CEMAC - CE-marking of cables

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Terence Journeaux

Europacable

Björn Sundström

SP Technical Research Institute of Sweden

Patrik Johansson

SP Technical Research Institute of Sweden

Michael Försth

SP Technical Research Institute of Sweden

Stephen J Grayson

Interscience Communications, UK

Sean Gregory

Interscience Communications, UK

Suresh Kumar

Interscience Communications, UK

Hervé Breulet

ISSEP, Belgium

Silvio Messa

LSF, Italy

Reiner Lehrer

VDE, Germany

Marc Kobilsek

Europacable

Hans-Detlef Leppert

Europacable

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Abstract

CEMAC, CE MArking of Cables, is a project with the objective of supporting a smooth transfer from national reaction to fire requirements in Europe to harmonised CE-marking requirements. The starting point is the European Commission decision on classification criteria from 2006 and the test procedures referenced by the decision. The CEMAC project has improved the testing standards, developed procedures for Extended Application of Test Results, EXAP, and contributed with a large test data base. CEMAC is a co-operation between a group of research institutes, testing laboratories and industry, Europacable. It is believed that the results will be used in the European system shortly.

Key words: Burning behaviour of cables, Fire Growth Rate of cables, fire testing, CE-marking, reaction to fire of cables, extended application of test results on cables, FIPEC, prEN 50399, EN 61034-2, EN 60332-1-2, EN 50267-2-3.

SP Sveriges Tekniska Forskningsinstitut SP Technical Research Institute of Sweden SP Report 2010:27

ISBN 978-91-86319-65-6 ISSN 0284-5172

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Abstract

2

3

1 Background to the CEMAC project

6

2 Executive summary and conclusions

9

3 Cable selection and procurement

11

4 Experimental program and laboratory qualification through

round robin

17

4.1 Qualifying programme of work 18

4.2 Data base cable tests 18

5 Data management

19

5.1 Introduction 19

5.2 Data bank 19

5.2.1 Contents of the data bank 19

5.2.2 Organisation and handling of data base 20

5.2.3 Availability of the data 20

5.3 Data formats, storing and exchanging 20

5.3.1 Internal laboratory formats 20

5.3.2 Data stored in the data bank 20

5.3.3 Data stored at the laboratories 21

5.3.4 Analysis 21

5.4 Exchanging data 21

5.4.1 Codes for identification of CEMAC tests in the data bank 21

6 Large scale tests results

22

6.1 Test method 22

6.2 Measurements and derived parameters 23

6.3 Number of tests 24 6.4 Test results 25 6.4.1 Group 1 25 6.4.2 Group 3st 26 6.4.3 Group 3lt 26 6.4.4 Group 3ct 27 6.4.5 Group 3tb 27 6.4.6 Group 5 28 6.4.7 Group 6 28 6.4.8 Group 7 29 6.4.9 Group 8a 29 6.4.10 Group 8b 30 6.4.11 Group 9 31 6.4.12 Group 10 31 6.4.13 Group 11 32 6.4.14 Group 12 32 6.4.15 Group 13 33

6.4.16 Spread of results – all groups 34

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7 Extended application, EXAP

40

7.1 Safety margin 40

7.2 Cables with singular behaviour. 45

7.3 Cables larger than the tested range 51

7.4 Generic rules for cables not included in CEMAC 52

7.5 Flaming droplets/particles 55

7.6 EXAP for Data cables 56

7.6.1 General discussion 56

7.6.2 “Extrapolation” rule 57

7.7 EXAP for Optical cables 61

7.8 EXAP for EN 60332-1-2 62

7.9 EXAP for EN 61034-2 62

7.10 EXAP flow chart 63

8 Test results EN 60332-1-2 and EN 61034-2

64

8.1 Analysis of EN 60332-1-2 results from Europacable laboratories 64

8.1.1 Spread of results by Group 64

8.1.2 Spread of results by Class 64

8.1.3 Conclusions 64

8.2 Analysis of prEN 50399 smoke results versus EN 61034-2 tests results

obtained by Europacable laboratories 65

8.2.1 Smoke classification analysis 65

8.2.2 Discriminant parameter for s classification according to prEN 50399. 65 8.2.3 Correlation between prEN 50399 and EN 61034-2 66 8.2.4 EXAP cable parameter and EN 61034-2 measurement 68

8.2.5 Conclusions 68

References

69

9 Annex A, Cable details and photographs

70

10 Annex B, Test results EN 60332-1-2 and EN 61034-2

87

11 Annex C, Analysis of results

91

11.1 Peak HRR 95 11.2 THR 98 11.3 FIGRA 101 11.4 Flame spread 104 11.5 Peak SPR 107 11.6 TSP 110

12 Annex D, Proposal for EXAP rules for power cables

113

12.1 Definition of a product family for EXAP for power cables 113

12.2 EXAP with safety margin 114

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d [m] Outer diameter.

N [] Number of cables on the ladder, or, when applicable, number of bundles on the ladder.

Vcombust [m2] Non-metallic volume per meter ladder.

vcombust [m2] Non-metallic volume per meter cable.

νclass different Value for classification in EXAP.

νmax different Maximum measured value in EXAP.

ν_sm different Safety margin to be used in EXAP.

c [] Number of conductors in one cable.

Acknowledgements

CEMAC, CE MArking of Cables, is a project financed by Europacable. CEMAC was performed in close co-operation between a group of research laboratories, the RTD-group, and a group of Europacable companies. The RTD group consisted of SP, Interscience, ISSEP, LSF and VDE. The project was lead by Europacable and the RTD contributions were led by SP. The project was financed by Europacable and the expertise and testing work of the Europacable laboratories were invaluable for the project results. The involved Europacable laboratories were Acome, Draka DE, General Cable, Prysmian UK, Draka NL, Nexans DE, Nexans FR and NKT. Finally the joint competence and work of the researchers and the testing teams of the RTD laboratories was the necessary prerequisite for the project to be successful.

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1 Background to the CEMAC project

CE-marking according to the Construction Products Directive (CPD) requires that harmonised test standards and corresponding classification criteria are available. In the case of fire properties it is also necessary that harmonised procedures of so called extended application of test results, EXAP, are available. EXAP allows a family of products to be classified to a certain fire property without testing all of the individual members of the family. Availability of EXAP is an essential requirement for cables as the individual variation of the products is so large that the number of tests required for classification would become impossible to handle. The European Commission can take a decision on classification without further testing, CWFT (Classification Without Further Testing), provided that the appropriate technical basis is given. Smooth introduction of CE-marking for cables in the fire area requires that the technical testing standards are tried out, validated and reproducible. The EXAP procedures must be developed and available and further CWFT decisions from the Commission may be required. The CEMAC project provides the technical data and EXAP procedures that would simplify CE-marking of the reaction to fire properties of cables in Europe.

The standard prEN 50399 is the major test procedure for reaction to fire of cables, see section 6.1. This test specification derives from work done in a large project funded by the EU called FIPEC, Fire Performance of Electric Cables [1]. The FIPEC project was performed by a research group consisting of SP, Interscience, ISSEP and CESI.

The FIPEC project included a study of cable installations and relevant reference scenarios as well as a comprehensive test program of different kinds of cables. This together with some additional test data was used in the development of the proposal for the European testing and classification system. The proposal of reaction to fire classes was developed in co-operation with European regulators and the cable industry in Europe and presented in 2003 [2], [3]. The European Commission decided on a testing and classification system on cables during 2006 [4], see Table 1. The system is built in the same way as that used for linings and pipe insulation. However, it also included the possibility to declare acidity of the smoke gases, the sub-classes a1, a2 and a3.

