DONIESIENIA NAUKOWE RESEARCH REPORTS

Drewno. Pr. Nuk. Donies. Komunik. 2012, vol. 55, nr 187 DONIESIENIA NAUKOWE RESEARCH REPORTS Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí, Thierry Delorme, Sébstien Lcourt 1 REPEATABILITY AND REPRODUCIBILITY OF DRY AND WET HEAT RESISTANCE TESTS ACCORDING TO EN 12721 AND EN 12722 The Europen Stndrds 12721 nd 12722 specify method for the ssessment of the surfce resistnce to wet nd dry het of furniture respectively. The im of the reserch is to estblish dt on the test precision of both tests in order tht this precision is mentioned on the stndrds nd test reports bsed on them. It is intended to mesure the reproducibility nd repetbility ccording to the stndrd ISO 5725-2 of dt obtined in n interntionl round-robin exercise crried out by eight prticipting lbortories expert in furniture surfces. The results presented show tht the repetbility vrince is lmost 0, while the between-lbortory vrince is between 0 nd 1, ccording to the order of increment of the ssessment rting code. Keywords: dry het, wet het, repetbility, reproducibility, round-robin test Ros Mrí Pérez, AIDIMA - Furniture, Wood nd Pckging Technology Institute, Vlenci, Spin e-mil: rperez@idim.es Mrie-Lise Roux, FCBA Institut Technologique, Pris, Frnce e-mil: mrie-lise.roux@fcb.fr José Luis Millá, AIDIMA, Vlenci, Spin e-mil: jlmill@idim.es Stephne Grcí, AIDIMA, Vlenci, Spin e-mil: sgrci@idim.es Thierry Delorme, FCBA, Pris, Frnce e-mil: thierry.delorme@fcb.fr Sébstien Lcourt, FCBA, Pris, Frnce e-mil: sebstien.lcourt@fcb.fr

106 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Introduction A resistnce-to-het test is crried out to evlute the effect produced by direct contct of hot object on the surfce under investigtion (dry het or interposing wet textile between the two surfces (wet het. It is simultion of possible common ctions hppening frequently in domestic environment [Bulin, Gryston 2009]. There re two Europen Stndrds regrding this subject, EN 12721 nd EN 12722, which give the procedure, equipment nd relted informtion to ssess the resistnce of furniture surfces to wet nd dry het. These methods permit the comprison of different finishes or my be used s qulity control of the product. In the ltest versions of these Europen Stndrds from 2009, there is no vilble dt bout their precision. An interntionl round-robin exercise to mesure the reproducibility nd repetbility of both tests ws crried out. Five mterils were used in the inter-comprison test in n ttempt to represent those to which the test method is expected to be pplied in norml use due to its implementtion in the mrket. Furthermore, the influence of the light source, direct or diffuse, ws studied. Ech lbortory received seprte set of specimens from the sme mnufcturing btch, nd instructions to be followed s closely s possible. The results obtined were sent to the inter-lbortory coordintors, AIDIMA nd FCBA, in chrge of the smple preprtion nd the sttisticl nlysis of the rw dt ccording to the stndrd ISO 5725-2. Dt on the repetbility nd reproducibility re presented. For the ssessment of the results, the test res were evluted ccording to descriptive numericl rting scle with two lighting conditions, diffuse nd direct light source. The nlysis of these kinds of vribles bsed on numericl rting code cretes chllenges in the nlysis nd leds to n old controversy. According to the Theory of Scle Types developed by Stevens [1946], there re four different rting scles depending on how the dt re mesured: nominl (lso denoted s ctegoricl, ordinl, intervl nd rtio vribles. On the nominl scle, ny numbers used re mere lbels, they express no mthemticl properties. On the ordinl scle, numbers indicte the reltive position of items, they describe order but not the mgnitude of difference. On the intervl scle, numbers indicte the mgnitude of difference between items, but there is no bsolute zero point; quntittive ttributes re ll mesurble on intervl scles. On the rtio scle, numbers indicte mgnitude of difference nd there is fixed zero point. Tking into ccount the theory developed by Stevens, he lso clssified the sttisticl nlysis methods permissible ccording to ech scle. It follows therefore tht permissible sttistics for determining the centrl tendency of group of items with ordinl dt could be described by using the mode or its medin, nd

