ORBIT Offshore User Manual

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DNV SOFTWARE PRODUCTS AND DEVELOPMENT

User Manual

ORBIT Offshore V2.2

Issue Log

Revision No

Issue Date Prepared by Reviewed by Approvedby

Comments

01 27-July-2000 P. Mathieson J. Edwards S. Angelsen ORBIT Offshore 2.0, First Issue02 29 July 2001 G. Korneliussen P. Topalis P. Topalis ORBIT Offshore 2.1, Revision03 28 August 2002 P Mathieson P. Topalis, G.

Korneliussen & F.Saint Victor

P. Topalis ORBIT Offshore 2.2, Revision

Revision No: 03

User Manual Page 2 of 7728 Aug. 02 ORBIT Offshore V2.2 Revision 03

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Table of Contents1. INTRODUCTION..............................................................................................................................................6

1.1 INTRODUCTION TO ORBIT OFFSHORE USERS GUIDE ......................................................................................61.2 INTRODUCTION TO ORBIT OFFSHORE ............................................................................................................6

2. INSTALLATION AND LICENSING................................................................................................................8

3. WORKING WITH ORBIT OFFSHORE ..........................................................................................................9

3.1 INTRODUCTION..............................................................................................................................................93.2 DATA INTEGRITY...........................................................................................................................................93.3 DOCUMENTATION..........................................................................................................................................93.4 WORKING PROCESS OVERVIEW.....................................................................................................................103.5 QRA: EXISTING DOCUMENT OR TO BE CALCULATED BY ORBIT ...................................................................103.6 POF MODELLING .........................................................................................................................................103.7 MENUS AND TOOLBARS ...............................................................................................................................11

4. LOGGING ON, CREATING AND MANAGING PROJECT FILES ............................................................12

4.1 LOGGING ON ...............................................................................................................................................124.2 PROJECT FILE MANAGEMENT.......................................................................................................................12

4.2.1 Opening an existing file.......................................................................................................................124.2.2 Selecting a new project file name.........................................................................................................13

4.3 MASTER DATABASE ....................................................................................................................................13

5. EXECUTE THE PROJECT ............................................................................................................................14

5.1 WORKING PROCESS .....................................................................................................................................145.2 SCREENING .................................................................................................................................................15

5.2.1 Create a new Record Sheet..................................................................................................................155.2.2 Screening - Information.......................................................................................................................165.2.3 Screening Probability of failure evaluation .......................................................................................165.2.4 Screening Consequence of failure evaluation ....................................................................................165.2.5 Screening Risk Evaluation ................................................................................................................165.2.6 Screening Reporting .........................................................................................................................16

5.3 DETAILED ANALYSIS....................................................................................................................................175.3.1 The Parts table....................................................................................................................................175.3.2 Data requirement for models ...............................................................................................................195.3.3 Degradation mechanisms ....................................................................................................................215.3.4 Objects table .......................................................................................................................................235.3.5 Area table ...........................................................................................................................................245.3.6 Segments table ....................................................................................................................................25

5.4 RUNNING THE ANALYSIS ..............................................................................................................................275.4.1 Probability of failure for parts.............................................................................................................275.4.2 Consequence of failure for Parts .........................................................................................................275.4.3 Risk calculation for Parts ....................................................................................................................275.4.4 Time to Risk Limit ...............................................................................................................................275.4.5 Inspection Plans..................................................................................................................................275.4.6 Calculate All .......................................................................................................................................285.4.7 Consequence of failure analysis...........................................................................................................285.4.8 Consequence Analysis using External QRA..........................................................................................295.4.9 Individual Part analysis.......................................................................................................................305.4.10 Individual Object Analysis...................................................................................................................31

6. REPORTING ...................................................................................................................................................32

7. DATABASE MANAGEMENT, TOOLS & VIEWS .......................................................................................34

7.1 DATABASE MANAGEMENT...........................................................................................................................347.1.1 ORBIT Project ....................................................................................................................................347.1.2 Multiple Users Entries.........................................................................................................................34


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7.1.3 Backing Up The Data ..........................................................................................................................347.1.4 Saving Data During A Work Session....................................................................................................347.1.5 Buffered Mode ....................................................................................................................................347.1.6 A Warning: Do Not Tamper With The Database File. ..........................................................................357.1.7 Master database..................................................................................................................................35

