F I N A L R E P O R T

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1 Textile Testing Institute Notified Body No Accredited Testing Laboratory No Václavská 6, Brno Czech Republic F I N A L R E P O R T on results of international interlaboratory comparison of results pertaining to safety testing of floor coverings used in building industry Radiant panel according to EN ISO Prepared by: Vladimír Štork Approved by: Pavel Malčík Brno, on 30/08/2005

2 1. Contents 1. Contents Selected abbreviations, definitions and symbols Introduction Time schedule Preparation of test specimens Results and evaluation Evaluation of the data submitted Test evaluation Detailed examination of consistency and outlying values Summary of results in a graphic form of z-score Calculation of deviation estimations Summary of results Conclusions Selected abbreviations, definitions and symbols CF... critical heat flow HF-X... heat flow in minute X CHF... critical heat flow of quenching Umin... integral of darkening resulting from smoke Symbols used for the statistical assessment are shown directly in the text. 3. Introduction Accredited laboratories are requested to participate in interlaboratory comparisons, particularly if the test is requested by Authorised Bodies or Decrees of the Government. Flammability of floor coverings come under the requirements on structural products and it is one of the main criteria of the safety assessment. Therefore, we organised this interlaboratory comparison on the international basis to verify the accuracy of this test method. More than 20 laboratories had been addressed and ten laboratories actually participated. These include testing laboratories functioning within the frame of the European Notified Bodies, scientific institutions as well as laboratories involved in flammability testing of structural products. The following list of the trial participants is arranged in the alphabetical order and any potential relation to the laboratory code number is a pure coincidence. Textilní zkušební ústav, Václavská 6, Brno Page: 2 of 15

3 Institution name Address WWW AITEX - Instituto Tecnológico Textil Plaza Emilio Sala, Alcoy Spain CENTEXBEL Technologiepark 7 B-9052 ZWIJNAARDE Belgium CSI, Stock Company Pražská Praha 10, Hostivař Czech Republic Prüfinstitut Hoch Lerchenweg 1 D Fladungen Germany ITB - Building Research Institute ul. Ksawerów Warszawa Poland pros.vanhoeyland@centexbel.be dirk.simoens@centexbel.be vanis@csias.cz hoch.fladungen@t-online.de mailto:andrzej.borowy@itb.pl LNEC/DED Av Brasil, LISBON Portugal pina.santos@lnec.pt Laborleitung Fußbodentechnik ÖTI Ökologie.Technik.Innovation Österr. Textil-Forschungsinstitut Spengergasse 20 A-1050 Wien Austria vittek@oeti.at www: PAVUS, Stock Company Fire-fighting testing laboratory Čtvrť J.Hybeše Veselí nad Lužnicí Czech Republic TZU, State Enterprise Václavská Brno Czech Republic ZAG Ljubljana Dimiceva 12 SI-1000 Ljubljana Slovenia http: // kapl@pavus.cz stork@tzu.cz milan.hajdukovic@zag.si 4. Time schedule The samples were prepared during May The offers for participation were sent out early in March The samples were dispatched on Tuesday, May 24, In most cases, the measurements were carried out according to our instructions (as early as feasible) after receiving the samples, namely between June 1 and July 15, Some laboratories submitted the results belatedly, up to the end of August. The results obtained were received from all laboratories in the period of June 20 to August 31, This Report was completed on September 5, Textilní zkušební ústav, Václavská 6, Brno Page: 3 of 15

4 5. Preparation of test specimens Test specimens for the interlaboratory comparison were provided by a supplied directly for the purpose of the interlaboratory comparison. The selected textile and resilient floor coverings were provided from the regular production and cut to the size suitable for testing in accordance with requirements of EN ISO , being (1050 ± 5) mm long and (230 ± 5) mm wide. The specimen surfaces were not treated in order to keep equal conditions for the participating laboratories. The only requirements were a concrete base and a dispersing adhesive. The adhesive type was not specified assuming that a common type in each country would be used. Two basic materials were chosen for the interlaboratory comparison, namely: a textile floor covering sample A and a resilient floor covering sample B. 6. Results and evaluation Individual testing laboratories were allotted identification numbers according to the sequence in obtaining the test results. Each of the participating laboratories can find its own number in the Certificate on participation in the comparative tests. All laboratories, except for laboratory No. 6, carried out the determination with the glued specimens, as requested in the instructions. The specimens were neither cleaned nor maintained prior to the radiant panel test, as indicated above 6.1. Evaluation of the data submitted For the lucidity sake, all the data submitted by the participants are presented in a separated Annex Test evaluation The interlaboratory comparison participants reports have revealed that most of the participants executed the determination without problems within the time period prescribed. Values of the heat flow, HF, and/or CHF expressed as CF and Umin were used for the statistical processing. The arithmetic mean of all values obtained by the participants was selected after the statistical processing, excluding the outlying values (marked by ** ). The following table shows how the results obtained by the participants differed. The specimens were marked for the processing as follows: Sample designation Sample denomination A Textile floor covering B Resilient floor covering Textilní zkušební ústav, Václavská 6, Brno Page: 4 of 15