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Aca EN ISO 1716 PCS ≤ 2,0 MJ/kg (1) B1ca FIPEC20 Scen 2 (5) And FS ≤ 1.75 m and THR1200s ≤ 10 MJ and Peak HRR ≤ 20 kW and FIGRA ≤ 120 Ws-1

Smoke production (2, 6_{) and Flaming}

droplets/particles (3_{) and Acidity (}4, 8₎

EN 60332-1-2 H ≤ 425 mm B2ca FIPEC20 Scen 1 (5) and FS ≤ 1.5 m; and THR1200s ≤ 15 MJ; and Peak HRR ≤ 30 kW; and FIGRA ≤ 150 Ws-1

EN 60332-1-2 H ≤ 425 mm Cca FIPEC20 Scen 1 (5) And FS ≤ 2.0 m; and THR1200s ≤ 30 MJ; and Peak HRR ≤ 60 kW; and FIGRA ≤ 300 Ws-1

EN 60332-1-2 H ≤ 425 mm Dca FIPEC20 Scen 1 (5) And THR1200s ≤ 70 MJ; and Peak HRR ≤ 400 kW; and FIGRA ≤ 1300 Ws-1

EN 60332-1-2 H ≤ 425 mm

Eca EN 60332-1-2 H ≤ 425 mm

Fca No performance determined

(1_{) For the product as a whole, excluding metallic materials, and for any external component (i.e. sheath) of the product.}

(2_{) s1 = TSP}

1200 ≤ 50 m2 and Peak SPR ≤ 0.25 m2/s

s1a = s1 and transmittance in accordance with EN 61034-2 ≥ 80% s1b = s1 and transmittance in accordance with EN 61034-2 ≥ 60% < 80% s2 = TSP1200 ≤ 400 m2 and Peak SPR ≤ 1.5 m2/s

s3 = not s1 or s2

(3_{) For FIPEC}

20 Scenarios 1 and 2: d0 = No flaming droplets/particles within 1200 s; d1 = No flaming droplets/ particles

persisting longer than 10 s within 1200 s; d2 = not d0 or d1.

(4_{) EN 50267-2-3: a1 = conductivity < 2.5 μS/mm and pH > 4,3; a2 = conductivity < 10 μS/mm and pH > 4.3;}

a3 = not a1 or a2. No declaration = No Performance Determined.

(5_{) Air flow into chamber shall be set to 8000 ± 800 l/min.}

FIPEC20 Scenario 1 = prEN 50399-2-1 with mounting and fixing as below

FIPEC20 Scenario 2 = prEN 50399-2-2 with mounting and fixing as below

(6_{) The smoke class declared for class B1}

ca cables must originate from the FIPEC20 Scen 2 test.

(7_{) The smoke class declared for class B2}

ca, Cca, Dca cables must originate from the FIPEC20 Scen 1 test.

(8_{) Measuring the hazardous properties of gases developed in the event of fire, which compromise the ability of the persons}

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Further work was done on the test procedure in CENELEC which has resulted in improvement of a number of technical details to prEN 50399 which now is ready for final vote (December 2009). Two round robin exercises have been carried out on the test [5], [6]. The first round robin was performed on behalf of Europacable with industry laboratories together with the developers of the system, the FIPEC laboratories. The second round robin was performed through CENELEC and included many test sites. The results were good and comparable to the results of the SBI test used for linings. Thus the test procedure used is quite robust and well developed. These test results were validated in the FIPEC project for real fires by using reference scenarios and through further analysis and comparisons to other building products under the CPD, see [1], [7].

With this background the CEMAC project was created to add EXAP procedures and further test data on different cables. Additional testing laboratories, LSF and VDE, and a large group of Europacable laboratories formed together with the FIPEC partners a group to undertake the CEMAC project. The project test data base includes approximately 200 large scale test results on which the EXAP analysis were performed. The work in the project was divided into the following tasks.

Table 2. Responsible partner for each activity.

Activity Responsible partner

Project management ECBL

Project management RTD group SP

Cable selection ECBL

Basic calibration exercise of test equipment and qualification to run tests in the project

Interscience

Collection of raw data and analysis of

HRR, Smoke etc Interscience

Tests according to prEN 50399 with

FIPEC scen 1 SP ISSEP

LSF VDE 43 tests 41 tests 21 tests 10 tests Tests according to prEN 50399 with

FIPEC scen 1, EN 60332-1-2 and EN 61034-2

Europacable industry laboratories. prEN 50399: 83 tests

EN 60332-1-2: 88 tests EN 61034-2: 88 tests Analysis and development of EXAP

procedure SP

Final report and Web-based data base SP

The authors of the various sections are as follows: Sections 3, 7.6.2, 7.8, 7.9, 8 and 10 were written by ECBL. Sections 1, 2, 7.1 - 7.5, 7.10, 9, 11 and 12 were written by SP. Sections 4, 5, 13, 14 and 15 were written by Interscience. Sections 6, 7.6, 7.6.1 and 7.7 were written by ISSeP.

The EXAP rules presented in this study are applicable for the test method presented in standard prEN 50399 FIPEC scen 1, i.e. European Class B2CA- Class DCA. In addition analysis is performed

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2 Executive summary and conclusions

The CEMAC project is based on the findings of many years of research in the area of testing, modelling and classifying the burning behaviour of cables. CEMAC work has now added additional test data and analysis for predicting fire classification of cables. The underpinning technology that can be used to support CE-marking can be summarised as follows:

The selection of cables for the CEMAC project was based on the cables being representative of the European market and was selected to have a wide range of burning behaviour. This means that conclusions drawn from the project are representative of real European market situations.

The test procedure according to prEN 50399 FIPEC scen 1 originates from the FIPEC project [1] and was further improved through the work of CENELEC TC 20 WG 10.

The Round Robin which used the improved procedure showed good results comparable to the European SBI test round robin [6]. This was confirmed during the course of the CEMAC test programme.

The classification criteria according to the Commission decision [4] were considered during the course of the EXAP analysis and they were found to be consistent and posed no problems in developing the EXAP-system.

The calculation procedures required for the EXAP rules for cables are not obvious as the fire performance of a cable is quite complex. Thus simple rules based on simple single parameters such as the amount of combustible materials, and testing worst and best case are not possible. There will be outliers due to influences of the number of conductors, type of shield etc. A new parameter “

χ

” was developed to facilitate EXAP development. This is defined by the equation:

combust V d c 2 =

χ

where d [m] Outer diameter.

Vcombust [m2] Non-metallic volume per meter ladder. c [] Number of conductors in one cable.

This parameter was used to calculate which cables to select for test and a specific EXAP procedure was developed. In addition cable families that fall outside of the ranges of the database can also, under certain conditions, be subjected to EXAP using a statistical analysis developed in this project.

The precision of the specific EXAP was calculated using the database. The result was that the risk for drawing the wrong conclusion based on the EXAP procedure is virtually zero, see Table 3 below.

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Table 3. Error rate for the different classification parameters.

