SIST EN 50577:2016
(Main)Electric cables - Fire resistance test for unprotected electric cables (P classification)
Electric cables - Fire resistance test for unprotected electric cables (P classification)
This European Standard specifies a test method to evaluate the maintenance of circuit integrity of electric cables which have intrinsic resistance to fire under fire conditions, in order to classify the electric cable according to EN 13501-3.
The test determines the survival time for circuit integrity of the electric cable when exposed to fire under the conditions of the standard time/temperature curve.
This European Standard is used in conjunction with EN 1363-1.
This European Standard applies to cables of rated voltages up to and including 600/1 000 V and control cables with rated voltage.
The cable is tested in a standardized installation condition.
The test does not assess the performance of the cable management system.
NOTE Optical and data cables could be tested using this method but do not form part of this European Standard as the verification procedures for such cables are still under development.
Kabel und Leitungen - Feuerwiderstandsprüfung an ungeschützten Kabeln und Leitungen (P-Klassifikation)
Diese Europäische Norm legt ein Prüfverfahren zur Bewertung des Funktionserhalts von elektrischen Kabeln und Leitungen fest, welche unter Brandbeanspruchung Feuerwiderstandsfähigkeit aufweisen, mit dem Ziel, die elektrischen Kabel und Leitungen nach EN 13501-3 zu klassifizieren.
Die Prüfung ermittelt die Dauer des Funktionserhalts eines Kabels oder einer Leitung, wenn diese einem Brand unter den Bedingungen der in EN 1363-1 genormten Temperaturzeitkurve ausgesetzt ist.
Diese Europäische Norm wird zusammen mit EN 1363-1 angewendet.
Diese Europäische Norm gilt für Starkstromkabel und -leitungen und für Steuerleitungen mit Nennspannungen bis einschließlich 600/1 000 V.
Das Kabel oder die Leitung wird in einem genormten Standardtragesystem installiert geprüft.
Die Prüfung beurteilt nicht das Verhalten des Kabelführungssystems.
ANMERKUNG Lichtwellenleiter- und Datenkabel könnten nach diesem Verfahren geprüft werden, jedoch waren die Prüfverfahren für derartige Kabel zum Zeitpunkt der Veröffentlichung zur formellen Abstimmung dieser Norm noch in der Entwicklungsphase (2015-07-24).
Diese Europäische Norm beinhaltet den Bereich der direkten Anwendung (Anhang A) und erweiterte Anwendungsregeln (Anhang B) von Prüfergebnissen (en: EXtended APplication, EXAP).
Die Auswahl der zu prüfenden Kabel und Leitungen zur Klassifizierung einer Familie wird in Anhang B beschrieben. Erfüllt die Auswahl der Kabel und Leitungen nicht die Anforderungen in Anhang B, gelten die Prüfergebnisse nur für die geprüften Kabel und Leitungen.
Câbles électriques - Essai de résistance au feu des câbles électriques non protégés (Classification P)
Cette Norme européenne spécifie une méthode d’essai permettant d’évaluer le maintien de l’intégrité au feu de circuits de câbles électriques ayant une résistance au feu intrinsèque en cas d’incendie, et finalement classer le câble électrique conformément à l'EN 13501-3.
L'essai permet de déterminer le temps de survie de circuits de câbles électriques en cas d'une exposition au feu décrite par la courbe de temps-température de l'EN 1363-1.
La présente Norme européenne doit être utilisée conjointement avec l'EN 1363-1.
La présente Norme européenne s’applique aux câbles de puissance et de commande électriques de tensions assignées inférieures ou égales à 600 V/1 000 V.
Le câble est soumis à essai dans les conditions d'installation représentative normalisée.
L’essai n’a pas pour objet d’évaluer les performances des systèmes de câblage.
NOTE Il est possible de soumettre à essai les câbles à fibres optiques et de communication en cuivre au moyen de la présente méthode d’essai. Cependant, les procédures de vérification de ces types de câbles étaient encore en cours d’élaboration au moment de la diffusion du présent document pour vote (2015-07-24).
La présente Norme européenne inclut le domaine d’application directe (en Annexe A) et les règles d’application étendue des résultats d’essai (EXAP) (en Annexe B).
