AS 3894.3-2002

1 - AS 3894.3-2002 SITE TESTING OF PROTECTIVE COATINGS - DETERMINATION OF DRY FILM THICKNESS
3 - PREFACE
4 - CONTENTS
5 - FOREWORD
6 - METHOD
6 - 1 SCOPE
6 - 2 REFERENCED DOCUMENTS
6 - 3 DEFINITIONS
6 - 3.1 Dry film thickness
6 - 3.2 Primary standards
6 - 3.3 Reference substrate
7 - 3.4 Secondary standards
7 - 4 TEST METHODS
7 - 5 PRECAUTIONS
8 - 6 INSPECTION PERIOD
8 - 7 INSPECTION PLANS
8 - 7.1 General
8 - 7.2 Point reading
8 - 7.3 Large surface areas
12 - 7.4 Small surface areas
12 - 7.5 Statistical sampling
12 - 8 INSPECTION OBJECTIVES
12 - 8.1 General
12 - 8.2 Severe environment
13 - 8.3 Atmospheric exposure
13 - 8.4 Large numbers of small components
13 - 9 MAGNETIC INSTRUMENT METHOD-METHOD A
13 - 9.1 Scope
13 - 9.2 Principle
13 - 9.3 Apparatus
13 - 9.3.1 Calibration standards
13 - 9.3.2 Magnetic pull-off instrument
13 - 9.4 Preparation of test surface
14 - 9.5 Precautions
14 - 9.5.1 General
14 - 9.5.2 Reproducibility
14 - 9.5.3 Vibration
14 - 9.5.4 Measuring
14 - 9.5.5 Probe position
14 - 9.6 Procedure
15 - 9.7 Report
15 - 10 MAGNETIC INDUCTION AND EDDY CURRENT METHODS-METHOD B
15 - 10.1 Scope
15 - 10.2 Application
16 - 10.3 Principle
16 - 10.4 Apparatus
16 - 10.5 Preparation of test surface
16 - 10.6 Precautions
17 - 10.7 Procedure
18 - 10.8 Report
19 - APPENDIX A - MICROGRAPHIC EXAMINATION OF CROSS-SECTIONS
19 - A1 SCOPE
19 - A2 PRINCIPLE
19 - A3 APPARATUS
19 - A4 PREPARATION OF TEST SPECIMENS
19 - A4.1 General
19 - A4.2 Mounting of test specimen (see Note 1)
19 - A4.3 Grinding and polishing
20 - A5 PROCEDURE
20 - A6 REPORT
22 - APPENDIX B - MICROSCOPIC MEASUREMENT OF PAINT FLAKES
22 - B1 SCOPE
22 - B2 PRINCIPLE
22 - B3 APPARATUS
22 - B3.1 Optical microscope
22 - B3.2 Camera
22 - B4 PREPARATION OF THE TEST SPECIMEN
22 - B5 PROCEDURE
23 - B6 REPORT
24 - APPENDIX C - WET FILM THICKNESS BY COMB GAUGE
24 - C1 SCOPE
24 - C2 PRINCIPLE
24 - C3 APPARATUS - COMB GAUGE
24 - C4 PROCEDURE
24 - C5 ESTIMATION OF DRY FILM THICKNESS
25 - C6 REPORT
29 - APPENDIX D - CALIBRATION OF MEASURING INSTRUMENTS
29 - D1 SCOPE
29 - D2 GENERAL
29 - D3 CALIBRATION STANDARDS
29 - D3.1 General
29 - D3.2 Primary standards
29 - D3.3 Secondary standards
29 - D4 REFERENCE SUBSTRATES
30 - D5 PROCEDURE
30 - D5.1 General
30 - D5.2 Magnetic pull-off gauges
30 - D5.3 Magnetic induction and eddy current instruments
32 - APPENDIX E - A SAMPLE REPORT FORM FOR DRY FILM THICKNESS TESTING*

This Standard provides practical test methods for the on-site determination of the range of thicknesses and the mean dry film thickness of a protective coating system, or its component coats, upon a metallic structure or fabrication. The coated fabrications to which the methods may be applied include tanks or reservoirs, bridge girders, equipment used in processing chemicals or petroleum, pipelines, and articles such as vehicles, white goods and other items of industrial production, where there is lack of uniformity of substrate thickness, metallographic character, surface condition and the film of the protective coating.

This Standard provides practical test methods for the on-site determination of the range of thicknesses and the mean dry film thickness of a protective coating system, or its component coats, upon a metallic structure or fabrication.The coated fabrications to which the methods may be applied include tanks or reservoirs, bridge girders, equipment used in processing chemicals or petroleum, pipelines, and fabricated articles such as vehicles, white goods and other items of industrial production, where there is lack of uniformity of substrate thickness, metallographic character, surface condition and the film of the protective coating.NOTES: 1 Appendix A provides a laboratory test method for the microscopic determination of the thickness of the film adhering to a substrate. This method would only be used where no other method is acceptable.2 Appendix B provides a method for determining the thickness of a flake of the coating using an optical microscope.3 ISO 2808 provides information on additional methods of determining film thickness.

Originated as AS 3894.3-1993.
Second edition 2002.