This standard contains the general requirements for the safe and effective use of APC equipment, operated either manually hand-held or through use of automation, to prepare various metallic surfaces for maintenance, repair, recoating, or lining. This standard does not address surface preparation of concrete.
APC is applied to the entire surface specified to be prepared for a new coating or lining. Poorly adhered surface material and coating that cannot withstand the APC process are removed, while, depending on the chosen cleanliness level, any remaining coating is suitably prepared prior to the application of a new coating layer over the existing. In the case of metallic substrates, the underlying surface profile will be revealed whenever surface contamination and coatings are removed.
At present multiple standards on blast-cleaned surfaces are in use depending on region and specifications of the project. However, most standards are relatively clear on the description of a surface some overlap each other. These overlaps are often considerate as the norm for the most comparisons between ISO and related documents, however, sometimes are significantly off. Some of these documents will be highlighted to compare the results and their impact on the coating job.
Over the past decade, coating manufacturers have made significant strides in the formulation of new products, utilizing new polymers and enhanced pigments that produce improvements in weatherability, corrosion protection, and ease of application, while improving compatibility with existing coatings, and offering enhanced physical, and thermal resistance. However, coating product data sheets typically portray anticipated coating performance under favorable laboratory conditions that may not reflect actual field conditions during surface cleaning and application operations.
The presentation reviews the utilization of color analyses for the assessment and rating of rust, whereas particular attention is spent to flash rusting. The background of flash rust formation is discussed first, along with a brief review about the composition of flash rust. The fundamentals of the HSV color model, which is selected as a simple suitable model, are introduced. Finally, the author discusses the utilization of the suggested approach for the evaluation of steel substrate cleanliness and flash rust assessment.
The objective of surface preparation is to create proper adhesion of a coating over the substrate. Proper surface preparation is vital to the long life and effectiveness of a coating applied in corrosive service. In some projects, the owners ask for the additional water jet cleaning prior to blasting work.
The Benefits of Steel Grit Blasting and Recycling was presented at the 2017 SSPC Conference. The white paper detailed the advantages of blasting with steel grit to clean a surface, remove rust, create a surface profile, and prepare a surface for coating. As a continuation, Steel Grit Blasting Improves Productivity and Quality has been written to inform contractors the purity the steel grit holds and contains once blasted on a steel structure and recycled through a four-stage cleaning process.
Surface cleanliness has been measured visually for the past 30 years using SSPC –VIS- 1 (ISO 8501-1) reference photographs. This method, while recognized as the industry standard, does have its disadvantages. It is deemed a subjective measurement rather than objective and is vulnerable to human error.