L’Annexe B traite de la sélection des câbles à soumettre à essai pour la classification d’une famille. Lorsque la sélection des câbles ne satisfait pas aux dispositions de l’Annexe B, les résultats d’essai ne s’appliquent qu’aux câbles soumis à essai.
Električni kabli - Preskus požarne odpornosti za nezaščitene električne kable (klasifikacija P)
Ta evropski standard določa preskusno metodo za ocenjevanje vzdrževanja neprekinjenosti tokokroga električnih kablov, ki so sami po sebi odporni proti požarom v požarnih razmerah z namenom razvrščanja električnih kablov v razrede v skladu s standardom EN 13501-3.
Preskus določi čas neprekinjenosti tokokroga električnega kabla, ko je ta izpostavljen požaru pod pogoji standardne krivulje čas/temperatura.
Ta evropski standard se uporablja v povezavi s standardom EN 1363-1.
Ta evropski standard se uporablja za kable z nazivnimi napetostmi do in vključno s 600/1000 V in krmilnimi kabli z nazivno napetostjo.
Med preskusom je kabel izpostavljen standardnim razmeram električnih inštalacij.
Preskus ne ocenjuje delovanja sistema upravljanja kablov.
OPOMBA: Ta metoda se lahko uporabi za preskušanje optičnih in podatkovnih kablov, vendar ti niso zajeti v tem delu evropskega standarda, ker so postopki za preverjanje teh kablov še v izdelavi.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 50577:2016
01-marec-2016
(OHNWULþQLNDEOL3UHVNXVSRåDUQHRGSRUQRVWL]DQH]DãþLWHQHHOHNWULþQHNDEOH
NODVLILNDFLMD3
Electric cables - Fire resistance test for unprotected electric cables (P classification)
Kabel und Leitungen - Feuerwiderstandsprüfung an ungeschützten Kabeln und
Leitungen (P-Klassifikation)
Câbles électriques - Essai de résistance au feu des câbles électriques non protégés
(Classification P)
Ta slovenski standard je istoveten z: EN 50577:2015
ICS:
13.220.50 Požarna odpornost Fire-resistance of building
gradbenih materialov in materials and elements
elementov
29.060.20 Kabli Cables
SIST EN 50577:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN 50577:2016
---------------------- Page: 2 ----------------------
SIST EN 50577:2016
EUROPEAN STANDARD EN 50577
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2015
ICS 13.220.50; 29.060.20
English Version
Electric cables - Fire resistance test for unprotected electric
cables (P classification)
Câbles électriques - Essai de résistance au feu des câbles Kabel und Leitungen - Feuerwiderstandsprüfung an
électriques non protégés (Classification P) ungeschützten Kabeln und Leitungen (P-Klassifikation)
This European Standard was approved by CENELEC on 2015-11-02. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50577:2015 E
---------------------- Page: 3 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Contents
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Test equipment . 7
4.1 Test furnace . 7
4.2 Continuity and voltage withstand checking arrangement . 7
4.3 Fuse . 8
4.4 Standardized representative installation . 8
4.5 Installation of standardized representative installation . 11
5 Test conditions . 16
5.1 Environmental conditions . 16
5.2 Furnace control . 16
6 Test specimen. 16
6.1 Length of test specimen. 16
6.2 Number of test specimens . 17
6.3 Conditioning . 17
6.4 Specimen preparation . 17
6.5 Mounting of test specimens . 17
7 Test procedure . 18
7.1 General . 18
7.2 Measuring temperature . 18
7.3 Applying the voltage . 20
7.4 Starting the test . 21
8 Duration of survival . 21
8.1 Point of failure . 21
9 Test report . 22
Annex A (normative) Field of direct application . 23
A.1 Definitions . 23
A.2 Cable Management System . 23
A.3 Orientation . 23
A.4 Bending radius . 23
Annex B (normative) Extended application of test results . 24
B.1 Definitions . 24
B.2 Product families for EXAP . 24
B.3 EXAP procedure . 25
Bibliography . 27
2
---------------------- Page: 4 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Figures
Figure 1 — Plan view of “U” bend arrangement incorporating straight or curved
corners in both horizontal and vertical furnaces . 10
Figure 2 — End elevation of “U” bend arrangement in both horizontal and vertical
furnaces . 10
Figure 3 — Plan view of “S” bend arrangement in horizontal furnace only . 11
Figure 4 — End elevation of “S” bend arrangement in horizontal furnace only . 11
Figure 5 — Plan view of “U” bend standardized installation with curved or
straight corners . 12
Figure 6 — End elevation of “U” bend standardized installation . 12
Figure 7 — Plan view of “S” bend standardized representative installation with
curved and straight corners . 13
Figure 8 — End elevation of “S” bend standardized representative installation . 14
Figure 9 — Exit in the furnace wall of the “U” bend installation . 15
Figure 10 — Exit in the furnace wall of the “S” bend installation. 16
Figure 11 — Arrangement of test specimens in “U” bend installation . 17
Figure 12 — Arrangement of a test specimen in “S” bend installation . 18
Figure 13 — Locations of plate thermometers in “U” bend installation . 19
Figure 14 — Locations of plate thermometers in “S” bend installation . 19
Figure 15 — Basic circuit diagram — Electric power and control cables with rated
voltage up to and including 600/1 000V . 21
3
---------------------- Page: 5 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
European foreword
This document (EN 50577:2015) has been prepared by CLC/TC 20 "Electric cables".
