Abrasive Blast Cleaning

Surface preparation by abrasive grit propelled at high velocity against steel substrate. Quality is graded under ISO 8501-1:2007 — Sa 1 (light blast cleaning), Sa 2 (thorough), Sa 2.5 (very thorough, near-white metal), and Sa 3 (white metal). PSPC (MSC.215(82)) requires Sa 2.5 in ballast tanks of new-builds. The grade affects substrate roughness and contamination level and therefore the coating life. Inspection during application uses the ISO 8503 reference comparator and surface dust class checks; deviations require re-blasting before paint is applied.