Zpráva - ANG - Textilní zkušební ústav

Transkript

Textile Testing Institute
Notified body No. 1021
Václavská 6, 658 41 Brno, Czech Republic
REPORT
Evaluation of interlaboratory test results in the field of
geotextiles and geomembranes (geosynthetics) according to
EN 12224 – Determination of the resistance to weathering
further to
EN 12226 – General tests for evaluation following
durability testing
used for conformity evaluation of constructional products
according to NV No. 190/2002 Sb. (corresponding to Building
Directive 89/106 EEC)
Prepared by: Ing. Markéta Ondráčková
Approved by: RNDr. Pavel Malčík
Brno, November 16, 2007
Textilní zkušební ústav, Václavská 6, 658 41 Brno
www.tzu.cz
Stránka 1 ze 1
Contents
Contents...................................................................................................................................... 2
1. Introduction ............................................................................................................................ 2
2. Time schedule ........................................................................................................................ 3
3. Preparation of test specimens ................................................................................................. 3
4. Results and evaluation............................................................................................................ 3
4.1Technical parameters of equipments used ........................................................................ 3
4.2Test evaluation .................................................................................................................. 5
4.2.1Detailed examination of consistency and outlaying values ....................................... 7
4.2.2Summary of results expressed in the z-score graphic form ..................................... 11
4.2.3Summary of results................................................................................................... 13
5. Conclusion............................................................................................................................ 16
Annex – Testing of homogeneity ............................................................................................. 17
Homogeneity test of sample A ............................................................................................. 17
Homogeneity test of sample B ............................................................................................. 18
1.
Introduction
More than 60 laboratories had been addressed and 6 laboratories actually participated. These
include testing laboratories functioning within the frame of the European Notified Bodies.
The following list of the trial participants is arranged in the alphabetical order and any
potential relation to the laboratory code number is a coincidence only.
Institution name
Address
WWW
AITEX - Instituto Tecnológico Textil
Plaza Emilio Sala, 1
03801 Alcoy - Spain
PASEO 22 DE JULIO, 218
TERRASSA (BARCELONA)
08221 Spain
www.aitex.es
Arsenal, Objekt 213
www.ofi.at
LEITAT TECHNOLOGICAL CENTRE
ÖFI TECHNOLOGIE & INNOVATION
GMBH
1030 Wien
Austria
SP Sveriges Tekniska Forskningsinstitut AB Box 857501
15 BORAS
Sweden
TZU – Textile Testing Institute
Václavská 6
Accredited Testing Laboratory
658 41 Brno
Czech Republic
Technical and Testing Institute of Structural Laboratory in Tatranská Štrba
Materials, N. O.
Štefánikova 24 059 41
Tatranská Štrba
Slovakia
www.tzu.cz
www.leitat.com
www.sp.se
www.tzu.cz
www.tsus.sk
Stránka 2 ze 2
2.
Time schedule
The offers for participation were sent out during May 2007. The samples were prepared
during June 2007. In this period, also homogeneity of the samples was verified. The samples
were sent out on July 2, 2007. In most cases, the measurements were carried out according to
our instructions as early as feasible after receiving the samples, namely between July 10 and
October 30, 2007. The results were received from four laboratories by the date stated, i.e.
September 28, 2007. However, two laboratories sent the results as late as the end of October.
This Report was completed on November 16, 2007
3.
Preparation of test specimens
Two test fabrics ready for the interlaboratory comparison were prepared at the Textile Testing
Institute, Brno. The first sample labelled by capital “A” was non-woven polypropylene textile
fabric and sample labelled by capital “B” was woven polyester textile fabric.
From each of the materials were prepared specimens for homogeneity tests and also
specimens for each participating laboratory. Their sizes were selected so that enough material
was available for testing. Homogeneity of both materials was tested using original samples.
(Annex – Testing of homogeneity)
4.
Results and evaluation
Individual testing laboratories were allotted identification numbers according to the sequence
in obtaining reply to participate in the test trial. Each of the participating laboratories can find
its own number in the “Certificate on participation in the comparative tests”.
