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What are the Advantages of SIL3 Certified Actuators?
  • 16 Jun 2022

What is SIL Certificate?

Process safety has an important place, especially for production lines with dangerous process conditions such as the chemical industry. The Bhopal Disaster, one of the biggest disasters known in the world, accidentally ejected 40 tons of methyl isocyanate gas in the pesticide-producing factory of the US-based Carbide company in 1984, causing the death of more than 10,000 people and the poisoning of more than 100,000 people. In addition, 15 people died and more than 170 people were injured as a result of the explosion in the BP Texas City Refinery accident, which is considered the biggest refinery accident in the last 15 years in America.

All these disasters cause the death of thousands of people, damage nature irreversibly, and their total cost exceeds billions of dollars. Depending on this purpose, various standards have been established for process safety. Accordingly, in accordance with the Regulation on the Control of Major Industrial Accidents, companies must prove that there is sufficient reliability in their processes. In particular, the requirements in the functional safety and ATEX directives should be examined at the design stage of the company.

The functional safety standards EN 61508 and EN 61511 define part of the process safety or protection level depending on the correct operation of the systems.

SIS (Safety Instrumented System): A system that uses process control equipment to reduce the likelihood of one or more hazardous situations occurring. SIS is the system that controls the entire system and makes the system safe in dangerous situations.

SIF (Safety Instrumented Function): It is the function of detecting a dangerous situation that may occur during any operation and preventing this situation. For example SIF; It is the process of detecting an overheated engine temperature with a thermal sensor and stopping the engine. All of the SIF functions make up the SIS system.

SIL (Safety Integrity Level): Instruments, PLCs and end elements working in this system must have the desired and required level of SIL certificate. SIL certification is a security level related to the entire system. The fact that the instruments used in the system comply with the SIL level does not make the system suitable for the SIL level. For this, it is necessary to examine the whole system.

SIL certificate; It is defined in four different levels according to the probability of failure of the system in case of demand. The higher the SIL level, the less likely the system will malfunction and the higher the system performance.

The SIL level is determined by the magnitude of the risk and the level of protection the process needs when an undesirable situation occurs in the process.

SIL Certificate Test Period

Our actuator valves in 11 different sizes were tested before obtaining SIL certification. In the specially made test setup, the products were run according to the following scenarios:

1 on/off per hour
on/off every 3 hours
on/off every 6 hours
on/off every 12 hours
One on/off per day
on/off every 2 days
on/off every 4 days
on/off every 8 days
on/off in 16 days
on/off in 32 days

In the test setup, the products are at +90 °C for 31 days; It was subjected to the above scenario at -20 °C for 11 days and ambient temperature for 23 days. The purpose of these tests is to observe whether the products perform their duties in different working environments and under different process conditions. Our special test setup made within the scope of this project is connected to the internet. All tests were observed instantly by the certification body.

As a result of the successful passing of our products through these challenging test conditions, our products have been given SIL3 certificate. With a SIL3 certified actuator, you can manage your process with a product that has been tested in international standards and has a continuous working performance. In this way, it has a longer life actuator and your maintenance costs are also reduced. The risk of error in your process is reduced. You will have a long-lasting, safe system.

You can safely use TORK SIL3 certified pneumatic actuators in processes such as chemistry and petrochemistry, where safety is important and within the scope of Seveso.