report no. 1038 paint - round 26 proficiency testing

Report No. 1038

Paint - Round 26 Proficiency Testing Program

August 2017

ACKNOWLEDGMENTS PTA wishes to gratefully acknowledge the technical assistance that was provided for this program by Ms S Bartlett, Quality Systems. This assistance included preparation and input into the design of the program, technical advice and discussion in the final report. PTA would also like to thank Mr J Rodgers-Falk, Valspar Paint Australia, for supplying the samples and discussion in the final report.

© COPYRIGHT PROFICIENCY TESTING AUSTRALIA 2017 PO Box 7507, Silverwater NSW 2128, Australia

CONTENTS Page

1 Foreword 1 2 Statistical Design of the Program 1 3 Features of the Program 1 4 Summary of Results

Table A: Summary of Results 2 2

5 Statistical Outlier Results Table B: Outlier Results

2 3

6 PTA and Technical Adviser’s Comments 3 7 References 4

APPENDIX A - Results and Data Analysis Consistency by Brookfield A1 Consistency-Rotothinner Viscometer A3 pH of Water-Based Paints A5 Density A7 Non-Volatile Content by Mass A9 APPENDIX B - Sample Homogeneity Homogeneity Testing B1 Table C: Homogeneity Testing Results B1 APPENDIX C - Documentation Instructions to Participants C1 Results Sheets C2

1

1. FOREWORD

This report summarises the results of the twenty-sixth round of a proficiency testing program covering a series of paint tests (to AS 1580). Proficiency Testing Australia (PTA) conducted the program in June 2017. The Program Coordinator was Dr M Li. The Technical Adviser was Ms S Bartlett, Quality Systems. This report was authorised by Mrs F Watton, PTA Quality Manager. The aim of the program was to assess laboratories’ ability to competently perform the prescribed analyses.

2. STATISTICAL DESIGN OF THE PROGRAM

Robust statistical procedures were used to generate the z-scores and summary statistics for each test - number of results, median, normalised interquartile range, uncertainty of the median, robust coefficient of variation, minimum, maximum and range.

3. FEATURES OF THE PROGRAM

(a) A total of twenty-three laboratories received samples, with all laboratories returning results.

(b) Each participant was supplied with two 500ml tins of water-based paint labelled

“Sample A” and “Sample B”.

(c) Laboratories were asked to perform the following consistency analyses on both Samples A and B: (i) AS/NZS 1580.214.5 - 1997 Paints and related materials - Methods of test -

Consistency - Rotational viscometer (Brookfield) (ii) AS/NZS 1580.214.4 - 1996 Paints and related materials - Methods of test -

Consistency - Rotothinner

(iii) AS/NZS 1580.505.1 - 1996 Paints and related materials - Methods of test - pH of water-based paints

(iv) AS/NZS 1580.202.1 - 1995 Paints and related materials - Methods of test -

Density

(v) AS/NZS 1580.301.1 - 2005/Amdt 1 - 2006 Paints and related materials - Methods of test - Non-volatile content by mass

(d) Participating laboratories were requested to perform their tests according

2

to the “Instructions to Participants" and to record their results on the accompanying "Results Sheets”. These were distributed to participants with the samples (Appendix C).

(e) Each laboratory was randomly allocated a unique code number for the

program to enable confidentiality of results. Reference to each laboratory in this report is made by its code number.

(f) Prior to sample distribution, randomly selected samples were analysed for homogeneity. Based on this testing, it was concluded that the samples were sufficiently homogeneous. Therefore any results identified as outliers could not be attributed to sample variability (Appendix B).

