Sa 2½ Oberflächenreinheit
Sa 2½ is a widely used surface cleanliness standard defined in ISO 8501-1. It describes a very thorough blast cleaning where nearly all rust, mill scale, paint and other contaminants are removed, leaving only slight staining on the steel surface.
Where is Sa 2½ applied?
Sa 2½ is the most common specification for:
- Oil & Gas industry – pipelines, storage tanks, offshore structures.
- Chemical & Petrochemical plants – vessels, reactors and piping.
- Marine & Offshore wind – ship hulls, substations and steel decks.
- Infrastructure – bridges, cranes and heavy steel constructions.
For you as an asset owner or contractor, Sa 2½ ensures that protective coatings adhere properly and provide long-term corrosion protection.
Extra explanation and standards
The ISO 8501-1 standard defines four main blast cleaning grades:
- Sa 1 – light blast cleaning.
- Sa 2 – thorough blast cleaning.
- Sa 2½ – very thorough blast cleaning.
- Sa 3 – blast cleaning to visually clean steel.
Sa 2½ requires that:
- At least 95% of the surface is free from visible oil, rust, mill scale, paint and foreign matter.
- Only light shadows or slight discolorations remain.
- The prepared surface has a uniform metallic appearance.
Meeting Sa 2½ is critical for coating performance and is often specified in project standards such as NORSOK, ISO and SSPC.
Pinovo and Sa 2½
With Pinovo’s dust-free vacuum blasting system, you can achieve Sa 2½ while ensuring:
- No dust clouds – safer for operators and surrounding teams.
- ATEX compliance – safe for explosive atmospheres.
- Consistent surface quality – stable surface profile for optimal coating adhesion.
- Environmental protection – no microplastic or grit release.
Do you want to achieve Sa 2½ cleanliness safely and without environmental risk?
Request a demo or training to see Pinovo’s vacuum blasting in action.