FMECA - DNV

Introduction to the basics of FMECA Lesson 1

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History

Today Mid 1970s 1967 Civil aviation industry 1960s NASA

1949 US army

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Automotive industry (Ford Pinto affair) Toyota Design Review Based on Failure Mode (DRBFM)

Petroleum, semiconductor processing, food service, plastics, software, healthcare, +++++

Major standards for FMEA/FMECA       

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British Standard BS5760 Part 5: 1991 (+BS EN 60812:2006) US Military Standard MIL-STD-1629A UK Defence Standard 00-41/Issue 3 Society of Automotive Engineers (SAE) ARP926A IEC 60812: 2006 (FMEA) DNV-RP-D102 (FMEA of redundant systems) DNV-RP-A203 (qualification of new technology)

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FMECA – Why and when?  Identify unwanted potential events on a system potentially resulting in negative impact  Highlight importance of existing safeguards  Satisfy contractual requirements

 Basis for improvement to design and/or operating & maintenance procedures with respect to reliability and safety  Can be used in both design phase and operations phase, but with different objectives

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FMECA +/Pros: – FMECA is a structured method for evaluating system design – The concept and application are easy to adopt, also for a novice – The approach enables evaluation of complex systems – Identification of single point failures – Screening critical aspects with the system – Provides basis for more detailed evaluation

Cons: – The FMECA process may be tedious, time-consuming (and expensive) – The approach is not well suited for multiple failures (can perform RAM after FMECA) – Human errors are often missed out

– Is not well suited to handle multifunctional systems – Ultimately, all failure modes need to be identified by human beings in the team

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What is FMECA?  Methodology to identify and analyse:

All potential failure modes of all the subsystems

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The effects these failures may have on the system

Risks that need to be avoided or mitigated

What can FMECA be used for?  Ensure that all conceivable failure modes and their effects on the operation have been considered  Identify single point failures that may lead to system failure (eg DP2, NCSP)  List potential failures and identify the severity of their effects

 Assist in selecting design alternatives with high reliability and high safety potential during the early design phases  Develop early criteria for test planning and requirements for test equipment  Provide historical documentation for future reference to aid in analysis of field failures and consideration of design changes  Provide a basis for maintenance planning  Provide a basis for quantitative reliability and availability (RAM) analyses.  +++

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Important Definitions Failure: The termination of the ability of an item to perform a required function Failure Mode: The failure mode describes the loss of required function(s) that result from failures. (Manner in which the inability of an item to perform a required function occurs, or How does is fail?.) Failure Mechanism: The circumstances (design, installation, use etc.) or mechanism (corrosion, pressure, load, etc.) which have caused the failure. Why does it fail? Safeguard: (mitigating action) Provisions in the system that will reduce either the likelihood or the consequence of a failure. This may also include operating procedures or the operator intervention provided they have been trained to respond to the particular failure and that it can be detected.

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Remember  There are several variations of FMECA, some simple and some elaborate, but the objective is the same: – Systematic breakdown of a system to uncover unwanted risks and single point failures.

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Available Techniques

•Rarely used or •inappropriate

•Commonly •used

•Conceptual Design •Detailed Engineering •Construction/Start-Up •Operation •Expansion or Modification •Incident Investigation •Decommissioning

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HAZID

Hazard Identification is the first and most critical step of risk management – Why?

 Typically done at an earlier stage in system/procedure development  Carried out at slightly higher level – system rather than component

 No guidewords  Assumes that a hazard occur and investigates what events may cause this

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PREVENTION OF MAJOR ACCIDENT HAZARD (MAH) MANAGEMENT SYSTEM

Safety Assessments

• QRA • Fire Risk Analysis • Hazid • HAZOP • ETRERA

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Credible Major Accident Hazards (MAH)

• Fire and explosion • Structural failure • Ship collision • Subsea release • Etc

Safety Case

Describes • Facility • SMS • Hazards and Risks • Justifies continued operation

List of Safety Critical Elements (SCEs)

Role to: • Prevent • Detect • Control • Mitigate MAH

Performance Standards & Verification Scheme

Details SCE: • Functional performance • Reliability • Maintenance Mgt • Operations Mgt

Independent & Competent Person (ICP) Verification & Audit

Verification carried out by • IVB – WSV • Technical Authorities • HSE Audit • OSHAS/ISO Audits



•Commonly •used

•Conceptual Design •Detailed Engineering •Construction/Start-Up

•Operation •Expansion or Modification •Incident Investigation •Decommissioning DNV GL © 2013