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 107 the dispersion by mens of the percentiles, or resorting to nonprmetric methods, while when using intervl dt, the use of mens nd stndrd devitions re lso llowed [Vellemn, Wilkinson 1993]. Consequently, it would be not possible to pply the methodology detiled in the stndrd ISO 5725-2 to the results of the het resistnce tests, s they work on n ordinl scle. Nevertheless, there hs been, nd continues to be, debte on this subject. On the one hnd, there is the view tht the scle on which set of mesurements lies determines the type of sttisticl tretments tht re suitble for ppliction to the mesurements. However, the opposite view is tht there is no reltion between the mesurement scle nd sttisticl procedures [Townsend J.T., Mrín G. 1983]. Moreover, there is controversy bout the merits of the clssifiction mde by Stevens due to the scle types not being precise ctegories, prticulrly in the cses of the nominl nd ordinl clssifictions. This is often justified on the bsis tht ordinl scles re relly somewhere between true ordinl nd intervl scles; lthough the intervl difference between two ordinl rnks is not constnt, it is often of the sme order of mgnitude. On ccount of this, nd considering the current of opinion of opertionl nd clssicl theories, which justify for different resons tht there is no reltionship between mesurement scles nd sttistics, nd therefore contrdict Stevens s prescriptions (representtionl theory [APA, 1986], in this reserch the dt nlysis will estimte the men nd the stndrd devition of the results in order to obtin the repetbility nd the reproducibility. The Europen Committee for Stndrdiztion CEN/TC 207/WG7 Surfces nd surfce finishes of furniture developed test methods for the ssessment of surfce resistnce to wet nd dry het, but were unble to resolve the estimtion of the reproducibility nd repetbility. This study ws crried out in response to this need. Consequently, the results of this round-robin exercise will not only provide informtion to be included in future stndrds review, but will lso inform lbortories, with the im of disseminting this knowledge in client s reports. Mterils nd methods There were 8 prticipting lbortories (tble 1 in the collbortive interlbortory tril, which ws set up in ccordnce with ISO 5725-2 (1994, with the im of estimting the reproducibility nd repetbility of EN 12721:2009 Furniture Assessment of surfce resistnce to wet het nd EN 12722:2009 Furniture Assessment of surfce resistnce to dry het. In essence, in both tests stndrd luminium lloy block t specified test temperture (100ºC for dry het, nd 70º for wet het is plced on the surfce of the test pnel, which fter specified period of time (20 minutes is removed. Then, the test re is wiped dry nd the test pnel is left undisturbed for

108 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... 16 hours. Finlly, it is exmined under specified lighting conditions for signs of dmge nd evluted ccording to descriptive numericl rting code. In the wet het resistnce test, dmp cloth is plced between the lloy block nd the test pnel. Tble 1. Prticipting lbortories Tbel 1. Uczestniczące lbortori Lbortory Lbortorium CATAS (A FIRA (B ITD (C IKEA (D LGA (E IHD (F FCBA (G AIDIMA (H Country Krj Itly Włochy United Kingdom Zjednoczone Królestwo Polnd Polsk Sweden Szwecj Germny Niemcy Germny Niemcy Frnce Frncj Spin Hiszpni All prticipting lbortories were rndomly lbelled from A to H. Five mterils were used in the inter-comprison test in n ttempt to represent those to which the test method is expected to be pplied in norml use in the finished furniture. Smples were prepred ccording to levels 1 to 5 s shown in the following tble: Tble 2. Tested smples Tbel 2. Bdne próbki 1 2 Description Opis Pper-bsed decor finish foil Substrte: Prticlebord Dekorcyjn foli finish n bzie ppierowej Podłoże: płyt wiórow Monocomponent wter bsed trnsprent coting Substrte: prticlebord covered with beech veneer Jednoskldnikowe przejrzyste pokrycie wodorozcieńczlne Podłoże: płyt wiórow z okleiną bukową

