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Routine Analytical Chemistry Sub-Group
Technical Report
2016 Collaborative Study of
CORESTA Ignition Propensity Monitor Test Piece CM IP 2 for the
Determination of Ignition Propensity
March 2017
Project Leader:
Guy Jaccard, Philip Morris International, Switzerland
Authors:
Donatien Tafin Djoko and Guy Jaccard, Philip Morris International, Switzerland
Table of Contents
Table of Contents ............................................................................................................................. 2
1. Introduction ............................................................................................................................. 3
2. Organisation ............................................................................................................................ 3
2.1 Participants ................................................................................................................... 3
2.2 Protocol ........................................................................................................................ 4
3. Raw data ................................................................................................................................. 4
4. Statistical Analysis .................................................................................................................. 5
5. Results ..................................................................................................................................... 7
6. References ............................................................................................................................... 8
Appendix A: Descriptive Statistics .................................................................................................. 9
Appendix B: Test protocol ............................................................................................................. 12
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 3/13
1. Introduction
The CORESTA Routine Analytical Chemistry Sub-Group has been given the responsibility to
provide a monitor test piece specific for ignition propensity testing, according to ISO
12863:2010.
A candidate CORESTA monitor test piece had been manufactured in the Philip Morris
International Neuchâtel (Switzerland) factory in January 2014, with product specifications
established on the basis of prototype cigarettes previously analyzed.
It has been qualified as CORESTA Monitor Test Piece CM IP 2 in 2015, on the basis of a
2014 collaborative study and re-confirmed a year later (see CORESTA RAC Technical
Report, 2014 collaborative study of CORESTA Ignition Propensity Monitor Test piece CM IP
2 for the determination of ignition propensity and the corresponding 2015 collaborative study
report, edited in March 2015 and April 2016 respectively).
The need to continue checking the stability of CM IP 2 monitor test piece and using the
results to support the laboratories proficiency and maintain their accreditation on the basis of
a collaborative study of CM IP 2 and of NIST standard reference material 1082 for
comparison purpose has been agreed during the CORESTA RAC Lausanne meeting in April
2016. The project has been approved by the CORESTA Scientific Commission and registered
as project RAC-113.
The goal of this report is to provide the statistical assessment of the results of the
collaborative study mentioned above.
2. Organisation
2.1 Participants
In total 14 laboratories participated in the collaborative study, according to the below list:
British American Tobacco, Germany
delfortgroup, Austria
Essentra Scientific Services, UK
Global Laboratory Services, USA
Heintz van Landewyck, Luxemburg
ITL Reemtsma, Germany
ITL Seita, France
Japan Tobacco, Japan
Karelia, Greece
Philip Morris International, Germany
Philip Morris International, Poland
Philip Morris International, Switzerland
Sampoerna, Indonesia
SWM, France
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 4/13
2.2 Protocol
Participants were requested to follow the method ISO 12863:2010 with 10 layers of the
required substrate. The number of replicates per brand (CM IP 2 and NIST Monitor) and
laboratory was set to 5 on 5 different days. Each ignition propensity test consisted of a sample
of 40 cigarettes. The protocol sent to participants is provided in Annex B (pp. 11-12).
CM IP 2 Monitor Test Piece and NIST standard reference material 1082 were to be obtained
directly from respective suppliers: Borgwaldt and Cerulean for CM IP 2; NIST for NIST
reference material.
3. Raw data
The table below lists the results obtained by individual laboratories for the number (n) and the
percentage (%) of cigarettes with full length burn (FLB).
