SIL Gas Control – SGC

The SGC monitors, controls and safely shuts down potentially hazardous gas mixtures, for example with hydrogen or natural gas. As part of a Safety Instrumented Function (SIF), it detects hazardous or impermissible mixing ratios and automatically brings the system into the safe state when the limit is exceeded – designed to IEC 61511 and suitable up to SIL 3.

That depends on the risk assessment of your plant. The Safety Integrity Level describes how reliably a safety function must reduce a risk. The SGC can be designed for SIL 1, SIL 2 or SIL 3; the whole series is qualified up to SIL 3.

That depends on what is already in place. SGC Monitor only monitors the gas streams, for example at the inlet of an existing mechanical gas mixer. SGC Manual adds two needle valves at the outlet – the most economical solution for gas mixing with SIL 3 monitoring at a relatively constant supply pressure. SGC Mix comes with a digital gas mixer in a shared housing, SGC Sense additionally with process gas analysis.

Every variant comes in both versions. Limit shutdown monitors the flows of inert gas and fuel gas, calculates their ratio and shuts down before an explosive atmosphere can form. Flow monitoring with automatic pre- and post-purge inerts the downstream system before the fuel gas is released, monitors the absolute flows during operation and purges the system with inert gas again at the end.

Yes. In the limit shutdown version, the SGC ensures that no explosive atmosphere can form. This means that older furnaces not approved for explosive atmospheres can continue to be operated safely and in compliance with regulations on fuel gas. We design the connection to the furnace control and alarm system for each project.

As standard for hydrogen and CNG, further gases on request, with any number of gas lines. The total flow is 4 – 300 m³n/h, the inlet pressure 35 barg, the outlet pressure the inlet pressure minus 2 bar, and the gas temperature -10 to +60 °C. We design higher flow rates and pressures on the same qualified platform.

With Coriolis meters, which measure mass directly. Pressures and flows are monitored continuously; in the Mix and Sense variants, digital mass flow controllers control each gas stream separately, with ± 0.3 % of full scale plus ± 0.5 % of reading.

That depends on zoning, risk assessment and installation site, for thermal process plants for example to EN 746. Our devices are permanently leak-tight by design; together with TÜV we assessed that the device itself poses no explosion hazard. An ATEX-certified version is available as a custom solution.

By SMS, email, relay contact and signal tower. Every shutdown is recorded with a time stamp in the event log; in the Gasyco Dashboard you see pressures, flow and switching state of all lines – across several sites as well.