5 The following statistical evaluation was made in accordance with ISO Laboratory CF A CF B Umin A Umin B 1 4,70 10,60 79,00 261,00 10,10 10,80 62,00 273,00 10,30 10,90 52,00 248,00 2 6,60 9,65 80,62 80,79 7,26 9,21 65,17 109,57 7,03 9,43 87,58 104,10 3 5,13 11,06 200,55 160,31 6,18 10,04 116,78 121,28 6,56 9,44 278,24 66,48 4 4,47 9,41 516,71 469,91 4,33 10,26 577,52 472,77 4,47 9,22 541,80 513,78 5 6,00 10,60 210,90 197,30 6,20 10,80 184,00 186,10 6,10 10,80 214,60 219,60 6 2,90 8, , ,00 3,50 8, , ,00 1,60 7, , ,00 7 5,90 11,00 337,80 286,40 6,90 11,00 129,20 125,60 5,50 10,90 323,50 176,00 8 5,70 9,80 128,50 44,50 5,50 10,20 130,60 41,00 5,90 10,50 126,80 36,30 9 5,40 9,80 256,00 163,00 5,00 8,70 314,00 177,00 4,80 9,40 216,00 371, ,00 10,80 182,10 154,80 6,80 10,80 153,40 129,40 10,80 10,60 179,40 91,30 Table No.1 Data obtained by all participants used for statistical processing Textilní zkušební ústav, Václavská 6, Brno Page: 5 of 15

6 lab.\specimen CF A CF B Umin A Umin B 1 8,37** 10,77 64,33 260,67 2 6,96 9,43 77,79 98,15 3 5,96 10,18 198,52 116,02 4 4,42 9,63 545,34 485,49 5 6,10 10,73 203,17 201,00 6 2,67 8, ,33** 2733,33** 7 6,10 10,97 263,50 196,00 8 5,70 10,17 128,63 40,60 9 5,07 9,30 262,00 237, ,53 10,73 171,63 125,17 mean from all values 6,09 10,01 540,83 449,34 mean without outlying values 5,83 10,01 212,77 195,57 Table No. 2 Mean values from particular participants lab.\specimen CF A CF B Umin A Umin B 1 3,18** 0,15 13,65 12,50 2 0,34 0,22 11,47 15,28 3 0,74 0,82 80,75 47,14 4 0,08 0,55 30,56 24,54 5 0,10 0,12 16,70 17,05 6 0,97 0,38 843,58** 291,43** 7 0,72 0,06 116,53 82,24 8 0,20 0,35 1,90 4,11 9 0,31 0,56 49,27 116, ,37 0,12 15,85 31,96 Table No. 3 Standard deviations from particular participants Footnote - ** outlying values excluded from the set Detailed examination of consistency and outlying values To assess the results consistency, two measures of the Mandel's statistics were used; namely h (interlaboratory statistics of consistency) and k (intralaboratory statistics of consistency). The horizontal lines shown correspond to the values of the Mandel's indicators at the levels of statistical significance of 1 % and 5 %, respectively. Parameters of Mandel s statistics h: 2,18 1% 1,8 5% Parameters of Mandel s statistics k: 2 1% 1,68 5% Textilní zkušební ústav, Václavská 6, Brno Page: 6 of 15

7 Mandel s statistics h CF - A CF - B U min A U min B Chart No. 1 Mandel's statistics of interlaboratory consistency h, grouped according to the laboratories Mandel s statistics k CF - A CF - B U min A U min B Chart No. 2 Mandel's statistics of intralaboratory consistency k, grouped according to the laboratories It follows from Chart No.1 that results of laboratory 6 reveal a substantial inconsistency and they are not acceptable even within the tolerance of 5 %. Chart No. 2 shows what was the level of intralaboratory consistency (differences in repeated measurements) of the participants. The differences of laboratories 1 (CF of specimen A) and 3 (CF of specimen B), 6 (Umin of both specimens A and B) and 10 (specimen A) can be evaluated as significant. It would be advisable to learn the causes of fluctuation and try to remedy them. Textilní zkušební ústav, Václavská 6, Brno Page: 7 of 15

