Simplified Iec Risk Assessment Calculator Sirac 🔖 👑

SIRAC: Bridging the Gap Between Theory and Practice in Machinery Safety

In the world of machinery safety, the IEC 62061 standard provides a rigorous framework for assessing risk. However, its formal methodology—requiring detailed parameter scoring (Severity, Frequency, Avoidance, Probability) and complex calculations—can be daunting for small to medium-sized enterprises or for early-stage design reviews.

Enter the Simplified IEC Risk Assessment Calculator (SIRAC) . While not an official IEC product, SIRAC represents a growing class of practical tools designed to democratize functional safety. simplified iec risk assessment calculator sirac

Simplified Assessment Steps

1. Identify hazard and define the safety function.
2. Estimate consequence severity (e.g., Minor, Serious, Fatal).
3. Estimate exposure frequency (e.g., Rare, Occasional, Frequent).
4. Estimate probability of avoidance (e.g., Very Likely, Likely, Unlikely).
5. Combine these inputs via a simple scoring matrix to derive a Risk Score.
6. Map Risk Score and demand mode to required SIL (or equivalent RRF/PFDavg).
7. Recommend architectural measures, diagnostics, and proof test intervals to meet required risk reduction.

Step 1: Identify Machine Limits

Before touching the calculator, define the machine's lifecycle (transport, installation, operation, cleaning, maintenance). SIRAC is only accurate if you know who is exposed and when. SIRAC: Bridging the Gap Between Theory and Practice

2. Core Methodology – How SIRAC Works

SIRAC operationalizes the risk graph from IEC 62061 (Annex A). It calculates Risk Reduction and determines required SIL (Safety Integrity Level) or PL (Performance Level) by scoring four parameters: Identify hazard and define the safety function

| Parameter | Meaning | Typical Levels | |-----------|---------|----------------| | S (Severity of injury) | Minor to irreversible (fatality) | S1 (minor), S2 (serious) | | F (Frequency/duration of exposure) | How often a person enters danger zone | F1 (rare/short), F2 (frequent/long) | | P (Possibility of avoiding hazard) | Can operator react to stop or escape? | P1 (possible), P2 (hardly possible) | | Pr (Probability of hazardous event) | Likelihood hazard leads to injury | Low/Medium/High (or 5-step scale) |

Step 5: Implement Risk Reduction

The calculator tells you the target. You must now design a safety system (light curtains, safety PLC, interlocking gates) that meets SIL 3 / PL e.