Why 90% of Safety Functions Fail to Meet Functional Safety Standards

Despite strict standards like IEC 61508 and IEC 61511, our experience shows that up to 90% of safety functions are not fully compliant. The problem is not the standards—it is how they are applied.

The Reality of Functional Safety Compliance

Across industries, organizations are required to comply with functional safety standards such as IEC 61508, IEC 61511, EN 50128, DO-178C, IEC 62061, ISO 13849, ISO 26262, ISO 25119, and many more.

Yet compliance remains a major challenge. In many cases, end users assume they are compliant—while in reality, their safety functions fall short.

The key question is: if your safety functions are not compliant, would you actually know?

Top 10 Reasons Why Safety Functions Fail Compliance

1. Lack of Functional Safety Management (FSM)

Without a structured FSM system, safety activities become inconsistent and uncontrolled. FSM is the foundation of functional safety—without it, everything else becomes unreliable.

2. Insufficient Competence

Functional safety requires expertise across the lifecycle. In practice, many engineers lack formal training, especially in safety software development, leading to critical gaps in implementation.

3. Inadequate Hazard and Risk Analysis

Poor or rushed hazard analysis leads to incorrect safety requirements. Techniques like HAZOP are often under pressure, resulting in incomplete or incorrect outcomes.

4. Missing or Weak Safety Requirements Specification (SRS)

The SRS defines what the safety function must do. If it is incomplete or incorrect, the entire system is compromised—even if everything is “working.”

5. Poor Selection of Safety Equipment

Cost-driven decisions often lead to selecting non-compliant devices. “SIL-certified” does not automatically mean suitable for your application.

6. Flawed System Architecture

Even with compliant components, the overall architecture may not meet safety requirements. Poor design can also lead to excessive spurious trips and operational losses.

7. Inadequate Software Development Practices

Safety software is often developed without proper standards, testing, or verification. A Factory Acceptance Test (FAT) does not prove software compliance.

8. Insufficient Validation Testing

Most testing focuses on expected behavior (“happy flow”). Robustness testing—how systems behave under abnormal conditions—is often missing.

9. Neglect of Operation, Maintenance, and Repair

Functional safety does not end at commissioning. Without proper procedures and trained personnel, safety performance degrades over time.

10. Lack of Proof Testing

Proof testing is essential to detect hidden failures. Skipping or poorly executing proof tests directly leads to non-compliance and increased risk.

Breaking the Non-Compliance Cycle

Addressing these issues requires a structured and disciplined approach:

• Implement a strong Functional Safety Management system
• Invest in competence and training
• Perform rigorous hazard and risk analysis
• Develop clear and complete SRS documentation
• Select appropriate and verified safety equipment
• Design robust system architectures
• Apply proper software development practices
• Execute comprehensive validation and robustness testing
• Maintain systems throughout their lifecycle
• Perform regular and effective proof testing

Conclusion

The fact that most safety functions are not compliant is not a small issue—it is a systemic industry problem.

Functional safety is not achieved by documentation alone. It requires competence, discipline, and continuous attention throughout the lifecycle.

Organizations that address these root causes will not only achieve compliance—they will significantly reduce risk and improve operational performance.

Challenge yourself: What steps can you take today to verify whether your safety functions are truly compliant?