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
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: SIS Component Selection – Safety Instrumented System
Share
Notification Show More
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
Follow US
All rights reserved. Reproduction in whole or in part without written permission is prohibited.
Inst Tools > Blog > Safety Instrumented System (SIS) > SIS Component Selection – Safety Instrumented System

SIS Component Selection – Safety Instrumented System

Safety Instrumented System (SIS) component selection is to be done as per plant safety requirements and must follow International standards.

Last updated: May 23, 2022 11:14 pm
Editorial Staff
Safety Instrumented System (SIS)
No Comments
Share
4 Min Read
SHARE

Safety Instrumented System (SIS) component selection is to be done to suit the plant safety requirements and must follow all the specifications as per the below International standards.

Contents
SIS Component SelectionSafety Instrumented System General RequirementsWhether to go for Certified Instruments or not?Advantages of Certified InstrumentsCertification FlawsPrior use InstrumentsConclusion

SIS Component Selection

SIS components selection has to be done rigorously with experienced, qualified design Engineers under the supervision of Safety experts.

  • Verify SIS component suitability for the operating environment.
  • All the device subsystems shall meet the fault tolerance requirements.
  • Overall SIS should achieve the target probability of failure on demand (PFD) for a demand mode system and meet the SIL.
  • Use the measurement instruments selection tool and identify the proper instrument for a given service.
  • Each plant owner and their approved Engineering/Technology provider shall develop best practices for instrumentation selection.
  • Experts shall be used to select measurement principles and perform proper instrument selection and instrument design work.
Safety Instrumented System SIS Component Selection
Image Courtesy: Emerson

Safety Instrumented System General Requirements

Components selected for use in an SIS must either be certified for use in SIS applications or selected based upon prior user experience. Of course, the components and the overall design must meet the requirements for the SIF as defined in Safety Requirements Specification.

Prior use is based on the installation of similar instruments under an identical environment in multiple facilities and the instruments are proved for use for several years.

Whether to go for Certified Instruments or not?

  • Certified instruments for SIL applications are not a must. However, certified instruments can be specified if
    • Additional instrument cost with SIL certification does not exceed the cost of the proof test effort.
    • New Technology or new model
    • Special requirements exist (e.g. fire eyes acc. Burner Management Guideline
  • Certificates can be issued by
    • Commercial Organizations (Exida/ TUV)

Find below the pressure transmitter (Emerson) used in SIS approved with safety agency – Exida.

  • SIS Component Selection
  • SIS Instruments Exida Certificate
Image Courtesy: Exida

Advantages of Certified Instruments

  • Data provided for
    • Failure Rates
    • Safe Failure Fraction
    • Diagnostic Coverage
  • The supplier takes control of software and hardware modifications
  • Safety manual provided

Certification Flaws

  • Some certificates issued by lesser reputable institutes are based on hardly anything more than manufacturers’ claims and a simple failure mode analysis. 
  • Some instrument manufacturers are busy having their products certified to be in accordance with IEC 61508 in urgency without completing the complete test.

Prior use Instruments

  • Definition
    • when a documented assessment has shown that there is appropriate evidence, based on the previous use of the component, that the component is suitable for use in a safety instrumented system
  • The standards and tools implemented by various manufacturers enable to provide appropriate evidence that the sensors and final elements are suitable for use in the safety instrumented system based on prior use.

Conclusion

End users to select the SIS instruments with careful evaluation of certifications or the Prior use category of those instruments that are well proven in many plants.

If you liked this article, then please subscribe to our YouTube Channel for Electrical, Electronics, Instrumentation, PLC, and SCADA video tutorials.

You can also follow us on Facebook and Twitter to receive daily updates.

Read Next:

  • What is HIPPS System?
  • Emergency Block Valves
  • SIS Common Cause Failure
  • SIS Verification & Validation
  • Testing and Repair Deferral
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

Layers of Protection Analysis (LOPA) Interview Questions
Safety Requirement Specifications (SRS) – Safety Instrumented System
Direct-actuated Safety and Relief Valves
Common Cause Failure – Safety Instrumented System
Functional Safety Questions & Answers
Test Questions on Safety Instrumented System
Share This Article
Facebook Whatsapp Whatsapp LinkedIn Copy Link
Share
Leave a Comment

Leave a Reply Cancel reply

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

Stay Connected

128.3kFollowersLike
69.1kFollowersFollow
208kSubscribersSubscribe
38kFollowersFollow

Categories

Explore More

BPCS Control System and ESD Safety System of Delta-V DCS
SIS Safety Requirements
Purpose of Emergency Shutdown (ESD) System
Partial Stroke Testing Device (PSD) in SIS Final Control Element
Transmitter Proof Testing
SIS Instrument Sharing – Transmitters Shared for BPCS and SIS Example
Process Safety and Instrumentation
SIS Instruments and Valves Inline Testing – Safety Instrumented System

Keep Learning

pilot-operated pressure relief valve

Pilot-operated Safety and Relief Valves

Safety Control System

What is Safety Control System ?

Difference between Availability, Reliability & SIL

Difference between Availability, Reliability & SIL

Rupture disks

Rupture disks

SIL Levels

Understanding Safety Integrity Level IEC 61511

Typical schematic of Butterfly valve

Automated Block Valve (ABV)

Emergency Shutdown System Philosophy

Shutdown Philosophy

SIS PFD - Safety Instrumented System

SIS PFD – Safety Instrumented System

Learn More

Comparison of CB, CE & CC Amplifiers

Comparison of Transistor Configurations

Automated Garage Gate Control - PLC Ladder Logic

Automated Garage Gate Control – PLC Ladder Logic

Instrument Air Quality

Instrument Air Quality

Digital Electronics Multiple Choice Questions

Asynchronous Counter Objective Questions

Sand Probe Functional Testing

Sand Probe Functional Testing

Combining Independent Voltage Sources in Series

Combining Independent Voltage Sources in Series

Pneumatic Moment-balance Differential Pressure Transmitter

Pneumatic Moment-balance Differential Pressure Transmitter

Trip Valve Shown Tripped

Trip Valve Principle

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?