Abrasive Blasting, Shot Peening & Surface Prep calculator

Abrasive Blast Surface Contamination FMEA Calculator

Score one contamination failure mode as severity × occurrence × detection, then compare it with the same severity after planned controls. Enter six 1 to 10 ranks from the approved ranking tables.

What this calculator does

  • FMEA-style severity × occurrence × detection scoring with residual risk and a critical-severity override that a lower RPN cannot hide.

Formula used

  • Current RPN = severity × occurrence × detection
  • Mitigated RPN = unchanged severity × mitigated occurrence × mitigated detection
  • Reduction = (current RPN − mitigated RPN) ÷ current RPN × 100
  • Critical escalation = severity at or above the approved threshold

Inputs explained

  • Contamination Consequence Severity: Approved FMEA severity rank for the failure consequence.
  • Current Occurrence Likelihood: Approved rank from contamination history and current controls.
  • Current Detection Difficulty: Approved rank where higher means harder to detect.
  • Critical Severity Threshold: Severity rank that triggers mandatory escalation regardless of RPN.
  • Occurrence After Planned Controls: Expected occurrence rank after defined prevention actions.
  • Detection After Planned Controls: Expected detection rank after defined inspection actions.

How to use the result

  • Best suited to media contamination FMEA, compressed-air cleanliness review, pre-coating handling risk.
  • RPN is ordinal prioritization, not a probability or expected loss. Different score combinations can share the same RPN. Customer and quality-system escalation rules control.

Common questions

  • Is a lower RPN automatically acceptable? No. Acceptance thresholds, critical characteristics, special controls and residual-risk approval stay separate decisions from the numeric score.
  • Why does severity stay the same? Prevention and detection controls change likelihood or detection. Severity changes only when the consequence of the failure mode itself changes.
  • Can two different risks share the same RPN? Yes, which is why the component scores and the critical-severity flag remain visible beside the product.
  • Does this replace an FMEA? No. It calculates one failure-mode line using scores selected through the approved FMEA process and its ranking tables.

Last reviewed 2026-10-01.