4. SUMMARY OF RESULTS

Sample Median Robust CV No. of Results

A 473.50 11.6% 20

B 465.00 11.7% 20

A 1.90 43.9% 12

B 1.85 36.1% 12

A 8.40 1.2% 20

B 8.40 1.4% 20

A 1.040 0.6% 26

B 1.040 0.6% 26

A 31.430 4.0% 23

B 31.660 3.5% 23

Non-Volatile Content by Mass (%)

pH of Water-Based Paints

Density (kg/L)

TABLE A: SUMMARY OF RESULTS

Analyses

Consistency by Brookfield(cP)

Consistency-Rotothinner Viscometer

(poise)

5. STATISTICAL OUTLIER RESULTS

In order to achieve the program's aim of assessing laboratories' testing performance, a robust statistical approach, which uses z-scores has been utilised. The z-score is a measure of how far the result(s) is from the consensus value - a normalised value which gives a "score" to each result relative to the other results in the group. Therefore a z-score close to zero means that the result agrees well with

3

those from other laboratories. An outlier will be any result(s) which has an absolute z-score value greater than or equal to 3.0. For further information on the calculation and interpretation of z-scores, please see the Guide to Proficiency Testing Australia (2016)¹. TABLE B: OUTLIER RESULTS

6. PTA AND TECHNICAL ADVISER’S COMMENTS Metrological Traceability and Measurement Uncertainty of Assigned Values

Consensus values (median) derived from the participants’ results are used in this

program. These values are not metrologically traceable to an external reference. Analysis of Results by Method Groups

All participants were required to use the AS 1580 Paints and Related Materials - Methods of Test series, therefore, results were pooled for analysis. Comments

Consistency by Brookfield - Samples A and B were identical, however, there was a noticeable difference between the medians for each sample for the Consistency by Brookfield test. Laboratories 10B and 20 returned outliers for this test. These laboratories should investigate the cause of the outliers, such as interferences from the matrix, instrument conditions, transcription and calculation errors, sample preparation errors and human errors. Consistency-Rotothinner Viscometer - The repeatability for the Consistency-Rotothinner Viscometer test is 0.01 PaS, while the reproducibility is 0.05 PaS. The results for laboratories 10A and 10D are outside of this, which should be investigated. The results for laboratory 14 were classified as outliers for this test.

Test

Z-Score Outliers (Laboratory Codes)

Sample A Sample B Consistency by Brookfield 20 10B, 20

Consistency-Rotothinner Viscometer 14 14 pH of Water-Based Paints nil nil

Density nil 15 Non-Volatile Content by Mass 2, 4 2, 4

4

pH of Water-Based Paints - The repeatability of the pH method is 0.07 and the reproducibility is 0.34 (for a Product with pH 8.06). The range for the two samples varies between the minimum and maximum by 0.6 pH units which is outside the reproducibility limits of the pH method. Density - The results are good and this method is relatively robust. Laboratory 15 has one outlier. The results compare well to the repeatability and reproducibility ranges. Non-Volatile Content by Mass - The results are good and this method is relatively robust. Laboratories 2 and 4 have outliers. This method has a 2.5% reproducibility, and median results between Sample A and Sample B are good. 7. REFERENCES

[1] Guide to Proficiency Testing Australia, 2016. This document can be found on the PTA website at www.pta.asn.au

[2] AS/NZS 1580.214.5 - 1997 Paints and related materials - Methods of test - Consistency - Rotational viscometer. [3] AS/NZS 1580.214.4 - 1996 Paints and related materials - Methods of test - Consistency - Rotothinner. [4] AS/NZS 1580.505.1 - 1996 Paints and related materials - Methods of test - pH of water-based paints. [5] AS/NZS 1580.202.1 - 1995 Paints and related materials - Methods of test - Density. [6] AS/NZS 1580.301.1 - 2005/Amdt 1-2006 Paints and related materials - Methods of test - Non-volatile content by mass.

en laboratory variability (excluding the outliers) is quite good. For future 10

APPENDIX A

Results and Data Analysis

Consistency by Brookfield A1 Consistency-Rotothinner Viscometer A3 pH of Water-Based Paints A5 Density A7 Non-Volatile Content by Mass A9

A1

Consistency by Brookfield - AS/NZS 1580.214.5

Results by Laboratory Code

Results (cP)