8 It was decided that all the results would be included in the overall assessment provided that they will be subjected to the Cochran's and Grubb's tests for outlying values. For three repeated determinations (n = 3) and the total number of participants (p = 10), critical values of Cochran's test are 0,445 and 0,536 for 5 % and 1 % levels of significance, respectively. Application of the Cochran's test on scattering of the intralaboratory data showed a good congruity of CF data for specimen B. The test statistics at the remaining levels pointed out the CF result for specimen A of laboratory No. 1, where the scattering exceeded the probability level of 1 % and 5 % as deviating and the result was marked ** in the Table. The results of laboratory No. 6 for specimens A and B in parameter Umin % was marked as deviating by the test. Also, a comparison with the results of the Mandel's statistics k reveals a suspicion against these values. In order to assess outlying of the results, the Grubb's test was applied. Level One small One large Two small Two large Test type CF A 1,77 1,79 0,472 0,369 Grubb s test statistics CF B 2,06 1,10 0,337 0,727 Umin A 0,46 2, Umin B 0,50 2, Deviating value 2,290 0,1864 (5%) Outlying value (1%) 2,482 0,1150 Table No. 4 Values of Grubb's test of mean values Grubb s test statistics The Grubb's statistics G determines whether the mean measured value can be considered as: a) correct b) deviating (if G is higher or equal to 5 % of the critical value) it was not observed c) outlying (if G is higher or equal to 1 % of the critical value), marked ** in Tables No. 2 and 3 The Grubb's test assessed the Umin results obtained in laboratory 6 as outlying for both A and B samples. Therefore, the pairs of the lowest and highest mean values have not been tested further. The results of this laboratory were excluded from calculation of the overall mean value. For that reason, the following statistical analysis includes 9 laboratories only. The concluding review of results provides z-score calculated from all measured values according to the equation: x X z = RSD where: x is a mean value of determinations from a particular laboratory X is a mean value of all determinations of a given level RDS is a mean value of relative standard deviation of the evaluated parameter obtained from the measured values Textilní zkušební ústav, Václavská 6, Brno Page: 8 of 15

9 It was of utmost importance to select for the graphic presentation by the z-score form the most suitable means of calculation of the standard deviation from the data of both specimens. The value obtained from the results of the particular participants, i.e. calculated from the data obtained (excluding the outlying results), was selected as the most credible deviation value. The following table shows a review of the standard deviation values and presents the resulting value used: Specimen CF A CF B Umin A Umin B Mean 5,83 10,01 212,77 195,57 RSD (%) relative standard deviation used 31,9 8,6 67,5 66,4 Table No. 5 Values of standard deviation used for calculation of z-score RDS (%) Relative standard deviation expressed in percentage of the mean of results obtained by the participants of the interlaboratory comparison. The following equation was used for calculation of standard deviation (SD): 2 n x ( x) SD = n( n 1) Summary of results in a graphic form of z-score Lab. Parameter evaluated CF A CF B Umin A Umin B RSZ SSZ 1 1,9 0,9-1,0 0,5 1,1 5,7 2 0,8-0,7-0,9-0,8-0,8 2,6 3 0,1 0,2-0,1-0,6-0,2 0,4 4-1,1-0,4 2,3 2,2 1,5 11,7 5 0,2 0,8-0,1 0,0 0,5 0,7 6-2,4-2,1 22,8 19,5 19,0 913,6 7 0,2 1,1 0,4 0,0 0,8 1,4 8-0,1 0,2-0,6-1,2-0,9 1,8 9-0,6-0,8 0,3 0,3-0,4 1,2 10 2,8 0,8-0,3-0,5 1,4 8,8 Table No. 6 Values of z-score for particular laboratories RSZ relative sum of z-score for both specimens SSZ sum of z-score squares for both specimens z < ± 2 acceptable result ± 2 < z < ± 3 cautionary borderline z > ± 3 unacceptable result 2 Textilní zkušební ústav, Václavská 6, Brno Page: 9 of 15