7.2 DATA LOADING AND DATA ENTRY ..............................................................................................................357.2.1 Data available electronically...............................................................................................................357.2.2 Data available in paper form...............................................................................................................36

7.3 TOOLS.........................................................................................................................................................367.3.1 Info .....................................................................................................................................................367.3.2 Details ................................................................................................................................................377.3.3 Set manual rates and PoF....................................................................................................................377.3.4 Screening data exchange .....................................................................................................................377.3.5 Update from Group Data ....................................................................................................................377.3.6 Source Materials.................................................................................................................................387.3.7 Source Product Service .......................................................................................................................387.3.8 Risk analysis for Segments...................................................................................................................387.3.9 Allocate and Calculate All...................................................................................................................387.3.10 Repairing and Compacting the Database.............................................................................................397.3.11 Options ...............................................................................................................................................39

7.4 VIEWS AND FILTERS ....................................................................................................................................397.4.1 View Fields .........................................................................................................................................397.4.2 Filter ..................................................................................................................................................407.4.3 Search and Replace.............................................................................................................................407.4.4 Edit Copy, Paste...............................................................................................................................417.4.5 Sort.....................................................................................................................................................41

8. CONFIGURATION .........................................................................................................................................42

8.1 INTRODUCTION............................................................................................................................................428.2 WHY CONFIGURATION?................................................................................................................................428.3 DESCRIPTION OF BACKGROUND TABLES....................................................................................................42

8.3.1 Fixed values for tables.........................................................................................................................428.3.2 Installation..........................................................................................................................................43

8.4 PROBABILITY OF FAILURE TABLES................................................................................................................448.4.1 Insulation Types ..................................................................................................................................448.4.2 Coating Types .....................................................................................................................................458.4.3 Pipe classes (Optional)........................................................................................................................478.4.4 Functions (Optional) ...........................................................................................................................488.4.5 Product Service Codes ........................................................................................................................498.4.6 Materials ............................................................................................................................................518.4.7 Systems ...............................................................................................................................................528.4.8 Corrosion groups ................................................................................................................................53

8.5 CONSEQUENCE OF FAILURE TABLES..............................................................................................................548.5.1 Repair categories ................................................................................................................................548.5.2 Repair category properties ..................................................................................................................558.5.3 Production loss profiles.......................................................................................................................568.5.4 Production loss profile properties........................................................................................................578.5.5 Leak sizes............................................................................................................................................598.5.6 Extents ................................................................................................................................................608.5.7 Segment extents...................................................................................................................................618.5.8 Segment Leak Sizes .............................................................................................................................628.5.9 Segment Leak Size Extents...................................................................................................................63

8.6 INSPECTION PLANNING ................................................................................................................................648.6.1 Inspection tasks...................................................................................................................................648.6.2 Inspection Effectiveness.......................................................................................................................658.6.3 PoD Curves ........................................................................................................................................66

8.7 MATRIX DEFINITION....................................................................................................................................678.7.1 Risk Matrix Design..............................................................................................................................678.7.2 Probability categories .........................................................................................................................688.7.3 Consequence categories ......................................................................................................................69


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8.7.4 Risk categories....................................................................................................................................708.7.5 Risk Matrix definition..........................................................................................................................71

8.8 OTHER DEFINITIONS ....................................................................................................................................728.8.1 Hole sizes............................................................................................................................................728.8.2 Status definitions (Optional) ................................................................................................................73

8.9 PROTECTED DATA .......................................................................................................................................748.9.1 DNV Materials....................................................................................................................................748.9.2 DNV Product Services.........................................................................................................................748.9.3 Object Types .......................................................................................................................................748.9.4 Degradation........................................................................................................................................748.9.5 Probability..........................................................................................................................................758.9.6 Configure Report ................................................................................................................................75

9. TROUBLESHOOTING ...................................................................................................................................76

9.1 PROBABILITY OF FAILURE = 1.00..................................................................................................................769.2 CURSOR REMAINS AS HOURGLASS................................................................................................................76

10. REFERENCES .............................................................................................................................................77


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1. INTRODUCTION

1.1 Introduction to ORBIT Offshore Users Guide

This document describes how to use the DNV software package ORBIT Offshore for creation andmodification of risk-based inspection plans for offshore topsides pressure systems. It is assumedthat the operator is familiar with MS Windows operation and terminology, and so this is notcovered in this document.