Table 1: Results of the individual laboratories
Laboratory CM IP 2 (n FLB) CM IP 2 (% FLB) NIST (n FLB) NIST (% FLB)
1 2; 1; 2; 5; 1 5; 2.5; 5; 12.5; 2.5 4; 3; 7; 3; 9 10; 7.5; 17.5; 7.5; 22.5
2 1; 0; 3; 0; 0 2.5; 0; 7.5; 0; 0 0; 2; 1; 1; 0 0; 5; 2.5; 2.5, 0
3 1; 1; 0; 0; 1 2.5; 2.5; 0; 0; 2.5 2; 2; 1; 2; 1 5; 5; 2.5; 5; 2.5
4 1; 0; 0; 0; 0 2.5; 0; 0; 0; 0 0; 0; 0; 1; 0 0; 0, 0; 2.5; 0
5 4; 2; 3; 3; 4 10; 5; 7.5; 7.5; 10 4; 4; 4; 4; 5 10; 10; 10; 10; 12.5
6 4; 1; 1; 2; 2 10; 2.5; 2.5; 5; 5 3; 0; 3; 0; 3 7.5; 0; 7.5; 0; 7.5
7 2; 3; 2; 3; 0 5; 7.5; 5; 7.5; 0 5; 6; 5; 5; 5 12.5; 15; 12.5; 12.5; 12.5
8 1; 0; 1; 1; 2 2.5; 0; 2.5; 2.5; 5 5; 3; 2; 2; 5 12.5; 7.5; 5; 5; 12.5
9 0; 2; 0; 0; 0 0; 5; 0; 0; 0 3; 5; 10; 13; 5 7.5; 12.5; 25; 32.5; 12.5
10 1; 1; 0; 2; 1 2.5; 2.5; 0; 5; 2.5 No data No data
11 3; 6; 1; 3; 3 7.5; 15; 2.5; 7.5; 7.5 6; 13; 9; 6; 8 15, 32.5; 22.5; 15; 20
12 3; 2; 1; 2; 0 7.5; 5; 2.5; 5; 0 5; 3; 8; 6; 3 12.5; 7.5; 20; 15; 7.5
13 1; 2; 0; 0; 1 2.5; 5; 0; 0; 2.5 4; 3; 4; 5; 5 10; 7.5; 10; 12.5; 12.5
14 5; 3; 3; 3; 2 12.5; 7.5; 7.5; 7.5; 5 No data No data
Two laboratories did not report results for the NIST reference material (laboratories 10 and
14).
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 5/13
4. Statistical Analysis
Ignition propensity tests are typical types of proportion-based analysis with a binary response
variable: Full Length Burning or not. Statistical analysis is performed assuming that the data
generating process is binomial.
Within each laboratory, over a short period, each cigarette is a realization of a Bernoulli
random variable with parameter 𝑝. If a random sample of 𝑛 cigarettes is selected, and if 𝐵 is
the number of units fully burned, then 𝐵 has binomial distribution with parameters 𝑛 and 𝑝:
𝑃{𝐵 = 𝑥} = (𝑛
𝑥) 𝑝𝑥 (1 − 𝑝)𝑛−𝑥 𝑥 = 0, 1, ⋯ , 𝑛
The sample fraction of Full Length Burn is defined as the ratio of the number of cigarettes
fully burned 𝐵 to the sample size 𝑛:
�̂� = 𝐵
𝑛
And the distribution of the random variable �̂� can be obtained from the binomial with
𝑚𝑒𝑎𝑛, 𝜇𝑝 = 𝑝, 𝑎𝑛𝑑 𝑣𝑎𝑟𝑖𝑎𝑛𝑐𝑒, 𝜎𝑝2 =
𝑝 (1 − 𝑝)
𝑛
In our case, for each replicate, we have:
n = 40: Number of cigarettes in each replicate
r = 5: Number of replicates per laboratory
Having 𝐵𝑗,𝑖 fully burned cigarettes for laboratory 𝑗 in sample 𝑖, fraction of individual
determination of fully burned cigarettes in the 𝑖th sample is computed as
�̂�𝑗,𝑖 =𝐵𝑗,𝑖
𝑛 𝑖 = 1, 2, ⋯ , 𝑟
The average (amongst individual determination) within each laboratory is given by
�̅�𝑗 =∑ 𝐵𝑗,𝑖
𝑟𝑖=1
𝑟 ∗ 𝑛=
∑ �̂�𝑗,𝑖𝑟𝑖=1
𝑟
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 6/13
Therefore the within standard deviation for laboratory 𝑗 is computed as
𝜎𝑗 = √�̅�𝑗 (1 − �̅�𝑗)
𝑛
The aggregated within laboratory standard deviation (repeatability standard deviation) is
defined as
𝑆𝑟 = √∑ 𝜎𝑗
2𝐿𝑗=1
𝐿, 𝑗 = 1, ⋯ , 𝐿 is the number of laboratory
The between-laboratory standard deviation 𝑆𝐿,
𝑆𝐿 = √∑ (�̅�𝑗 − �̿�)2𝐿
𝑗=1
𝐿 − 1−
𝑆𝑟2
𝑟
Where
�̿� = ∑ �̅�𝑗
𝐿𝑗=1
𝐿 , 𝑗 = 1, 2, ⋯ , 𝐿
The reproducibility standard deviation,
𝑆𝑅 = √𝑆𝐿2 + 𝑆𝑟
2
The repeatability coefficient of variation,
𝐶𝑉𝑟[%] = 𝑆𝑟
�̿�∗ 100
The reproducibility coefficient of variation,
𝐶𝑉𝑅[%] = 𝑆𝑅
�̿�∗ 100
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 7/13
The 95% confidence repeatability limit
𝑟 = 2 ∗ √2 ∗ 𝑆𝑟
The 95% confidence reproducibility limit,
𝑅 = 2 ∗ √2 ∗ 𝑆𝑅
Mandel’s h between consistency statistics is computed as
ℎ𝑗 = �̅�𝑗 − �̿�
𝑆𝐿
The within laboratory consistency statistics
𝑘𝑗 = 𝜎𝑗
𝑆𝑟
The approach implemented here is well documented in the statistical and scientific literature.
