# Sil Calculator

> Safety Integrity Level calculation skill for SIF design and verification per IEC 61511

- Skill: `a5c-ai/sil-calculator` (Agent Skill)
- Install (CLI): `npx skillmds@latest add a5c-ai/sil-calculator`
- Raw SKILL.md: https://api.skillmd.com/api/skills/a5c-ai/sil-calculator/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: a5c-ai (https://skillmd.com/u/a5c-ai)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/a5c-ai/sil-calculator

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# SIL Calculator Skill

## Purpose

The SIL Calculator Skill determines Safety Integrity Levels for Safety Instrumented Functions and verifies SIF designs meet required risk reduction per IEC 61511.

## Capabilities

- SIL determination (risk graph, LOPA, risk matrix)
- PFDavg calculations
- Proof test interval optimization
- Common cause failure analysis
- Hardware fault tolerance verification
- Diagnostic coverage assessment
- Systematic capability evaluation
- SIF verification calculations

## Usage Guidelines

### When to Use
- Determining SIL requirements
- Designing safety instrumented functions
- Verifying SIF performance
- Optimizing proof test intervals

### Prerequisites
- HAZOP recommendations available
- Risk criteria defined
- Component failure data available
- Architecture selected

### Best Practices
- Use consistent methodology
- Document all assumptions
- Consider common cause failures
- Verify systematic capability

## Process Integration

This skill integrates with:
- Safety Instrumented System Design
- HAZOP Study Facilitation
- Pressure Relief System Design

## Configuration

```yaml
sil-calculator:
  determination-methods:
    - risk-graph
    - lopa
    - risk-matrix
  failure-databases:
    - OREDA
    - SINTEF
    - exida
```

## Output Artifacts

- SIL determination reports
- PFDavg calculations
- SIF specifications
- Verification reports
- Test interval recommendations