RIMAP - European Approach

7/17/2019 RIMAP - European Approach

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RIMAP (RISK BASED INSPECTION AND

MAINENANCE FOR EUROPEAN INDUSTRIES)

THE EUROPEAN APPROACH

Sture Angelsen (DNV) – Mikael Johansson (DNV) – Alasdair Pollock (Corus) – Gjermund Våge (DNV)

Key words: risk, maintenance, inspection

ABSTRACT

This paper presents an overview of the European project RIMAP (Risk Based Inspection andMAintenance Procedures for European industries). The paper also provides a short review ofthe results from the demonstration case in the steel industry.

INTRODUCTIONCurrent practice to inspection and maintenance planning is for most industries based

on tradition and prescriptive rules, rather than being an optimized process where riskmeasures for safety and economy are integrated. New technology for taking risk baseddecisions is emerging in a broad range of sectors, and they have proven to be a very efficienttool (Fig. 1). There is, however, a great need to define the technical content, links to locallegislation and to integrate this approach with the day-to-day operation of the plants.

Profitability

Detailed requirements:

• owner own and• authorities requirements

Excellence:

plant lifetime

Past regime Current Future

Previous practice

Short term goals

Long term goal

Integration

of tools &

best practice

Best practices and analysis tools:

• risk based inspection (RBI)

• reliability centred maintenance (RCM)

• life cycle cost

Fig. 1 RIMAP objective to develop a unified approach to risk based decisions withininspection and maintenance.

This is the background for the RIMAP project, where a consortium of 16 Europeancompanies representing a broad industry base have joined forces to develop a Europeanbest practice and to demonstrate its applicability in several case studies. The projectaddresses the petrochemical, chemical, steel works and the power industry in particular, but

the techniques can easily be extended and used in other industry sectors as well.



The objective of the project is to define a unified approach to making risk baseddecisions, within the field of inspection and maintenance (Fig.2). Risk is here understood asthe combined effect of the probability of failure and the consequence of failure (to personnelsafety, quality of product, environmental damage, and economic loss).

Current Status:

• Prescriptive rules

• No accepted standard

• Old plants

• Cost constrain for investment

Wanted situation:• Cost optimised plants

• Safe and reliable operations

• Extended lifetime of old plants

• Enhanced competitiveness

• Uniform legislation in Europe

Means:

• Structured risk based decisions process

• Use of modern risk analysis tools

• Standardisation of methods for RBMI

• Development of best practice

• Experience transfer between industry sectors

• Damage model development

Fig. 2 RIMAP objective to develop a unified approach to risk based decisions withininspection and maintenance.

The RIMAP project has• developed a unified approach to risk based inspection and maintenance planning• set requirements to the contents of an analysis, personnel qualifications, and tools• form the basis for future standardization in this area.

The EU has recently introduced the pressure equipment directive (PED), which is astandard for design and construction of pressure equipment. The EU has no similar standardfor the in-service phase. The RIMAP project will develop the technological basis for astandard for risk based maintenance and inspection planning (RBMI).



RIMAP (RISK BASED INSPECTION AND MAINTENANCE PROCEDURESFOR EUROPEAN INDUSTY)

Project OverviewRisk Based Inspection and Maintenance Procedures for European Industry (RIMAP)

is a European project that shall develop a unified approach for making risk based decisionswithin inspection and maintenance. The focused industries are:• Power,• Petrochemical,• Chemical and• Steel.

The project is divided into three sub-projects:• RTD (Research and Technology Development)• DEMO (Demonstration for each industry sector)• TN (Thematic Network)

The RIMAP RTD/DEMO/TN projects started in 2001. The RTD/ DEMO projects will becompleted in 2004, while the RIMAP TN will be completed in 2005.

Point of

departure

RIMAP WP-relations

WP2:

Generic

Method

WP3: Risk

Assessment

Methods

WP4:

RIMAP

Application

Workbooks

WP5:

Validation and

comparison R T D

D e m o

T N

•State of practice

from inv. industries

•User requirements

Workshop on

utilisation of methods

Discuss revised

methods

Exchange of experience,

Recommendations

Standardisation

Demo:

chemical,

power,

steel,...

Update on RBMI

Time

WP1:

Current

Practice

Fig. 3 Relationship between the RIMAP RTD WPs, the RIMAP Demo and the interactionwith the RIMAP Thematic Network.

The RIMAP RTD project is divided in 5 main technical work packages (WP), see Fig. 3.The WP's are structured with a clearly defined interrelation in order to achieve an efficientexecution of the project.