The reader may refer to NIST Technical Note 1436. Additional and advanced details on
proportion data analysis are deeply covered by Joseph L. Fleiss, et al. in “Statistical Methods
for Rates and Proportions, 3rd
Edition, Wiley”.
5. Results
The average proportions of FLB, standard deviations and the Mandel h and k statistics by
participant and brand are reported in Table 3 and in Table 4 in Appendix A. The statistics h
and k are illustrated in figures 1 and 2 in Appendix A.
Table 2 summarizes the overall statistics of the two test items in proportion of FLB for the
collaborative test organized in 2016 in comparison with the previous collaborative studies.
The CM IP 2 results are well in line with the results obtained in 2014 and 2015, in terms of
global mean, repeatability and reproducibility. Results for CM IP 2 are stable in terms of
ignition propensity test.
If used as a monitor test piece with one replicate of 40 test pieces, and assuming that a range
of mean value of ± 2SR is acceptable, one can expect values between 0 and 10.8 % (or 0 and 4
cigarettes with FLB). For the NIST 1082 standard reference material, values between 0 and
24.8% (or 0 and 10 cigarettes) would be acceptable.
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 8/13
Table 2: Global summary statistics by test item
Global mean (%)
Sr SLc SR CVr (%)
CVR (%)
r R Test item
3.96 3.06 2.66 3.82 77.15 96.31 8.65 11.66 CM IP 2, coll. test
2016
4.10 3.12 1.39 3.42 76.11 83.34 8.83 9.66 CM IP 2, coll. test
2015
3.24 2.78 1.75 3.28 85.81 101.38 7.86 9.29 CM IP 2, coll. test
2014
9.83 4.61 6.27 7.50 46.90 76.31 13.04 23.36 NIST 1082, 2016
10.34 4.74 5.06 6.93 45.83 67.05 13.41 19.61 NIST 1082, 2015
8.73 4.44 2.58 5.13 50.81 58.78 12.55 14.51 NIST 1082, 2014
6. References
• Gann, R.G., Steckler, K.D., Ruitberg, S., Guthrie, W.F., and Levenson, M.S., "Relative
Ignition Propensity of Test Market Cigarettes" NIST Technical Note 1436, National
Institute of Standards and Technology, Gaithersburg, MD, 34 pages (2001).
• Joseph L. Fleiss, Bruce Levin, Myunghee Cho Paik, "Statistical Methods for Rates and
Proportions" 3rd
Edition, Wiley, 800 p. (2003).
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 9/13
Appendix A: Descriptive Statistics
Table 3: Descriptive statistics for CM IP 2 monitor test piece per laboratory. h and k stands for
Mandel h (between laboratories) and k (within deviation) consistency statistics.
Laboratory P (%) SD Mandel h Mandel k
1 5.5 3.60 0.577 1.179
2 2.0 2.21 -0.737 0.724
3 1.5 1.92 -0.925 0.628
4 0.5 1.12 -1.301 0.365
5 8.0 4.29 1.515 1.403
6 5.0 3.45 0.389 1.127
7 5.0 3.45 0.389 1.127
8 2.5 2.47 -0.550 0.807
9 1.0 1.57 -1.113 0.514
10 2.5 2.47 -0.550 0.807
11 8.0 4.29 1.515 1.403
12 4.0 3.10 0.013 1.013
13 2.0 2.21 -0.737 0.724
14 8.0 4.29 1.515 1.403
Table 4: Descriptive statistics for NIST 1082 standard reference material per laboratory. h and
k stands for Mandel h (between laboratories) and k (within deviation) consistency statistics.