4.1
Technical parameters of equipments used
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Stránka 3 ze 3
Table No.1 – Determination of resistance to weathering according to EN 12224
Lab
Type of
Age of light
Type of equipment used
Radiation intensity
code
UV lamp
source
Filters
used
1
not available
UVA 340
200 h
0.68 W/m2/340 nm
none
2
UV 2000
UVA 340
-
0.76 W/m2/340 nm
none
3
QUV Accelerated Weathering Tester
Model QUV / spray – with Solar Eye UVA 340
Irradiance Control
-
0.68 W/m2/340 nm
none
4
Weathering tester - Model QUV/spray
UVA 340
14334 h
0.68 W/m2/340 nm
none
5
not available
UVA 340
-
0.95 W/m2/340 nm
none
6
Atlas UV 2000
UVA 340
1883 h
0.68 W/m2/340 nm
none
Table No. 2 - Tensile properties according to EN 12226
Lab
Type of equipment used
Conditioning
code
24 h
1 not available
relative humidity 62,3 %, temperature 20 °C
24 h
2 not available
relative humidity 50±4 %, temperature 22±2 °C
3
FPZ 10/1
WPM Leipzig, Germany
4
ZWICK 1454 (CRE)
ZDM 30
5
ZWICK 1474
6
not available
24 h
relative humidity 50 %, temperature 23 °C
24 h
relative humidity 65±4 %, temperature 20±2 °C
72 h
relative humidity 50 %, temperature 23°C
48 h
relative humidity 52 %, temperature 23 °C
www.tzu.cz
Exposition
time
426 h
(71 cycles)
not
available
Testing
conditions
5 h dry phase
1 h spraying
5 h dry phase
1 h spraying
Energy of
irradiation
1042 kJ/m2
(340 nm)
426 h
(71 cycles)
5 h dry phase
1 h spraying
50 MJ/m2
426 h
(71 cycles)
426 h
(71 cycles)
426 h
(71 cycles)
5 h dry phase
1 h spraying
5 h dry phase
1h spraying
5 h dry phase
1 h spraying
50 MJ/m2
50 MJ/m2
51,15 MJ/m2
50 MJ/m2
Strength range
Gauge length
Rate of head traverse
5000 N
Length – 200 mm
100 mm/min
100000 N
Width – 50 mm
100 mm/min
0-400 N
0-2000 N
0-4000 N
0-5000 N
0-300kN
Length– 200 mm
Width – 50 mm
100 mm/min
Length – 200 mm
Width – 50 mm
100 mm/min
100000 N
Length – 200 mm
100 mm/min
2500 N
Width – 50 mm
100 mm/min
Stránka 4 ze 4
4.2 Test evaluation
The average values for both test specimens from all participants was selected after statistical processing and after excluding the outlying values (these being
denoted by “**”). It should be remarked that original data provided by the participants were used, i.e. no effort to round them up has been made.
After irradiation
Sample A
Original
Table No. 3 – Measured values from all participants for sample A
Lab code
1
2
Strength
Strength
Direction
SD
SD
(N)
(N)
longitudinal
368,5
34,5
371,47
40,19
transverse
1384,5
30,5
1324,21
77,05
Elongation
Elongation
Direction
SD
SD
(%)
(%)
129,99
8,76
longitudinal
138,4
7,5
transverse
62,7
3,0
63,60
2,28
Strength
Strength
Direction
SD
SD
(N)
(N)
longitudinal
370,5*
15,0
59,13
23,93
transverse
1546,0**
27,5
88,91
12,46
Elongation
Elongation
Direction
SD
SD
(%)
(%)
longitudinal
117,1
2,7
83,58
12,40
transverse
60,0
1,5
28,09
1,89
Percenlongitudinal
100,5
15,92
tage of
residual
transverse
111,5
6,72
strength
Percenlongitudinal
84,5
64,30
tage of
residual
transverse
95,5
44,17
elongation
* - distant values
** - outlying values
SD – standard deviation
3
Strength
(N)
388
1310
Elongation
(%)
120,0
63,5
Strength
(N)
3,4
90
Elongation
(%)
31,5
28,5
11,5
3,1
4
Strength
(N)
359,18
1382,46
Elongation
(%)
118,9
59,03
Strength
(N)
33,47
132,64
Elongation
(%)
58,44
21,87
0,9
-
9,3
-
22,1
-
70,5
-
6,9
-
9,6
-
11,2
-
74,7
-
26,3
-
49,2
-
64,5
-
35,0
-
45,1
-
37,1
-
40,8
-
48,6
-
www.tzu.cz
SD
11,7
81,4
SD
5,4
1,2
SD
2,5
27,4
SD
Stránka 5 ze 5
11,0
2,40
5
Strength
(N)
308
1158*
