Inst ToolsInst ToolsInst Tools
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Search
  • Books
  • Software
  • Projects
  • Process
  • Tools
  • Basics
  • Formula
  • Power Plant
  • Root Cause Analysis
  • Electrical Basics
  • Animation
  • Standards
  • 4-20 mA Course
  • Siemens PLC Course
Reading: Understanding Safety Integrity Level IEC 61511
Share
Font ResizerAa
Inst ToolsInst Tools
Font ResizerAa
  • Courses
  • Design
  • PLC
  • Interview
  • Control System
Search
  • Courses
  • Automation
    • PLC
    • Control System
    • Safety System
    • Communication
    • Fire & Gas System
  • Instrumentation
    • Design
    • Pressure
    • Temperature
    • Flow
    • Level
    • Vibration
    • Analyzer
    • Control Valve
    • Switch
    • Calibration
    • Erection & Commissioning
  • Interview
    • Instrumentation
    • Electrical
    • Electronics
    • Practical
  • Q&A
    • Instrumentation
    • Control System
    • Electrical
    • Electronics
    • Analog Electronics
    • Digital Electronics
    • Power Electronics
    • Microprocessor
  • Request
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Safety Instrumented System (SIS) > Understanding Safety Integrity Level IEC 61511

Understanding Safety Integrity Level IEC 61511

Last updated: March 22, 2019 11:01 am
Editorial Staff
Safety Instrumented System (SIS)
1 Comment
Share
3 Min Read
SHARE

IEC standard 61511 is a technical standard which sets out practices in the engineering of systems that ensure the safety of an industrial process through the use of instrumentation. Such systems are referred to as Safety Instrumented Systems. The title of the standard is “Functional safety – Safety instrumented systems for the process industry sector”.

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).

The requirements for a given SIL are not consistent among all of the functional safety standards. In the functional safety standards based on the IEC 61508 standard, four SILs are defined, with SIL 4 the most dependable and SIL 1 the least.

A SIL is determined based on a number of quantitative factors in combination with qualitative factors such as development process and safety life cycle management.

Understanding Safety Integrity Level IEC 61511

Assignment of SIL is an exercise in risk analysis where the risk associated with a specific hazard, that is intended to be protected against by a SIF, is calculated without the beneficial risk reduction effect of the SIF. That unmitigated risk is then compared against a tolerable risk target.

The difference between the unmitigated risk and the tolerable risk, if the unmitigated risk is higher than tolerable, must be addressed through risk reduction of the SIF. This amount of required risk reduction is correlated with the SIL target. In essence, each order of magnitude of risk reduction that is required correlates with an increase in one of the required SIL numbers.

There are several methods used to assign a SIL. These are normally used in combination, and may include:

  • Risk matrices
  • Risk graphs
  • Layers of protection analysis (LOPA)

Of the methods presented above, LOPA is by far the most commonly used by large industrial facilities.

The assignment may be tested using both pragmatic and controllability approaches, applying guidance on SIL assignment. SIL assignment processes that use the HSE guidance to ratify assignments developed from Risk Matrices have been certified to meet IEC EN 61508 1

Understanding Safety Integrity Level IEC 61511

Safety Integrity Level Calculation IEC 61508

Safety System Architectures SIL

SIL Probability of Failure on Demand

Safe Failure Fraction IEC 61508

SIL Calculation Formula

SIL Calculation Example

Source : GM International 

Website : gminternational.com

Download:

  1. Safety Integrity Level Chart IEC 61511
  2. SIL Levels Guide
Don't Miss Our Updates
Be the first to get exclusive content straight to your email.
We promise not to spam you. You can unsubscribe at any time.
Invalid email address
You've successfully subscribed !

Continue Reading

Concept of Redundancy in Control Systems
What is Safety Instrumented Functions ?
De-energize to Safe Loop philosophy
What is Burner Management System (BMS)?
SIS Component Selection – Safety Instrumented System
Safety Instrumented System Handbook – SIS Tutorials
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
1 Comment
  • umesh shukla says:
    November 26, 2018 at 10:48 am

    very nice information

    Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
210kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

Safety Requirement Specifications (SRS) – Safety Instrumented System
What is HIPPS System in Oil and Gas?
SIS Final Control Elements
Reliability of a Control System
What is Maintenance Override Switch (MOS) ?
Safety Instrumented System Probability
What is Shutdown Valve?
What is Emergency Shutdown System (ESD) ?

Keep Learning

Bathtub curve

Bathtub Curve

P&ID

Over Pressure Protection Devices

Typical schematic of Butterfly valve

Automated Block Valve (ABV)

redundant transmitters

SIS Sensors

Project Management of Safety Instrumented System

Project Management of Safety Instrumented System (SIS)

hipps

What is High Integrity Pressure Protection System?

Safety Instrumented System Interview Questions Answers

Safety Instrumented System Interview Questions and Answers

safety control system

Safety Instrumented Burner Management System

Learn More

Control Valve Direction of Control Action

PID Controller Action : Directing Acting & Reverse Acting

PLC Timer Application in Security Camera Recording

PLC Timer Application in Security Camera Recording

Difference between Router, Switch, and Hub

Difference between Router, Switch, and Hub

Fieldbus Control Loop

Foundation Fieldbus Communication Management

Mathematical Models of Physical Systems

Differential Equations of Physical Systems & Dynamics of Robotic Mechanisms

Difference Between RCCB and MCCB

Difference Between RCCB and MCCB

Digital output block add-on for Variable speed drive

Steps to Import PlantPAx Add-On Instructions in Studio 5000

Types of Calibration

Types of Calibration

Menu

  • About
  • Privacy Policy
  • Copyright

Quick Links

  • Learn PLC
  • Helping Hand
  • Part Time Job

YouTube Subscribe

Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Welcome Back!

Sign in to your account

Username or Email Address
Password

Lost your password?