[article]
| Titre : |
Measuring dry film coating thickness according to SSPC-PA 2 |
| Type de document : |
texte imprimé |
| Auteurs : |
William D. Corbett |
| Année de publication : |
2013 |
| Article en page(s) : |
p. 20-37 |
| Langues : |
Américain (ame) |
| Catégories : |
Acier L'acier est un alliage métallique utilisé dans les domaines de la construction métallique et de la construction mécanique.
L'acier est constitué d'au moins deux éléments, le fer, très majoritaire, et le carbone, dans des proportions comprises entre 0,02 % et 2 % en masse1.
C'est essentiellement la teneur en carbone qui confère à l'alliage les propriétés du métal qu'on appelle "acier". Il existe d’autres métaux à base de fer qui ne sont pas des aciers comme les fontes et les ferronickels par exemple.
Couches minces
Epaisseur -- Mesure
Revêtements -- Appareils et matériels:Peinture -- Appareils et matériels
Revêtements -- Normes:Peinture -- Normes
Revêtements:Peinture
|
| Index. décimale : |
667.6 Peintures |
| Résumé : |
Coating thickness shall be measured in accordance with SSPC: The Society for Protective Coatings Paint Application Standard No. 2 (SSPC-PA 2) is a simple enough statement, yet this common specification requirement is often misinter-preted or regarded as a document that simply states how to measure the dry film thickness (DFT) of coatings, something we already profess to know how to do. Yet the requirements of SSPC-PA 2 regarding gage calibration, verification of gage accuracy and adjustment procedures, the number of measurements to obtain, and the tolerance of the measurements are complex and should be fully understood by the specification writer before invoking PA 2 in a contract.
On more than one occasion, I have heard the question, "When did SSPC-PA 2 and dry film thickness measurement become so complicated?" In fact, when you take a close look, measuring DFT isn't that complex. We have allowed it to become more technologically complex while making the data easier to analyze. We can gather hundreds of gage readings in a relatively short time; batch the measurements; print the data or upload it to a computer for graphing; report the highest, the lowest, the mean, and standard deviation of the collected data; incorporate digital images of the structure or coated area; and even program the gage to pro-duce an audible signal if a spot measurement is outside of the tolerance range. I am no doubt leaving out other bells and whistles, but my point is that while we are able to do a lot with the readings obtained, measuring DFT involves four or five basic steps.
• Step 1: Instrument Calibration
• Step 2: Verification of Gage Accuracy on Certified Coated Standards or Certified Shims
• Step 3: Base Metal Reading Acquisition or Gage Adjustment (using certified or measured shims)
• Step 4: Measurement of Coating Thickness
• Step 5: Correction for Base Metal Reading (if acquired). After a brief review of the history of SSPC-PA 2, this article will describe each of the five steps, based on the 2012 edition of SSPC-PA 2. Special attention will be given in the article to how PA 2 addresses the required number of coating thickness measurements; the acceptability of gage readings, spot measurements, and area measurements; nonconforming thickness; measuring DFT on coated edges; and measuring DFT on pipe exteriors. |
| Note de contenu : |
- SOME HISTORY
- GAGE TYPES
- GAGE CALIBRATION, ACCURACY VERIFICATION, AND ADJUSTMENT
- VERIFYING ACCURACY : Verifying the accuracy of type 1 gages - Verifying the accuracy of type 2 gages - Adjusting type 2 gages
- REQUIRED NUMBER OF COATING THICKNESS MEASUREMENTS
- DETERMINING THE MAGNITUDE OF NONCONFORMING THICKNESS
- APPENDICES TO THE STANDARD : Method for measuring the dry film thickness of coating on edges - Method for measuring dry film thickness on coated steel pipe exterior |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18795 |
in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 30, N° 4 (04/2013) . - p. 20-37
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Measuring dry film coating thickness according to SSPC-PA 2 in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 30, N° 4 (04/2013)
