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Anonymous Poster

SIL levels

12/20/2008 9:56 AM

Dear Sirs

Please clarify how the SIL levels are made and where Ican find them

thanks

Chandra

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Guru

Join Date: Nov 2006
Location: OH USA
Posts: 549
Good Answers: 27
#1

Re: SIL levels

12/20/2008 10:49 AM

Do you mean Switching Impulse Insulation Levels?

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Power-User

Join Date: Mar 2008
Location: Mumbai
Posts: 250
Good Answers: 2
#2

Re: SIL levels

12/20/2008 1:07 PM

Hi ,

Its a very Complex Subject, As a preliminary ref IEC 61508 Part (1-6) & IEC 61511(1-3), else ISA 84 Series & BS 61882.

Regards

Jose

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Participant

Join Date: Oct 2008
Posts: 1
#3

Re: SIL levels

12/21/2008 8:00 AM

Dear Chandra,

It's difficult subject as one of member mentioned. SIL stand for Safety Integrity Level and category into 4 leves SIL1, 2, 3 and 4. SIL 4 is the most and SIL 1A is the lest reliable of fault tolorance (hardware reliability to failure). As I knew it related to the following industrial guidelines, Standards and Regulations:

1) HSE - PES : Programmable Electronic Systems In Safety Related Applications, Parts 1 & 2,

2) AIChE - CPPS : Guidelines for Safe Automation of Chemical Processes, AIChE

3) IEC 61508 : Functional Safety - Safety Related Systems, IEC standard 61508

4) ANSI/ISA-84.00.01 (IEC 61511 Mod) & ANSI/ISA-84.01 Functional Safety: Safety Instrumented Systems for the Process Industry Sector, ISA Standard 84.00.01-2004, Parts 1-3 (IEC 61511 Mod)

5) NFPA 85 : Boiler and Combustion Systems Hazard Code

6) API RP556 : Recommended Practice for Instrumentation and Control Systems for Fired Heaters and Steam Generators

7) API RP 14C : Recommended Practice for Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms

8) OSHA (29 CFR 1910.119 - Process Safety Management of Highly Hazardous

You can further study in Safety Instrumented Systems - Design, Analysis, and Justification.

Sorry for my poor English.

spanwang

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Active Contributor

Join Date: Nov 2008
Posts: 13
#4

Re: SIL levels

12/25/2008 5:15 AM

hi

SIL defines as Safety Integrity Level. As the word defines different levels of safety of the system. SIL was divided into 4 levels.

SIL1 - .1 TO .01

SIL2 - .01 TO .001

SIL3 - .001 TO .0001

SIL4 - .0001 TO .00001

in which SIL4 is given max for Railway signalling system. SIL3 is given for Industrial systems (PLC).

regards

foreveryone

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Commentator
India - Member - ADIL MOULA Engineering Fields - Instrumentation Engineering - Adil Moula

Join Date: Jun 2008
Location: India
Posts: 95
Good Answers: 1
#6
In reply to #4

Re: SIL levels

06/09/2011 11:42 AM

SIL1 - .1 TO .01

SIL2 - .01 TO .001

SIL3 - .001 TO .0001

SIL4 - .0001 TO .00001

the value are PFD values actual sil defines on the functional safety of the system,in worst case what is the requirement of safety , risk assessment matrix is made and accordingly sil system is brought into picture .

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Anonymous Poster
#5

Re: SIL levels

01/25/2009 6:06 PM

Hello Chandra,

You may find a number of interesting articles and video that will help you understanding the SIL concept. Simply go to www.safetyusersgroup.com

This website is dedicated to functional safety and safety instrumented systems.

Most of the content is simply access free!

I hope it will help you,

Best

DM

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