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 109 Tble 2. Continued Tbel 2. Ciąg dlszy 3 4 5 Bicomponent polyurethne Substrte: prticlebord covered with beech veneer Poliuretn dwuskłdnikowy Podłoże: płyt wiórow z okleiną bukową Pigmented coting bsed on polyester UV curing Substrte: MDF Brwione pokrycie n bzie poliestru, utwrdzne promienimi UV Podłoże: płyt MDF HPL, plin drk colour, high gloss Substrte: Prticlebord HPL, zwykły ciemny kolor, wysoki połysk Three replictes were crried out per mteril. Tble 3. Assessment code Tbel 3. Kod oceny Description Opis No chnge. Test re indistinguishble from djcent surrounding re. Żdnych zmin. Powierzchni bdn nie dje się odróżnić od przyległej, otczjącej ją powierzchni Minor chnge. Test re distinguishble from djcent surrounding re, only when the light source is mirrored on the test surfce nd is reflected towrds the observer s eye, e. g. discolortion, chnge in gloss nd colour. No chnge in the surfce structure, e.g. deformtion, swelling, fibre rising, crcking, blistering. Niewielkie zminy. Bdn powierzchni dje się odróżnić od przyległej, otczjącej ją powierzchni tylko wówczs, gdy źródło świtł odbij się n powierzchni i jest odbijne w stronę oczu obserwtor, np. przebrwienie, zmin połysku i koloru. Nie m zmin w strukturze powierzchni, np. deformcji, pęcznieni, podnoszeni się włókien, pęknięć, pęcherzy Moderte chnge. Test re distinguishble from djcent surrounding re, visible in severl viewing directions, e.g. discolortion, chnge in gloss nd colour. No chnge in the surfce structure, e.g. swelling, fibre rising, crcking, blistering. Umirkowne zminy. Bdn powierzchni dje się odróżnić od przyległej, otczjącej ją powierzchni, jest widoczn w kliku kierunkch obserwcji, np. przebrwienie, zmin połysku i koloru. Nie m zmin w strukturze powierzchni, np. pęcznieni, podnoszeni się włókien, pęknięć, pęcherzy Numericl rting Ocen liczbow 5 4 3

110 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Tble 3. Continued Tbel 3. Ciąg dlszy Significnt chnge. Test re clerly distinguishble from djcent surrounding re, visible in ll viewing directions, e.g. discolortion, chnge in gloss nd colour, nd/or structure of the surfce slightly chnged, e.g. swelling, fibre rising, crcking, blistering. Znczne zminy. Bdn powierzchni wyrźnie dje się odróżnić od przyległej, otczjącej ją powierzchni, jest widoczn we wszystkich kierunkch obserwcji, np. przebrwienie, zmin połysku i koloru, i/lub niezncznie zmienion struktur powierzchni, np. pęcznienie, podnoszenie się włókien, pęknięci, pęcherze Strong chnge. The structure of the surfce distinctly chnged nd / or discolortion, chnge in gloss nd colour, nd/or the surfce mteril totlly or prtilly removed. Silne zminy. Wyrźnie zmienion struktur powierzchni i/lub przebrwienie, zmin połysku i koloru i/lub mterił powierzchniowy cłkowicie lub częściowo usunięty 2 1 Sttisticl dt nlysis Originl test results The interlbortory study involved p lbortories clled i (i = 1, 2,, p, ech testing q mterils (levels clled j (j = 1, 2,, q with n replictes (ech ij combintion. All replictes of ech ij re ssigned to one cell (minly 3 individul vlues. The cell mens nd cell spred (stndrd devition for ech cell, combintion of lbortory nd level were clculted s follows: (1 (2 Where n ij (number of replictes is the number of test results in the cell for the lbortory i nd mteril j, nd is ny one of the test results (k = 1, 2,, n ij. Scrutiny of results for consistency nd outliers During the first stge of the evlution, the dt were criticlly exmined in order to identify outlier vlues nd other inconsistencies. Both grphicl consistency technique nd numericl outlier tests were pplied.

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 111 Normlly, the criticl vlues in the consistency tests t the significnce levels α = 1% nd α = 5% re used s criteri for outliers nd strgglers, respectively. If the sttistic is greter thn its 1% criticl vlue, the item tested is clled sttisticl outlier. If the test sttistic is greter thn its 5% criticl vlue but less thn or equl to its 1% criticl vlue, the item tested is clled strggler. If the test sttistic is less thn or equl to its 5% criticl vlue, the item tested is ccepted s correct. Grphicl technique Mndel s h-sttistic is between-lbortory consistence sttistic which indictes devition of the cell men mesured from one lbortory when compred with the generl men obtined from the ll lbortories in the round-robin test. h-vlue is defined s: (3 (3b where: d p j = the devition of the cell verge from the verge of the cell verges = the stndrd devition of the cell verges = is the number of lbortories reporting t lest one test result for mteril j. Mndel s k-sttistic is within-lbortory consistency sttistic which indictes mesurement devition in one lbortory when compred within-cell stndrd devition (repetbility stndrd devition. The k-vlue is defined s: (4 (4b where: s ij = the cell stndrd devition for one lbortory s rj = the repetbility stndrd devition of the mteril Numericl technique Cochrn s sttistic C Cochrn s sttistic C is defined s:

112 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... (5 Where s mx is the highest stndrd devition in the set of stndrd devitions tested. Cochrn s test is one-sided outlier test becuse it exmines only the highest vlue in set of stndrd devition. Grubbs test In Grubbs test, the dt to be tested should be rrnged in scending order, tht is, for set of xi vlues (i = 1, 2,,p, where x 1 is the smllest nd x p is the lrgest. To exmine the significnce of the lrgest vlues, Grubbs sttistic G p is: where: (6 nd (7 To exmine the smllest vlue, Grubbs sttistic G 1 is: (8 (9 Clcultion of the generl men nd vrinces For level j, the generl men is: (10 Three vrinces re clculted for ech mteril, i.e., the repetbility vrince, the reproducibility vrince, nd the between-lbortory vrince.

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 113 The repetbility vrince is: (11 The between-lbortory vrince (or inter-lbs vrince is: where: (12 nd (13 (14 The reproducibility vrince is: (15 Results nd discussion Tble 4. Colltion of ll test result dt. EN 12722 (100ºC Diffuse light source Tbel 4. Porównnie wszystkich wyników bdń. EN 12722 (100ºC Źródło świtł rozproszonego Lbortory Lbortorium A 5 5 5 1 1 1 4 4 4 4 4 4 5 5 5 B 5 5 5 1 1 1 4 4 5 5 5 5 5 5 5 C 5 5 5 1 1 1 5 5 5 5 5 5 4 4 4 D 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 E 5 5 5 1 1 1 3 4 4 4 4 4 4 4 3 F 5 5 5 2 2 2 4 4 4 5 5 5 5 5 5 G 5 5-2 2 2 3 3 3 5 5-5 5 - H 5 5 5 1 1 1 4 4 4 3 3 3 4 4 4

114 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Fig. 1. Mndel s h plot EN 12722 Diffuse light Rys. 1. Wykres h Mndel EN 12722 Świtło rozproszone Fig. 2. Mndel s k plot EN 12722 Diffuse light Rys. 2. Wykres k Mndel EN 12722 Świtło rozproszone Tble 5. Appliction of Cochrn s test Tbel 5. Zstosownie testu Cochrn Cochrn s C test sttistics Sttystyki testu Cochrn Number of lbortories (pj Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 0.500 1.000 b Cochrn s criticl vlues Wrtości krytyczne wg Cochrn 8 8 8 8 8 0.516 0.516 0.516 0.516 0.516 0.615 0.615 0.615 0.615 0.615

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 115 Tble 6. Appliction of Grubb s test Tbel 6. Zstosownie testu Grubb Grubbs test sttistics (single low Sttystyki testu Grubb (pojedyncze niskie Grubbs test sttistics (single high Sttystyki testu Grubb (pojedyncze wysokie Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 0.540 1.750 2.102 1.569 2.340 b 1.250 0.625 0.713 Single Grubbs criticl vlues Pojedyncze wrtości krytyczne wg Grubb 8 8 8 8 8 2.126 2.126 2.126 2.126 2.126 2.274 2.274 2.274 2.274 2.274 Tble 7. Colltion of ll test result dt. EN 12722 (100ºC Direct light source Tbel 7. Porównnie wszystkich wyników bdń. EN 12722 (100ºC Źródło świtł bezpośredniego Lbortory Lbortorium A 5 5 5 1 1 1 5 5 5 4 4 4 5 5 5 B 5 5 5 1 1 1 5 5 5 5 5 5 5 5 5 C 5 5 5 1 1 1 5 5 5 5 5 5 5 5 5 D E F 5 5 5 2 2 2 4 4 4 5 5 5 5 5 5 G 5 5-2 2 2 4 4 4 5 5-5 5 - H 5 5 5 1 1 1 4 4 4 3 3 3 5 5 5

116 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Fig. 3. Mndel s h plot EN 12722 Direct light Rys. 3. Wykres h Mndel EN 12722 Świtło bezpośrednie Fig. 4. Mndel s k plot EN 12722 Direct light Rys. 4. Wykres k Mndel EN 12722 Świtło bezpośrednie Tble 8. Appliction of Cochrn s test Tbel 8. Zstosownie testu Cochrn Cochrn s C test sttistics Sttystyki testu Cochn Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe Cochrn s criticl vlues Wrtości krytyczne wg Cochrn 6 6 6 6 6 0.616 0.616 0.616 0.616 0.616 0.722 0.722 0.722 0.722 0.722