Total number of

combinations Number of incorrect classifications Percentage of incorrect classifications Peak HRR [kW] 166 0 0 THR [MJ] 166 0 0 FIGRA [Ws-1_] ₁₆₆ ₁ _0.6% Flame spread [m] 161 1 0.6% Peak SPR [m2_s-1_] ₁₆₆ ₃ _1.8% TSP [m2_] ₁₆₆ ₄ _2.4%

The error rates reported in the table are given for each individual classification parameter. As can be seen the number of incorrect classifications is very low for all parameters. It is highly unlikely that a cable would be wrongly classified in this system. In order that a cable should be erroneously classified as for example B2ca while in reality it is Cca it would need to have been classified as B2ca for

all classification parameters: peak HRR, THR, FIGRA and Flame spread. The confidence of the EXAP procedure is therefore high.

The developed EXAP procedures are not applicable to data cables and optical cables as they were outside the scope of the study. However, tests were performed on these cables and the data, although limited, was analysed. The analysis showed some promising trends for EXAP rules, but more work for a conclusion is needed.

The small flame test EN 60332-1-2 was found to be not significant in this project. The entire cable population tested passed this test. EXAP can therefore be similar to the main procedure as it seems not be important how this is done.

Smoke production measured according to EN 61034-2, the 3 m cube, is fundamentally different from how SPR is measured in prEN 50399. In EN 61034-2 a certain length of a cable is burning and the smoke is accumulated in a box having a volume of 27 m3_{. In the prEN 50399 test a cable ladder is}

burning and the instantaneous smoke production is measured, a so called flow through system. No correlation between the tests was expected, which was confirmed. The best agreement was found when comparing total smoke production, TSP, according to prEN 50399 with EN 61034-2. This would be expected as two integral values are compared; smoke accumulation in the 3 m cube box with integrated smoke production rate in the flow through system. It was also found that TSP was the determining parameter for classification in almost all cases. However, all of the products passing the s1 level in prEN 50399 were either s1a or s1 b according to the 3 m cube. In other words, you must meet the s1 criteria to be sure that the product will meet either s1a or s1b. This is consistent with the classification criteria, see Table 1, which are:

s1a = s1 and transmittance in accordance with EN 61034-2 ≥ 80% s1b = s1 and transmittance in accordance with EN 61034-2 ≥ 60% < 80%

However, since the s1 rating at least means that s1b is fulfilled, the deletion of the s1b class could be considered as it is not adding any further information.

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• The testing procedures are well developed, repeatable and reproducible.

• The error rates from the proposed EXAP procedure appears to be virtually zero considering the available data and therefore an EXAP according to this procedure should be quite stable. • The classification criteria from the commission decision seem to work well together with

testing and EXAP procedures.

• The developed EXAP procedures are not applicable to data cables and optical cables. • The small flame test may be subject to CWFT.

• Smoke production classification is consistent between the two tests involved in the sense that cables classified as s1a or s1b in the EN 61034-2 test are also classified as s1 according to prEN 50399. It can be considered whether the s1b class should be deleted.

3 Cable selection and procurement

Cable selection for the test program was made on the basis of achieving a selection of those generic power, data and optical fibre cable constructions (generic families) that are widely available on the European market.

The cables selected to represent each generic family of power cables include a range of conductor sizes from approximately the smallest to approximately the largest commonly available.

Within each generic family, specific sub families of cables containing PVC and halogen free materials were procured as both types are widely available on the market. Additionally, both copper and aluminium conductor were procured.

Because of the very wide market applicability of the unarmoured multicore power cable types and the varying national standard designs for such types, specific families from more than one country were procured.

The specific families of cables were also chosen to represent a wide range of burning behaviour as judged by pre-existing tests. This ranged from designs with no special reduced flame propagation performance which were expected to fall in Class Dca /Eca to those with good reduced flame

propagation performance which were expected to fall in Class B2ca/Cca. The test results achieved

have demonstrated that such a range of burning behaviour was achieved. Overall, some 115 samples from 9 countries were procured from within the Europacable membership.

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Within this report, the families of cables are identified by a Group number:

- Generic family - single core unsheathed power cables with copper conductor Sub family - PVC – Group 11

Sub family - halogen free – Group 12

- Generic family - single core sheathed power cables Sub family - PVC with copper conductor – Group 9

Sub family - halogen free with copper conductor – Group 10 Sub family - halogen free with aluminium conductor – Group 10

- Generic family - unarmoured multicore power cables with copper conductors Sub family - PVC - Group 7

Sub family - halogen free – Group 8a

Group 8b – Different manufacturer

Group 13 – Different manufacturers

- Generic family - armoured multicore power cables with copper conductors Sub family - PVC – Group 5

Sub family - halogen free – Group 6

- Generic family - screened and unscreened data cables – Group 1 - Generic family - optical fibre cables

Sub family - single tube – Group 3 Sub family - loose tube – Group 3 Sub family - corrugated tube – Group 3 Sub family - tight buffer – Group 3

- Generic family - telecommunication cables with copper conductors – Group 2 (No cables were supplied in this Group)

- Generic family - co-axial cables – Group 4 (No cables were supplied in this Group)

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Group number and

description Cable ref Conductors Outer diameter (mm) Cables or bundles per ladder EXAP-parameter c/(d2_∙V combust) 1 screened and unscreened data cables C/1/1 4pU/UTP 5.8 25 0.049

C/1/2 4pU/UTP 6 25 Not available

C/1/3 4pF/UTPC5 6 25 0.040

C/1/4 4pF/UTPC5 6.2 25 Not available

C/1/5 4pF/UTPC6 6.8 21 0.038

C/1/6 4pF/UTPC6 7.1 21 0.036

C/1/7 4pF/UTPC6 Not used

C/1/8 4pF/UTPC6 6.1 25 0.042

C/1/9 4pSF/UTP 6.1 25 Not available

C/1/10 4pSF/UTP Not used

C/1/11 4pS/FTP 7.7 19 0.038 C/1/12 4pS/FTPC7 7.6 19 0.027 C/1/13 4pS/FTPC7 7.5 19 0.034 C/1/14 4pS/FTPC7 7.3 21 0.029 C/1/15 4pS/FTPC7 7.4 21 0.033 C/1/16 32pF/UTPC5 16 9 0.094 2 copper telecommunication PVC and halogen free

No cables were supplied in this Group.

3st

optical fibre cables C/3/1 Central tube 2 fibre 10 15 – C/3/2 Central tube 12 fibre 6.2 25 – C/3/3 Central tube 24 fibre 10.8 14 – C/3/4 Central tube 12 fibre 9.5 15 – C/3/5 Central tube 12 fibre 6.5 25 –

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description Cable ref Conductors Outer diameter (mm) Cables or bundles per ladder EXAP-parameter c/(d2_∙V combust) 3lt

optical fibre cables C/3/6 Loose tube x fibre Not used C/3/7 Loose tube y

fibre Not used

C/3/8 Loose tube 12/24 fibre 21.5 7 – C/3/9 Loose tube 24 fibre 12.5 12 – C/3/10 Loose tube 60 fibre 12.4 13 – 3ct

optical fibre cables C/3/11 Corrugated loose buffer tube 6/72 14.1 11 – C/3/12 Corrugated loose buffer tube 6/72 14.4 11 – C/3/13 Corrugated loose buffer tube 12/144 18 8 – 3tb

optical fibre cables C/3/14 Tight buffer 6 fibre 5.1 30 – C/3/15 Tight buffer 12 fibre 6.2 24 – C/3/16 Tight buffer 24 fibre 8 19 – C/3/17 Tight buffer 12 fibre 6.7 21 – 4

co-axial cables No cables were supplied in this Group. 5

armoured multicore power cables with copper conductors PVC C/5/1 2 x 1.5 10 15 21.3 C/5/2 4 x 4.0 15 10 22.1 C/5/3 4 x 10 19 8 16.8 C/5/4 4 x 25 28 6 11.2 C/5/5 4 x 50 34 5 9.1 C/5/6 4 x 240 62 3 4.0 C/5/7 27 x 1.5 26 6 81.9 6 C/6/1 2 x 1.5 11 14 17.2