The Users Guide provides an introduction to the database tables, identifying the informationrequired to be inserted. It does not help with the sourcing of that information; for that, the WorkingProcedures document should be consulted. In addition, there is a comprehensive Help available aspart of the software, and the training documentation can also be consulted for theory.

The philosophy used in developing ORBIT Offshore was that the software should automate thecalculation of risk and the inspection plan without replacing engineering judgement. It is thereforeessential that competent personnel evaluate the data required for the program, and consider theresults carefully in the light of the inputs and their experience. At all times, care should be taken toavoid the automatic belief that the computer is always right, as the results are only as good as theinput data, and the assumptions made in generating that data.

Additionally, it is recognised that all the required data is not available in the necessary precision atthe time of carrying out RBI; it may be expensive to search for the data, or visit the platform tomeasure it, especially if the result is a low risk when the RBI is complete. To try to avoid this,ORBIT Offshore is designed with a multi-stage data fallback, such that where the required data ismissing, wherever possible a more conservative assumption is automatically made for example,use the design pressure values if the operating values are not given.

The sequence of menu selections used to access tables and functions are described in this manualthus: DataTechnicalInsulation Types. This shows the sequence of menu choices to beselected.

1.2 Introduction to ORBIT Offshore

DNV have developed RBI methods and sophisticated software for carrying out RBI for the entireoffshore installation jackets, FPSOs, process and utility systems, pipelines and risers, leading to arisk-based, cost-optimised inspection plan. The ORBIT Offshore package deals specifically withinspection planning for offshore topsides pressure systems.

Software tool for Inspection Planning

DNVs ORBIT Offshore software helps you carry out risk calculations, and outputs a detailedinspection plan. Inspection techniques are selected based on their cost-effectiveness, defined as thegreatest risk reduction per cost of inspection. Manual adjustment of the plan, to account forscheduling of inspection to fit other platform activities can be made, and the effects on riskrecalculated. This allows the user to stay in control


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Limit the Risk, Limit the Cost

ORBIT Offshore directly addresses the Client-specified acceptance limits for safety and EconomicRisk, and using the user-selected inspection methods calculates the cheapest inspection plan thatwill keep the risk below these acceptance levels

Ease of implementation

ORBIT Offshore can read from most inspection management databases, and output the finalinspection plan back to the database, thereby minimising data handling.

ORBIT Offshore is easy to use, with form or spreadsheet views for data handling, graphical andnumerical outputs for results, and can carry out sensitivity and what-if studies. Reports can becreated with a management or a technical focus.

Installation-specific results

For installations where a service history is available, ORBIT Offshore can use the inspectionresults already taken to adjust the risk levels according to actual findings, and revise the inspectionplan accordingly.

ORBIT Offshore can account for changes in the price of oil & gas, so that the inspectionschedule can be changed to reflect the change in economic risk as these prices fluctuate.

ORBIT Offshore will account for the installation process design and layout, as well asmaintenance and repair strategies when calculating the potential cost of lost production anddowntime

ORBIT Offshore allows detailed sensitivity and what-if calculations to be made to test theeffects of remedial actions before they are implemented

Results of inspection optimisation

ORBIT Offshore reports the following to allow focus where risk lies as well as detailed inspectionplanning and scheduling.

Risk distribution by module, degradation mechanism, equipment type, corrosion group, processor utility system, ESD segment

Effects of inspection on risk within the inspection planning period, shown as matrices Contribution of safety and economic risk to the total risk Detailed summary of results by system Inspection frame program, giving what to inspect and when for each inspection groupDeterministic results can also be given, such as remaining life.


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2. INSTALLATION AND LICENSING

An installation CD is supplied which contains the following:

The ORBIT Offshore installation files RMS License utility 1.3.3 or later ORBIT Offshore documentation Word reader (for viewing the Release Note if the computer does not have Word installed) Adobe Acrobat Reader (for viewing the Users Manual)The first step is to install ORBIT by running Setup.exe in the ORBITOffshore directory. Thesecond step is to install the RMS license utility (if it has not already been installed). This may beselected automatically at the end of the ORBIT installation or separately after ORBIT by runningSetup.exe in the DNV RMS License Utility directory. Finally you will need to run the License Utilityand enter a trigger code obtainable from DNV Software either in London (+44 20 77166545) or inHouston (+1 281 721 6802) or in Kuala Lumpur (+603 2050 2973)

