Watz Hydraulik Hydraulic Cylinders Achieve IEC 61508 SIL Certification
Risknowlogy has independently certified seven hydraulic cylinder products supplied by Watz Hydraulik, Germany, in accordance with IEC 61508:2010 — confirming systematic capability SC 2 and fitness for use up to SIL 1 in high-pressure valve actuation.
What Was Certified
The certified items are hydraulic cylinders that drive high-pressure valves to their safe position on demand. They sit in the final element of a safety instrumented function, where a failure to move is a failure to act.
Seven certificates were issued, one per product designation: ZSGL 130/60-22, ZSGL 140/60-25+Verblockung, ZSGL 110/60-20+Verblockung, ZS 350/300/180-45+Verblockung, ZS 150/50-55 mit Feder-vorspannung, ZS 300/160-85+Verblockung, and ZS 220/125-60+Verblockung. Certification confirms that the safety claims for each cylinder are technically justified, documented, and independently verified against IEC 61508:2010 — not that the product is good, but that what is claimed of it holds.
Scope of certification: Management of functional safety, safety requirements specification, hardware, hardware reliability, basic safety, and user documentation. Each certificate is issued under IEC 61508:2010 and carries five-year validity from its July 2026 issue date.
Verified Safety Performance
The following were reviewed and verified for each of the seven products:
- Device type classification — Type A
- Hardware fault tolerance (HFT) — 0
- Hardware safety integrity route — 1H
- Systematic safety integrity route — 1S
- Systematic capability — SC 2
- Mode of operation — low demand / demand mode
- Fit for use up to — SIL 1
Each value is printed on the face of the certificate, so a designer can read the assumptions behind the claim rather than infer them.
What This Means for Operators and Stakeholders
An operator specifying one of these cylinders as a final element knows the architectural constraint before design starts: Type A, HFT 0, route 1H, a stated ceiling of SIL 1. Engineering contractors and system integrators lose a round of guesswork during SIL verification: systematic capability and fitness limit are stated per product, not assumed from a family claim. Insurers, auditors, and regulators get an independent record that each product was assessed against the standard by a party with no stake in the result.
About Watz Hydraulik
Watz Hydraulik manufactures hydraulic cylinders for high-pressure valve actuation. Submitting seven product lines to independent assessment, and maintaining the documentation it requires, is what functional safety compliance looks like.
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