Elongation
(%)
141
61
Strength
(N)
68
130
Elongation
(%)
91
24,9
16,9
0,6
6
Strength
(N)
403
1387
Elongation
(%)
206*
107**
Strength
(N)
119
351
Elongation
(%)
134*
554
SD
26,13
51,08
SD
8,8
1,09
SD
6,7
19,30
SD
SD
6
18
SD
2,8
SD
6
20
SD
SD
15
34
SD
5
13
SD
16
97
SD
8
-
Percentage longitudinal
of residual
transverse
elongation
* - distant values
** - outlying values
SD – standard deviation
3
Strength
(N)
3200
2200
Elongation
(%)
8,5
9,0
Strength
(N)
2100
1000
Elongation
(%)
7,4
9,0
0,2
1,7
4
Strength
(N)
6197,72
4059,43
Elongation
(%)
11,79
11,95
Strength
(N)
2665,12
1660,79
Elongation
(%)
6,63
7,51
66,0
-
43,0
-
53,9
-
46,3
-
40,9
-
33,7
-
SD
49,7
138,3
SD
0,2
0,3
SD
189,2
58,9
SD
5
SD
222,37
120,28
SD
0,19
0,91
SD
47,67
53,25
SD
0,25
0,64
Sample was not tested
After irradiation
Sample B
Original
Table No. 4 – Measured values from all participants for sample B
Lab code
1
2
Strength
Strength
Direction
SD
SD
(N)
(N)
longitudinal
5601,0
5259,55
191,90
transverse
3619
3632,87
99,19
Elongation
Elongation
Direction
SD
SD
(%)
(%)
12,00
0,20
longitudinal
12,5
transverse
13,0
12,81
0,52
Strength
Strength
Direction
SD
SD
(N)
(N)
longitudinal
5588,0
2947,58
168,64
transverse
3609,0*
1646,64
57,02
Elongation
Elongation
Direction
SD
SD
(%)
(%)
8,07
0,19
longitudinal
13,0
9,04
0,48
transverse
13,0
Percentage longitudinal
99,5
56,04
of residual
transverse
99,5
45,33
strength
6
Strength
(N)
988
984
Elongation
(%)
28,7*
9,0
Strength
(N)
1521
1316
Elongation
(%)
9,3
8,9
SD
50
22
SD
6,7
0,4
SD
110
55
SD
0,3
0,3
104,0
-
67,25
-
86,1
-
56,2
-
67,6
-
100,0
-
70,56
-
99,0
-
62,8
-
1,1
-
It is evident from Tables No. 3 and 4 that the results (percentage of residual strength and elongation) provided by the relevant participants differ principally.
This observation also refers to the original (unexposed) samples!
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Stránka 6 ze 6
4.2.1 Detailed examination of consistency and outlaying values
To obtain consistency of the results, Mandel´s statistics h (interlaboratory statistics of
consistency) was used. Depicted horizontal lines correspond to the relevant values of
Mandel´s indicators on the levels of statistical significance of 1 and 5 %, respectively.
Chart No. 1 Mandel´s statistics of interlaboratory consistency h – for original sample A –
grouped according to the laboratories
Mandel´s statistics h
sample A – original
strength – longitudinal direction
strength – transverse direction
elongation – longitudinal direction
elongation – transverse direction
2,50
2,00
1,50
1,00
0,50
0,00
-0,50
-1,00
1
2
3
4
5
6
-1,50
-2,00
-2,50
Chart No. 2 Mandel´s statistics of interlaboratory consistency h - for sample A after
irradiation – grouped according to the laboratories
sample A – after irradiation
2,50
2,00
1,50
1,00
0,50
0,00
-0,50
-1,00
1
2
3
4
5
6
-1,50
-2,00
-2,50
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Stránka 7 ze 7
Chart No. 3 Mandel´s statistics of interlaboratory consistency h – for original sample B –
grouped according to the laboratories
sample B – original
2,00
1,50
1,00
0,50
0,00
-0,50
1
2
3
4
5
6
-1,00
-1,50
-2,00
Chart No. 4 Mandel´s statistics of interlaboratory consistency h – for sample B after
irradiation – grouped according to the laboratories
sample B –after irradiation
2,00
1,50
1,00
0,50
0,00
-0,50
1
2
3
4
5
6
-1,00
-1,50
-2,00
It follows from Chart No. 1 that laboratories 5 and 6 reported different results as compared to
other participants.
