temperature may be

lowered so far as to −40 °C until the ice is completely frozen and the ice temperature is

−10 °C or lower.
4) Raise the chamber temperature to −2 °C and hold this temperature for 1 h.

NOTE This is the temperature at which pure water experiences its greatest volume expansion as ice.

5) Measure the attenuation as indicated by the detail specification.

6) Elevate the chamber temperature to melt the ice. If the optional temperature monitoring

device is used, the chamber temperature may be raised so high as to +65 °C, in order to

accelerate the ice melting. Maintain the high temperature until the water reaches +15 °C.

Then, return the chamber temperature to +23 °C and hold this temperature until the water

reaches +23 °C ± 5 °C.
7) Measure the attenuation as indicated by the detail specification.

8) Remove the cable from the water tank and examine the exterior of the gauge length for any

physical damage.
4.5 Requirements

After exposure, there shall be no visible cracks or other openings in the cable sheath. The

maximum increase in attenuation during and after the test shall be as shown in the relevant

detail specification, when frozen and no change after thawing.
4.6 Details to be specified
The detail specification shall include the following:
a) change of attenuation during and after the test;
b) any deviations from the criteria specified herein;
c) minimum bend diameter.
5 Method F15B – Cable external freezing test in a rigid conduit (duct)
5.1 Object

This test determines the ability of a cable to withstand the effects of freezing water in a rigid

conduit (duct) that can immediately surround the optical fibre cable sheath by observing any

changes in the physical appearance of the sheath, or in the measured cable optical attenuation.

NOTE This external freezing test of F15B simulates freezing of the medium surrounding an outside cable in a rigid

conduit (duct). The similar test of F15A addresses the freezing of a medium surrounding a buried cable, as wet earth

or water, thus not constrained by a rigid duct.
5.2 Sample

The sample length shall be of a length sufficient to carry out the specified test. Additional length

sufficient to make the required optical measurements and to connect the cable from the

apparatus to the measuring equipment shall be provided. The sample length shall be as

specified by the detail specification. The sample shall be loosely installed in the conduit (duct).

NOTE The typical sample length is longer than L when the sample gauge length of L is 5 m.

1 1
---------------------- Page: 10 ----------------------
IEC 60794-1-215:2020 © IEC 2020 – 9 –
5.3 Apparatus

The apparatus (see Figure 1) shall be the conduit (duct) suitable to contain the sample gauge

length (L , per the detail specification, typically 5 m) covered with water. To keep the water in

the conduit (duct) without water blocking or sealing, the entrances of the conduit (duct) are

gradually curved with a sufficient large bending radius with no change of the physical and optical

property of the sample. The water shall be common tap water.

Figure 1 – Example of F15B apparatus of cable external freezing test in a rigid conduit

This procedure is written in view of the use of tap water. Other types of water, such as sea

water or the like, shall be as specified by the detail specification. In these cases, the detail

specification may need to prescribe temperatures other than those specified herein.

The conduit (duct) shall be positioned in a climatic chamber suitable for freezing the water.

The climatic chamber of a suitable size to accommodate the sample and whose temperature

shall be controllable to remain within ±3 °C of the specified testing temperature shall be used.

Optionally, a temperature monitoring device may be used to monitor the cable temperature or

nearby position temperature of the cable. In this case, the device shall be in close proximity to

the sample under test.

NOTE 1 For example, thermocouple can be used as the device to monitor the temperature near the sample.

Conventionally, the thermocouples are attached on the outer surface of the conduit (duct).

A heat insulating material is arranged at the central section (L , per the detail specification,

typically 1 m to 2 m) of the conduit to delay freezing the water in this section.

NOTE 2 In the field, the temperature of the conduit depends on the buried depth. The freezing delay between the

central section and the others can well simulate freezing the water in the conduit in the underground.

An attenuation measuring apparatus for the determination of attenuation changes shall comply

with IEC 60793-1-46.
5.4 Procedure

1) Place the cable gauge length in the conduit (duct). Fill the conduit (duct) and cover the

cable with water.

As required by the detail specification, freezing pressure absorber elements, such as a cable

outer element, shall be placed in the conduit (duct) with the cable sample.

NOTE 1 For example, a cable outer element is a specially designed PE pipe (see [3] and Annex A). The

preponderance of experience with freezing of cables in ducts indicates that some sort of pressure absorber

element is important for acceptable performance of installed duct cable subject to freezing.

2) The sample at ambient temperature shall be introduced into the climatic chamber which is

also at that temperature.
---------------------- Page: 11 ----------------------
– 10 – IEC 60794-1-215:2020 © IEC 2020

3) Perform initial attenuation measurements as indicated by the detail specification.

4) If specified, after that, measure the attenuation with a period of specified time of t (typically

1 h) during the test.

NOTE 2 The optional measurement of the attenuation during the test can terminate the test as soon as the

attenuation change exceeds the specified criteria.

5) The temperature in the chamber shall then be lowered to the specified low temperature T

(typically −20°C).

6) After temperature stability in the chamber has been reached, the sample shall be exposed

(typically 40 h). At the end of
to the low temperature conditions for the appropriate period t
the exposure to low temperature conditions, the attenuation shall be measured.

7) The temperature in the chamber shall then be raised to the specified high temperature T

(typically 60°C), in order to accelerate the ice melting. Maintain the high temperature for the

appropriate period t (typically 3 h). Then, return the chamber temperature to the ambient

temperature.
8) The steps 3) through 7) constitute one cycle.

9) The sample shall be subjected to 3 cycles unless otherwise required in the relevant detail

specification.

10) At the end of the last cycle, the sample shall be held at ambient temperature for the

appropriate period t (typically 6 h).

11) The sample under test and the chamber shall have reached temperature stability at ambient

temperature.

12) Remove the cable from the conduit (duct) and examine the exterior of the gauge length (L )

for any physical damage.
5.5 Requirements

After exposure, there shall be no visible cracks or other openings in the cable sheath. The

maximum increase in attenuation during and after the test shall be as shown in the relevant

detail specification, when frozen and no change after thawing.
5.6 Details to be specified
The detail specification shall include the following:
a) change of attenuation during and after the test;
b) any deviations from the criteria specified herein;
c) length and outer diameter of cable sample;
d) conduit (duct) length;
e) inner and outer diameters, thickness and material of conduit (duct);
f) length, material and thickness of thermal insulating material;
g) number of fibres to be tested;
h) number of cycles, if other than three;

i) change of attenuation at a specified wavelength as a function of temperature cycling; that

is, at the required values of T and ambient after;
j) number of cables in the conduit (duct);

k) as required, number of freezing pressure absorber elements, such as outer cable elements;

l) if required, specification of the freezing pressure absorber elements such as typical outer

diameter and detailed configuration of outer cable element.
---------------------- Page: 12 ----------------------
IEC 60794-1-215:2020 © IEC 2020 – 11 –
Annex A
(informative)
Example of freezing pressure absorber elements
Annex A shows a typical measure to pr
...

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