application of iec 61508 and iec 61511 in the norwegian
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Application of IEC 61508 and IEC 61511 in the Norwegian
Petroleum Industry
Lars BodsbergResearch Director
SINTEF, Trondheim, Norway
[email protected]://www.sintef.no/
30 November 2005Delft, the Netherlands
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This is SINTEFThe Foundation for Scientific and Industrial Research
at the Norwegian Institute of Technology
The vision:Technology for a better society
Business concept:SINTEF sell research-based knowledge and related services to Norwegian and international clients.
Social perspective:SINTEF wishes to contribute to the creation of value and to a society in healthy sustainable development.
Locations:SINTEF has 1700 employees, mainly 350 situated in Oslo and 1350 in Trondheim.
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Widespread use in the Norwegian Petroleum Industry
• The International standard IEC 61508: Functional safety of electrical/-electronic/programmable electronic (E/E/PE) safety-related systems“(7 parts)– Generic standard
• The International standard IEC 61511: Functional safety – Safetyinstrumented systems for the process industry sector (3 parts)– Sector specific standard
The Petroleum Safety Authority Norway recommends the use of IEC 61508 and 61511
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Development of Safety System Requirements
Isolate and depressurize vessel
9999 out of 10000times
EUC Hazard
Risk
EUCrisk
Overpressure
Tolerablerisk
Safety requirements&
Safety Integrity Level
E/E/PES
OtherSafety-relatedsystems
Externalfacilities
Not part ofIEC 61508
Allocation
R
Design, etc
Req.
h/w s/w
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IEC 61508 Implications on Risk and Reliability Analyses
• The IEC 61508 standard sets out a risk-based approach for deciding the Safety Integrity Level (SIL) for systems performingsafety functions– On-going R&D to improve Quantitative Risk Analyses (QRA) in
Norway.
• The IEC 61508 standard requires evaluation of reliability performance of the safety instrumented systems– The PDS method – Reliability Assessment of Safety Instrumented
Systems
Safety Integrity: “Probability of performing required safety functions”
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QRA
FGD/ESD SYSTEMPSD SYSTEMPC SYSTEM
Normalequipmentcondition
Stableprocess
Accidentexternal to
process
Processupset
(transient)
Leak(Process
equipmentfailure)
Fire orexplosion Pollution
Failure ofcontrol or
safety system
Mechanicaldegradation
Mistake bypersonnel
Function
Implementation(Example) CONTROL
S PSL GD
FD
FDMM
Loss ofproduction
Personnelinjury
Facilitydamage
PSV FSV
NORMALOPERATIONALSITUATION
HAZARD ACCIDENT CONSEQUENCE
Equipment Processfunction
Platform Extent of shut-down action
Production
Detectableconditon
SHUTDOWNCMMS
CM:Condition Monitoring, S:Process sensor, PSV:Pressure relief, PSL:Pressure switch low, FSV:Check valve, GD:Gas detector, FD:Fire Detector, M:Manual
SELF-ACTING
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IEC 61508 Implications on Risk Analyses
• Traditional offshore quantitative risk analyses (QRA):– Starts with assuming that a HC leak has happened– Frequency of HC leaks from historical data -
causes of HC leak not modelled– Safety systems often not explicitly modelled
• Risk analyses needs adaptation and development
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Guideline for use of IEC 61508 and IEC 61511
• Joint industry project between operators and the various suppliers of services and equipment (PDS forum)
• The Norwegian Oil Industry Association (OLF) provided financial support
• Guideline published at: www.itk.ntnu.no/sil
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Guideline Objective• Adapt and simplify the application of the IEC 61508 and IEC
61511• Guidance on
– Design – Operation and maintenance – Modification– Mangement activities to ensure that functional safety requirements
are met.• Provide minimum SIL levels• Provide approach for reliability quantification of safety integrity
Guideline for the use of IEC 61508 and IEC 61511 in the Norwegian Petroleum Industry
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PDSPDS is the Norwegian acronym for
"Reliability and availability of computer based safety systems"
• SINTEF has developed a method for quantifying the reliability/availability of instrumented safety system, called the PDS method
• The method is continuously updated
• Regular meetings in the PDS Forum.
The PDS Forum's vision is to become the
Norwegian centre of force for development of
safety systems within the petroleum industry.
http://pds.sintef.no/
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PDS Forum ParticipantsOil companies:• BP Amoco Norge AS • TotalFinaElf Exploration Norge AS • Norsk Hydro ASA • Shell • Statoil • ConocoPhillips• Eni Norge
Consultants / Engineeringcompanies:
• Aker Kvaerner Engineering & Technology Oil
• Det Norske Veritas • NEMKO• Safetec Nordic AS • Scandpower Risk Management
AS
Vendor companies: • ABB • FMC Kongsberg Subsea• Honeywell• Invensys Triconex• Kongsberg Simrad• SAAS System AS • Siemens • Simrad Optronics ASA
Governmental bodies:• The Petroleum Safety Authority
Norway (Observer)• The Directorate for Civil Protection
and Emergency Planning (Observer)
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ReliabilitySafety Maintenancez
t
OREDA® = Offshore Reliability Data
http://www.sintef.no/static/tl/projects/oreda/
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Safety vs. Life Cycle Cost
Acceptance criteria
0.006
0.005
0.004
0.003
0.002
0.001
100 200 300 400 500
LCC in 1 000 Norwegian kroner
Probability of failure on demand
Primary Investment
Operation and maintenance cost
Unavailability cost of trip
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