Industry Expertise

Functional Safety

Functional safety systems & expertise

Functional Safety


For years, ASCO solenoid pilot valves, Actuator Control Systems (ACS) and Redundant Control Systems (RCS) have played an important role in safety instrumented systems (SISs). With manual reset and fully redundant options, ASCO functional safety products are proven in use, certified per IEC 61508 Parts 1 and 2, and rated SIL 3 capable for domestic and international markets (ATEX). The ASCO RCS is the only pilot valve system that has no single point of failure that could result in an unwanted closure of the process valve. Self-diagnostic testing ensures higher asset availability with less risk of spurious trips. That's why so many engineers responsible for mission-critical applications in areas such as refining and power generation turn to ASCO for functional safety systems and expertise.

Solenoid Pilot Valves

ASCO 3-way solenoid valves, 314, 316, 320, 327, 551, and 553 are the most widely used solenoid pilot valves in the world. For your spring return actuator applications, these valves are proven in use and have undergone 3rd party evaluation by Exida per IEC 61508 Parts 1 & 2. Most of the ASCO 314, 316, 320, 327, 551, and 553 series valves are SIL 3 capable, certified by Exida, TÜV or both. Individual pilot valves are most commonly used in 1-out-of-1 voting architectures but can be easily piped into a 2-out-of-2 configuration. ASCO pilot valves are used as the primary device for process valve actuation as well as the shutdown valve when used with digital valve controllers for on-off and control valve applications.

Manual Reset & Redundant Coil Solenoid Pilot Valves

ASCO Manual Reset Pilot Valves are a process industry standard. For harsh plant environments where reliability is a must, ASCO has the products to keep your process going. Lever operated manual reset valves are designed with corrosion resistant materials and industrial strength components. When you need to manually engage the final control element of your process system, ASCO has the proven solutions for your applications. Redundant coil pilot valves are also available for your high availability applications.

Actuator Control Systems

The ASCO ACS improves the reliability of your installation and reduces engineering time. The ACS is available in ¼" and ½" sizes with a full 316L stainless steel construction, which enables the ACS to be corrosion resistant. This system is engineered by ASCO which saves you engineering time and it will be designed to meet the maximum possible pressures and temperatures of your application. The ACS comes up with solenoid valves that are ATEX compliant and TÜV certified to IEC 61508, which means they can be used up to SIL 4. This system is designed for processes performed in highly aggressive and/or potentially explosive atmospheres. Learn More>>

Redundant Control Systems

The ASCO RCS is a redundant pilot valve system that acts as a single 3-way valve. The added features of this system above an individual valve include the ability to perform automatic online testing of the redundant solenoid valves, automatic partial stroke testing of the process valve, and online maintenance capabilities. This product is built for high reliability applications and functional safety. The redundant solenoids can operate in 1-out-of-1 Hot Standby mode or 2-out-of-2 diagnostic mode. Both modes of operation are certified per IEC 61508 Parts 1 and 2 and SIL 3 Capable, Certified by Exida (SIL Certificate and SIL Certificate for Stainless Steel Units), ATEX Approved. Learn more>>

For an overview of all our certificates, including SIL, please click here.

View All ASCO Capabilities & Expertise