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(mm) per ladder c/(d2_∙V combust) 7 unarmoured multicore power cables with copper conductors PVC C/7/1 2 x 1.5 9 17 23.6 C/7/2 7 x 1.5 12.5 13 73.5 C/7/3 3 x 2.5 10 15 32.1 C/7/4 4 x 4.0 12.5 13 33.0 C/7/5 5 x 16 22 7 21.8 C/7/6 4 x 35 27 6 12.0 C/7/7 4 x50 28 6 11.8 C/7/8 4 x 185 48 4 6.1 8a unarmoured multicore power cables with copper conductors halogen free C/8a/1 2 x 1.5 9.7 15 21.2 C/8a/2 7 x 1.5 12.5 12 55.9 C/8a/3 3 x 2.5 10.6 14 29.4 C/8a/4 4 x 4.0 12.6 12 32.2 C/8a/5 5 x 16 21.3 7 18.2 C/8a/6 4 x 35 28 6 15.0 C/8a/7 4 x 50 28.3 6 13.4 C/8a/8 5 x 150 49.1 4 8.8 8b unarmoured multicore power cables with copper conductors halogen free C/8b/1 2 x 1.5 9.6 15 23.0 C/8b/2 7 x 1.5 11.9 13 56.9 C/8b/3 3 x 2.5 11.5 13 29.1 C/8b/4 4 x 4.0 12 13 35.7 C/8b/5 5 x 16 21.8 7 20.9 C/8b/6 4 x 35 27.5 6 13.3 C/8b/7 4 x 50 31.4 6 12.9 C/8b/8 4 x 150 51.9 4 7.8 9

single core sheathed power cables with copper conductor PVC C/9/1 1 x 1.5 6 25 20.0 C/9/2 1 x 4 7 21 17.3 C/9/3 1 x 10 10 15 9.5 C/9/4 1 x 25 12 13 8.3 C/9/5 1 x 50 15 10 5.3 C/9/6 1 x 95 19 8 3.7 C/9/7 1 x 150 22 7 3.0 C/9/8 1 x 240 27 6 2.3 10

single core sheathed power cables with copper conductor halogen free C/10/1 1 x 2.5 6.3 25 18.0 C/10/2 1 x 6 9 17 11.1 C/10/3 1 x 10 11.8 13 9.3 C/10/4 1 x 25 14.2 11 6.8 C/10/5 1 x 70 18.8 8 4.2 C/10/7 1 x 95 21.4 7 3.8 C/10/9 1 x 150 22.9 7 3.3 C/10/11 1 x 240 28.7 6 2.4

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description Cable ref Conductors Outer diameter (mm) Cables or bundles per ladder EXAP-parameter c/(d2_∙V combust) 10

single core sheathed power cables with aluminium conductor halogen free C/10/6 1 x 70 Al 18.6 8 4.3 C/10/8 1 x 95 Al 20.6 7 3.4 C/10/10 1 x 150 Al 22.3 7 2.9 C/10/12 1 x 240 Al 27.4 6 2.4 11 single core unsheathed power cables with copper conductor PVC C/11/1 1 x 1.5 2.92 15 98.6 C/11/2 1 x 4 4.08 15 47.4 C/11/3 1 x 10 6.04 25 11.9 C/11/4 1 x 25 9.05 17 6.9 C/11/5 1 x 50 12.2 12 4.4 C/11/6 1 x 95 15.9 9 3.0 C/11/7 1 x 150 19.3 8 2.7 C/11/8 1 x 240 25.1 7 2.2 12 single core unsheathed power cables with copper conductor halogen free C/12/1 1 x 1.5 2.8 15 114.5 C/12/2 1 x 4 4 15 49.8 C/12/3 1 x 10 6.1 25 12.1 C/12/4 1 x 25 8.9 17 7.1 C/12/5 1 x 50 11.2 14 5.2 C/12/6 1 x 95 15 10 3.1 C/12/7 1 x 150 19.5 8 2.7 C/12/8 1 x 240 25 7 2.0 13 unarmoured multicore power cables with copper conductors halogen free C/13/1 2 x 1.5 10.1 15 22.4 C/13/2 3 x 10 16.2 9 17.3 C/13/3 4 x 25 24.3 7 15.6 C/13/4 2 x 1.5 9.9 15 22.1 C/13/5 3 x 10 16.6 9 17.7 C/13/6 4 x 25 23.3 7 15.6 C/13/7 2 x 1.5 12 13 15.8 C/13/8 3 x 10 18.2 8 15.7 C/13/9 4 x 25 26.8 6 13.2 C/13/10 5 x 1.5 9.9 15 45.9 C/13/11 4 x 10 15.3 10 18.3 C/13/12 5 x 16 20.5 7 19.4

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4 Experimental program and laboratory qualification

through round robin

The main experimental programme consisted of testing 12 groups of cables in accordance with the procedures outlined in prEN 50399. Work was carried out in parallel in 4 laboratories that were nationally accredited to undertake cable testing. These were defined as the “research laboratories”. Tests were carried out in parallel by a group of industry laboratories. In all 115 different cables were tested and each cable was tested both in one research laboratory and in one industry laboratory. The CEMAC study was initiated shortly after the CENELEC TC20 WG10 prEN 50399 round robin. The latter was intended to investigate the compliance of a number of laboratories equipment with prEN 50399, to identify any anomalies in the test method prEN 50399 that CLC TC20 WG10 may wish to consider for improvement and to investigate the repeatability and reproducibility of the test method using 4 cable types and a standard particle board. These same tests and procedures were used to qualify the Research Laboratories for equipment and operational compliance with the specification prEN 50399.

In the CENELEC TC20 WG 10 round robin 18 laboratories participated in this work programme. All 18 laboratories had submitted questionnaires and had completed calibration studies. Although there were some marginally non compliant equipment matters in that group, all 18 laboratories were asked to progress to test particle board. Particle board was used as reference material due to its stable and repeatable performance. 12 laboratories had submitted cable test data and others were improving their systems for testing when the round robin closed.

The particle board and 4 cables were tested in duplicate to ascertain the data on repeatability and reproducibility amongst the laboratories that participated in this work.

In comparison with other standard fire test methods, the heat release data examined using ISO 5725 demonstrated good repeatability and reproducibility with the poorest results coming from bunched cable tests. For the samples tested the results were equal or better than those seen in the recent SBI round robin which benefited from having a larger product test set and a wider range of product performances.

Smoke production results were also acceptable and similar to the SBI round robin results. Some laboratories had considerable equipment problems which only became apparent after calibration checking when they tested products that generated smoke. This indicated that some form of smoke calibration check should be introduced into the standard.

As a result of this finding, a calibration procedure based on burning 1250 g of heptane was introduced as a smoke calibration check.