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 117 Tble 9. Appliction of Grubb s test Tbel 9. Zstosownie testu Grubb Grubbs test sttistics (single low Sttystyki testu Grubb (pojedyncze niskie Grubbs test sttistics (single high Sttystyki testu Grubb (pojedyncze wysokie Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 0.645 0.913 1.927 1.291 0.913 0.550 Single Grubbs criticl vlues Pojedyncze wrtości krytyczne wg Grubb 6 6 6 6 6 1.887 1.887 1.887 1.887 1.887 1.973 1.973 1.973 1.973 1.973 Tble 10. Colltion of ll test result dt. EN 12721 (70ºC Diffuse light source Tbel 10. Porównnie wszystkich wyników bdń. EN 12721 (70ºC Źródło świtł rozproszonego Lbortory Lbortorium A 2 2 2 2 2 2 4 4 4 3 3 3 5 5 5 B 1 1 1 2 2 2 4 4 4 4 4 4 5 5 5 C 1 1 1 2 2 2 4 4 4 3 3 3 5 5 5 D 4 4 4 4 4 4 4 4 4 5 5 5 5 5 5 E 1 1 1 2 2 2 5 4 4 3 3 3 5 5 5 F 2 2 2 1 1-4 4 4 5 4 4 5 5 5 G 1 1-2 2 2 4 4 4 5 5-5 5 - H 2 2 2 2 2 2 3 3 3 3 3 3 5 5 5

118 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Fig. 5. Mndel s h plot EN 12721 Diffuse light Rys. 5. Wykres h Mndel EN 12721 Świtło rozproszone Fig. 6. Mndel s k plot EN 12721 Diffuse light Rys. 6. Wykres k Mndel EN 12721 Świtło rozproszone Tble 11. Appliction of Cochrn s test Tbel 11. Zstosownie testu Cochrn Cochrn s C test sttistics Sttystyki testu Cochrn Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 1.000 b 1.000 b Cochrn s criticl vlues Wrtości krytyczne wg Cochrn 8 8 8 8 8 0.516 0.516 0.516 0.516 0.516 0.615 0.615 0.615 0.615 0.615

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 119 Tble 12. Appliction of Grubb s test Tbel 12. Zstosownie testu Grubb Grubbs test sttistics (single low Sttystyki testu Grubb (pojedyncze niskie Grubbs test sttistics (single high Sttystyki testu Grubb (pojedyncze wysokie Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 0.725 1.348 2.307 b 0.955 2.174 2.247 0.903 1.337 Single Grubbs criticl vlues Pojedyncze wrtości krytyczne wg Grubb 8 8 8 8 8 2.126 2.126 2.126 2.126 2.126 2.274 2.274 2.274 2.274 2.274 Tble 13. Colltion of ll test result dt. EN 12721 (70ºC Direct light source Tbel 13. Porównnie wszystkich wyników bdń. EN 12721 (70ºC Źródło świtł bezpośredniego Lbortory Lbortorium A 2 2 2 3 3 3 5 5 5 3 3 3 5 5 5 B 1 1 1 2 2 2 3 3 3 3 3 3 5 5 5 C 1 1 1 2 2 2 4 4 4 4 4 4 5 5 5 D E F 2 2 2 1 1 4 4 4 5 5 5 5 5 5 G 1 1 2 2 2 4 4 4 5 5 5 5 H 2 2 2 2 2 2 3 3 3 3 3 3 5 5 5

120 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Fig. 7. Mndel s h plot EN 12721 Direct light Rys. 7. Wykres h Mndel EN 12721 Świtło bezpośrednie Fig. 8. Mndel s k plot EN 12721 Direct light Rys. 8. Wykres k Mndel EN 12721 Świtło bezpośrednie Tble 14. Appliction of Cochrn s test Tbel 14. Zstosownie testu Cochrn Cochrn s C test sttistics Sttystyki testu Cochrn Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe Cochrn s criticl vlues Wrtości krytyczne wg Cochrn 6 6 6 6 6 0.616 0.616 0.616 0.616 0.616 0.722 0.722 0.722 0.722 0.722