It is evident from Chart No. 2 that the participating laboratories obtained different results of
strength and elongation after irradiation. Large differences were observed particularly in
laboratories No. 1 and 6.
It can be deduced from Chart No.3 that laboratory No. 6 obtained different results as
compared to other laboratories. Laboratory No.5 did not test sample B.
Chart No. 4 reveals different results after irradiation for sample B in laboratory No.1.
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Stránka 8 ze 8
It was decided that all results would be included into overall assessment providing that they
would be subjected to Grubbs´ test related to outlying values.
Table No. 5 Values of Grubbs´ test for mean values of strength
STRENGTH
SAMPLE A
SAMPLE B
Direction
One small
One large
One small
One large
1,793
1,126
1,521
0,909
longitudinal
Original
1,889*
0,711
1,495
0,906
transverse
After
0,789
1,955*
0,922
1,676
longitudinal
irradia0,523
2,011**
0,828
1,724*
transverse
tion
Distant value (5 %)
1,887
1,715
Outlying value (1 %)
1,973
1,764
Table No. 6 Values of Grubbs´ test for mean values of elongation
ELONGATION
SAMPLE A
SAMPLE B
Direction
One small
One large
One small
One large
0,723
1,959*
0,776
1,754*
longitudinal
Original
2,032**
1,074
0,922
0,565
transverse
After
1,711
0,951
0,899
1,646
longitudinal
irradia 0,635
1,935*
0,960
1,701
transverse
tion
Distant value (5 %)
1,887
1,715
1,973
1,764
Test type
Grubb´s
test
statistics
Grubb´s
critical
values
Test type
Grubb´s
test
statistics
Grubb´s
critical
values
The Grubbs´ statistics G determines whether or nor it is possible to consider the mean value
of the determination as
a) correct
b) distant (if G is higher or equal to 5 % of critical value); it is denoted as “*” in Tables No 2, 3 and 6
c) outlying (if G is higher or equal to 1 % of critical value); it is denoted as “**” in Tables No 2, 3
and 6
The Grubbs´ test found the results of results of laboratory 1 for strength of sample A and
laboratory 6 for elongation of sample B as outlying. Therefore, the pairs of the lowest and
highest mean values were not tested any further. The results of these laboratories were
excluded form calculation of total mean value for particular properties. Therefore, the
following statistical analysis includes five laboratories only.
The concluding overview of results is offered by z-score, which was calculated from all
measured values according to the equation:
x−X
z=
σ
where:
x – mean value of determination for the particular laboratory
X – mean value of all determinations of the particular samples
σ − mean value of standard deviation for particular samples
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Stránka 9 ze 9
It was most important for graphical expression of results employing z-score to select the most
suitable way of calculation of standard deviation of values obtained for particular samples.
As the most trustworthy value of deviation was selected the value obtained from results of the
particular participants; i.e. from the measured values after excluding outlying results for
sample A. There were no outlying values for sample B; therefore, all results obtained were
used for the calculation. The following table shows a summary of standard deviations and
mean values and presents the resulting values employed for statistical processing (denoted by
bold letters).
Table No. 7 Values of standard deviation employed for calculation of z-score
STRENGTH
Parameter
Overall
mean
value
RSD**
SD
Mean
a.e.o.v.*
RSD
a.e.o.v.
SD
a.e.o.v..*
Sample A
SAMPLE B
original
after irradiation
original
after irradiation
A – long. A – trans. A – long. A – trans. B – long. B – trans. B – long. B – trans.