Sample A Sample B

1 432.9 427.5 -0.74 -0.69

2 460.0 500.0 -0.25 0.64

3 469.0 479.0 -0.08 0.26

4 429.6 427.2 -0.80 -0.69

6 496.0 460.0 0.41 -0.09

7 554.0 536.0 1.47 1.30

9 472.0 457.0 -0.03 -0.15

10A 630.0 540.0 2.85 1.37

10B 625.0 675.0 2.76 3.84 §

10C 464.0 456.0 -0.17 -0.16

10D 454.0 444.0 -0.36 -0.38

11 475.0 470.0 0.03 0.09

12 470.0 450.0 -0.06 -0.27

14 499.2 512.0 0.47 0.86

16 484.4 450.4 0.20 -0.27

19 436.0 424.0 -0.68 -0.75

20 680.0 710.0 3.76 § 4.48 §

21 530.0 520.0 1.03 1.01

22 452.5 453.3 -0.38 -0.21

23 540.0 540.0 1.21 1.37

No of Results: 20 20Median: 473.50 465.00

Normalised IQR: 54.86 54.63Robust CV: 11.6% 11.7%

Minimum: 429.60 424.00Maximum: 680.00 710.00

Range: 250.40 286.00Uncertainty

(Median) 15.37 15.31

NOTES: 1). "§" denotes an outlier (i.e. those results for which |z-score | ≥ 3.0).

Lab Code

Sample A

Robust Z-score1

Sample B

Robust Z-score1

A2

Consistency by Brookfield (Sample A)

Consistency by Brookfield (Sample B)

A3

Consistency-Rotothinner Viscometer - AS/NZS 1580.214.4


Results (poise)

Sample A Sample B

3 1.7 1.8 -0.24 -0.07

4 1.5 1.5 -0.54 -0.60

6 1.6 1.6 -0.36 -0.37

10A 2.5 1.5 0.72 -0.52

10B 2.8 2.7 1.08 1.27

10C 2.8 2.9 1.08 1.57

10D 3.1 2.4 1.44 0.82

14 5.3 5.3 4.08 § 5.17 §

16 1.8 1.8 -0.12 -0.07

20 1.9 1.9 0.00 0.07

21 1.9 1.9 0.00 0.07

23 1.3 1.3 -0.72 -0.82

No of Results: 12 12

Median: 1.90 1.85

Normalised IQR: 0.83 0.67

Robust CV: 43.9% 36.1%

Minimum: 1.30 1.30

Maximum: 5.30 5.30

Range: 4.00 4.00

Uncertainty (Median) 0.30 0.24

NOTES: 1). "§" denotes an outlier (i.e. those results for which |z-score | ≥ 3.0).

Lab Code

Sample A

Robust Z-score1

Sample B

Robust Z-score1

A4

Consistency-Rotothinner Viscometer (Sample A)

Consistency-Rotothinner Viscometer (Sample B)

A5

pH of Water-Based Paints - AS/NZS 1580.505.1


Results

Sample A Sample B

1 8.3 8.3 -1.00 -0.87

2 8.6 8.7 2.00 2.61

3 8.5 8.6 1.00 1.74

4 8.5 8.4 0.50 0.35

5 8.3 8.3 -1.30 -1.22

6 8.3 8.2 -1.50 -1.83

10A 8.3 8.3 -1.00 -0.87

10B 8.3 8.3 -1.00 -0.87

10C 8.4 8.4 0.00 0.00

10D 8.3 8.3 -1.00 -0.87

11 8.6 8.6 2.00 1.74

13 8.5 8.5 1.00 0.87

15 8.1 8.2 -2.70 -1.57

17 8.4 8.3 0.00 -0.87

18 8.4 8.4 0.00 0.00

19 8.4 8.4 0.00 0.00

20 8.4 8.6 0.30 1.31

21 8.3 8.3 -1.00 -0.87

22 8.4 8.4 0.00 0.00

23 8.4 8.4 0.00 0.00


Median: 8.40 8.40


Robust CV: 1.2% 1.4%

Minimum: 8.1 8.2

Maximum: 8.6 8.7

Range: 0.5 0.5

Uncertainty (Median)

0.03 0.03

NOTE: 1). "§" denotes an outlier (i.e. those results for which |z-score | ≥ 3.0).

