What is SIL used for?

SIL is a relative level of risk reduction provided by a safety function. SIL ratings correlate to the frequency and severity of hazards. They determine the performance required to maintain and achieve safety — and the probability of failure.

What is a SIL device?

SIL certification is a tool to measure the amount of risk reduction provided by a Safety Instrumented Function. It assesses the tolerable/acceptable failure rate of an individual device. This is important when installing or retrofitting an instrument into a SIS.

What does SIL safety stand for?

Safety Integrity Level
SIL stands for Safety Integrity Level. A SIL is a measure of safety system performance, in terms of probability of failure on demand (PFD).

How is SIL measured?

The SIL value for the safety system is determined by comparing the required probability of failure to the international standards of functional safety, defined in IEC 61508 and IEC 61511. In this case, the failure rate is measured by the average probability of failure per hour (PFH).

What is SIL testing?

The term ‘software-in-the-loop testing’, or SIL testing, is used to describe a test methodology where executable code such as algorithms (or even an entire controller strategy), usually written for a particular mechatronic system, is tested within a modelling environment that can help prove or test the software.

How is PFD calculated?

exact PFD = 1 – (1 – PFD1) · (1- PFD2). e.g. for a 1oo1 voting PFDUK = λDU·T1/2. subscript will indicate the configuration, (e.g. PFD1oo2 giving the formula for 1oo2).

What is SIL in oil and gas?

Functional safety is a formal discipline that analyses a system to identify: Safety Function Requirements – what safety functions are performed by the system.

What is a SIL 2 rating?

SIL2 – Low statistical risk of failure that you do not know about in the product. SIL3 – Redundant measurement capability – one of the primary differentiators between SIL2 and SIL3. SIL4 – Very few instruments available on the market, and extremely harsh demands to be certified for this.

What is SIL relay?

A SIL (Safety Integrity Level) certified relay (Safety Relay) has a known and guaranteed ability to perform a given Safety Function and reach a specific safe state on demand (i.e. open a relief valve or activate a Fire Extinguishing System).

Does an entire system have to have the same SIL level?

It is a common misconception that an entire system must have the same SIL level for each safety function. SIL stands for Safety Integrity Level. A SIL is a measure of safety system performance, in terms of probability of failure on demand (PFD).

What is a Safety Integrity Level (SIL)?

SIL is an acronym for “Safety Integrity Level” that comes from two voluntary standards used by plant owners/operators to quantify safety performance requirements for hazardous operations: IEC 61508: Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems

What does SIL stand for?

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:

What is the SIL level of a SIF loop?

Each SIS has one or more Safety Instrumented Functions (SIF). To perform its function, a SIF loop has a combination of logic solver (s), sensor (s), and final element (s). Every SIF within a SIS will have a SIL level. These SIL levels may be the same, or may differ, depending on the process.