Follow these instructions to install ORBIT Offshore:

1. Load the CD into the drive.2. Choose the directory you want ORBIT Offshore installed in. If this directory does not exist, the

install shield program will create it. After installation, ORBIT Offshore can be run from theStartProgramsORBIT Offshore menu or by creating a shortcut on your desktop toORBITOffshore.exe in the ORBIT Offshore installation folder.Also installed with ORBIT Offshore is the DNV Licensing utility. This requires the owner ofthe software to register with DNV, to prevent unauthorised copying and distribution of ORBITOffshore. Before attempting to run ORBIT Offshore for the first time, you will need to followthe instructions below. The licence utility interrogates the PC to generate a unique encryptedcode based on the system time, date and BIOS and which will be different each time you run theutility. This is then used by DNV to unlock the software, and so it is essential that the sequencebelow is run without cancelling.

3. Follow the menu sequence StartProgramsRisk Management Licence Utility LicenceUtility (Local)

4. The utility will ask which software you want a licence for; select the radio button for ORBITOffshore.

5. With Software security selected, click on Add New Licence button. This will give you aCode Entry Number and Computer ID number. These should be given to your nearest DNVRisk Management Software office (London or Houston) by telephoning the appropriate numberabove. They will respond with a number that should be entered in the space marked EnterCode. Save and exit. Do not quit the telephone call.

6. Run ORBIT Offshore to test the licence utility before quitting the telephone call.The licence is valid for the period given in the contract with DNV. Upon expiry, the sequence 3through 6 above should be followed to obtain the new licence.

On successful completion of the licensing routine, ORBIT Offshore can be started from the Startmenu, from the ORBITOffshore.exe icon in the Explorer, or from a shortcut button placed onthe Desktop. Once started, the Status bar at the bottom of the screen will show the status oflicensing.


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3. WORKING WITH ORBIT OFFSHORE

3.1 Introduction

This chapter gives an overview of the working process to generate a risk-based inspection planusing ORBIT Offshore. Details of the process can be adjusted to follow specific projectcircumstances, but the design of the database and its reference tables requires that these tables arefilled out in a certain sequence, otherwise a considerable time will be spent in switching from tableto table, resulting in ineffective working.

The working process for ORBIT comprises the accessing of data, configuring the database byfilling-out the reference tables, then the completion of the main data table, the Parts table. This isfollowed by calculation of probability of failure, consequence of failure, risk and the inspectionplan, with reporting of the results to finish the project.

There is a data import utility to allow import of bulk data from inspection management databasesand other similar sources, to allow easy data exchanges and avoid the need to duplicate the work.The use of this utility requires that the data in the other database is checked for quality; as poor dataquality will lead to an unnecessarily complex RBI evaluation.

3.2 Data Integrity

It is important to be aware that the calculation routines in ORBIT Offshore are complex, and towork they require that data is entered in the correct format (numeric or text). Experience has shownthat databases used purely for recording data, as opposed for calculation, can have several means ofrecording the same value, and these depend on the person interpreting the data for example,atmospheric pressure has been recorded as 0 (zero), 1 (one), Atmos, Atmos., Amb., atm, all ofwhich can be interpreted by the operator as atmospheric, but the computer sees six differentvalues, two of which are numeric and four of which are text. If it expects a number, the four textversions are then in error and the analysis stops.

It is therefore essential that the data used in RBI is correct and consistent, and uses the correctformat for the database. Although the checking of the source data can be time consuming, theefforts add value to the data, as incorrect or incomprehensible results from inspection implies thatthe inspection effort is wasted and might even be dangerous in that they give a false sense ofsecurity.

3.3 Documentation

The following documents have been created by DNV to guide and instruct users in the execution ofRBI Offshore projects using ORBIT Offshore software:

1. Training Course manual Offshore Topsides Systems Risk Based Inspection. This documentcontains training materials giving information on the purpose of RBI, an overview of topsidesprocess and utilities, theory of materials degradation and probability of failure calculation,consequence of failure calculation, risk analysis and inspection planning, with the emphasis onthe use of ORBIT Offshore software.

2. RBI Upstream Working Procedures and Guidance. This gives detailed instruction and guidanceon the working process where data is extracted from source documents, evaluated and enteredinto ORBIT Offshore. Assistance is given on the derivation of assumed values where noprecise information is available.