The following dates are fixed:
(dop) 2016-11-02
• latest date by which this document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2018-11-02
• latest date by which the national
standards conflicting with this
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying
any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association.
The cables are tested in a standardized representative installation, under conditions of
minimum bending radius and subject to exposure to fire under conditions of the EN 1363-1
standard time/temperature curve which satisfies the requirements of Mandate M/117 for the P
classification.
NOTE The test method in EN 50200 includes exposure to fire under specified conditions of constant
temperature attack and satisfies the requirements of Mandate M/117 for the PH classification.
4
---------------------- Page: 6 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Introduction
The purpose of this test is to evaluate the ability of an electric cable to maintain electrical
circuit integrity during a defined time whilst exposed to fire under conditions of the EN 1363-1
standard time/temperature curve and when installed in a standardized representative
condition.
The fire exposure conditions and general arrangement in this European Standard are similar
to those given in prEN 1366-11 [1], developed by CEN/TC 127, and a future document on
Cable management systems (CMS) for fire resistant installations, to be developed by
CLC/TC 213 [2]. Each of these standards has been developed under a Mode 4 co-operation
between CEN/TC 127, CLC/TC 213 and CLC/TC 20.
The test installation has been designed such that vertical and horizontal furnaces can be used
to carry out the test.
The standardized representative condition can be arranged in the following configurations:
a) a “U” or “S” in the horizontal furnace;
b) a “U” and “S” in the horizontal furnace and
c) a “U” in the vertical furnace.
Caution — The attention of all persons concerned with managing and carrying out this
fire resistance test is drawn to the fact that fire testing may be hazardous and that there
is a possibility that toxic and/or harmful smoke and gases may be evolved during the
test. Mechanical, electrical and operational hazards may also arise during the
construction of the test elements or structures, their testing and the disposal of test
residues.
An assessment of all potential hazards and risks to health should be made and safety
precautions should be identified and provided. Written safety instructions should be
issued. Appropriate training should be given to relevant personnel. Laboratory
personnel should ensure that they follow written safety instructions at all times.
5
---------------------- Page: 7 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
1 Scope
This European Standard specifies a test method to evaluate the maintenance of circuit
integrity of electric cables which have intrinsic resistance to fire under fire conditions, in order
to classify the electric cable according to EN 13501-3.
The test determines the survival time for circuit integrity of the electric cable when exposed to
fire under the conditions of the EN 1363-1 standard time/temperature curve.
This European Standard is used in conjunction with EN 1363-1.
This European Standard applies to electric power and control cables with rated voltage up to
and including 600/1 000 V.
The cable is tested in a standardized representative installation condition.
The test does not assess the performance of the cable management system.
NOTE Optical fibre cables and copper communication cables could be tested using this test method,
however verification procedures for such cables were still under development when this document has
been circulated for vote (2015-07-24).
This European Standard includes field of direct application (Annex A) and rules for extended
application of test results (EXAP) (Annex B).
The selection of cables to be tested for classification of a family is given in Annex B. In case
the selection of the cables does not comply with Annex B, the test results are only applicable
to the tested cables.
