ENOTEC OXITEC, COMTEC, AQUATEC and SILOTEC Gas Analyzers Achieve SIL 2 Certification Under IEC 61508
Risknowlogy has independently certified the in-situ oxygen gas analyzer systems supplied by ENOTEC GmbH — OXITEC® 5000/500E, COMTEC® 6000/600E, AQUATEC® 1000 and SILOTEC® 8000 — in accordance with IEC 61508:2010, confirming they are fit for use up to SIL 2 in low-demand safety instrumented functions in the process industry.
What Was Certified
The analyzers use an in-situ zirconium oxide probe to measure oxygen in process gases and convert the value into a 4–20 mA analogue NAMUR signal, within 2% of full span. That is the certified safety function; only the 4–20 mA output is suitable for safety-related use.
The certification confirms those claims are technically justified, documented and independently verified. It rests on a proven-in-use assessment: field performance since 2011 evidences the systematic integrity required for SIL 2. ENOTEC holds no certified functional safety management system; an IEC 61508-compliant modification procedure preserves that integrity across future changes.
Scope: hardware, reliability, software, fault injection testing, basic safety, user documentation. Certificate 2770.408.11-2, issued 2026-07-28, valid to 2031-07-28; Risknowlogy report 2770.408.10 is an integral part.
This revision extends the certified scope to two reviewed product modifications: additional probe variants, and a display PCB revision replacing obsolete components. Both were independently assessed as not affecting the certified safety function.
Verified Safety Performance
The safety function was reviewed and verified, covering:
- Oxygen measurement converted to a 4–20 mA output signal
- Type B device, HFT 0, low-demand mode, hardware route 2H, systematic route 2S, systematic capability SC2
- Failure rates in FIT: SD 404, SU 181, DD 2432, DU 793
- Diagnostic coverage of 75%
- Fit for use up to SIL 2, and up to spurious trip level STL 3
The figures come from an FMEDA corroborated by field data, so a SIL verification rests on both design expectation and operating experience.
What This Means for Operators and Stakeholders
Plants now have verified reliability data and defined conditions of use, rather than a manufacturer assertion. Contractors and integrators can take the failure rates, diagnostic coverage and SIL 2 capability straight into SIL verification. Insurers, auditors and regulators get independent third-party evidence. Correct design, installation, operation and maintenance remain the end user’s responsibility.
About ENOTEC GmbH
ENOTEC GmbH, of Marienheide, Germany, manufactures gas analyzers for the process industry and continuous emission monitoring. Submitting these families to independent assessment demonstrates a commitment to functional safety engineering.
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