Checklist Application

 Used traditionally to ensure compliance with standard practices  Checklists are a powerful hazard identification technique  Incorporate past experience in convenient lists of do‟s and don'ts  Valuable for revealing an otherwise overlooked hazard  They can be expected to reveal most common hazards

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CHECKLISTS Advantages

 All of the issues on the list are addressed

 Easy to do and can be applied at any stage of a project life-cycle  Minimal manpower compared with HAZOP, etc.  Standard checklist can be developed to ensure consistency

Disadvantages 

Limited by the experience and knowledge of the author



Rely on past experience (not predictive)



Comprehensive checklists can be very lengthy documents



Checklists need to be audited and kept up to date

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•Commonly •used


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What-If Analysis  Creative brainstorming using “What-If?” questions to develop scenarios for undesirable events  Based on plant systems or sub-systems  Identify the hazards and consequences of the scenario

 Identify existing safeguards

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Slide 17

“What-If” Questions

What if ...? How could ...? Is it possible ... ?

Has anybody ever ...? Etc., Etc., Etc.?

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SWIFT’s 10 Question Categories

 Material problems (MP)  External effects or influence (EE/I)  Operating error and other human factors (OE&HF)  Analytical or sampling errors (A/SE)  Equipment/instrumentation malfunction (E/IM)  Process upsets of unspecified origin (PUUO)  Utility failures (UF)

 Integrity failure or loss of containment (IF/LOC)  Emergency operations (EO)  Environmental release (ER)

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•Commonly •used


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How do we perform a HAZOP?  By considering the plant section by section, line by line, item by item  By defining „normal operation‟  By considering deviations from normal operation  By using guidewords to identify these deviations and to initiate the discussion

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Guidewords / Deviations Original Guideword Flow No Reverse (Wrong) More

Less Part of As well as Other than

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   

Parameters Pressure Temp

 

 

Composition

  

HAZOP process Describe design intention, operating conditions etc.

Consider first or next guide word

Identify all causes and record

Identify all consequences and record

List existing safeguards and record

Agree any actions necessary and responsible person /org. and record No Last guide word? Yes Take next section DNV GL © 2013

HAZOP / HAZID logsheet Step

1.

1.1

1.2

2.

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Guideword / Deviation

Cause

Consequence

Existing Safeguards

Finding / Recommendation R: Remark / A: Action

Action responsible

Time



•Commonly •used


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Fault tree  Identifies causes for an assumed failure (top event)  A logical structure linking causes and effects  Deductive method  Suitable for potential risks

 Suitable for failure events

Top event

OR

A

Intermediate Event

Component 1

And Gate

E1

E2

Component 2

E3

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AND

Component 3

E4

Basic Event

The outp the

The the whe occ

The basi requ of f

Fault Tree Case - Late for Work Fail to arrive at work on time Or

Overslept

Trafic hold up

Car will not start

And

TRF

Or

Went to bed to late

Alarm clock ineffective

Mechanical fault

Fuel system fault

Ignition fault

Starter fault

Bed

Or

Mech

Fuel

IGN

And

Alarm clock fails

Alarm not set

Alarm not loud enough

No batery power

Set

Loud

Or

CLKF

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Solenoid fault Sol

No alternative power is available

Battery is flat

And

Flat

No jump cables available

No other car available

JCBL

NCAR

Wiring fault

Starter jammed

Wire

JAM

Use a Fault Tree to  identify possible causes for a system failure  predict; – reliability – availability

– failure frequency  identify system improvements  predict effects of changes in design and operation  understand system

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Production assurance and reliability management (ISO 20815) “The petroleum and natural gas industries involve large capital investment costs as well as operational expenditures. The profitability of these industries is dependent upon the reliability, availability and maintainability of the systems and components that are used.” [ISO 20815 - Production assurance and reliability management ]

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Production assurance and reliability management (ISO 20815) Examples for design measures/factors to optimise the cost-benefit ratio:

Feasibility

Conceptual design

Engineering

Procurement

Assembly

Installation & Commissioning

Operation

[Life cycle phases as per ISO 20815]

 Choice of technology

 Capacities

 Redundancy at system level

 Reduced complexity

 Redundancy at equipment or component level

 Material selection

 Functional dependencies

[ISO 20815 - Production assurance and reliability management ]

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Quantitative Picture of Performance

Reliability

 Equipment performance 

data (failure frequencies) System configuration

Availability

 Equipment/System uptime  Achieved

Productivity

Maintainability  Maintenance resources  Shift constraints  Mob delays  Spares constraints

Operability

   

production Production losses Criticality Contract shortfalls Delayed cargoes

NPV

 Plant interdependencies  Discounted Total Cashflow  Plant re-start times  Production/demand rates Unit Costs/Revenue  Storage Size  Tanker Fleet and  Product price Operations  Manhour/spares costs  Transport costs  Discount rates 31

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Objective 1 – Prognosis

 Forecast:

sub system availability, system availability, production availability etc.