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3.4 Working process overview

The working process using ORBIT Offshore is described in detail elsewhere/1/, but consists of thefollowing basic steps:

1. Agree risk acceptance criteria with the Client2. Establish the ORBIT Offshore database and begin to configure it3. Collect information and carry out screening4. Collect information and carry out detailed probability of failure and consequence of failure

analysis5. Calculate risk and review6. Calculate the inspection plan, review and adjust manually7. Report the analysis findings and the inspection plans and frame programThe description of the use of ORBIT Offshore will follow the above sequence.

3.5 QRA: Existing Document or to be calculated by ORBIT

ORBIT Offshore allows the use of an existing QRA to calculate the consequences of an ignitedrelease, or if this is not available, can calculate using its own built-in RBI-QRA. If the existingQRA is available, its use is advantageous as it avoids duplication of work already carried out andtime taken in searching for information, as well as using the same basis for the consequenceanalyses. Using the built-in RBI-QRA allows the inspection department to have its own QRAmodel that allows updates to be made quickly based on, for example, changes in manning due tomodifications or work-over, or changes in the value of production. Such changes can affect the risklevels and therefore the inspection timings, but would not normally be recalculated as an update tothe existing QRA.

Section 5.4.7 describes in detail how either option should be carried out.

3.6 PoF modelling

In modelling the probability of failure, the parts evaluated are assumed to be exposed to a marineatmosphere moist, salty air, with potential for soaking by the operation of the sprinkler and delugesystems. Therefore, external degradation is allocated based on a materials marine atmospherecombination only. For this release of ORBIT Offshore, care must therefore be taken whenassessing parts not exposed to marine atmosphere, such as heat exchanger tubing.

Internal degradation mechanisms can be selected manually through the Product Service table, wherethe DNV suggested degradation mechanisms per service code can be switched on or off by manualselection.


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3.7 Menus and Toolbars

ORBIT Offshore, in common with MS Windows applications, uses toolbars and menus situated atthe top of the screen. These are enabled and disabled depending on the windows that are opened.Disabled toolbar buttons are not shown, disabled menu items are greyed out. The function of thetoolbar buttons is shown below.

The function of each button is shown by holding the cursor on the button for a few seconds.

The Working Process window gives guidance on the working process and the filling-out oftables, and the Explorer window allows filtering according to the user selection from Materials,Areas, Systems, Objects, Product Service codes, Corrosion groups, Segments, Objects, Functioncodes, degradation mechanisms, safety risk categories, or economic risk categories.

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4. LOGGING ON, CREATING AND MANAGING PROJECT FILES

4.1 Logging on

Start ORBIT Offshore from you desktop or the taskbar menu system.

When the ORBIT splash screen appears, enter name and password, and then hit the Open button.

4.2 Project File Management

After logging on, the project file dialog box appears and allows you to:

select a project from the list shown, or create a new project.If the project you want to open is not in the list shown, then double-click more files or canceland use the File-Open command from the menu, or the open file button on the toolbar.

When no file is open, many of the menu items in the top bar are deactivated, and all the frames areempty.

4.2.1 Opening an existing file

Select a file from the list of existing files, double click or click Open. Typically, ORBIT will be used for longer periods on the same project: When ORBIT is opened

it will offer the previously used file name as first choice in the list. Note that you can also create, load and delete project files later by using the File menu on the

top left.


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4.2.2 Selecting a new project file name

If you select to create a new file, a new dialog box appears, showing any other orbit files in theORBIT folder. You can move through the explorer to select both a drive and folder where you wantto place the project file. Enter the desired name and click Save.

It is recommended that a project file is created on a suitable path using a name such as theinstallation /platform name.

It is strongly recommended that you avoid having more than one file for each installation, (e.g. donot create one file for vessels and one for piping) as this will create extra work in entering andmaintaining configuration data, as well as the possibility of creating errors in this duplicatedactivity.

4.3 Master Database

For operators who use common materials and coding systems, a master database can be establishedon a server. This database is used as the template for all new projects, and will therefore containmuch common information, so reducing the need for repetitive data entry.

When you wish to establish the master database, select Tools->Options, thereafter specify the pathwhere the project template is to be found. Copy separately the database that is to be the master tothat location. This will then be available to all those logged on to your network and using ORBITOffshore, after they have adjusted their ORBITs to point to that location.

