Download - SIS How to Primer The System
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Safety Instrumented Systems: A How To Primer
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Presenter IntroductionPresenter Introduction
Michael Scott, PE, CFSE Vice President, AE Solutions 18 Years Experience ISA Committees - S84, WG6 FGS
Chair, WG3 BMS Core Team Member Past ISA Safety Division BMS
Chairman Past ISA Safety Division FGS
Chairman ISA Course Developer / Instructor ISA, AIChE, NFPA, SFPE Member Past PIP Safety System Task Team
Member BSME, University of Maryland MS, University of South Carolina
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What is an SIS?What is an SIS?
Informal Definition: Instrumented Control
System that detects out of control conditions and automatically returns the process to a safe state
Last Line of Defense Not basic process control
system (BPCS)
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Common SIS ApplicationsCommon SIS Applications Emergency Shutdown Systems Process Interlock Systems Burner Management Systems for Fired
Heaters High Integrity Pressure Protection Systems
Flare Load Reduction Fire and Gas Detection and Mitigation Many are Installed and in Operation in
typical Process Plants
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How SIS are Different from BPCS?How SIS are Different from BPCS?
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SIS Program
Safetyvalve
Output
Process Process
Logic solver(s)
Input
Transmitter
Final Element(s)Sensor(s)
SV
IAS
SIS ComponentsSIS Components
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What is NOT an SIS?What is NOT an SIS?
Many Instrumented Protective Functions (IPF) fall outside the industry-accepted definition Equipment Protective Functions ESD Functions that are solely initiated by manual
means Emergency Isolation Valves Alarm Systems Mechanical Devices, e.g., Fire Safety Valves with
Fusible Link, Overspeed protection, etc.
Not all interlocks in a Not all interlocks in a SIS will be associated with SIS will be associated with
Preventing a Specific Safety HazardPreventing a Specific Safety Hazard
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Installation and Commissioning 6%
Changes after Commissioning 21%
Specification 44%
Operation and Maintenance 15%
Design and Implementation 15%
HSE Study of Accident CausesHSE Study of Accident Causes
Accidents involving inadequate control systems
Out of Control: Why Control Systems go Wrong and How to Prevent Failure, UK Heath and Safety Executive, 1995
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Conceptual Process DesignConceptual Process Design
Process Hazards AnalysisProcess Hazards Analysis
SIFSIF DefinitionDefinition
TargetTarget SelectionSelection
Conceptual DesignConceptual Design
TargetTarget VerificationVerification
Design SpecificationsDesign Specifications
Construction, Installation, Construction, Installation, And CommissioningAnd Commissioning
PSATPSAT
Operation, Maintenance Operation, Maintenance and Testingand Testing
Procedure DevelopmentProcedure Development
Management of ChangeManagement of Change
Typical SIS design lifecycleTypical SIS design lifecycle
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Key Regulatory RequirementsKey Regulatory Requirements
Process Safety Information OSHA Process Safety Management (PSM) Standard
29 CFR 1910.119(d) (3) (ii) The employer shall document that equipment
complies with recognized and generally accepted good engineering practices.
Also cited in EPA Accidental Release Prevention Program 40 CFR Part 68 (68.65)
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OSHA Endorsement of ISA 84.01OSHA Endorsement of ISA 84.01 In 2000, OSHA Endorsed ANSI/ISA 84.01 via
Letter of Interpretation Complies with Process Safety Management Is one example of RAGAGEP Not the only way Applies to 1996 version of ANSI/ISA 84.01 Also have endorsed 2004 version
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GeneralGeneral SIS StandardsSIS Standards
ANSI/ISA 84.01 (1996, 2004) Application of Safety Instrumented Systems for
the Process Industries (1996) Functional Safety: Safety Instrumented Systems
for the Process Industry Sector, (2004) IEC 61511
Functional Safety: Safety Instrumented Systems for the Process industry Sector
IEC 61508 Functional Safety of
Electrical/Electronic/Programmable Electronic Safety Related Systems
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Application Specific StandardsApplication Specific Standards Burner Management Systems
NFPA 85, Boilers NFPA 86, Ovens and Furnaces
Fire and Gas Systems NFPA 72 Compressor Systems API 617-619 Turbine Driver Systems API 616 Offshore Oil & Gas Applications API RP
14C
Application Specific Standards tend to be More-Prescriptive in Nature. Not Flexible, or Performance-Based Standards
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Existing versus New SystemsExisting versus New Systems OSHA Process Safety Management
29 CFR 1910.119(d) (3) (ii) The employer shall document that
equipment complies with recognized and generally accepted good engineering practices.
(iii) For existing equipment designed and constructed in accordance with codes, standards, or practices that are no longer in general use, the employer shall determine and document that the equipment is designed, maintained, inspected, tested, and operating in a safe manner.
The Grandfather Clause
Grandfathering applies onlyGrandfathering applies onlyIf no upgrades are made to SISIf no upgrades are made to SIS
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Regulatory ComplianceRegulatory Compliance Good Engineering Practice
Is a moving target as industry practices change Does allow for a large degree of flexibility based on
industry- and company- practices Is not an OPTION in the eyes of Process Safety
Regulations
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How is Implementation of SIS going How is Implementation of SIS going to affect my Plant?to affect my Plant?
