Don't Just Guess You're Safe — Prove It.

Bridge the gap between target risk reduction and reality with data-driven SIL Verification.

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Industrial safety engineers reviewing verification data.

The Core of Performance-Based Safety

IEC 61511 is a performance risk-based standard, meaning compliance is not only about having the safety equipment in place — it requires you to determine the specific risk reduction target needed (SIL Determination) and then verify that your design achieves the SIL Target. This is SIL Verification.

If the SIL Verification process is not executed correctly, the results can affect your entire facility:

  • Over-designed systems: Leading to unnecessary and excessive capital expenses.
  • Under-designed systems: Resulting in much higher operational risk than you realize.
  • Operational burdens: Specifying overly frequent proof tests that drain resources, or nuisance (spurious) trips that disrupt production.

Stop over-engineering and start optimizing. With exida’s tools and expertise, you’ll gain a clear, data-driven view of your SIL Verification that is defensible and audit-ready.

exida's Approach

The Three Barriers of SIL Verification

A common pitfall in SIL Verification is focusing solely on the calculation of PFDavg / PFH. exida’s solution ensures you meet the target SIL by simultaneously satisfying all three mandatory performance criteria:

BARRIER 1

PFDavg / PFH (Probabilistic Performance)

Proving the mathematical probability of failure on demand meets your target.

BARRIER 2

Minimum Architectural Constraints (Hardware Fault Tolerance)

Verifying that the hardware redundancy complies with IEC 61511 or IEC 61508 standards.

BARRIER 3

Systematic Capability

Ensuring the equipment is designed and manufactured with the quality required for the specific SIL using SIL certified devices.

The SIL achieved is only as strong as its weakest link. By taking the lowest of these three barriers (minimum selection), our solution guarantees a truly compliant and safe result.

Understanding SIL Verification — visual summary of the three barriers and how they are evaluated.

Reference Asset

Understanding SIL Verification Infographic

Download the full SIL Verification infographic — a one-page visual reference covering the three barriers and how exida’s solution ties them together.

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What Gets in the Way

The Roadblocks to Accurate SIL Verification

Designing a Safety Instrumented Function (SIF) is more than just a math exercise. Many teams find that manual calculations or generic tools lead to costly delays or, worse, a false sense of security.

  1. Optimistic or Unreliable Data

    Generic failure rates or optimistic assumptions can silently shift your SIL conclusion. exida ties calculations to field-proven data and transparent assumptions so results hold up in review.

  2. The “Spreadsheet Trap”

    Disconnected spreadsheets hide versioning issues, inconsistent formulas, and audit gaps. A structured verification workflow keeps assumptions, inputs, and outputs traceable.

  3. Spurious Trip Overload

    Focusing only on dangerous failures ignores nuisance trips that erode trust in the safety system. Modeling and testing strategy should balance safety integrity with operational availability.

  4. Architectural Confusion (Route 1H vs. Route 2H)

    Teams can mis-apply architectural constraints or mix route requirements. Clear routing, automated constraint checks, and certified device data reduce interpretation risk.

  5. Inconsistent Methodologies

    Different calculators, rounding rules, and test intervals across sites make corporate roll-ups painful. Standardized methodology and shared libraries align sites to one defensible standard.

  6. Failing to Consider All Three SIL Criteria

    PFDavg alone is not enough — systematic capability and hardware fault tolerance matter. Verification should explicitly score the weakest barrier, not a single “passing” metric.

Stop wrestling with inconsistent data and complex hurdles. We provide you with a proven framework and the industry’s most trusted field-failure data to make your SIL verification seamless and defensible.

exida’s approach addresses each roadblock directly: validated SERH failure data, a structured workflow, and certified device libraries ensure your verification is traceable, methodology-consistent, and grounded in all three SIL criteria.

How exida Delivers

Actionable Safety Intelligence — Beyond Pass/Fail

Move beyond a “Pass/Fail” result. Leverage the power of exSILentia® and our world-class engineering team to create actionable safety intelligence.

The SERH Database

Direct access to the Safety Equipment Reliability Handbook, providing field-verified failure data for thousands of devices.

Sophisticated Modeling

Support for complex voting logic (1oo2, 2oo3, MooN, etc.), SIL 3 safety functions, high-demand applications, batch processes, and diversified technology configurations.

Automated Compliance Checks

Real-time validation against IEC 61511 architectural constraints or IEC 61508 (Route 1H and Route 2H).

Lifecycle Integration

Seamless data transfer from your LOPA and SRS (Safety Requirements Specification) directly into the verification engine.

Advanced Test Modeling

Model the impact of Partial Stroke Testing (PST), varying proof test intervals, and imperfect proof testing (clean service, dirty service, tight shut-off). Automatically generate Proof Test documents.

Custom Failure Rate Analysis

If using unique or legacy equipment, perform a “Prior Use” or “Proven in Use” analysis to justify reliability data.

Optimize Operations & Maintenance

Models all key variables impacting PFDavg/PFH; understand how design decisions impact availability, redundancy, spurious trip rates, and proof test frequency. See site-specific improvements via exida SSI (site safety index).

Accurate Failure Rate Predictions

Uses precise Markov Model rather than approximations — prevents over-design ($$$) or under-design (risk).

Analyze Common Cause Failures

Automatically determine the correct factor for Common Cause Failure with the exSILentia Beta estimator tool.

Take the Next Step

Whether you are in the middle of a major capital project or managing the safety of an existing facility, exida has the tools and expertise to ensure your systems perform when it matters most.

Perform SIL Verification calculations yourself with exSILentia

Train on how to use exSILentia for SIL Verification

Engage exida to peer review your calculations (onsite, remote, workshop, offline)

Retain exida to perform the SIL Verification calculations

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