Lab Code

Sample A

Robust Z-score1

Sample B

Robust Z-score1

A6

pH of Water-Based Paints (Sample A)

pH of Water-Based Paints (Sample B)

A7

Density - AS/NZS 1580.202.1


Results (kg/L)

Sample A Sample B

1 1.04 1.04 0.00 0.00

2 1.05 1.06 1.92 2.40

3 1.04 1.04 0.00 0.00

4 1.04 1.04 0.00 0.00

5 1.05 1.05 1.60 1.60

6 1.04 1.04 -0.32 -0.32

7 1.04 1.04 0.00 0.00

8 1.05 1.05 1.60 1.60

9 1.04 1.04 0.00 0.00

10A 1.04 1.04 0.00 0.00

10B 1.04 1.04 0.00 0.00

10C 1.04 1.04 0.00 0.00

10D 1.04 1.04 0.00 0.00

11 1.04 1.04 0.00 0.00

12 1.04 1.04 0.00 0.00

13 1.05 1.05 1.60 1.60

14 1.04 1.04 0.00 0.00

15 1.04 1.02 0.00 -3.21 §

16 1.04 1.04 0.00 0.00

17 1.04 1.04 0.00 0.00

18 1.04 1.04 0.00 0.00

19 1.04 1.04 0.00 0.00

20 1.04 1.05 0.64 0.96

21 1.04 1.04 0.00 0.0022 1.04 1.04 0.00 0.0023 1.04 1.04 0.00 0.00

No of Results: 26 26Median: 1.040 1.040


Robust CV 2 : 0.6% 0.6%Minimum: 1.04 1.02Maximum: 1.05 1.06

Range: 0.01 0.03Uncertainty

(Median)0.002 0.000

NOTE: 1). "§" denotes an outlier (i.e. those results for which |z-score | ≥ 3.0). 2). A target CV of 0.6% was used to calculate z-scores for both samples.

Lab Code

Sample A

Robust Z-score1

Sample B

Robust Z-score1

A8

Density (Sample A)

Density (Sample B)

A9

Non-Volatile Content by Mass - AS/NZS 1580.301.1


Results (%)

Sample A Sample B

2 46.12 46.74 11.76 § 13.43 §

3 32.81 32.59 1.10 0.83

4 36.20 37.14 3.82 § 4.88 §

5 32.61 32.46 0.94 0.71

6 31.37 32.64 -0.05 0.87

7 31.70 32.18 0.22 0.46

8 32.35 32.17 0.74 0.45

9 30.55 30.67 -0.70 -0.88

10A 30.67 31.02 -0.61 -0.57

10B 31.51 30.98 0.06 -0.61

10C 30.40 31.30 -0.82 -0.32

10D 31.15 30.59 -0.22 -0.95

11 32.63 32.75 0.96 0.97

13 30.17 30.14 -1.01 -1.35

14 31.43 31.67 0.00 0.01

15 32.78 31.66 1.08 0.00

16 31.51 30.92 0.06 -0.66

18 29.79 29.90 -1.31 -1.57

19 31.38 31.69 -0.04 0.03

20 29.96 29.78 -1.18 -1.67

21 30.92 30.81 -0.41 -0.76

22 31.99 32.30 0.45 0.57

23 31.07 31.40 -0.29 -0.23


Median: 31.430 31.660


Robust CV: 4.0% 3.5%

Minimum: 29.79 29.78

Maximum: 46.12 46.74

Range: 16.33 16.96

Uncertainty (Median)

0.326 0.293

NOTE: 1). "§" denotes an outlier (i.e. those results for which |z-score | ≥ 3.0).

