Cowan Dynamics announces the availability of linear and rotary (1/4 turn) actuators with up to a SIL 3 safety rating.
SIL 3 Valve Actuators Range
The SIL 3 capable rating is designed to provide our customers reliable actuation solutions in critical applications without compromising their Safety Instrumented Systems (SIS – compliant with IEC 61511/ISA 84).
The SIL 3 capable rating was achieved by certifying the products to IEC 61508 and was obtained from Exida Certification Services after passing rigorous Failure Mode Effects Diagnostic Analysis (FMEDA).
Cowan Dynamics’ SIL 3 capable products include:
Scotch Yoke Actuator
The CSY Scotch Yoke Actuator is SIL 3 capable and has a modular design that allows customization to fit specific needs. Bi-directional travel stop allows an adjustable stroke range of 80 degrees to 100 degrees. NAMUR mounting allows standardization of mounting hardware for a wide range of shaft-driven accessories.
- Double-Acting or Spring-Return
- Torques up to 2,500,000 in-lbs
- Operating Pressure: 40 – 100 PSIG
- Low Temp. -40ºC to 80ºC
- Standard Temp. -20ºC to 80ºC
- High Temp. -20ºC to 120ºC
SIL 3 Frequently Asked Questions:
What is SIL 3?
SILs represent the impact a Safety Instrumented Function (SIF) has on a specific hazard’s risk. A higher SIL level means that a function will be more effective at reducing risk it mitigates.
SIL 3 is one of the safety integrity levels defined by the IEC 61508 standard. It refers to reducing risk by 1.000 – 10.000 failures on demand and 10-8 – 10-7 failures per hour. Basically, it is an evaluation of the acceptable failure level for a security function and will represent the safety and reliability of that function.
SIL 1 to SIL 4 are the four safety integrity levels defined in IEC 61508. SIL 3 is the highest level of safety integrity economical for most industrial operations.
Why is SIL 3 Important?
The safety integrity level (SIL) of a Safety Instrumented Function (SIF) in a Safety Instrumented System (SIS) is not chosen at random, or on a best-effort basis.
Instead, the appropriate SIL level is determined, based on a number of methods such as Safety Layer Matrix (SLM), Layer of Protection Analysis (LOPA) or Fault Tree Analysis (FTA).
These methods take into account the types of accidents that could happen within your organization, their probability, their relationship, and the costs that may result from them. As a result, the SIL level they recommend corresponds to the risks that your organization faces.
A safety integrity level (including SIL 3) is not just a metric you should aim for, it is a reflection of the risks your organization faces. IEC 61508 defines risk in terms of cost per time unit.
SIL 3 is the integrity level that reduces the risk (that is, the cost per unit of time) associated with a particular hazard to an acceptable level if it is determined to be the appropriate SIL.
WHAT DOES SIL 3 MEAN IN TERMS OF ACTUATOR CHOICE?
The SIL 3 rating describes the function that a device (or a set of devices) performs, not the device itself. As a result, only certain devices can be used to implement a given level of safety integrity.
For functions requiring SIL 3, only devices rated for SIL 3 operation or redundance devices with a lower SIL rating can be used.