Safety Integrity Level (SIL)
“Safety integrity level (SIL) is defined as a relative level of risk-reduction provided by a safety function, or to specify a target level of risk reduction. In simple terms, SIL is a measurement of performance required for a safety instrumented function (SIF).”
“Functional Safety” means protection against hazards caused by incorrect function.
FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/ PROGRAMMABLE ELECTRONIC SAFETY- RELATED SYSTEMS which carry out a safety function, Functional safety is part of the overall safety that depends on a system or equipment operating correctly in response to its inputs.
Based on the Risk Analysis, every safety function that could lead to serious damage to human life and the environment should be verified under the Functional Safety requirement and FS certified.The Safety Integrity Level (SIL) Study is required to assess the distinct level for specifying the security integrity needs of the security instrumented functions (SIF) to be allotted to the security instrumented systems.
SIL certification provides recognition, increases the brand value of your product, and opens up new avenues earlier rendered inaccessible. SIL certificate most importantly underlines the reliability of your product.
A SIL is a measure of safety system performance, in terms of the probability of failure on demand (PFD) or probability of failure on hour (PFH)
The Safety Integrity Level (SIL) Study is required to assess the distinct level for specifying the security integrity needs of the security instrumented functions (SIF) to be allotted to the security instrumented systems.
The International Electrotechnical Commission’s (IEC) standard IEC 61508 defines SIL using requirements grouped into two broad categories: hardware safety integrity and systematic safety integrity. A device or system must meet the requirements for both categories to achieve a given SIL.
Manufacturers can certify themselves by fulfilling the standards of IEC 61508 & IEC 61511 standards, but a true and objective evaluation of risk and performance is more reliable when performed by an external company or consultant doing the math. In this case, the math is called FMEDA…,
The process for equipment or system certification under IEC 61508 is an evidence-based, structured and methodical approach to evaluate how product (or system) development (design, engineering and manufacturing) meets the requirements for achievement of the specified Safety Integrity Levels (SILs) in IEC 61508 and overall safety system performance targets.
The concept of an element which is part of a sub-system used in a Safety Function being SIL rated fundamentally contravenes the definition of Safety Integrity Level in IEC 61508-4 clause 3.5.8. Note 4, which states; “SIL is the property of the function not of the element, sub-system or system. SIL is the property of the Safety Function and a “SIL n safety system” should be interpreted as a system capable of supporting safety functions with a SIL “n” requirement”.
For more information or to apply for Functional safety or SIL certification, please contact us.