Analysis Required Identify Safety Instrumented Functions Select and Verify Achievement of Performance
Targets Develop Safety Requirements Specs.
New Equipment Transmitters Valves Logic Solver (PLC)
Testing and Maintenance Increase (Decrease?) Effort Level
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Layers of ProtectionLayers of Protection
Prevention Mitigation
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What is a What is a StandardStandard SIS Design?SIS Design?
In Most Cases, The Prescriptive Approach to SIS Design is Not Optimal from the Standpoint of Cost or Safety
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Industry Standards for Industry Standards for SSafety afety IInstrumented nstrumented SSystems (SIS)ystems (SIS)
Instrumentation, Systems, and Automation Society (ISA), ANSI/ISA S84.00.01-2004, Functional Safety: Safety Instrumented Systems for the Process Industry Sector, 2004.
International Electrotechnical Commission (IEC), IEC 61511, Functional Safety: Safety Instrumented Systems for the Process Sector
Performance Oriented Standards
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What does ISA 84.01 require?What does ISA 84.01 require?
Performance based Defines a safety
lifecycle Requires selection of
performance target Requires confirmation of
target achievement, quantitatively
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A measure of the amount of risk reduction provided by a Safety Instrumented Function (SIF)
Safety Integrity
Level
SIL 4
SIL 3
SIL 2
SIL 1
Risk Reduction Factor
100,000 to 10,000
10,000 to 1,000
1,000 to 100
100 to 10
Safety
> 99.99%
99.9% to 99.99%
99% to 99.9%
90% to 99%
What is a Safety Integrity Level What is a Safety Integrity Level (SIL)?(SIL)?
Probability of Failure on Demand
0.001% to 0.01%
0.01% to 0.1%
0.1% to 1%
1% to 10%
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Consequence
Likelihood
Tolerable RiskRegion
ALARPRisk Region
Unacceptable Risk Region
Consequence Reduction, e.g., material reduction, containment dikes, physical protection
Inherent Risk of the Process
Increasing Risk
SIL 1
SIL 2
SIL 3
Non SIS Risk Reduction, e.g. Pressure Relief Valves
SIS Risk Reduction
Reducing RiskReducing RiskNonNon--SIS Risk ReductionSIS Risk ReductionSIS Risk ReductionSIS Risk Reduction -- PreventivePreventive
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Conceptual DesignConceptual Design Select Technology
Device Failure Rate Certifications Proven in Use (Prior Use) Safety Manual for Certified
Equipment
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Conceptual DesignConceptual Design Select Architecture /
Voting Select degree of
Fault Tolerance Redundancy for Safety Redundancy for Nuisance
Trip Avoidance Identify potential
common-cause failures that could defeat redundant architecture
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Conceptual DesignConceptual Design Functional Proof Tests
Frequency Online or during Shutdown Full Functional Test or
Partial Test
Diagnostic Testing Frequency Response to detected fault
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Typical SIL 1 DesignTypical SIL 1 Design
Atmospheric Storage Tank
LT-101
V-101
LIC 101
LAL
LT-102
SV
IAS
LV-101 XV-101
Product Separator
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Typical SIL 1 Design Typical SIL 1 Design Low MTTFsLow MTTFs
Atmospheric Storage Tank
LT-101
V-101
LIC 101
LAL
SV
IAS
Vote 2oo2
LV-101 XV-101
Product Separator
LAL
LT-102
LT-103
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Typical SIL 2 DesignTypical SIL 2 Design
Atmospheric Storage Tank
LT-101
V-101
LIC 101
LAL
SV
IAS
Vote 1oo2
SV
IAS
LV-101 XV-101 XV-102
Product Separator
Overhead to Vapor
Recovery
LAL
LT-102
LT-103
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Typical SIL 2 Design Typical SIL 2 Design Low MTTFsLow MTTFs
Atmospheric Storage Tank
LT-101
V-101
LIC 101
LAL
IAS
Vote 2oo3
LV-101 XV-101 XV-102
Product Separator
Overhead to Vapor
Recovery
LAL
LT-102
LT-103
LT-104
2oo2SOV
2oo2SOV
IAS
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Certified Functional Safety Expert
"...ensuring that applicable parties involved in any of the overall E/E/PE or software safety lifecycle activities are competent to carry out activities for which they are accountable"
- IEC 61508, Part 1, Paragraph 6.2.1 (h)
Competence of PersonnelCompetence of Personnel
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Certified Functional Safety ExpertCertified Functional Safety Expert PE type certification process for application
of IEC61508 / IEC61511 (www.csfe.org)
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TOSHIBAMigas Indonesia
Presenter IntroductionWhat is an SIS?Common SIS ApplicationsHow SIS are Different from BPCS?SIS ComponentsWhat is NOT an SIS?HSE Study of Accident CausesTypical SIS design lifecycleKey Regulatory RequirementsOSHA Endorsement of ISA 84.01General SIS StandardsApplication Specific StandardsExisting versus New SystemsRegulatory ComplianceHow is Implementation of SIS going to affect my Plant?Layers of ProtectionIndustry Standards for Safety Instrumented Systems (SIS)What does ISA 84.01 require?What is a Safety Integrity Level (SIL)?