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.
EN 1363-1, Fire resistance tests — Part 1: General requirements
EN 13501-3, Fire classification of construction products and building elements — Part 3:
Classification using data from fire resistance tests on products and elements used in building
1)
service installations: fire resisting ducts and fire dampers
EN 50200, Method of test for resistance to fire of unprotected small cables for use in
emergency circuits
EN 61537, Cable management — Cable tray systems and cable ladder systems (IEC 61537)
EN ISO 13943, Fire safety — Vocabulary (ISO 13943)
—————————
)
1
EN 13501-3 will be amended to include cables
6
---------------------- Page: 8 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
IEC 60269-3, Low voltage fuses — Part 3: Supplementary requirements for fuses for use by
unskilled persons (fuses mainly for household or similar applications) – Examples of
standardized systems of fuses A to F
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1363-1 and
EN ISO 13943 and the following apply.
3.1
circuit integrity
ability of an electric cable to continue to operate in a designated manner whilst subjected to a
specific source of heat for a specified period of time under specified conditions
3.2
standardized representative installation
cable management system based on perforated trays and perforated suspension supports
3.3
cable with intrinsic fire resistance
electric cable designed to continue to operate in a designated manner whilst subjected to a
specific source of heat for a specified period of time under specified conditions
3.4
rated voltage
reference voltage for which the cable is designed
4 Test equipment
4.1 Test furnace
The test furnace shall be capable of subjecting the electric cable when installed to the
standard heating and pressure conditions specified in EN 1363-1.
The internal dimensions of the test furnace shall be able to accommodate the standardized
representative installation as specified in 4.4.
NOTE 1 Furnaces of the following minimum internal dimensions have been found to be suitable:
— 3 m long;
— 1,5 m deep;
— 2,5 m high.
It is acceptable to extend the vertical furnace to achieve the above minimum internal dimensions that
have been found to be suitable.
NOTE 2 The typical dimensions of a horizontal furnace is 4 m (length) x 3 m (width) x 2,5 m (height)
and of a vertical furnace, including any necessary extensions, 3 m (length) x 1,5 m (depth) x 2,5 m
(height)
The centreline of burners shall be at least 500 mm away from the closest portion of the
standardized representative installation.
4.2 Continuity and voltage withstand checking arrangement (See Figure 15)
The arrangement for checking continuity and voltage withstand shall comprise a three-phase
star-connected or single-phase transformer(s).
7
---------------------- Page: 9 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
During the test a current for continuity checking shall be passed through all conductors of the
test sample. This shall be provided by a three phase star connected or single phase
transformer(s) of sufficient capacity to maintain the test voltage up to the maximum leakage
current allowable.
Consideration should be taken of the fuse characteristics when determining the power rating
of the transformer.
The current shall be achieved by connecting one end of the sample to the transformer and the
other end of the sample to a suitable load and an indicating device (e.g. lamp) to each
conductor, or group of conductors.
NOTE 1 A current of approximately 0,25 A at the test voltage through each conductor or group of
conductors is suitable at the beginning of the test.
NOTE 2 The voltage applied during the test is the rated voltage of the cable (subject to a minimum
a.c. voltage of 100 V).
4.3 Fuse
Fuses used in the test procedure in 7.3 shall be 2 A Type DII complying with IEC 60269-3.
Alternatively, a circuit breaker with equivalent characteristics may be used.
Where a circuit breaker is used, its equivalent characteristics shall be demonstrated by
reference to the characteristic curve shown in the relevant annex of EN 50200.
4.4 Standardized representative installation
4.4.1 General
The cables to be tested shall be installed in the standardized representative installation
described in the following subclauses. The standardized representative installation shall be
assembled and installed according to the manufacturer's instructions.
4.4.2 System components
The system components used shall comply with EN 61537 and shall be based on the
following:
4.4.2.1 Cable tray
Material: galvanized steel
Thickness: (1,5 ± 0,15) mm
Perforation in base: (15 ± 5) %
Width: (400 ± 20) mm
Side wall height: (60 ± 5) mm
Safe working load (SWL): 200 N/m
4.4.2.2 Suspensions and horizontal supports (U-shaped and perforated)
Material: galvanized steel
2
Cross section: (220 ± 10) mm
Safe working load: 10 kN (Tensile Strength)
4.4.2.3 90-degree fittings
Material: galvanized steel
The 90-degree fittings shall be taken from the same system as the cable tray.