• WP1: Current practice within the involved industries.• WP2: Development of a generic RBMI method, based on a multi-criteria decision

process.• WP3: Development of detailed risk assessment methods, damage models for

participating industry sectors, the use of inspection data.• WP4: Development of RIMAP application workbooks for each industry sector:

guidelines for development of Risk Based Inspection and Maintenance plans.• WP5: Validation of the RIMAP methodology.



The RIMAP DEMO project consists of 4 demonstration cases, one for each industry

sector, to prove the applicability of the methodology. The RMAP TN project accompanies theentire development by disseminating the information and results of the RTD and DEMO partto a wider community of companies to review what has been developed and to get an overallacceptance.

Exec. Summary & Introduction to RIMAP

RIMAP Procedure

RIMAP Validation / Benchmarking

Overview Document (D3.1)

Damage

MechanismsHuman

factorsPoF CoF

Power Petrochemical Steel Chemical

D4.x

D3.1 and I3.x as Appendices to D3.1

D2.2

D2.1

WP5

RIMAP Documentation Level - III

RIMAP Documentation Level - II

RIMAP Documentation Level - I

RIMAP Tools

RIMAP Application

Workbooks

RIMAP Framework

NDT

Efficiency

Fig. 4 RIMAP document hierarchy

The main deliverables from the RIMAP RTD project will be (compare Fig. 4):• A method describing a unified approach to maintenance and inspection planning

based on risk decision criteria and cost optimization.• Guidelines for practical use, in the format of one "Workbook" for each industry sector.• Spread knowledge between industry sectors.

The project is currently completing WP4 and WP5 in addition to having started the industryspecific demonstration projects.

RIMAP Work Process To implement and manage a system for risk based inspection and maintenance

management sets requirements to a plant’s (maintenance) management system. Fig. 5illustrates the work processes involved in developing a risk based maintenance and

inspection plan as well as implementing and managing this plan at a plant or facility.RIMAP defines the working processes and provides requirements to the personnel

that shall execute the working processes. Implementation of RIMAP also requires an activemanagement that focuses on the following issues:

• Management of change• Operating procedures• Safe work practices• Pre-start-up reviews• Emergency response and controls• Investigation of incidents• Training

• Quality assurance



Resources Management of work processes Results

Define goals &

requirements

EstablishInsp . & Maint.

Programme

PlanTasks &

Activities

ExecuteWork

orders

Perform Corrective Actions

PrepareImprovement

Tasks

EvaluateTechnicalcondition

Repor tFailures& Status

Activemanage-ment

Organisation

Materials

Support

Costs

SHE level

Reliability Resourceneeds

Technicalcondition

Fig. 5: RIMAP Work process

Risk based inspection and maintenance planning is a multidisciplinary task. Itrequires a team, where all necessary competencies are represented and expertise are

available. Another important issue is the regular evaluation to assess the performance of themaintenance and inspection activities based on the new data that becomes available fromthese activities. The steps in the process above are the same for all involved industry sectors(petrochemical, power, steel, chemical).

The RIMAP description of Risk, PoF, CoFThe RIMAP project provides guidelines on how to perform risk based inspection and

maintenance planning for all types of equipment: active components, static components, aswell as instrument protective functions (IPF).

Fig. 6 illustrates how different methods of analysis are applied to each type ofequipment.

Equipment

databaseScreening

Risk Level High Risk

Low Risk

Containment RBI

Protective

Function

SIL-

assessment

RCM Run to Failure

evaluation

Y

Y

N

N

Experience

SIL: Safety Integrity Level

RBM

Fig. 6 Structure of analysis

The steps required to perform maintenance and inspection planning are similar foreach type of equipment:

Plant hierarchy: The plant hierarchy is a prerequisite for an efficient risk assessment andmaintenance and inspection planning, since the plant is divided into manageable sections.



Failure mode: Assigning functions and sub-functions to the physical items at the plantsimplifies the identification of failure modes. The failure modes are then used to identifyfailure causes, root causes, and damage mechanisms.

Scenario development: RIMAP uses risk, the combination of probability and consequenceof failure, to prioritize inspection and maintenance activities. The assessment of theprobability and consequence of failure are combined in the bow-tie model, see Fig. 7. Ascenario is damage mechanisms leading to a potential event with a consequence (safety,health, environment, or business).

PoF

CoF

Event

Failure or main event (e.g. – “adverse event”, problem, issue, functional problem, operationaldisturbance or similar) the probability andconsequences of which are analyzed in order to

define risk related to it.

Cause tree:PoF analysiscovering e.g.failure modes,

causes etc.