 Verify production-assurance objectives or requirements Technical availability, Annual average

70 %

75 %

80 %

85 %

different systems

Base case, 4x25% 85% ASF 95% ASF 4x30% @ 85% ASF 4x59.95% @ 85% ASF Repair on lost function Repair on lost function @ 85% ASF Repair modules on lost function Wait for weather Wait for weather @ 85% ASF, Repair on lost function Wait for weather @ 85% ASF Dedicated vessel Ormen Lange Dedicated vessel Ormen Lange, Repair on lost function Dedicated vessel incl. nearby fields Dedicated vessel nearby fields, 4x30% @ 85% ASF Dedicated vessel Ormen Lange, 4x30% @ 85% ASF, Dedicated vessel Ormen Lange, 4x30% @ 85% ASF Dedicated vessel nearby fields, Repair on lost function VSD Spare sensitivity Wait for weather @ 85% ASF, Repair modules on lost

P10

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Mean

P90

90 %

95 %

100 %

Objective 2 – Analysis of weak points

 Identify equipment units critical to availability (what are the main downtime-contributors),  Identify technical and operational measures with potential for performance improvement Downtime distribution

Case 8A

100 MP20: Process template 80

Cost per intervention (MNOK)

MP20x: Tie-in manifold

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MP1: Umbilical and pow er cable 40

20

MP16: Transformer and HV w et connections

MP4: VSD compressor

MP2: Compressor and motor

MP5: Circuit Breaker Module MP7: VSD pump

0 -0.5

0

0.5

1

MP6: Pump and motor 1.5

2

2.5

No. of interventions per year

MP20x: Tie-in manifold MP3: Anti Surge Valve MP6: Pump and motor MP9: V-cone MP16: Transformer and HV wet connections MP22: SDU

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MP1: Umbilical and power cable MP4: VSD compressor MP7: VSD pump MP14: SCM MP20: Process template MP8b: Cooler

MP2: Compressor and motor MP5: Circuit Breaker Module MP8b: Separator MP15: SCM MB MP21: Bridge spool Bub b le size: Deferred volume MP23: UPS per intervention

Objective 3 – Alternative comparison

 Compare (concept, design, operation) alternatives with respect to different availability aspects  Enable selection of facilities, systems, equipment, configuration and capacities based on economic optimization assessments

 Provide input to other activities, such as risk analyses or maintenance and spare-parts planning

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Steps in a study

Preparation

 Review of technical documentation Site visit if required

Study basis

System description Reliability data/ Input from system experts

Model Model

Analysis Simulation and

Reporting and

development development

assessment and analysis

recommendations

Functional breakdown

Identify performance measures

Consequence of failures

Sensitivity analyses

Inclusion of events and compensating measures

FMECA

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Importance measures

State all assumptions Document input data Present results Outline recommendations

Model building (similar to fault tree..) 

Discrete Event Simulation



Probability distributions for frequencies of component failure/ repair etc. based on historical data or expert judgment



Model consequences of failure

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DRY GAS FILTER

WATER BATH HEATER

PRESS. REGULAT OR

DRY GAS FILTER

WATER BATH HEATER

PRESS. REGULAT OR

METER SKID CHROMATOGRAPH METER SKID

Final delivery

Recommendations to optimize performance through:  improving the design Prediction of the performance/ availability of possible concepts Cost-benefit for possible concepts Cost-benefit optimization of development  improving the operation Maximizing performance/ production availability Optimizing operational costs Minimizing downtime Optimizing operational procedures/ strategies

by analyzing:

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- performance - costs - availabilities - and other uncertainties

Buzz group work – Pair and Share  Arrange yourselves into groups of 4  Discuss: – Could FMECA be applied both early and late in a project? – Advantages / Disadvantages

Early Project Phase

Late Project Phase

• FMECA advantages •… •… • FMECA disadvantages •… •…

• FMECA advantages •… •… • FMECA disadvantages •… •…

 Produce key points and be prepared to defend your conclusions…..

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FMECA - DNV

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