Welcome to the SKC PPI Silica Sampling Video. SKC Parallel Particle Impactor or PPI Samplers are your silica sampling solution. SKC PPI Samplers are specifically designed to meet requirements in the 2013 OSHA Silica Notice of Proposed Rule Making (NPRM) including a requirement that size-selective samplers for silica conform to ISO/CEN respirable criteria with minimal bias. PPI Samplers provide the most precise match to the ISO/CEN respirable criteria. See how SKC PPI Samplers work and why they are your silica sampling solution.