Click here if youwant a newproject.

The file you usedpreviously is in thetop of the list readyto go.

Use File menulater to manageproject files.


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5. EXECUTE THE PROJECT

5.1 Working Process

An overview of the working process is shown below. The details of each stage are given inreference /1/, and the use of the software is described in the following sections.

Create Project(Chapter 4)

Line / equipmentdata available? Yes

Load Data(Chapter 7.2)

No Configure Database(Chapter 8)

Carry out Screening(Chapter 5.2)

Detailed Analysis(Chapter 5.3)

PoFWorking

CoFWorking

InspectionPlanning

Line / Equipment dataalready loaded? Yes

Get and Load Data

(Chapter 7.2)

Configure Database

(Chapter 8)No

Complete Area and Segments table

Couple Areas, Segments, RepairsProduction loss profiles to partsin Parts table

Couple Objects, MaterialsProduct Service codes, Groupsto parts in Parts table

Add CO2, sand, water,flow conditions to partsin Parts table

Allocate and CalculatePoF (Chapter 5.4)

Calculate Risk Analysis for Segments

Calculate CoF (Chapter 5.4)

Calculate time toRisk Limit (Chapter 5.4)

Check for errors /inconsistencies & fix

CalculateInspection Plan(Chapter 5.4)

Report(Chapter 6)



Review & adjust manually(Chapter 5.4.5)

Re-calculate

Identify relevant inspectiontasks and costs (Chapter 5.3)

Select appropriatePoD curves

Evaluate inspection taskeffectiveness againstdegradation mechanism

Complete Repairs andProduction Loss tables


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5.2 Screening

AnalyseScreening

This screen logs the results of the screening process. See reference /1/ for the screening process.The screening form can be opened without any other table being open.

It is preferable that a Screening is performed by assessing each system in turn. In some casessystems may be poorly defined, or identical to Product Service groups. In these cases Screeningmay be carried out by assessing each Product Service group in turn.

The form looks like the screen dump below, and is broken into 4 sections. The button by thesection title allows the section to be opened up or collapsed, to ease the view.

5.2.1 Create a new Record Sheet

To create a new record sheet, use the EditInsert Record menu or the Insert button. This isnecessary before starting work on the first system. The screening group name must be given as thefirst action.

To the right is a navigator bar, and a selection of buttons that are used to create, refresh or delete thescreening lines on the record sheet in view. Create a new line before adding data. This will create aprobability of failure as well as a consequence of failure and risk line; data common to both iscopied from one to the other automatically when the field is exited.


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5.2.2 Screening - Information

The top section concerns information on the system, with description, function, and what othersystems depend on this one for their continued operation.

Select whether the record sheet relates to a system, product code or user-defined screening group.

5.2.3 Screening Probability of failure evaluation

The second section records the probability of failure evaluation.

Select the DNV Product Service Code by pull-down menu as the equivalent to the Clientsproduct service code, which is a text field with no links.

Choose the material category from the pull-down menu. Input temperatures and pressures if known. Evaluate internal, external, fatigue, other probability of failure as either High or Low in relation

to the acceptance level. This is selected by keystroke H or L, or can be toggled using thespace bar.

Mark the degradation models with X by toggling with the space bar as a reminder for thedetailed analysis what mechanisms have been identified.

Add comment as desired to the PoF Comment field, to record the reasoning behind theevaluation.

5.2.4 Screening Consequence of failure evaluation

The third section records the consequence of failure evaluation.

Evaluate Safety, Economic, environment, other consequence of failure as either High or Low in relation to theacceptance level. This is selected by keystroke H or L, or can be toggled using the space bar.

Add comment as desired to the CoF Comment field, to record the reasoning behind the evaluation.

5.2.5 Screening Risk Evaluation

The last section reports the risk, with recommended actions. Colour is used to highlight thefindings. The evaluations appear as the process continues.

5.2.6 Screening Reporting

Screening Evaluation Forms: With the screening evaluation form open, clicking on the PrintPreview icon will show the preview; at the top left of the preview screen there is a Print icon. Useof this will print out all the forms using the default printer. Print settings can be adjusted asrequired.

Screening Results Summary: From the menu bar, select Report->Screening Results Summary.This shows a report sorted by system, product service code and material, of the PoF, CoF and riskevaluations, together with recommended actions. This is printed using the Print icon on the previewscreen.