Consequence treeCoF analysis e.g. by

means of an event tree

Fig. 7 The “Bow-tie-model”

RIMAP distinguishes between two types of scenarios:• Worst case scenario: Combine a given root cause/damage mechanism with the

most serious/severe consequence that the given root cause/damage mechanism maylead to, e.g. loss of all fluid within the segmentation area, ignition, etc.

• Expected scenario: Combine the root cause/damage mechanism with the expectedor typical consequence that the given root cause/damage mechanism will lead to.

RIMAP recommends the use of the expected scenario in analyses. It is essential that thechoice of approach is made before the analysis starts and that the same method is usedconsistently throughout the analysis. If not, this will affect the choice of risks that will bemitigated. This may lead again lead to a sub-optimal maintenance and inspection plan.

Probability of failure (PoF): A number of methods for determining the probability of failureare discussed (expert judgement, rate models, statistical, physical models, etc.) The industryspecific workbooks contain industry specific models.

The PoF assessment enters into the analysis in different ways for the staticequipment, instrument protective functions and active components:

• Static equipment: For trendable degradation mechanisms, the acceptable risk iscombined with the consequence of failure to determine a PoF limit. The PoF limit iscombined with the damage rate to obtain a maximum time to inspection.

• Instrument protective functions: For instrument protective functions the riskassessment is used to determine a requirement on availability. This limit is then usedto determine maintenance strategies that meet the requirements.

• Active components: The PoF assessment, given a certain maintenance program, is

combined with the CoF assessment to obtain a risk for the given maintenanceprogram.



For all types of equipment more frequent inspection or maintenance (than currently used orlegally required) may be proposed if this is cost effective.

Consequence of failure (CoF): A set of requirements to CoF assessments have beenformulated. Complying with the requirements implies that the RIMAP procedure has beenfollowed. Methods have been provided for assessing

• Safety – instant consequences on humans within or outside the plant’s area.• Health consequences – long term effects on humans within or outside the plant’s

area.• Environmental consequences and business consequences of failure.• Financial consequence of failure.

The consequence assessment applies to all equipment types (rotating, static, instrumentprotective functions) and to all industry sectors represented in the project. The methods areeasily extended to other industry sectors.

Risk assessment: Risk is the combinations of the probability of failure and consequence offailure. The level of risk is compared to the company acceptance criteria regarding safety and

environmental risk. For financial and cost consequences, a cost-benefit assessment isproposed. The cost related to the mitigation cost, the benefit is the reduced risk related to themitigation.

Mitigating activities and risk reduction: Based on the risk assessment (safety, health,environment, business) mitigating activities are proposed for the high-risk items as illustratedin the figure below. Mitigation activities can be maintenance/inspection, redesign, operationalconstrains depending on the actual case. Fig. 8 provides a decision tree for identifyingmitigating activities.

Can failure cause be identified andis elimination clearly cost effective?

Can failure cause be identified andis elimination clearly cost effective?

Establish maintenance strategyEstablish maintenance strategy

Implement• P rocedures• Modif icat ion• Operating condit ions

Implement• P rocedures• Modif icat ion• Operating conditions

Maintenance strategy impliesa low risk for personnel andintroduction of new failures.

Maintenance strategy impliesa low risk for personnel andintroduction of new failures.

Substitution of maintenancestrategy possible?

Substitution of maintenancestrategy possible?

RedesignRedesign

NO

YES

YES

Apply Apply

YES NO

NO

Fig. 8 Method for identifying mitigating activities

RIMAP STEEL DEMO APPLICATIONThe RIMAP steel application workbook was tested on the vacuum degassing (VDG)

subsystem at the BOS plant, at the Corus Scunthorpe (UK) site. The objective of the VDGunit is to purify the liquid steel and clean out gas emissions in the molten steel. The VDG unitwas chosen based on foreseen increased utilisation and that the unit represents a cross-section of the equipment types within a steel plant. A sketch of the VDG unit is shown in Fig9.

The overall aim for Corus was to test out the methodology presented in the RIMAP

program and to establish a maintenance program for the VDG unit that optimise operationsin a future increased demand for the VDG unit. Corus carried out this work in close



cooperation with Det Norske Veritas, service area asset risk management of DNVConsulting.

The RIMAP steel demonstration project has shown that an RBIM (risk basedinspection and maintenance) analysis and a risk based approach to maintenance andinspection planning may improve Corus’ performance in a number of areas.

