effective process safety management program requires a systematic approach to evaluating the whole process employers need to develop the necessary expertise, experiences, judgment and proactive initiative within their workforce to properly implement and maintain an effective process safety management program that the design and construction along with the testing, inspection and operation are still suitable for the intended use. Where the process technology requires a design which departs from the applicable codes and standards, the employer must document that the design and construction is suitable for the intended purpose.
Process Safety
There are many common aspects
Integrity Management
Many benefits result from an Integrated approach to Safety and Integrity
Why does equipment fail? Lab Data. No of Failures
40 35 30 25 20
No of Failures
15 10 5 0
n o i s o r r o C
C C S
e d e n u l r i u o g e l s i i t a o a W r F E F
r e e l t u t t i r c B a r f
l p a c e e i e n r r u a l C i h a c F e M
r e g r n r u a i e t s W a e v s e O e h r r P e v O
Identifying root causes
80 70 60 50 40
Series1
30 20 10 0 Operation
Design flaw
Maintenance Error
Fabrication Defect
Failed repair
Other
Failure of process plant !
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There are very few failures reported on pressure equipment Statistics suggest failure rates of 1x103 to 1x104 yrs: !
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But what level of ‘failure’? (deterioration, leak, major loss)
When could failure occur? !
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This year, next!..in 5 years or more Most failure statistics exclude corrosion damage
Objective is Avoiding unplanned ‘failure’ - production impact
Ageing plant - The ageing stage •Approaching design limits •Evidence of significant accumulated damage •Changes in process use •Repairs, refits, modifications •Deficiencies in systems and skills
e g a m a D d e t a l u m u c c A
Time Initial Operation
Mature Stage
Ageing Stage
Terminal Stage
Ref: HSE RR 509 – Plant Ageing – Management of equipment containing hazardous fluids or pressure
What affects asset life? Understanding the challenge
Design quality - Life-limiting factors assumed at design stage
Design
Quality of the original fabrication and installation
Construction
Obsolescence of equipment Operating within original design limits
Suppliers
Knowledge of equipment condition e.g. Inspection of static equipment or condition monitoring of rotating equipment
Operation Inspection
Maintenance
Maintaining equipment in ‘fit for service’ condition Quality of spare parts and repairs
Modifications
Asset life factors across the life cycle
Change of equipment or operations that negates original design
Life extension - challenges
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Application of life extension practices change to equipment and operating regimes, incremental over time
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Not simply fatigue or creep life operating cycles and / or time related factors not in design (fatigue or thermal)
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Progressive corrosion model for life & inspection time of initiation of corrosion operational change over time
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Condition Monitoring systems knowing what to monitor?
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Primarily containment of high hazard substances – not pressure
Asset life extension
Remnant Life
How to understand remaining Asset Life? Asset Life
Product grade change Feedstock change Process optimisation – temperature changes
Ti centrifuge suffering wear
Wear & Corrosion of centrifuge scrolls !
!
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New grades of product contained higher residual acid and increased abrasion Spare scroll installed when required - repair was carried between shutdowns Limited management of repair – no evaluation of damage extent
Actions taken !
Evaluation & application of surface coating to scroll tips to extend life
Life extension “Management Cycle” Business strategy
Project Delivery
Corporate production planning
Project Scoping
Data gathering
Asset Life Actions
Project priority evaluation
Prioritisation of assets
Asset Sustenance plan
Condition & life assessment
Typical results of Ageing Plant Study Items need to be replaced within next 20 years
Items need major repairs within next 20 years
Items need further evaluation 8%
7%
1%
11%
Items need minor repairs within next 20 years
73%
Items can continue to be operated for the next 20 years
Interpreting the results financially Deterioration Mechanism (s) Over required lifetime
Not significant
Major
Minor
No routine maintenance – “operate to failure” £
Routine maintenance £
Minor repair
Significant
Replacement
repair ££
£££
££££
Typical study output. Spend map is predicted Estimated Investment per Year (overall) Total
Asset life extension – part of an integrated study Asset Life Studies
Criticality and Management of Risk
Process Hazard Review Training, Coaching and People Development
SIL
Total Plant Reliability
RBI+ and RCM
Effective Turnaround Management
Specialist Technical Consultancy
Rotating & Machines Electrical Control Instrumentation Civil & Structural Vessels Piping Fired Equipment Materials Process
Example of top down asset life assessments Heat Exchanger
Process Pump
Original Design Standards
Normal Design Life
40 years plus
30 to 40 years
Best Practice
Maintenance Practices Inspection Methods & History
Operating Practices
Impact of Deterioration Mechanisms
Service & process Corrosion fretting
Corrosion or Erosion
Assessed Asset Life
20 years or less
10 years or less
Environmental Conditions
Asset life extension
Effective & efficient application:
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Criticality or vulnerability study Identified investment required Actions necessary to maintain integrity Achieving Safety Standards Sustain or achieve operating performance Meet future production requirements
In the short term (typically up to 5 years) In the longer term (typically 10 to 20 years)