10 Calculation of deviation estimations For each parameter tested, three estimations of deviations, expressed as the standard deviations of repeatability and reproducibility, as well as the interlaboratory standard deviation. Number of assessed participants Mean values Standard deviation of repeatability Standard deviation of reproducibility Interlaboratory standard deviation CF A 9 5,8 0,963 2,022 1,777 CF B 10 10,0 0,407 0,926 0,832 Umin A 9 212,8 53, , ,220 Umin B 9 195,6 54, , ,015 Table No. 7 Estimation of deviations z-score of values CF 30A 3,0 2,0 1,0 0,0-1, ,0-3,0 Chart No. 3 z-score for parameter CF of specimen A (5,83 kw.m -2 ) Textilní zkušební ústav, Václavská 6, Brno Page: 10 of 15

11 z-score of values CF 30B 3,0 2,0 1,0 0,0-1, ,0-3,0 Chart No. 4 z-score for parameter CF of specimen B (10,01 kw.m -2 ) z-score of values Umin A 3,0 2,0 1,0 0,0-1,0-2,0-3, Chart No. 5 z-score for parameter Umin of specimen A (212,77 %) Textilní zkušební ústav, Václavská 6, Brno Page: 11 of 15

12 z-score of values Umin B 3,0 2,0 1,0 0,0-1,0-2,0-3, Chart No. 6 z-score for parameter Umin of specimen B (195,57 %. min) z-scores of all parameters evaluated 3,0 2,0 1,0 0,0-1, ,0-3,0 CF - A CF - B U min A U min B Chart No. 7 Overall review of z-score results from all participants Textilní zkušební ústav, Václavská 6, Brno Page: 12 of 15

13 Summary of results The following characteristics summarize values of z-score and provide information on how a particular laboratory holds its own against other participants in all measurements. z RSZ = SSZ = z m where: RSZ is a relative sum of z-score SSZ is a sum of the z-score squares m is a number of the z-score for each parameter 2 RSZ 5,0 4,0 3,0 2,0 1,0 0,0-1,0-2, Chart No. 6 Relative sum of z-score for all parameters SSZ 20,0 18,0 16,0 14,0 12,0 10,0 8,0 6,0 4,0 2,0 0, Chart No. 7 Sum of z-score squares for all parameters Textilní zkušební ústav, Václavská 6, Brno Page: 13 of 15

14 It is evident again from the chart of the values of z-score squares a statistically significant deviation of the results of laboratory No 6. The critical distribution value χ 2 (α=0,05) = 18,31. This graphical expression allows at the same time a mutual comparison of particular laboratories, considering the determination of all four parameters tested. Thus, the sequence of numbers in the chart corresponds to the overall success of a laboratory in the test. 7. Conclusions This European standard specifies the method for the assessment of behaviour brought about by a reversed air flow and propagation of flame on the horizontally laid floor coverings exposed to graded radiant heat flow in a test chamber after ignition. As the results serve to the certification bodies as well as to the producers and designers for a correct classification of the floor coverings considering building safety in case of fire, an interlaboratory comparison was announced designated for a comparison of the test results using the required device. The results of the interlaboratory comparison were intended to answer the question whether the device used for performing the tests and the test procedure employed together with the knowledge of the operator carrying the test are within the tolerance limits requested for expression of the results. In case it is not so, then the differences observed should serve as an indication of rectification steps. Even though that the interlaboratory comparison has not been announced officially by an official European authority competent in this particular field, the participation of ten laboratories from the European Union was a gratifying fact. One laboratory did not glue the specimens and thus, these results deviated from those obtained by other laboratories. This fact testifies again that the execution or non-execution of gluing the specimen (as already documented earlier) influence the results substantially. Other laboratories met the criterion requested in the basic parameter of the critical heat flow for the textile as well as for the resilient floor coverings. Some dissimilar results were obtained pertaining to the smoke appearance expresses as an integral of darkening resulting from smoke (% x min). It is true that this parameter is complementary only, but it is envisaged that it will be certainly considered as having the same importance as other parameters tested. For this reason, we recommend to carry out the test always and to use the results in case that they are requested. The organizers wish to thank to all the participants and they look forward to a further collaboration. Team of the TZU s staff members Textilní zkušební ústav, Václavská 6, Brno Page: 14 of 15

15 Reference: 1 ISO Accuracy (trueness and precision) of measurement methods and results-part 2: Basic method for determination of repeatability and reproducibility of a standard measurement method Textilní zkušební ústav, Václavská 6, Brno Page: 15 of 15