Lab Code

Sample A

Robust Z-score1

Sample B

Robust Z-score1

A10

Non-Volatile Content by Mass (Sample A)

Non-Volatile Content by Mass (Sample B)

APPENDIX B

Sample Homogeneity

B1

HOMOGENEITY TESTING The samples utilised in this program were supplied by Valspar Paint Australia. Each participant was provided with two samples, labelled Sample A and Sample B. For this program, eight samples were randomly selected for both Sample A and Sample B, and tested for homogeneity. Statistical analysis showed that the samples were sufficiently homogeneous so that any results identified as outliers could not be attributed to sample variability. The results of the homogeneity testing, along with the summary statistics are provided in Table C.

Sample A Sample B1 1.0431 1.0434 1 1.0433 1.04302 1.0432 1.0433 2 1.0435 1.04373 1.0433 1.0431 3 1.0438 1.04374 1.0434 1.0434 4 1.0434 1.04315 1.0431 1.0430 5 1.0437 1.0434

Mean: 1.0432 1.0432 Mean: 1.0435 1.0434st dev 0.000 0.000 st dev 0.000 0.000

CV 0.0% 0.0% CV 0.0% 0.0%

TABLE CHomogeneity Testing Results

Density Density

APPENDIX C

Documentation

Instructions to Participants C1

Results Sheets C2

C1

PROFICIENCY TESTING AUSTRALIA

Paint Proficiency Testing Program Round 26

INSTRUCTIONS TO PARTICIPANTS

Please read the following carefully BEFORE commencing testing. Each participant will be supplied with two 500ml tins of water based paint. These have been labelled “PTA Sample A” and “PTA Sample B”. To ensure the appropriate analysis of results, participants are asked to adhere carefully to the following instructions: 1) The following tests are to be performed on samples A and B as per the Results

Sheet:

(i) AS 1580.202.2 - density

(ii) AS 1580.214.5 - consistency by Brookfield

(iii) AS 1580.214.4 - consistency-rotothinner viscometer

(iv) AS 1580.301.1 - non-volatile content by mass

(v) AS 1580.505.1 - pH of Water-based paints

2) Determinations on each sample are to be conducted in accordance with the appropriate method (stated on the Results Sheet). All laboratories are also encouraged to attempt those tests not included as part of their routine methods.

3) The following specific instructions will apply: a. Report the nominal volume of the pycnometer used for AS1580.202.2. b. Report viscosity and viscometer model used. Report model and spindle to be uses and how many RPM used for AS1580.214.5.(Use spindle X and speed Yrpm). 4) For this program your laboratory has been allocated the following code number:

«Code» . This is to allow for the confidential treatment of your results in the final report.

5) Testing may commence as soon as samples are received. Please return results,

NO LATER THAN 23 June 2017, to:

Dr Michael LI Proficiency Testing Australia PO Box 7507 Silverwater NSW 2128 Email: [email protected] TEL: (02) 9736 8397 FAX: (02) 9743 6664

C2

PROFICIENCY TESTING AUSTRALIA

Paint Proficiency Testing Program Round 26

Results Sheet

Lab «Code»

Test AS 1580 PTA Sample A

PTA Sample B

Density

(report in kg/L to 2 decimal places) 202.2

Consistency by Brookfield (report in cP to 2 decimal places)

214.5

Consistency - Rotothinner Viscometer (report to the nearest 0.1 poise)

214.4

Non-volatile Content by Mass

(report in % to 2 decimal places) 301.1

pH of Water-based Paints

(report to the nearest 0.1 pH unit)

505.1 or in-house method

NOTES: 1 Report the nominal volume of the pycnometer used for AS1580.202.2. 2. Report viscosity and viscometer model used. Report model and spindle to be uses and how many RPM used for AS1580.214.5.(Use spindle X and speed Yrpm). 3. Report make and model of pH meter used. Signed: Date: Results are to be returned to PTA by 23 June 2017.

Dr Michael LI Proficiency Testing Australia PO Box 7507 Silverwater NSW 2128 Email: [email protected] TEL: (02) 9736 8397 FAX: (02) 9743 6664

-- End of Report --

report no. 1038 paint - round 26 proficiency testing

Documents