SSPC-SP5 White Metal Blast Cleaning
SSPC-SP5, also known as White Metal Blast Cleaning, is a surface preparation standard developed by the Society for Protective Coatings (SSPC). It defines the requirements for achieving a clean, bare metal surface free of all visible rust, mill scale, paint, and other foreign matter. White Metal Blast Cleaning is the highest level of surface preparation specified by SSPC and is typically used in situations where maximum coating adhesion and performance are required.
The process of White Metal Blast Cleaning involves using abrasive blasting equipment to propel abrasive media, such as steel shot or grit, at high velocities onto the surface being prepared. This impact removes contaminants and creates a profile on the metal surface, promoting better adhesion of subsequent coatings. The blasting process must be performed carefully to avoid damaging the substrate or creating an excessive profile depth.
SSPC-SP5 specifies several requirements for White Metal Blast Cleaning, including:
- Removal of all visible rust, mill scale, paint, and other foreign matter.
- No more than 5% staining, which refers to discoloration or shadows left on the surface after cleaning.
- No visible oil, grease, or other contaminants.
- No more than 5% of tightly adherent residues, such as paint or coating, in isolated areas.
- Surface profile requirements, which may vary depending on the specific coating system being applied.
It's important to note that White Metal Blast Cleaning is a demanding and time-consuming process that requires skilled operators and appropriate equipment. The surface preparation standard is often used in industrial applications, such as in the marine, oil and gas, and infrastructure sectors, where long-term corrosion protection is critical.
When specifying or contracting White Metal Blast Cleaning, it is advisable to refer to the complete SSPC-SP5 standard to ensure all requirements are understood and met.
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