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Emergency shutdown (ESD)
SIL study Have you heard about SIL studies? What does it mean?
What does SIL, SIF and SIS mean?
Terms defined in ANSI/ISA-84.00.01-2004 (IEC 61511-1) Functional Safety: Safety Instrumented Systems for the Process Industry Sector
SIF: Safety Instrumented Function
SIS: Safety Instrumented System: Sensor + logic solver + final element
SIL: Safety Integrity Level: Level used for specifying the safety integrity requirement of SIFs. There are 4 levels:
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Emergency shutdown (ESD)
SIL study Have you heard about SIL studies? What does it mean?
What does SIL, SIF and SIS mean?
Terms defined in ANSI/ISA-84.00.01-2004 (IEC 61511-1) Functional Safety: Safety Instrumented Systems for the Process Industry Sector
SIF: Safety Instrumented Function
SIS: Safety Instrumented System: Sensor + logic solver + final element
SIL: Safety Integrity Level: Level used for specifying the safety integrity requirement of SIFs. There are 4 levels:
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Emergency shutdown (ESD)
SIL study Have you heard about SIL studies? What does it mean?
What does SIL, SIF and SIS mean?
ANSI/ISA-84.00.01-2004 (IEC 61511-1)
Functional Safety: Safety Instrumented Systems for the Process Industry Sector
SIF: Safety Instrumented Function
SIS: Safety Instrumented System: Sensor + logic solver + final element
SIL: Safety Integrity Level: Level used for specifying the safety integrity requirement of SIFs. There are 4 levels:
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Emergency shutdown (ESD)
SIL study Have you heard about SIL studies? What does it mean?
What does SIL, SIF and SIS mean?
ANSI/ISA-84.00.01-2004 (IEC 61511-1)
Functional Safety: Safety Instrumented Systems for the Process Industry Sector
SIF: Safety Instrumented Function
SIS: Safety Instrumented System: Sensor + logic solver + final element
SIL: Safety Integrity Level: Level used for specifying the safety integrity requirement of SIFs. There are 4 levels:
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SIL study
Step 1: SIL Determination, “assignment workshop”
Identification of Instrumented Interlocks on the P&IDs = inventory of Safety Instrumented Function (SIF)
For each SIF: • Qualitative evaluation of consequences if the event the SIF is
designed to safeguard from
• Qualitative evaluation of the likelihood of the event
• Determination of risk level (likelihood * consequence) and resulting SIF required performance (SIL level)
Deliverable: SIL assignment logsheet / worksheets
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Emergency shutdown (ESD)
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Emergency shutdown (ESD)
SIL study LIKELIHOOD CATEGORY
DEFINITION POTENTIAL FREQUENCY
A Possibility of repeated incidents 20 or more times per Facility life
B Possibility of isolated incidents 5 times per Facility life
C Possibility of occurring sometime Once in Facility life
D Not likely to occur Once every 10 Facility lives
E Practically impossible Once every 100 Facility lives
CONSIDERATIONS CONSEQUENCE CATEGORY Health/Safety Public Disruption Environmental Impact Financial Impact
Abbreviation S – Safety P – Public E – Environmental F – Financial
I Fatalities/ Serious Impact on Public
Large Community (10,000+)
Major/Extended Duration/ Full Scale
Response
Major Impact to Company
(>$50 million)
II Serious Injury to
Personnel/ Limited Impact on Public
Small Community (1,000 to 10,000)
Serious/Significant Resource
Commitment
Significant Impact To Company ($2 - $50 million)
III Medical Treatment for Personnel/ No Impact
on Public
Minor (10 to 100)
Moderate/Limited Response of Short
Duration
Moderate Impact To Company
($500M - $2 million)
IV Minor Impact on
Personnel
Minimal to None
(1 or 2)
Minor/Little or No Response Needed
Minor Impact To Company
($50M-$500M)
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1 – Assignment workshop
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SIL Study
Step 1: SIL Determination, “assignment workshop”
Deliverable: SIL assignment logsheet / worksheets
Summary:
What is the second step of the SIL?
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SIL Study
Step 2: calculations and recommendation
SIS Performance Verification
Evaluate the performance of each SIF, based on device selection, architecture, voting, testing etc.
Compare to required SIL level and specify modifications to the SIF design (device selection, component redundancy) or testing intervals
Deliverable: SIS Performance Verification Results and recommendations
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SIL Study
Step 2 – SIS Performance verification Results
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SIL Study
Step 2: calculations and recommendation - Summary