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 121 Tble 15. Appliction of Grubbs test Tbel 15. Zstosownie testu Grubb Grubbs test sttistics (single low Sttystyki testu Grubb (pojedyncze niskie Grubbs test sttistics (single high Sttystyki testu Grubb (pojedyncze wysokie Number of lbortories (p j Liczb lbortoriów (p j Strggler vlues Wrtości wątpliwe Outlier vlues Wrtości nietypowe Strggler; b Outlier Wątpliwe; b Nietypowe 0.913 1.581 1.107 1.044 0.913 1.581 1.550 1.167 Single Grubbs criticl vlues Pojedyncze wrtości krytyczne wg Grubb 6 6 6 6 6 1.887 1.887 1.887 1.887 1.887 1.973 1.973 1.973 1.973 1.973 Clcultion of the generl men nd vrinces An outlier cn be considered s result which is sufficiently different from ll other results to wrrnt further investigtion. The ISO 5725-2 stndrd recommends confidence levels of 95% for outliers termed strgglers nd 99% for outliers termed sttisticl outliers. When crrying out the outlier tests, it should be understood tht outliers should not be discrded or rejected purely from sttisticl point of view. In this round robin test it should be noticed tht the Cochrn s test nd the Mndel s k test (used s mesure of within-lbortory consistency reported some cell stndrd devitions s exceptionlly lrge, when they only show one point of difference in the ssessment of the three replictes tested by the sme lbortory. Generlly this is due to the different lbs not exhibiting ny difference in their results. Tking into ccount tht the mesurements in both methods (EN 12721 nd 12722 re clculted ccording to ctegoriztion or sorting scheme nd divided into five ctegories. These consistency nd outlier test results re not considered potentil outliers.

122 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... When pplying Mndel s h sttistic or Grubbs test (used to mesure the between-lbortory consistency, ny result which ppered to be n outlier is not included in the clcultion of the overll men nd vrinces. Strggler vlues were retined in these clcultions. Dry het resistnce 100ºC Diffuse light source (EN 12722 Tble 16. Computed vlues of generl men nd vrinces Tbel 16. Obliczone wrtości ogólnej średniej i wrincji Number of lbortories Liczb lbortoriów Generl men Ogóln średni Repetbility vrince Wrincj powtrzlności Between-lbortory vrince Wrincj pomiędzy lbortorimi Reproducibility vrince Wrincj odtwrzlności Repetbility std. dev. Odchyl. stnd. powtrzlności Reproducibility std. dev. Odchyl. stnd. odtwrzlności Number of excluded outliers Liczb wykluczonych wrtości nietypowch Outlier lbortories Lbortori nietypowe *Without discrding the sttisticl outlier vlues *Bez odrzucni sttystycznych wrtości nietypowych 1 2* 2 3 4 5 p j 8 8 7 8 8 8 5.0 1.8 1.3 4.1 4.5 4.6 0.0 0.0 0.0 0.1 0.0 0.0 0.0 1.9 0.2 0.4 0.6 0.3 0.0 1.9 0.2 0.5 0.6 0.4 0.0 0.0 0.0 0.3 0.0 0.2 0.0 1.4 0.5 0.7 0.8 0.6 0 0 1 0 0 0 Lb D The strggler vlues were retined s correct items nd the sttisticl outliers were discrded. After the exclusion of outlier observtions, the consistency nd outlier tests were repeted on the remining vlues, nd no more outliers were detected. The remining dt were used for the clcultion of the generl men nd vrinces.

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 123 Dry het resistnce 100ºC Direct light source (EN 12722 Tble 17.Computed vlues of generl men nd vrinces Tbel 17. Obliczone wrtości ogólnej średniej i wrincji Number of lbortories Liczb lbortoriów Generl men Ogóln średni Repetbility vrince Wrincj powtrzlności Between-lbortory vrince Wrincj pomiędzy lbortorimi Reproducibility vrince Wrincj odtwrzlności Repetbility std. dev. Odchyl. stnd. powtrzlności Reproducibility std. dev. Odchyl. stnd. odtwrzlności Number of excluded outliers Liczb wykluczonych wrtości nietypowch Outlier lbortories Lbortori nietypowe p j 6 6 6 6 6 5.0 1.3 4.5 4.5 5 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.7 0.0 0.0 0.3 0.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.5 0.9 0.0 0 0 0 0 0 Wet het resistnce 70ºC Diffuse light source (EN 12721 Tble 18.Computed vlues of generl men nd vrinces Tbel 18. Obliczone wrtości ogólnej średniej i wrincji Lbortory Lbortorium Number of lbortories Liczb lbortoriów Generl men Ogóln średni Repetbility vrince Wrincj powtrzlności Between-lbortory vrince Wrincj pomiędzy lbortorimi 1* 1 2* 2 3** 4 5 p j 8 7 8 7 8 8 8 1.8 1.5 2.2 1.9 3.9 3.7 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.1 0.3 0.7 0.1 0.1 0.8 0.0