366,4
1324,4
108,9
389,8
4249,3
2899,1
108,9
389,8
8,9
32,6
6,7
88,1
122,8
133,8
147,5
574,9
50,4
2143,7
44,2
1280,6
122,8
133,8
147,5
574,9
365,9
1312,3
56,6
158,5
-
-
-
-
9,9
7,1
76,0
69,2
-
-
-
-
36,4
92,8
43,0
109,6
-
-
-
-
ELONGATION
Parameter
Sample A
Sample B
original
after irradiation
original
after irradiation
A – long. A - trans A – long. A – trans. B – long. B – trans. B – long. B – trans.
Total
142,4
69,5
79,7
49,6
14,7
11,2
8,9
9,5
mean *
RSD**
22,8
26,6
51,9
88,0
54,3
18,0
28,2
21,7
SD*
32,5
18,5
41,3
43,6
8,0
2,0
2,5
2,1
Mean
value
129,7
62,0
71,8
32,7
a.e.o.v..*
RSD
7,9
3,1
57,0
47,4
a.e.o.v...
SD
10,2
1,9
40,9
15,5
a.e.o.v..*
a.e.o.v.. – after exclusion of outlying values
* - values used for statistical processing
**
- selected standard deviation expressed in percentage from mean of results obtained by the
participants of the test
SD =
n∑ x 2 − ( ∑ x) 2
n(n − 1)
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Stránka 10 ze 10
4.2.2 Summary of results expressed in the z-score graphic form
Table No. 8 Values of z-score of particular laboratories for samples A and B
STRENGTH
Sample A
Sample B
Laboratory
original
after irradiation
original
after irradiation
z A long. z A trans. z A long. z A trans. z B long. z B trans. z B long. z B trans.
0,1
0,8
7,3
12,7
0,6
0,6
1,7
1,7
1
0,2
0,1
0,1
-0,6
0,5
0,6
0,0
-0,2
2
0,6
0,0
-1,2
-0,6
-0,5
-0,5
-0,6
-0,8
3
-0,2
0,8
-0,5
-0,2
0,9
0,9
-0,2
-0,2
4
-1,6
-1,7
0,3
-0,3
5
1,0
0,8
1,5
1,8
-1,5
-1,5
-0,9
-0,5
6
ELONGATION
Sample A
Sample B
Laboratory
original
after irradiation
original
after irradiation
z A long. z A trans. z A long. z A trans. z B long. z B trans. z B long. z B trans.
0,9
0,4
1,1
1,8
-0,3
0,9
1,6
1,7
1
0,0
0,8
0,3
-0,3
-0,3
0,8
-0,3
-0,2
2
-1,0
0,8
-1,5
-0,3
-0,8
-1,1
-0,6
-0,2
3
-1,1
-1,6
-0,3
-0,7
-0,4
0,4
-0,9
-1,0
4
1,1
-0,5
0,5
-0,5
5
7,5
23,7
1,2
6,5
1,8
-1,1
0,2
-0,3
6
z A, B – obtained z-score values for particular participants
z<±2
acceptable result
± 2 < z < ± 3 cautionary borderline
z>±3
unacceptable result
Chart No. 5a,b,c,d - z-score values of strength for sample A from particular laboratories
Sam ple A, original
Sample A, original
2,0
1,5
2,0
1,0
z - score
1,0
0,5
0,0
-0,5
-1,0
-1,5
-2,0
5
4
1
2
3
6
z - score
1,5
0,5
0,0
-0,5
5
3
2
4
1
6
-1,0
-1,5
-2,0
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Stránka 11 ze 11
Sam ple A, after irradiation
12,0
10,0
7,0
z - score
6,0
z - score
5,0
4,0
3,0
2,0
6,0
4,0
2,0
1,0
0,0
-1,0
8,0
3
5
2
4
6
0,0
1
5
3
2
-2,0
-2,0
4
1
6
Chart No. 6a,b,c,d - z-score values of elongation for sample A from particular laboratories
Sam ple A, original
Sam ple A, original
2,0
1,5
7,5
1,0
6,5
z - score
5,5
z - score
4,5
3,5
2,5
1,5
0,0
-0,5
5
4
1
3
2
6
-1,0
0,5
-0,5
-1,5
0,5
4
2
3
1
5
-1,5
6
-2,0
-2,5
Sample A, after irradiation
7,0
6,0
2,0
5,0
z - score
1,0
0,5
0,0
-0,5
3
2
4
1
5
6
z - score
1,5
4,0
3,0
2,0
1,0
-1,0
0,0
-1,5
-1,0
-2,0
-2,0
4
5
1
3
2
6
Chart No. 7a,b,c,d - z-score values of strength for sample B from particular laboratories
Sample B, original