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4.1 Qualifying programme of work

Each laboratory participating in the CEMAC project was required to fulfil a number of qualification criteria before being qualified to test the CEMAC database cables. These were the compliance requirements that had been implemented in the CENELEC round robin and the same cables were used for this work. Commissioning calibration and daily calibration procedures listed in Paragraph 5 and Appendix E of prEN 50399 were undertaken and checked by the coordinator Interscience Communications. Data was supplied to the assessor Interscience Communications who adjudicated compliance. The qualification procedure included:

1. Each laboratory submitting a questionnaire to the coordinator detailing the instrumentation used and the equipment set up at their laboratory, in order to investigate any non compliances issues.

2. Each laboratory performed a set of commissioning flow profile and calibration tests in accordance with the protocols described in prEN 50399RR and the coordinator examined these measurements

3. Each laboratory tested specimens of particle board (with dimensions of 2500 mm x 300 mm x 12 mm) in accordance with the coordinator test protocol and submitted the results for analysis.

4. Each laboratory tested 4 different cables in accordance with the procedures given in prEN 50399RR.

4.2 Data base cable tests

The cable described in Section 3 were selected and supplied by Europacable companies and tested as groups in the Research Laboratories using the test protocols described in prEN 50399.

The results were supplied along with daily calibrations to the coordinator who checked the calibrations and analyzed the data and entered the data into a central data base. The results were transposed into excel files for easy viewing by project partners. One excel sheet was provided for each of the 12 cable groups

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5 Data management

5.1 Introduction

The CEMAC programme uses the new generation of fire tests, based on the oxygen consumption technique and the output from theses tests is vector data. Such test results make available the complete time histories of variables which include the heat release rate and smoke production rate. So much data creates a problem in the management of test data generated by more than one source and hence an efficient test data management needed implementing in this project. Within the CEMAC programme a large number of tests were performed which produced a large amount of data. In total approximately 200 tests were conducted and the results had to be made available to the participants of the CEMAC programme. Data had to be transferred between the laboratories in a convenient and reliable way.

The laboratories that produced the data used various systems for data acquisition and data reduction, which meant that data was initially collected and stored in different formats. There was a potential for problems when data was to be transferred to other participating laboratories. Also the users of the data worked with different data-evaluation systems requiring specific input formats. The problem was solved by creating a common data format and the data base managers working closely with the participating laboratories to enable data to be transferred to the common raw format. Laboratories were each supplied with proven data analysis software. One result of this exercise was that this raw format has now been integrated into the final draft of EN 50399

5.2 Data bank

All data produced in the CEMAC project is available from a central data bank held by the data coordinator Interscience Communications Ltd,. Though the actual storage volume of data is not extremely large, it is best to view the results via 12 composite Excel workbooks containing the reformatted experimental data on each test within each Group.

5.2.1 Contents of the data bank

The test data, stored in the data bank, contain a large amount of information about each test. The most important information stored is the vector data, such as the time histories of heat release rate and smoke release rates. In addition to the vector data, relevant scalar data are stored. Different categories of data can be distinguished in the information kept in the data bank:

Organisation

Data on the testing organisation have been stored for each test.

Material and product information

The information in this block contains specifications on the tested cable product.

Scalar test data

For every test performed, a number of scalar values were stored. These give a summary of a test, with such parameters as peak heat release rate, peak smoke production, average heat release rate, etc.

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Vector data

For every test performed, a number of vectors of data were stored. These are a time history of various raw data readings and fire parameters measured for a test, with such parameters as oxygen concentration, heat release rate, smoke production rate etc.

5.2.2 Organisation and handling of data base

All calibration and cable test raw data was sent to the coordinator after each days testing. This was sent in an agreed raw data format (See Section 14) that can be generated by several commercial software data acquisition packages. The coordinator worked with participating laboratories whose software could not provide this format to facilitate conversion.

5.2.3 Availability of the data

The database contents were available to all participating RTD laboratories in the CEMAC project. This was constantly updated and distributed as each test became available in the project. After each test was analysed by the coordinator and the calibrations checked, the results were added to the appropriate Excel workbook for the cable group which was then emailed to appropriate laboratories. The Excel workbooks contain all vector information on the key parameters of heat and smoke release and the integral summary sheet also contains information on flame spread, flaming droplets and any smoke overspills.

To give all the participants in the project an opportunity to follow the actions in the project, all information was published at the CEMAC-website. This was accessible by password which was sent to the participant after registration. All documentation from meetings together with a summary in an Excel workbook of all the test results were published and updated throughout the project. The summary includes, besides the test results, important cable parameters, e.g. combustible volume per meter ladder, which were used in the EXAP-analysis.

5.3 Data formats, storing and exchanging

One of the objectives of the data management programme within CEMAC was to enable all participating laboratories to use their own systems for data acquisition, reduction and evaluation. The individual laboratories did not have to develop new software in order to access the data they generated in the programme.

5.3.1 Internal laboratory formats

The individual laboratories were able to store data in any format. The only restriction was that test results should be converted to the standard CEMAC format.

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Each participating laboratory was required to store the raw data from all of the tests, at least as long as the CEMAC programme was running. It was also required to send the raw data to IC for secondary backup storage and data conversion.

5.3.4 Analysis

All Raw data sent to the co-ordinator was analysed by Fire Testing Technology Ltd CableSOFT software. This software had been checked for accuracy against SPs independently written analysis software at the early phases of the project. Each participating RTD laboratory was also given a set of this software to check daily calibration and to analyse the converted data.

5.4 Exchanging data

The structure of the CEMAC programme means that at a certain time, data had to be retrieved from the database and also exchanged between the individual laboratories.

The method of communicating information was to transfer data as e-mail attachments to IC. A CEMAC–only mailbox was used for transferring data, text and information to the CEMAC programme.

5.4.1 Codes for identification of CEMAC tests in the data bank

In order to minimise the information that had to be transferred and to create unique sample identification for the CEMAC programme, a common coding and test numbering protocol was used identifying tests and files throughout the project.

It was essential that the coding was always used in the reporting to the central data bank. The coding involved identifying each test by a unique code that identified the laboratory, the test type (i.e. calibration or cable test) and the incremental test number. These unique codes were used to label each file for each specific test.

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6 Large scale tests results

6.1 Test method

The test method is based upon the full scale test developed in the European project FIPEC (previously referred as FIPEC Sc. 1) and further amended for its use for main Euroclasses for cables (Euroclasses B2ca to Dca).

The test method is described in prEN 50399, which specifies the test apparatus and test procedures for the assessment of the reaction to fire performance of cables to enable classification under the Construction Products Directive to be achieved.

With regard to the former FIPEC full-scale test (for description see [1]), the main modification included in prEN 50399 concerns a better defined air input system, with a standard design and recommendations for the air flow measuring system. prEN 50399 has also included a heptane calibration in order to further check the smoke measuring system.

All the tests were performed according to prEN 50399 for Class B2ca, Cca and Dca (i.e. a burner output

= 20.5 kW and no backing board on the ladder).

HRR calculations were done as described in Annex A of prEN 50399 and smoke production calculations were done according to Annex B of prEN 50399.

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Measurements of HRR (kW) and SPR (m²/s):

For HRR, the raw data were processed by first subtracting the burner output (20.5 kW) and then a sliding 30-s average was calculated in order to obtain the HRR30 for the cable only. For SPR, a sliding

60-s average was calculated in order to obtain the SPR60.