124 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Tble 18.Continued Tbel 18. Ciąg dlszy Reproducibility vrince Wrincj odtwrzlności Repetbility std. dev. Odchyl. stnd. powtrzlności Reproducibility std. dev. Odchyl. stnd. odtwrzlności Number of excluded outliers Liczb wykluczonych wrtości nietypowch Outlier lbortories Lbortori nietypowe 1.0 0.3 0.7 0.1 0.2 0.8 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.0 1.0 0.5 0.8 0.3 0.4 0.9 0.0 0 1 0 1 0 0 0 Lb D Lb D *Without discrding the sttisticl outlier vlues *Bez odrzucni sttystycznych wrtości nietypowych ** The reson mentioned in the preceding prgrph is lso used for not discrding ny vlue in the cse of the level 3, where in the first stge the tests indicted s outlier the results from lbortory H which differed only one point from the results from the rest of the lbortories ** Powód wspomniny w poprzedzjącym kpicie jest również powodem nie odrzucni żdnej wrtości w przypdku poziomu 3., gdzie w pierwszym etpie testy wskzywły, że wyniki z lbortorium H odstwły od innych, chociż różniły się one zledwie jednym punktem od wyników z reszty lbortoriów The strggler vlues were retined s correct items nd the sttisticl outliers were discrded. After exclusion of outlier observtions shown in the wet het resistnce results, the consistency nd outlier tests were repeted on the remining vlues. After repeting the consistency nd outlier tests, no more sttisticl outliers were detected in the level 1. When repeting the tests with level 2, the results from lbortory F turned out to be outlier, but they were not considered nor rejected becuse they were the result of difference of one point in the ssessment scle. Wet het resistnce 70ºC Direct light source (EN 12721 Tble 19. Computed vlues of generl men nd vrinces Tbel 19. Obliczone wrtości ogólnej średniej i wrincji Lbortory Lbortorium Number of lbortories Liczb lbortoriów Generl men Ogóln średni p j 6 6 6 6 6 1.5 2.0 3.8 3.8 5.0

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 125 Tble 19.Continued Tbel 19. Ciąg dlszy Repetbility vrince Wrincj powtrzlności Between-lbortory vrince Wrincj pomiędzy lbortorimi Reproducibility vrince Wrincj odtwrzlności Repetbility std. dev. Odchyl. stnd. powtrzlności Reproducibility std. dev. Odchyl. stnd. odtwrzlności Number of excluded outliers Liczb wykluczonych wrtości nietypowch Outlier lbortories Lbortori nietypowe 0.0 0.0 0.0 0.0 0.0 0.3 0.4 0.6 0.9 0.0 0.3 0.4 0.6 0.9 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.6 0.8 1.0 0.0 0 0 0 0 0 According to the stndrd, there should be one observer, nd in cse of doubt, three. Due to the nture of this study nd the problems which rise from hving number of observers t severl of the centres, the number of observers involved in ech lbortory ws determined by ech centre. Diffuse/Direct light comprison Fig. 9. Diffuse/Direct light comprison for level 1 Rys. 9. Porównnie świtł rozproszonego/bezpośredniego dl poziomu 1

126 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... Fig. 10. Diffuse/Direct light comprison for level 2 Rys. 10. Porównnie świtł rozproszonego/bezpośredniego dl poziomu 2 Fig. 11. Diffuse/Direct light comprison for level 3 Rys. 11. Porównnie świtł rozproszonego/bezpośredniego dl poziomu 3 Fig. 12. Diffuse/Direct light comprison for level 4 Rys. 12. Porównnie świtł rozproszonego/bezpośredniego dl poziomu 4