Screening Results Matrix: From the menu bar, select Report->Screening Risk Matrix. Thisshows a 2 x 2 risk matrix with a table showing how many screening lines fall within each category.This is printed using the Print icon on the preview screen.


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5.3 Detailed analysis

5.3.1 The Parts table

DataParts

This table defines the dimensions, materials, conditions of operation, and consequence calculationparameters for each part. It consists of some 68 fields, but all of these do not require data! Many ofthe fields are used to link to the other tables, allowing assigning of consequences and degradationmechanisms, and so have pull-down menus.

Due to the size of the table, and that most work in the analysis is carried out in this table, there arefacilities to select which fields you want to view from the total, and to filter according to thecontents of one or more fields. Details of this are given in sections 7.4.1, 7.4.2, 7.4.3, and 0.

Details of the working process are contained in reference /1/.

The Parts table view is divided into two. The upper part shows the Part data used in the calculations,the lower part of the view shows the calculation results taken from the degradation mechanismstable.

The data fields are:

Field DescriptionPartID Automatically assigned identification for each line in the table. Not editable.PartName Name of the part. Often tag number for pipe, otherwise the description of the part, such

as Nozzle N3ObjectName Object name. From pull-down menu listing from Objects tableActuDiameterMm Part Outside Diameter in mmActuWallThickMm Part wall thickness in mm. Use the nominal value according to the specification if the

real, measured value is not available.InitialDamageMeanMm Mean value of wall loss used in damage update calculations. NOTE: this is NOT the

remaining wall thickness. May be NULL, otherwise must be given with EITHER CoVor Standard deviation (not both) see next 2 fields.

InitialDamageCoV% Coefficient of Variation for the distribution of wall loss. May equal NULL if meanvalue is NULL, but cannot equal zero.

InitialDamageSDmm Standard deviation of the distribution of wall loss. May equal NULL if mean value isNULL, but cannot equal zero..

InitialDamageYear Year when the wall loss was measured. Give as YYYY only.PipeClass Reference to Pipe Class table. Optional.SourceMaterialName Material name used by the Client for the Part. Free text field, max 50 characters.

Useful for information where the Client uses a different name to the materialsstandard.

MaterialName DNV material name equivalent to the Clients material name. Pull-down menu referringto the material table

CoatingYear Year in which the coating was applied. Give as YYYY only. If blank, uses buildyear in Installation table

CoatingType Type of coating as defined in Coating table. Pull-down menu to select.InsulationYear Year in which insulation was applied. Give as YYYY. If blank, uses build year in

Installation tableInsulationType Type of insulation as defined in Insulation table. Pull-down menu to selectInstallationYear Year when the part was installed. If blank, uses build year in Installation table.


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Field DescriptionDesignLifeYears Information field giving nominal design life of component. May be left blank.Location Location of component (inside module, outside, etc).AreaName Area in which the part is located. Pull-down list refers to table AreaSystemCode System description. Pull-down menu to select from systems table.SegmentName Segment description. Pull-down menu to select from Segments table.QRAsegment Segment as defined in QRAGroupName Corrosion group nameFunctionCode Function description for the part. Optional field. Pull-down menu from Functions tableSourceProdServiceCode Client-defined product service code.ProdServiceCode DNV product service code. Used to allocate degradation mechanisms. Pull-down menu

from product service table.MaxActuTempC Maximum observed temperature in oC. If NULL, ORBIT refers to MaxOperTempC.MinActuTempC Minimum observed temperature in oC.MaxOperTempC Maximum limit to operating temperature in oC If NULL, ORBIT refers to

MaxDesignTempC in Pipe table.MinOperTempC Minimum limit to operating temperature in oCMaxActuPressureBar Maximum observed pressure in bar gauge. If NULL, ORBIT refers to

MaxOperPressureBar, cross-referred by pipe class..MinActuPressureBar Minimum observed pressure in bar gaugeMaxOperPressureBar Maximum limit to operating pressure in bar gauge. If NULL, ORBIT refers to

