Chapter 6 – Hydroblasting Standards

Publisher Summary This chapter provides an overview of various standards used to define and to characterize steel surfaces prepared by hydroblasting. These standards are mostly based on the standard preparation grades given in ISO 8501-1 and ISO 8501-2. They can be classified into two types of standards, namely, written and visual standards. Written standards include surface preparation and cleaning of metals by waterjetting prior to recoating (SSPC-SP 12/NACE No. 5), and visual standards include standards issued by independent organizations include STG Guide No. 222, SSPC-VIS 4/NACE 7, and US Navy. Visual standards issued by paint manufacturers include standards issued by Hempel, International Paint, and Jotun. Hydroblasting surface standards cover surface issues such as initial condition, visual surface preparation definition, non-visible surface cleanliness definition, and flash-rusted surface definition. Visible contaminants and cleaning degrees are defined in all standards except Jotun's Flash Rust Standard and they include rust, previously existing coatings, mill scale, and foreign matter. The cleaning degrees designated in all standards are based on the definitions given in ISO 8501-1 for blast cleaned surfaces. Of particular interest are the definitions given in SSPC-12/NACE No. 4 as they are adapted by numerous other standards, and the definitions provide a quantitative measure of surface cleanliness.