During the test, occurrence of flaming droplets and/or particles was noted and their duration measured.

Table 5 to Table 7 summarize the parameters obtained and analysed. Parameters required to determine the Euroclassification are in bold.

Table 5 HRR Parameters Parameter Unit 1. Vector HRR30 kW 2. Scalar Peak HRR30 kW

t Peak HRR30 s Time to reach the peak HRR

THR1200 MJ FIGRA kW/s Table 6 SPR Parameters Parameter Unit 1. Vector SPR60 m²/s 2. Scalar Peak SPR60 m²/s

t Peak SPR60 s Time to reach the peak SPR

TSP1200 m² SMOGRA cm²/s² Table 7 Others Parameter Unit Flame spread m Flaming Droplets/Particles Y/N (≤10s, > 10s) *

* Every test was video recorded in part to enable the measurement of the duration of flaming droplets / particles when they occurred.

In addition, peculiar phenomena such as falling of specimen parts or smoke not completely captured by the hood were recorded.

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6.3 Number of tests

All cables (see Section 3) were tested by one RTD laboratory (SP, ISSeP, VDE and LSF).

Most cables were tested in duplicate, i.e. both in a RTD laboratory and in an Europacable laboratory. Unacceptable differences between the results of 2 laboratories were investigated and where considered necessary the concerned test was repeated.

The tested cables are distributed as follows: • Group 1: 14 • Group 3st: 5 • Group 3lt: 3 • Group 3ct: 3 • Group 3tb: 4 • Group 5: 7 • Group 6: 7 • Group 7: 8 • Group 8a: 8 • Group 8b: 8 • Group 9: 8 • Group 10: 12 • Group 11: 8 • Group 12: 8 • Group 13: 12

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Results from RTD laboratories were used to determine the classification and as input for EXAP. Detailed results are presented in Annex E (RTD laboratories).

A short review of the main results, Group per Group, is included in this section. Classifications were determined according to decision 2006/751/EC [4]and the draft of the amendment of prEN 13501-1.

6.4.1 Group 1

(Screened and unscreened data cables)

All but one cable are 4p, screened or unscreened cables. PVC and halogen free sheathed types are included. Their diameter is in the range 6 – 8 mm (except 26 mm for 32 p). No cable was tested in bundles.

The following tables give the extreme results obtained for the considered Group, for every parameter used for Euroclasses.

Table 8 HRR & FS

Peak HRR30 THR1200 FIGRA FS

Min 10.9 1.6 89.3 0.3

Max 408 57.9 2075 3.3

In terms of classification, this gives from B2ca to Eca, thus the whole range of Euroclasses is covered.

All cables with screened twisted pairs but one achieve B2ca classification. One amongst those cable

fails for class B2ca only by a short margin and for a single parameter (Peak HRR). All cables with

unscreened pairs but one are ranked Dca at best.

Table 9 SPR

Peak SPR60 TSP1200

Min 0.02 3.4

Max 3.8 393

Smoke classification ranges from s1 to s3 (s3 corresponding to the cable with Euroclass Eca, i.e. a

ranking for which smoke classification is normally not established). Flaming droplets / particles: from d0 to d2.

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6.4.2 Group 3st

(Optical fibre cables – central tube)

Their diameter is in the range 6 - 11 mm. No cable was tested in bundles.

Min 41.0 22.0 117 2.2

Max 229 51.3 758 3.3

Classification: All cables are ranked in one class, Dca. The performance does not seem to depend on

the number of fibres.

Table 11 SPR

Peak SPR60 TSP1200

Min 0.09 55.0

Max 0.46 104

Smoke classification: s2

Flaming droplets / particles: d0 or d1.

6.4.3 Group 3lt

(Optical fibre cables – loose tube)

Their diameter is in the range 12 - 22 mm, buffer count 6 - 24 and fibre count 24 - 288. No cable was tested in bundles.

The following tables give the extreme results obtained for the considered Group, for every parameter used for the Euroclasses.

Min 49.7 53.5 57.0 1.3

Max 177 75.7 268 3.3

Classification: Cca to Eca. The performance does not seem to depend on the number of fibres but more

on the actual design from different suppliers (one has to remain cautious considering the limited number of tested cables). The high buffer and fibre count cable with double sheath design obtained Cca.

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(Optical fibre cables – corrugated tube)

Their diameter is in the range 14 - 18 mm, buffer count 6 - 12 and fibre count 72 - 144. No cable was tested in bundles.

Min 18.8 9.6 34.8 0.5

Max 303 132 352 3.3

Classification: B2ca (2 cables from one supplier) or Eca (1 cable from a second supplier of different

design). The performance does not seem to depend on the number of fibres but more on the actual design from different suppliers (one has to remain cautious considering the limited number of tested cables). Table 15 SPR Peak SPR60 TSP1200 Min 0.07 30.4 Max 0.90 249 Smoke classification: s1 or s3 Flaming droplets / particles: d0.

6.4.5 Group 3tb

(Optical fibre cables – tight buffer)

Their diameter is in the range 5 - 8 mm, fibre count 6 - 24. No cable was tested in bundles.

Min 25.1 11.6 148 1.0

Max 156 49.6 242 3.3

Classification: B2ca to Dca. The performance does not seem to depend on the number of fibres (one has

to remain cautious considering the limited number of tested cables).

Peak SPR60 TSP1200

Min 0.03 11.1

Max 0.41 134

Smoke classification: s1 or s2. Flaming droplets / particles: d0.

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6.4.6 Group 5

(Armoured multicore power cables with copper conductors, PVC)

Their diameter is in the range 10 - 62 mm. No cable was tested in bundles.

The following tables give the extreme results obtained for the considered Group, for every parameter used for Euroclasses

Min 27.5 12.7 101.2 1.0

Max 344 112 1485 3.3

Classification: from B2ca to Eca, thus the whole range of Euroclasses is covered. Most cables belong to

Euroclass Eca due to their high THR. There is some trend that the fire performance increases with the

cable size, although this is not always true.

Peak SPR60 TSP1200

Min 0.27 113

Max 4.6 681

Smoke classification: s2 or s3

Flaming droplets / particles: d0 except one cable (d2).

6.4.7 Group 6

(Armoured multicore power cables with copper conductors, halogen free) Their diameter is in the range 11 - 62 mm. No cable was tested in bundles.

Min 14.4 9.8 30.0 0.9

Max 51.2 25.1 105 1.7

Classification: from B2ca and Cca, thus cables exhibiting high fire performance. There is some trend

that the fire performance increases with the cable size.

Peak SPR60 TSP1200

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(Unarmoured multicore power cables with copper conductors, PVC) Their diameter is in the range 9 - 48 mm. No cable was tested in bundles.

The following tables gives the extreme results obtained for the considered Group, for every parameter used for Euroclasses

Min 5.4 1.1 24.2 0.5

Max 190.2 85.4 177.5 3.3

Max without “outlier” 41.3 24.8 123.7 2.0

Classification: B2ca, with one cable Cca, and one cable Eca. This last cable (C/7/2, 7x1.5 mm²) behaves

as an “outlier”, i.e. its fire spread is in another order of magnitude. Due to this unexpected result, the concerned cable was retested in another RTD laboratory. This new test confirmed the “outlier” behaviour. There is some trend that the fire performance increases with the conductor size.