Sam ple B, original
2,0
1,5
2,5
1,0
1,5
0,5
z - score
1,0
0,5
0,0
-0,5
-1,0
6
3
2
1
4
z - score
2,0
0,0
-0,5
6
3
1
2
4
-1,0
-1,5
-1,5
-2,0
-2,5
-2,0
-2,5
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Stránka 12 ze 12
Sam ple B, after irradiation
Sample B, after irradiation
2,5
2,0
2,5
1,5
2,0
z - score
1,0
0,5
0,0
6
-0,5
3
4
2
1
z - score
1,0
1,5
0,5
0,0
3
-0,5
6
2
4
1
-1,0
-1,0
-1,5
-1,5
-2,0
-2,0
-2,5
-2,5
Chart No. 8a,b,c,d - z-score values of elongation for sample B from particular laboratories
Sam ple B, original
Sam ple B, original
2,0
1,5
2,0
1,0
z - score
1,0
0,5
0,0
-0,5
3
4
2
1
6
z - score
1,5
0,5
0,0
3
-0,5
6
2
4
1
-1,0
-1,0
-1,5
-1,5
-2,0
-2,0
2,0
1,5
2,0
1
z - score
1,0
6
0,5
0,0
-0,5
4
3
z - score
1,0
1,5
0,5
-0,5
2
1
0,0
4
6
3
2
-1,0
-1,0
-1,5
-1,5
-2,0
-2,0
4.2.3 Summary of results
The following characteristics summarise z-score values and provide information on how a
particular laboratory – in general terms - coped with other laboratories concerning all
measurements.
∑z
RSZ =
m
SSZ = ∑ z 2
where
RSZ is relative sum of z-score for sample A (B)
SSZ is sum of z-score squares for sample A (B)
www.tzu.cz
Stránka 13 ze 13
m is number of z-score values for each sample
Table No. 9 Values of relative sum of z-score and sum of z- score squares from particular
laboratories for samples A and B
Sample A
Sample B
Laboratory
RSZ
SSZ
RSZ
SSZ
8,8
219,4
3,0
12,9
1
0,2
1,3
0,3
1,5
2
-1,1
6,2
-1,8
3,8
3
-1,4
5,1
-0,1
3,7
4
-1,0
7,4
5
15,5
667,8
-1,4
10,1
6
Chart No. 9 Relative sum of z-score for sample A
RSZ
16,0
11,0
6,0
1,0
4
3
5
2
1
6
5
1
6
-4,0
Chart No. 10 Sum of z- score squares for sample A
SSZ
250,0
200,0
150,0
100,0
50,0
2
4
3
0,0
Chart 10 of square values of z-score reveals again statistically significant deviation of results
from two laboratories. Critical value of distribution χ2(α=0,05) = 12,59 for the six participating
www.tzu.cz
Stránka 14 ze 14
laboratories. This graphical expression allows at the same time to compare mutually particular
laboratories from the point of view of measurement at all levels. Hence, the sequence of
numbers in the chart corresponds with the overall success of the laboratory in the test.
Chart No. 11 Relative sum of z-score for sample B
RSZ
4,0
3,0
2,0
1,0
0,0
3
6
4
2
1
6
1
-1,0
-2,0
-3,0
-4,0
Chart No. 12 Sum of z- score squares for sample B
SSZ
14,0
12,0
10,0
8,0
6,0
4,0
2,0
2
4
3
0,0
Chart 12 of square values of z-score reveals an apparent deviation of results from laboratory
No. 1. Critical value of distribution χ2(α=0,05) = 11,07 for five participating laboratories.
www.tzu.cz
Stránka 15 ze 15
5.
Conclusion
The aim of this interlaboratory comparison was to provide to the participating laboratories
carrying out tests on the resistance to weathering an overview of their results within the frame
of the whole EU. The offers were sent out to a majority of notified bodies involved in
conformity evaluation of geotextiles. The interlaboratory comparison was attended by six
laboratories from five EU members.