8
---------------------- Page: 10 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
The 90-degree fittings taken from the same system as the perforated cable tray can be
perforated or non-perforated. In case of non perforated fittings, holes should be drilled for
attaching the steel chains.
4.4.2.4 Right-angled brackets
Material: steel
The right-angled brackets shall be attached to the side walls of the cable tray, outside the
furnace, in order to prevent any excessive movement inwards.
4.4.3 Loading
Steel chains shall be used of the following specification to ensure that the load on the
standardized installation system is uniformly distributed to the maximum working load:
Material: uncoated mild steel
Size: links can be any size
Unit weight: approximately 3,5 kg/m to 4,0 kg/m
4.4.4 General arrangements of installation in furnace
The assembly shall be installed into either a horizontal or a vertical furnace as shown in the
following general arrangements (Figures 1, 2, 3 and 4).
9
---------------------- Page: 11 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
“U” Bend
Key
1 tray 3 furnace wall
2 suspension 4 position of the chain
Figure 1 — Plan view of “U” bend arrangement incorporating straight or curved corners
in both horizontal and vertical furnaces
Key
1 tray 3 furnace wall
2 suspension 4 ceiling
Figure 2 — End elevation of “U” bend arrangement
in both horizontal and vertical furnaces
10
---------------------- Page: 12 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
“S” Bend
Key
1 tray 4 position of the chain
2 suspension 5 plane for end elevation (Figure 4)
3 furnace wall
Figure 3 — Plan view of “S” bend arrangement in horizontal furnace only
Key
1 tray 3 furnace ceiling
2 suspension
Figure 4 — End elevation of “S” bend arrangement in horizontal furnace only
4.5 Installation of standardized representative installation
4.5.1 Details of “U” bend arrangement
Figures 5 and 6 show how the assembly of trays and cables, mounted on the tray as
described in 6.4 and 6.5, is located in the furnace.
Suspensions shall be fixed to the ceiling of the furnace.
11
---------------------- Page: 13 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
The distance between the tray and the furnace walls shall be 150 mm to 200 mm for the inner
edge of the straight section and greater than 150 mm between the other parts and the side
walls and back wall (see Figure 5).
A maximum of 3 trays shall be installed directly above each other using the same vertical
suspension. The distance between the base of the top tray and the ceiling shall be greater
than 300 mm. If more than 1 tray is used then the vertical separation distance between any
2 trays shall be (300 ± 30) mm and the horizontal separation distance between trays shall be
at least 500 mm.
Dimensions in millimetres
Not to scale
Figure 5 — Plan view of “U” bend standardized installation
with curved or straight corners
Dimensions in millimetres
Not to scale
Figure 6 — End elevation of “U” bend standardized installation
12
---------------------- Page: 14 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
4.5.2 Details of “S” bend arrangement
Figures 7 and 8 show how the assembly of trays and cables, mounted on the tray as
described in 6.4 and 6.5, is located in the furnace.
The suspensions shall be fixed to the ceiling of the furnace.
The distance between the tray and the furnace walls shall be greater than 150 mm (with the
exception of the distance between the parts near the exit holes and the wall with the exit
hole).
A maximum of 3 trays shall be installed directly above each other using the same vertical
suspension. The distance between the base of the top tray and the ceiling shall be greater
than 300 mm. If more than 1 tray is used then the vertical separation distance between any
2 trays shall be 300 mm ± 30 mm and the horizontal separation distance between trays shall
be at least 500 mm.
Dimensions in millimetres
Not to scale
Key
1 length of straight section changes with cable diameter and manufacturer’s minimum bending radius
2 suspension support where corner sections are joined by straight section
3 plane for end elevation (Figure 8)
Figure 7 — Plan view of “S” bend standardized representative installation
with curved and straight corners
13
---------------------- Page: 15 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Dimensions in millimetres
Not to scale
Figure 8 — End elevation of “S” bend standardized representative installation
4.5.3 Application of the chains
Before or after the assembly has been located into the furnace, the chains (see 4.4.3) shall be
applied.