Fig. 9 The vacuum degasser unit (Courtesy of the Corus group)

The analysis shows that the annual cost of preventive maintenance and inspectioncould be reduced by 20% per year. This can be achieved without compromising regularityand at the same time increasing the safety level of the unit. The result of the RBIM study washence a major change in workload for a relatively small unit. The potential reduction onlyaccounts for the direct savings related to preventive maintenance labour costs. The new

maintenance program will also result in increase uptime in the VDG unit (due to a reductionof PM activities that require stops) as well as a reduction in use of spare parts. In additionthere is potential for additional savings after implementation, by means of continuousevaluation of effectiveness of maintenance and inspection activities.

The RIMAP approach provides a documented basis for decisions concerning theinspection and maintenance regime. The need for this is increasing as the demands fortraceability and history increases.

The RIMAP approach helps to document the knowledge of the personnel in themaintenance system. This reduces dependability of “experienced” personnel and facilitatessharing of knowledge between sections and sites.

By adopting a risk based regime the overall cost and SHE standard are optimised asthe resources are focused to the most important areas. Assigning risk to each plant item and

assigning mitigating actions based on the risk assessment, results in risk reduction. Thesuggested risk based methodologies are a means for satisfying the requirements from thegovernment, documenting decisions and processes and follow up of history.

The RIMAP steel demonstration project has shown that the RBIM methodology iseasy to adapt. During the analysis the team successively recognised the risk based mindsetand at the end they fully adopted the concept. The participants expressed excitement andsatisfaction, and the work was characterised as an eye-opening experience.

The work generated new ideas and revealed areas that needed focus. Somecomments made by Corus during the analysis is presented below:

“RIMAP challenges new ideas (what if? etc.) and encourages thought processes in astructured manner”

“Offers new tools in decision making - but with experienced input captured”



“The project gives management confidence that this work force has gone through astructured, documented thought process”

“An idea was to combine some (if suitable) electrical and mechanical inspections onthe same kit to the same times to avoid any extra plant downtime”

“In some cases it was decided that it would be beneficial to split some plant areasdown further on the CMMS so we can see where the money is being spent”

CONCLUSIONEuropean practices for risk based decision making are under development to create a

guideline and applicable tools for practical use. The current project RIMAP, involving morethan 40 companies promise to deliver a desired level of a consolidated European risk basedpractice.

The application of the RIMAP approach in the steel industry was very successful. Thecost of inspection and maintenance can be reduced and process proved successful inchanging the mindset of the participants and in implementing a risk based approach towardsinspection and maintenance.

Detailed information can be gathered on the project’s websites, (see References).

NOMENCLATURECoF Consequence of failureD DeliverableEU European Union

ISI In-service inspectionNDT Non-destructive testingPED European Pressure Equipment Directive 97/23PoF Probability of failureRIMAP Risk Based Inspection and MAintenance Procedures for European industryWP Work package

ACKNOWLEDGEMENTRisk Based Inspection and Maintenance Procedures for European Industry (RIMAP)

is a project partly financed by the European Commission for the "Growth Programme,Research Project RIMAP Risk Based Inspection and Maintenance Procedures for EuropeanIndustry"; Contract Number G1RD-CT-2001-03008. The authors would like to acknowledgethe financial support by the European Commission.

The following companies participate in the RIMAP project:Det Norske Veritas AS (DNV) ExxonMobil Chemical Ltd. (Exxon)

Bureau Veritas (BV) Energie Baden-Württemberg AG (EnBW)Staatliche Materialprüfungsanstalt(MPA)

Siemens AG (Siemens)

VTT Industrial Systems (VTT)Joint Research Centre of the EuropeanCommission (JRC)

TÜV Industrie Service, TÜV SÜD Group Electricity Supply Board (ESB)

TNO Industrial Technology (TNO) Corus Ltd.



Hydro Agri Sluiskil B.V. (Norsk Hydro) The Dow Chemical Company N.V. (DOW)

Mitsui Babcock Energy Ltd. (MBEL) Solvay S.A.

REFERENCESRIMAP RTD or RIMAP Demo project: http://research.dnv.com/rimap RIMAP TN: http://www.mpa-lifetech.de/rimap

Sture Angelsen, Mikael Johansson, Gjermund VågeDet Norske VeritasN-1322 Høvik, [email protected]

Alasdair Pollock

Corus Northern Engineering ServicesSteel HouseRedcarTeeside TS10 5QW [email protected]

http://research.dnv.com/rimap

http://www.mpa-lifetech.de/rimap

http://www.mpa-lifetech.de/rimap

http://research.dnv.com/rimap

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RIMAP - European Approach