Figure 2 HRR for all cables of Group 7, showing the « outlier »

Peak SPR60 TSP1200

Min 0.37 102

Max 2.9 1462

Smoke classification: s2 or s3 Flaming droplets / particles: d0.

6.4.9 Group 8a

(Unarmoured multicore power cables with copper conductors, halogen free)

Group 7: unarmoured multicore power cables with copper conductors PVC HRR30 -5 45 95 145 195 0 200 400 600 800 1000 1200 1400 1600 1800 time (s) HRR 30 (k W) 2 x 1.5 (1) 7 x 1.5 (1) 3 x 2.5 (1) 4 x 4 (1) 5 x 16 (1) 4 x 35 (1) 4 x 50 (1) 4 x 185 (1) 7x1.5(1)

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Min 10.7 7.6 39.7 0.6

Max 70.3 49.2 130 3.3

Classification: from B2ca and Dca. No cable with Cca performance.

Amongst the tested cables, those with conductor size 5x16 and higher are ranked B2ca

Peak SPR60 TSP1200

Min 0.03 5.1

Max 0.15 60.3

Smoke classification: s1 or s2

Flaming droplets / particles: d0 or d2.

6.4.10 Group 8b

(Unarmoured multicore power cables with copper conductors, halogen free) Their diameter is in the range from 10 to 52 mm. No cable was tested in bundles.

Min 20.7 13.2 48.0 0.7

Max 326 101 451 3.3

Classification: from B2ca and Eca. No cable is ranked Dca. There is an obvious trend that the fire

performance increases with the conductor / cable size. All cables in class Eca (4 cables) are relegated

due to high THR1200.

Peak SPR60 TSP1200

Min 0.03 13.7

Max 0.87 197

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(Single core sheathed power cables, PVC with copper conductor)

Their diameter is in the range from 6 to 27 mm. No cable was tested in bundles.

Min 199 46.3 334 3.3

Max 434 101 3409 3.3

All cables burnt completely (maximum damage length) Classification: Eca.. Table 29 SPR Peak SPR60 TSP1200 Min 1.5 630 Max 5.0 1013 Smoke classification: s3

Flaming droplets / particles: d0 to d2.

6.4.12 Group 10

(Single core sheathed power cables, halogen free with copper or aluminium conductor) Their diameter is in the range from 6 to 29 mm. No cable was tested in bundles.

Min 23.4 12.7 25.8 0.9

Max 209 63.9 343 3.3

Classification: from B2ca to Dca.. There is an obvious trend that the fire performance increases with the

conductor / cable size.

Peak SPR60 TSP1200

Min 0.02 5.0

Max 0.30 90.1

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6.4.13 Group 11

(Single core unsheathed power cables with copper conductor, PVC)

Their diameter is in the range from 2.9 to 25 mm. 2 cables were tested in bundles.

Min 11.0 3.4 54.8 0.6

Max 28.8 8.5 297 1.0

Classification: from B2ca to Cca. thus cables exhibiting high fire performance. FIGRA is the parameter

causing the cables to be ranked Cca. The smallest cables belong to Euroclass Cca (including the 2

cables tested in bundles). There is an obvious trend that the fire performance increases with the conductor / cable size.

Peak SPR60 TSP1200

Min 0.35 110

Max 3.5 582

6.4.14 Group 12

(Single core unsheathed power cables with copper conductor, halogen free)

Their diameter is in the range from 2.8 to 25 mm. Two cables were tested in bundles.

Min 7.3 4.4 43.8 0.4

Max 247 69.4 656 3.3

Classification: from B2ca to Dca. The two cables tested in bundles get the Euroclass Dca. There is an

obvious trend that the fire performance increases with the conductor / cable size.

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6.4.15 Group 13

(Unarmoured multicore power cables with copper conductors, halogen free)

This Group does not correspond to a homogeneous group of cables but a sampling of similar design multicore cables form four manufacturers. This group was included to check that the rules found for groups 8a and 8b (unarmoured multicore power cables with copper conductors) are valid for other cable manufacturers.

Their diameter is in the range from 10 to 27 mm. No cable was tested in bundles.

Min 11.1 5.8 27.7 0.7

Max 125 68.4 207 3.3

Classification: from B2ca to Dca..

Peak SPR60 TSP1200

Min 0.004 1.8

Max 0.52 252

Smoke classification: s1 or s2. Flaming droplets / particles: d1 or d2.

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6.4.16 Spread of results – all groups

The range of fire performance for all the cables groups is illustrated in the following figures (for the parameters required for the determination of the Euroclassification).

Figure 3 Peak HRR for all groups

THR1200

20

40

60

80

100

120

140 MJ

min

max

B2ca Cca Dca

Peak HRR30

0

50

100

150

200

250

300

350

400

450

500

1 3st

3lt

3ct

3tb

5

6

7 8a

8b

9

10

11

12

13 Group

kW

min

max

B2_ca C D_ca ca

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Figure 5 FIGRA for all groups

Figure 6 Peak SPR for all groups

Peak SPR

0 1 2 3 4 5 1 3st 3lt 3ct 3tb 5 6 7 8a 8b 9 10 11 12 13 Group m²/s min max s1 s2

FIGRA

0 200 400 600 800 1000 1200 1400 1 3st 3lt 3ct 3tb 5 6 7 8a 8b 9 10 11 12 13 Group kW/s min _max B2ca Dca Cca

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Figure 7 Peak TSP for all groups

6.4.17 Selection of typical results

Group 5: armoured multicore power cables with copper conductors PVC HRR30 0 50 100 150 200 250 300 350 400 0 200 400 600 800 1000 1200 1400 1600 time (s) HRR 30 (k W) 2 x 1.5 (R) 4 x 4.0 (R) 4 x 10 (R) 4 x 25 (R) 4 x 50 (R) 4 x 240 (R) 27 x 1.5 (R)

TSP

0 200 400 600 800 1000 1200 1400 1 3st 3lt 3ct 3tb 5 6 7 8a 8b 9 10 11 12 13 Group m² min max s1 s2

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Example 2: Group with “low level” of fire performance (HRR)

Example 3: Group with “high level” of fire performance (HRR)

0 50 100 150 200 250 300 350 400 450 500 0 200 400 600 _{time (s)}800 1000 1200 1400 1600 HRR 30 (k W) 1 x 1.5 (R) 1 x 4 (R) 1 x 10 (R) 1 x 25 (R) 1 x 50 (R) 1 x 95 (R) 1 x 150 (R) 1 x 240 (R)

Group 11 single core unsheathed power cables with copper conductor PVC

HRR30 0 5 10 15 20 25 30 35 40 45 0 200 400 600 800 1000 1200 1400 1600 time (s) H RR 30 (kW ) 1 x 1.5 (1) 1 x 4 (1) 1 x 10 (1) 1 x 25 (1) 1 x 50 (1) 1 x 95 (1) 1 x 150 (1) 1 x 240 (1)

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Example 4: “Low smoke” Group

Group 8a: unarmoured multicore power cables with copper conductors halogen free

SPR60 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0 200 400 600 800 1000 1200 1400 1600 time (s) SPR 60 (m ²/s ) 2 x 1.5 (1) 7 x 1.5 (1) 3 x 2.5 (1) 4 x 4 (1) 4 x 16 (1) 4 x 35 (1) 4 x 50 (1) 3 x 185 (1) 3x2.5(1R) 4x50(1R)

Group 11 single core unsheathed power cables with copper conductor PVC SPR60 0 0.5 1 1.5 2 2.5 3 3.5 4 0 200 400 600 800 1000 1200 1400 1600 time (s) SP R60 (m ²/s) 1 x 1.5 (1) 1 x 4 (1) 1 x 10 (1) 1 x 25 (1) 1 x 50 (1) 1 x 95 (1) 1 x 150 (1) 1 x 240 (1)

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Example 6: Reproducibility (RTD lab and Europacable Lab)

The reproducibility between the two laboratories is fairly good for all the cables of the selected group, as show by the figure for HRR vector results. Similar comparison is made for SPR results.