A chain or chains shall be attached along both the outer and inner edges of the tray. Each
chain shall be attached to the underside of the tray in loops using steel wire of at least
1,0 mm diameter at a maximum fixing distance of 250 mm.
At the corners, the fixing distance of the chain and the chain length between fixing points shall
be the same as for the straight tray sections. The length of the chain should be sufficiently
longer than the length of the standardized installation system so as not to restrict movement
of the assembly.
The distance between chains at corners shall be maintained at approximately 400 mm.
The lengths of loops formed during fixing of the chain to the tray shall be adjusted until the
total unit load applied to the tray by the combination of the chains and the cable test
+0
specimens reaches (200 ) N/m.
−20
Each chain shall follow a path as described above until coming to a vertical support at which
the chain path shall divert around the inner surface of the vertical support and rest onto the
upper surface of the horizontal support.
4.5.4 Exit holes from the furnace for the test installation
The gaps around the cable trays at the exit holes shall be filled with mineral wool in such a
way as to allow for movement of the components in the standardized representative
installation.
NOTE 1 This can be achieved by for example locating the regions of the standardized representative
installation exiting the furnace on appropriate high-density mineral wool insulation material. The
remaining gaps could be filled with appropriate low-density mineral wool insulation material.
3
NOTE 2 Mineral wool with a density of (95 ± 20) kg/m has been found appropriate as high-density
3
wool. Mineral wool with a density of (45 ± 10) kg/m has been found appropriate as low-density wool.
When in place the mineral wool shall be flush with the external and internal surfaces of the
furnace wall and shall completely surround each cable.
14
---------------------- Page: 16 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Right-angled brackets shall be attached to the outer edges of the tray as it exits the furnace in
order to prevent excessive movement inwards due to thermal effects. The brackets shall be
touching the outer surface of the furnace wall but not fixed to the wall.
Care shall be taken to install the cables such that they are not damaged during installation
and testing by the sharp edges at the point of where the tray ends.
Any movement of the test cables inside the furnace shall not be restricted during the test.
The exposed sheathed cable shall extend beyond the end of the tray and the tray shall extend
by (200 ± 20) mm from the outer surface of the furnace wall.
Figures 9 and 10 indicate how this shall be achieved. Figure 9 shows 50 mm – 60 mm gaps at
the outer edges of the “U” bend installation (to allow thermal expansion of the trays without
damaging the furnace wall), the locations of right angled brackets and the location of mineral
wool. Figure 10 shows equal gaps at the inner and outer edges of the “S” bend installation,
the locations of the right angled brackets and the location of the mineral wool.
Dimensions in millimetres
Not to scale
Key
mineral wool – see notes 1 and 2
1 hole in wall 6
mineral wool – see notes 1 and 2
2, 3, 4 right angled brackets 7
5 cable tray 8 cables (test specimens)
Figure 9 — Exit in the furnace wall of the “U” bend installation
15
---------------------- Page: 17 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
Dimensions in millimetres
Not to scale
Key
mineral wool – see notes 1 and 2
1 hole in wall 6
mineral wool – see notes 1 and 2
2, 3, 4 right angled brackets 7
5 cable tray 8 cables (test specimens)
Figure 10 — Exit in the furnace wall of the “S” bend installation
5 Test conditions
5.1 Environmental conditions
The interior of the test furnace shall be between 10 °C and 40 °C at the start of each test. The
furnace walls and ceilings constructed for the purpose of this test shall be allowed to dry in
ambient conditions for at least 16 h immediately prior to the test.
5.2 Furnace control
The heating and pressure conditions and the furnace atmosphere shall conform to those given
in EN 1363-1. The temperature shall be measured at the points specified in 7.2.
The furnace pressure shall be controlled to a pressure of 20 Pa throughout the test at the top
of the uppermost cable tray.
6 Test specimen
6.1 Length of test specimen
The length of each test specimen subjected to the test shall be sufficient to allow a minimum
of 250 mm and a maximum of 1 000 mm of sheathed cable to exit the furnace for electrical
connections.
16
---------------------- Page: 18 ----------------------
SIST EN 50577:2016
EN 50577:2015 (E)
6.2 Number of test specimens
Two test specimens shall be tested of each individual construction of
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.