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 127 Fig. 13. Diffuse/Direct light comprison for level 5 Rys. 13. Porównnie świtł rozproszonego/bezpośredniego dl poziomu 5 Conclusions With reference to the source light used in the ssessment, it could be observed tht the effects on the test surfces were more esily pprecited when the diffuse light ws used, except for one lbortory. This is shown in fig. 10 to 14. In Mndel s h grphs the respective hij vlues re plotted for ech cell grouped for ll levels nd exmined by ech lbortory. The horizontl lines on the plots re n indictor for Mndel s h t the 5% (blck line nd 1% (grey line significnce level. These indictor lines serve s guides when exmining ptterns in the dt. As could be observed, ll the lbortories hve both positive nd negtive vlues t different levels of the experiments, but lbortory D exhibits pttern of results tht re mrkedly different form the other lbortories in the study. Their results stnds out on the h plot s lwys hving positive vlues in the ssessment of the dry nd wet het resistnce of the surfces. Therefore it mens tht its results re usully higher thn the verge vlues. Moreover, individul extreme vlues re reported by lbortory D with the EN 12722 (level 2 nd with EN 12721 (levels 1 nd 2. Some precutions hve to be tken when the sttisticl outlier tests re crried out. When the within-lbortory vribility is nlysed, sometimes cell stndrd devition, tht only shows one point of difference in the ssessment of the three replictes tested by the sme lbortory. is shown in the tests to be sttisticl outlier due to the fct tht generlly the lbs do not exhibit ny difference in their own results. In the sme wy, when scrutinizing between-lbortory vribility, when ll the lbortories present the sme cell verge except one, which differs only by one point it ppers lso s sttisticl outlier. In these cses, nd bering in mind tht the mesurements in both methods (EN 12721 nd 12722 re mde ccor-

128 Ros Mrí Pérez, Mrie-Lise Roux, José Luis Millá, Stephne Grcí,... ding to rting code divided into five ctegories with one point s n increment of the ssessment. These consistency nd outlier test results re not considered. From the clcultion of vrinces, it could be concluded tht the repetbility vrince is nerly 0, while the between-lbortory vrince is between 0 nd 1. Subsequently, the reproducibility vrince lso hs vlues from 0 to 1 depending on the level tested. References Bulin F.. Grystone J. [2009]: Wood cotings: theory nd prctice: Elsevier Stevens. S.S. [1946]. On the theory of scles of mesurement. Science [103]: 677 680 Vellemn P. Wilkinson L. [1993]. Nominl. Ordinl. Intervl. nd Rtio Typologies Are Misleding. The Americn Sttisticin (Americn Sttisticl Assocition 47 [1]: 65 72 Townsend J.T.. Mrín G. [1983] Mesurement Scles ns Sttistics: The Misconception Misconceived. Psychologicl Bulletin [96]: 397 401 Mesurement Scles nd Sttistics. [1986] Americn Psychologicl Assocition (APA. Psychologicl Bulletin. 100 [3]: 398 407 Vn Dicth K. et l. [2000] Spectrometric determintion of silicon in food nd biologicl smples: n interlbortory tril. The Royl Society of Chemistry List of stndrds EN 12721:2009 Furniture Assessment of surfce resistnce to wet het EN 12722:2009 Furniture Assessment of surfce resistnce to dry het ISO 5725-2:1994 Accurcy (trueness nd precision of mesurement methods nd results. Prt 2: Bsic method for the determintion of repetbility nd reproducibility of stndrd mesurement method ASTM E 691-99. Stndrd Prctice for Conducting n Interlbortory Study to Determine the Precision of Test Method POWTARZALNOŚĆ I ODTWARZALNOŚĆ BADAŃ ODPORNOŚCI NA CIEPŁO SUCHE I MOKRE WEDŁUG NORM EN 12721 AND EN 12722 Streszczenie Normy europejskie 12721 i 12722 określją metodę oceny odporności powierzchni meblowych n mokre i suche ciepło. Celem bdń jest ustlenie dnych dotyczących precyzji oby rodzjów bdń w celu umieszczeni tych informcji w normch i sprwozdnich z bdń oprtych n tych normch. Zmierz się dokonć pomirów powtrzlności i odtwrzlności wyników międzynrodowego bdni round-robin przeprowdzonego

Repetbility nd reproducibility of dry nd wet het resistnce tests ccording to EN 12721... 129 przez osiem lbortoriów, które specjlizują się w bdniu powierzchni, zgodnie z normą ISO 5725-2. Zprezentowne wyniki wskzują, że wrincj powtrzlności jest blisk 0, ntomist wrincj pomiędzy lbortorimi mieści się w przedzile 0 i 1, zgodnie z porządkiem wzrostu kodów oceny. Słow kluczowe: suche ciepło, mokre ciepło, powtrzlność, odtwrzlność, test roun-robin