SIL analysis is a powerful methodology for functional safety, measuring the required performance of safety instrumented functions.

A safety integrity level is a measurement of safety system performance. Safety Integrity is defined as: The probability of a Safety Instrumented Function (SIF) satisfactorily performing the required safety functions under all stated conditions within a stated period of time. This contract research report describes the development by the authors, with funding from HSE, of a methodology for the assignment of required Safety Integrity Levels (SILs) of safety related electrical control systems of machinery. Safety integrity level studies assess the reliability of functional safety systems and gives a level of confidence to the system. This is an adaptation of the Safety Integrity Level used in IEC 61508 for the automotive industry.
Methods of Determining Safety Integrity Level.doc Page 6 of 17 10 December 2004 Geometric mean risk = (0.32 x 32% x 32%) / 10 fatalities per year = 1 fatality in ~300 years Best case risk = (0.1 x 10% x 10%) / 30 fatalities per year = 1 fatality in ~30,000 years i.e. Safety Integrity Level (SIL) is an indicator of the degree of risk reduction unit provided by an instrumental safety function (SIF) implemented by a security system (SIS) within a given process. It identifies all the hazards of a process and estimates the risks inherently involved and determines if that risk is tolerable/acceptable. Automotive Safety Integrity Level (ASIL) is a risk classification scheme defined by the ISO 26262 - Functional Safety for Road Vehicles standard. This is an adaptation of the Safety Integrity Level used in IEC 61508 for the automotive industry. by G.M. It is related to the probability of failure on demand. The rationale behind the methodology and how to use it in practice are also explained in some detail. the unprotected risk has a range of 4 orders of magnitude. With many years of experience in the management of safety, hazard and risk, Germanischer Lloyd (GL) are extremely well placed to deliver SIL assessments.

Safety Integrity Level (SIL) A common way of ranking the dependability of a Safety Instrumented Function (SIF) is to use a simple numerical scale from one to four, with four being extremely dependable and one being only moderately dependable:

A Safety Integrity Level (SIL) assessment determines the effectiveness of safety systems based on the probability of tolerable incidents that can occur within a number of processing demands. The higher the safety integrity level, the higher the associated safety level and the lower the risk of a safety failure. Safety integrity levels are a quantitative target for measuring the level of performance needed for a safety function to achieve a tolerable risk for a process hazard. IEC 61508 is the main functional safety standard.

Revised standard ANSI/ISA 84.00.01-2004 (IEC 61511-1 … Adresse : BP 74, Ain el Bia, village N°06, 31230, Oran :+ 213 561108 653, fax : +213 41 799 054, E-mailsbaitiche@avl.sonatrach.dz. Safety systems that are not required to meet a safety integrity level standard are referred to as SIL 0.
The SIL or Security Integrity Level is a level of safety integrity.The SIL notion results directly from the IEC 61508 standard. SIL 3 Safety Integrity Level. In other words, SIL can be seen as an indicator of the acceptable failure rate for a security function.. Safety Integrity Level, or as more usually referred to "SIL" or "SIL level", is a unit of measurement for quantifying risk reduction. International srl Via G. Mameli, 53-55 I-20852 Villasanta (MB) SIL3 or Safety Integrity Level (SIL) is based on the value of risk reduction associated with a Safety Instrumented Function (SIF) protecting against a specific hazardous event, or how the risk has to be reduced to reach an acceptable level.. A Safety Integrity Level is determined via a procedure called Risk/Process Hazard Analysis (PHA). International srl Via G. Mameli, 53-55 I-20852 Villasanta (MB) SIL3 or Safety Integrity Level (SIL) is based on the value of risk reduction associated with a Safety Instrumented Function (SIF) protecting against a specific hazardous event, or how the risk has to be reduced to reach an acceptable level.. The SIL may be defined as a measurement of operational safety that determines recommendations related to the integrity of the safety features to be assigned to E/E/PE systems.