-50 0 50 100 150 200 250 300 350 400 0 200 400 600 800 1000 1200 1400 1600 time (s) HRR 30 (k W) 2 x 1.5 (R) 2 x 1.5 (E) 4 x 4.0 (R) 4 x 4.0 (E) 4 x 10 (R) 4 x 10 (E) 4 x 25 (R) 4 x 25 (E) 4 x 50 (R) 4 x 50 (E) 4 x 240 (R) 27 x 1.5 (R) 27 x 1.5 (E)

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7 Extended application, EXAP

EXAP, extended application, is in this work approached as a way to predict classification based on a limited number of tests. Thus a substantial reduction of the number of tests for a certain product family is achieved. The EXAP procedure is based on the population of tests in the project. Each of the classification criteria, peak HRR, THR, FIGRA, peak SPR, and TSP needs to be considered in an EXAP. As will be seen below the same approach can be used for all classification criteria for a particular cable type.

In Section 7.1 the concept of classification rules and the concept of safety margin are introduced. Section 7.2 contains a discussion about cables with singular behaviour in the test program (in which one cable within the range seems to show a different fire behavior from the other cables in this range) and how these are handled within the EXAP procedure. Section 7.3 briefly discusses how test results can be extrapolated with sufficient confidence for cables that are larger than the maximum size tested within the CEMAC project. Section 7.4 describes how an EXAP can be used also for other cable types than those that were included in the CEMAC project. Sections 7.5 and 7.7 contain discussions about EXAP for data and optical cables. Sections 7.8 and 7.9 contain discussions about EXAP for EN60332-1-2 and EN61034-2. Section 0 summarizes the EXAP procedure by a flow chart. In Section 11 of this report the detailed analysis of the test results is presented. A formal proposal for the EXAP rules is given in Section 12.

7.1 Safety margin

EXAP for simple materials, such as mineral wool [8], is often limited to testing of one or more, by the product parameters, chosen products from a product group and classifying all included products in the group according to the worst result. Cables, on the other hand, have more complex fire behaviour and it is not certain that the worst result in the included range is obtained for one of the tested products when the tested products are chosen by fundamental product parameters. This is illustrated in the theoretical example in Figure 8 where the general trend is that THR decreases with increasing diameter, d, but where the fourth cable makes a sudden jump and breaks the monotonically1

Figure 8

decreasing trend. It is clear that if the second and fifth cable would be tested and classification for all intermediate diameters would be based only on the worst tested result, i.e. the result for the second cable, classification would be too generous since the fourth cable, which belongs to class Dca

according to its THR value, would actually be classified as class Cca according the EXAP. It is a

general feature of cables that although their fire performance can be qualitatively well described by a parameter, for example the diameter, the dependence is not necessarily monotonic, in contrast to less complex materials such as mineral wool. The selection of an appropriate parameter for describing the fire performance of cables is far from trivial. In the diameter has been chosen rather arbitrarily. The selection of cable parameter, that is the x-axis in the figures, depends not only on the intrinsic fire performance of one cable but also on the mounting procedures as described in prEN 50399. This topic is covered in Section 7.2.

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Figure 8 THR as a function of outer diameter. Theoretical example.

For this reason a safety margin needs to be added to the worst result for the two tested cables. The magnitude of the safety margin will depend on how large the deviations from monotonicity are. This is described by

sm

class

ν

= _max + Equation 1

where

ν_class is the value used for classification according to respective classification parameter

(peak HRR, THR, FIGRA, FS, peak SPR, and TSP),

νmax is the maximum, that is worst, test result of the tests that forms the basis of the EXAP,

and

νsm is the safety margin required for the particular classification parameter.

Taking Figure 8 as an example the deviation from monotonicity occurs between the third and the fourth cable. THR for the third cable is 28 MJ and THR for the fourth cable is 31 MJ. The required safety margin in this example, νsm, would therefore be 3 MJ. With such a safety margin the EXAP

would never, for this particular cable type, allow a too generous classification of any non-tested cable included in the EXAP. It has then been assumed that the data in Figure 8 include all cables. It should be noted that this safety margin is a result of the varying fire performance of different cables within one cable family. It is not a measure of the experimental uncertainty.

If, for example, a manufacturer wants to include the whole product range in Figure 8 in the EXAP, the first and the last (the eight) cable must be tested. νmax is obtained for the first cable and the result is:

MJ 32 3 29 max + = + = = _sm class

ν

Equation 2 0 5 10 15 20 25 30 35 0 20 40 60 80 100 THR [ M J] outer diameter [mm]

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This is above the class limit 30 MJ for class Cca for THR. Therefore classification, for THR, would be

into class Dca, where the class limit is 70 MJ, and the manufacturer would probably do more tests on a

cable diameter big enough that νmax ≤ 27 MJ. See Figure 9 for an illustration.

Figure 9 An attempt to include the entire product range in the EXAP results in a classification

value, νclass = νmax+νSM, that is higher than the THR class limit 30 MJ for class Cca.

If the manufacturers uses the fifth and the eighth cable for the EXAP the worst result, 20 MJ, would be obtained for the fifth cable and consequently:

MJ 23 3 20 max + = + = = _sm class

ν

Equation 3

This is below the class limit 30 MJ for class Cca for THR. This means that all cables with diameters

between 25 and 80 mm will be classified as Cca for THR, for the particular tested cable type. See

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Figure 10 The fifth (d=25 mm) and the eighth (d=80 mm) cable are tested and used as basis for the

EXAP. This results in a classification value νclass = νmax+νSM, that is lower than the THR

class limit 30 MJ for class Cca.

If the dependence of the classification parameter, e g THR, on the cable parameter, e g d, were always monotonic no safety margins would be required, see Figure 11. The reason for this is that if two cables are tested the intermediate cables will always have values of the classification that are lower than the maximum of the two tested cables.

Figure 11 THR as a monotonically decreasing function of outer diameter. Theoretical example.

0 5 10 15 20 25 30 35 0 20 40 60 80 100 outer diameter [mm] THR [ M J]

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Furthermore the graph can be allowed to be partly non monotonic as long as the non monotonic part is convex in the sense that there is one particular value of the classification parameters that is lower than its neighbours. An example of this is found in Figure 12.

Figure 12 THR as a function of outer diameter. The non monotonicity of the sixth cable is not a

problem since it is lower than its neighbours. Theoretical example.

In summary, it is results such as the fourth cable in Figure 8 that are the sources for the safety margins. The safety margins are determined based on the results from the tests in the CEMAC projects. Determination of safety margins is presented in Section 11 and the results are presented in Table 38. 0 5 10 15 20 25 30 35 0 20 40 60 80 100 outer diameter [mm] THR [ M J]