Safety Integrity Level (SIL)
Reduce Risk. Ensure Compliance. Strengthen Safety.
SIL is required to evaluate the performance of safety systems in high-risk environments.
Learn about how it supports reliability and operational integrity.
What is SIL?
Safety Integrity Level (SIL) is a key concept in functional safety, defining a system’s ability to reduce risk in hazardous industrial environments.
Applying SIL is fundamental to complying with IEC 61508 and industry-specific standards like IEC 61511.
SIL is a measure of the performance required of a safety instrumented function (SIF). There are four levels (SIL 1–SIL 4), with SIL 4 representing the highest risk reduction. These levels are determined by assessing the potential consequences, frequency, and probability of failure.
SIL is a core part of the functional safety framework and applies to electrical, electronic, and programmable systems that perform safety functions. It ensures a systematic approach to identifying and mitigating risk in design and operation.
- 1. Hazard and Risk Assessment – Identify risks and determine safety requirements.
- 2. Safety Requirement Specification (SRS) - Define functional and safety requirements.
- 3. System Design and Implementation - Design to meet specified SIL level.
- 4. Validation and Verification - Ensure the system meets design intent and performs reliably.
- 5. Operation and Maintenance - Maintain and periodically review safety systems (is this PTIs for SIL?).
In oxygen monitoring, SIL-capable systems are critical where failure could lead to combustion, explosion, or contamination. Industries like chemical processing, pharma, and power generation use SIL-capable oxygen analyzers to ensure safety-critical performance.
Industry Applications
Additive Manufacturing
Modern manufacturing processes of metal parts like metal powder additive manufacturing, sintering or HPI processes reply on the measurement of gas impurities....
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Gas Analysis for Process and Manufacturing
Monitor Oxygen, Moisture, and Gas Flow for Operational Safety and Efficiency.In manufacturing, precision and safety are...
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Controlling inert environments using SIL-capable Oxygen Analyzers
Metal Additive Manufacturing is a process of creating three-dimensional objects by adding successive layers...
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Safety Integrity Levels and your Process
Safety Integrity Level (SIL) capability is becoming more common. Many people are familiar with hazardous area...
Read MoreExplore our SIL-Capable Products
Compact SIL2 Capable Oxygen Analyzer - Ntron SIL-O2
- SIL2 Capable unit - Analyzer and galvanic isolation barrier in one device
- Measurement range: 0 to 25% O2
- Push button calibrations
- 3 configurable alarm outputs
- Compact for easy integration
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Oxygen Analyzer - Michell XTP601
- SIL2 Capable. General purpose or ATEX, UKCA, IECEx, cQPSus, TR CU & Ex hazardous area certified models
- Ranges available: 0...0.5 % up to 0...50 % & 20, 80 or 90...100 %
- Touch-screen display allows calibration or adjustment without the need for a hot works permit
- Intrinsic error (accuracy) is better than 1 % full scale
- Outputs include RS485 and two 4...20 mA (following NAMUR NE 44 standard)
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Binary Gas Analyzer for Hydrogen Monitoring - Michell XTC601
- Suitable for use in ATEX, UKCA, IECEx, TR CU Ex & cQPSus certified Hazardous Areas
- Compact and rugged design with an EExd enclosure and 4...20 mA output
- IP66 rated enclosure. Touch-screen display allows calibration or adjustment without the need for a hot works permit
- Accuracy of better than ±2 % full scale
- Typical ranges available: 0...5 % up to 0...100 % (others gas dependent)
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Paramagnetic Oxygen Analyzer – Michell XPM601
- SIL2 Capable. Hazardous area certified (Exd) – UKEX, ATEX, IECEx, cQPSus
- Measurement range from 0 to 5 % O2 in H2
- Through-glass display allows operation, configuration and calibration
- High accuracy measurement performance
- Analog, digital outputs and user configured alarm set points
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FAQs
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1) What is SIL and why should I care about it?
SIL (Safety Integrity Level) defines how reliably a safety system must perform to reduce risk. If your process involves combustion, toxic gases, or critical oxygen control, understanding SIL helps ensure compliance and protect your personnel, equipment and operations.
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2) How do I know which SIL level I need?
It depends on how serious the potential consequences are. A risk assessment or safety review will determine whether you need SIL 1, 2, or higher.
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3) Is SIL the same as ATEX or IECEx?
Not quite. ATEX and IECEx focus on equipment safety in explosive atmospheres, while SIL is about system performance and risk reduction. You may need both, depending on your process.
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4) Do I need SIL-rated oxygen analyzers?
If you're using gas analyzers in a safety-critical loop, like oxygen control to prevent explosions, then you likely need SIL-rated or SIL-capable instrumentation as part of a compliant safety system.
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5) Can I trust the SIL rating of a product?
Look for independent certification from recognized bodies (such as TÜV). Also check whether the product has been assessed for use in a Safety Instrumented System (SIS) under IEC 61508 or IEC 61511.
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6) Is achieving SIL compliance complicated?
It can be, but we’re here to help. Compliance involves analysis, documentation, and validation; with the right tools and advice, it is achievable. It’s important to understand that SIL compliance is an ongoing exercise for the duration of your equipment’s lifecycle.
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7) Can I use non-SIL-rated devices in a SIL system?
In some cases. A product without formal SIL certification can be used if it has been justified SIL-capable through proven-in-use data. This should be confirmed during your system design review.
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8) Where do I start if I’m new to SIL?
Start with understanding your process risks. Our SIL experts can help you assess your needs, recommend the products for your requirements, and support compliance from risk assessment to commissioning.
Contact us or Request a Quote
Contact our experienced engineers to discuss your application needs.