Laboratory P (%) SD Mandel h Mandel k
1 13.0 5.32 0.505 1.153
2 2.0 2.21 -1.250 0.480
3 4.0 3.10 -0.931 0.672
4 0.5 1.12 -1.489 0.242
5 10.5 4.85 0.106 1.051
6 4.5 3.28 -0.851 0.711
7 13.0 5.32 0.505 1.153
8 8.5 4.41 -0.213 0.956
9 18.0 6.07 1.303 1.317
10 No data
11 21.0 6.44 1.782 1.397
12 12.5 5.23 0.425 1.134
13 10.5 4.85 0.106 1.051
14 No data
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 10/13
Figure 1: Mandel h (upper plot) and Mandel k (lower plot) statistics of FLB (%) for CM IP 2
monitor test piece (the orange and red lines are the 95 and 99% limits respectively)
-2.500
-1.500
-0.500
0.500
1.500
2.500
1 2 3 4 5 6 7 8 9 10 11 12 13 14
CM IP 2
h
FLB(%): CM IP 2 - Mandel h statistic by laboratory
0.0000.2000.4000.6000.8001.0001.2001.4001.6001.8002.0002.200
1 2 3 4 5 6 7 8 9 10 11 12 13 14
CM IP 2
k
FLB(%): CM IP 2 - Mandel k statistic by laboratory
Laboratory Codes
Laboratory Codes
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 11/13
Figure 2: Mandel h (upper plot) and Mandel k (lower plot) statistics of FLB (%) for NIST 1082
standard reference material (the orange and red lines are the 95 and 99% limits respectively
-2.500
-1.500
-0.500
0.500
1.500
2.500
1 2 3 4 5 6 7 8 9 10 11 12 13 14
NIST
h
FLB(%): NIST Mandel h statistic by laboratory
0.0000.2000.4000.6000.8001.0001.2001.4001.6001.8002.0002.200
1 2 3 4 5 6 7 8 9 10 11 12 13 14
NIST
k
FLB(%): NIST Mandel k statistic by laboratory
Laboratory Codes
Laboratory Codes
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 12/13
Appendix B: Test protocol
1. Objective
To assess the long term performance of the CORESTA Monitor test Piece CM IP 2,
according to ISO standard 12863, in terms of global mean value and variability (intra-
and inter-laboratory). The NIST standard is used for comparison purpose.
2. Test coordinator
Guy Jaccard
Principal Scientist
Philip Morris Products SA
Reduced-Risk Products. Product Stewardship
CH-2000 Neuchâtel
Switzerland
E-mail: guy.jaccard@pmi.com
Tel: +41 (58) 242 11 44
3. Parameter to be measured
The parameter to be measured is the ignition propensity, according to the ISO method
12863
Table 1 Parameter to be measured
Parameter
1 Ignition propensity
Number of cigarettes with full length burn
% of cigarettes with full length burn
4. Test methods
For cigarette testing, we recommend applying the following standard:
ISO 12863
RAC-113-CTR 2016 Collaborative Study CM IP 2 – March 2017 13/13
5. Test samples
Test samples consist of 1 machine-made CORESTA Monitor IP No 2 and the NIST
standard. CORESTA CM IP 2 Monitor test pieces shall be bought at Cerulean or
Borgwaldt, NIST Standard cigarettes shall be taken from each laboratory stock or
purchased.
Table 3 Test cigarettes for the Proficiency Test
Test cigarette
CORESTA Monitor Test Piece CM IP 2
NIST STANDARD
6. Schedule
For a given brand, 1 replicate of 40 cigarettes should be measured in a single test day,
for a total of 5 replicates over 5 independent days. There are no constraints concerning
the spacing between the days of experiment, however please keep them as close as
possible.
The study starts in June 2016. Each laboratory is free to organize at its will the
timeframe during which it performs the study. However, the test results should be sent
to the test coordinator no later than August 30th, 2016.
7. Reporting of test results
The test results should be reported using the Excel file Template for coll test IP_IP
No2.xls. See also the example provided in Example.xls to fill the excel template (Data
COR Day 1 sheet) with the Ignition Propensity tests results (only use the number 1 in
the appropriate column)
In addition to IP test specific results, the temperature and relative humidity during the
testing shall be reported as well.
Results should be sent electronically:
To: Guy.Jaccard@pmi.com
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