The samples sent out:
A – needled non-woven textile fabric (100 % polypropylene)
B – woven textile fabric (100 % polyester)
The results have revealed that the participant reached very differing values for both
samples being tested. This refers particularly to the samples AFTER EXPOSURE, but
also to the original material – sample B. These results are very alarming. It means that
the same material would be assessed as satisfactory by some laboratories, while it would
be rated as unsatisfactory in other laboratories, considering the requirements of
harmonised standards.
The round robin test should be repeated as soon as possible and the results obtained should be
reported to the working group for geotextiles SG 11.
The successful participants will be provided with “Certificate on participation in
interlaboratory comparison”. This report is also available in electronic form.
The organisers wish to thank to all the participants and they look forward to a further
collaboration.
Team of the TZÚ´s (TTI´s) accredited testing laboratory
www.tzu.cz
Stránka 16 ze 16
Annex – Testing of homogeneity
The homogeneity testing of the samples was carried out before the interlaboratory
comparison. Homogeneity of both samples was tested independently. The materials were cut
to obtain particular samples. Using the random number generator (Microsoft Excel) program,
ten samples were randomly chosen from each of the materials. Each of the original samples
were subjected to determination of strength only. The values obtained were processed
statistically using Grubbs´ test and no outlying and distant values were found. Thus, it can be
concluded that the original samples were homogeneous.
Homogeneity test of sample A
Original sample A
Measurement
Direction: longitudinal
Direction: transverse
Strength
Elongation
Strangth
Elongation
1
306,0
132,8
1453,5
62,0
2
316,5
132,9
1429,5
69,9
3
344,0
136,8
1448,3
67,6
4
400,5
148,0
1539,1
67,2
5
291,7
134,0
1358,9
63,4
6
366,5
140,8
1370,8
61,3
7
342,9
138,4
1374,6
67,5
8
284,3
130,2
1500,3
63,2
9
372,7
132,2
1285,5
60,9
10
356,6
129,9
1444,6
60,8
www.tzu.cz
Stránka 17 ze 17
Mean value
338,2
135,6
1416,8
64,7
Standard deviation
37,8
5,6
77,8
3,4
STRENGTH
Direction x
longitudinal
Original
transverse
Distant value (5 %)
ELONGATION
One small
One large
One small
One large
1,43
1,65
1,02
2,22
1,69
1,57
1,11
1,54
2,290
2,290
2,482
2,482
Test type
Grubb´s
test
statistics
Grubb´s
critical
values
Homogeneity test of sample B
Original sample B
Measurement
Direction: longitudinal
Direction: transverse
Strength
Elongation
Strength
Elongation
1
5939,8
11,4
4141,5
12,6
2
6043,0
11,6
4141,5
11,0
3
6104,2
11,6
4007,7
11,4
4
5959,9
11,3
4141,5
13,0
5
6135,6
11,6
4007,7
12,7
6
6104,2
11,6
3935,1
11,3
7
6073,6
11,5
3903,7
12,4
8
6155,8
11,6
4152,0
12,4
9
5959,9
11,6
4027,6
11,2
10
5887,4
11,3
3811,0
12,1
Mean value
Standard
deviation
6036,3
11,5
4014,2
11,9
93,1
0,1
118,0
0,7
STRENGTH
Direction x
One small
One large
ELONGATION
One small
One large
www.tzu.cz
Test type
Stránka 18 ze 18
longitudinal
Original
transverse
Distant value (5 %)
1,60
1,28
1,86
0,94
1,72
1,17
1,29
1,43
2,290
2,290
2,482
2,482
Grubb´s
test
statistics
Grubb´s
critical
values
References:
1 - Thompson M., Wood R.: International Harmonized protocol for Proficiency testing of
(chemical) Analytical Laboratories, Journal of AOAC, Vol.76, No. 4, 1993, 926-940;
2 - RNDr. František Jaroš: Pravděpodobnost a statistika (druhé vydání), Ed. VŠCHT Praha,
1998 (in Czech)
3 - ISO 5725-2 Accuracy (trueness and precision) of measurement method and results – Part
2: Basic method for determination of repeatability and reproducibility of a standard
measurement method
4 – Doc. RNDr. Jiří Anděl CSc.: Matematická statistika (in Czech)
www.tzu.cz
Stránka 19 ze 19

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