MaxDesignPressureBar in Pipe table, cross-referred by pipe class.MinOperPressureBar Minimum limit to operating pressure in bar gaugeComment Comment to part analysis aimed at inspection planning. Memo fieldPoFcomment Comment to part analysis from PoF analysis. Memo fieldCoFcomment Comment to part analysis from CoF analysis. Memo fieldReference Text field intended as drawing number where the part can be foundScope Yes / No field.Status Pull-down menu from status definitions tableRepairCategorySmall Repair category used for small leaks. Pull-down menu from repair category tableRepairCategoryMedium Repair category used for medium leaks. Pull-down menu from repair category tableRepairCategoryLarge Repair category used for small large. Pull-down menu from repair category tableRepairCategoryRupture Repair category used for rupture. Pull-down menu from repair category tableProdAffectedName Production affected. Pull-down menu from Installation tableGradeOfRedundancy Redundancy of the part. Field used for information only.ProdLossProfileSmall Production loss profile for small leaks. Pull-down menu from production loss profile

tableProdLossProfileMedium Production loss profile for medium leaks. Pull-down menu from production loss

profile tableProdLossProfileLarge Production loss profile for large leaks. Pull-down menu from production loss profile

tableProdLossProfileRupture Production loss profile for ruptures. Pull-down menu from production loss profile tableCalcReport Text field generated by ORBIT Offshore, reporting the time of, and errors in, the

calculations.CO2H2ScalcPressureBar Pressure to be used in calculation of partial pressure for CO2 corrosion rates.CO2inGasMole% Mole % CO2 contained within the fluids & gases within the part.CO2fugacity Fugacity for C02 calculation. If NULL then calculated by ORBIT OffshoreCO2scaling Yes / No field. Switches on whether CO2 scaling is likely, affecting corrosion rates as

a result.Phactual Measured value of pH. If NULL, ORBIT Offshore estimates pH.


DET NORSKE VERITAS

Field DescriptionCO2condensationRateGm3s Optional field.GlycolWeight% %age glycol flowing through system. Affects CO2 corrosion rate.CO2inhibitor% % effectiveness of CO2 corrosion inhibitor in the system. Value given is mean of a

distribution of effectiveness, with fixed standard deviation.WaterWetting Yes/No field. Does water liquid condense on the part surface?SandErosion Yes/No field. Is sand erosion present?TotalMassFlowKgPerS Total Mass flow within the part, in kg per second. Only required if sand erosion = YesMassFlowSandGramPerS Mass flow of sand, in grams per second. Only required if sand erosion = YesVolumeFractionGas Volume fraction of gas in the product stream. Only required if sand erosion = YesWaterPresent Yes/no field. Is water vapour present in the part, whether or not it condenses?FlowRateMs Flow rate for water in utility water systems. Used in corrosion rate calculations.ChlorideConcWt% Concentration of Chloride ions for utility waters only.

5.3.2 Data requirement for models

As far as is possible, the information needs have been reduced to a minimum, but the user shouldnote that many fields are required for a complete analysis; consider, for example, what informationis needed to calculate CO2 corrosion rates without consideration of RBI, and what is required toestimate the consequences of a leak. The information needs also vary depending on the degradationmechanisms to be assessed there is no need to quote CO2 data where there is no CO2 corrosionmechanism operating, for example. Since data requirement is dependent on degradation mechanismand whether there is safety or economic consequence to a leak, DNV have developed the screeningapproach that can focus the need for data collection and entry so that the minimum effort isrequired.

The following table outlines what data is required in the Parts table for each activity, covering PoFmodelling, CoF modelling and inspection planning and updating, as well as efficient working withthe database. The key at the foot of the table explains the symbols used.

Field

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PartID A A A A A A A A A A A A A APartName R R R R R R R R R R R R R RObjectName P P P P P P P P P P P P P PActuDiameterMm R R R R R R R R R R R R R RActuWallThickMm R R R R R R R R R R R RInitialDamageMeanMm RInitialDamageCoV% RInitialDamageSDmm RInitialDamageYear RPipeClass O O O O O O O O O O O OSourceMaterialName O O O O O O O O O O O OMaterialName R R R R R R R R R R R R


DET NORSKE VERITAS

Field

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CoatingYear P P P P PCoatingType R R R R RInsulationYear P R P P PInsulationType R R R R RInstallationYear P P P P PDesignLifeYears O O O O PLocation P O O P O P P O O O O O O PAreaName O O O O O O O O O O O P P PSystemCode O O O O O O O O O O O P P OSegmentName R OQRAsegmentGroupName P P P P P P P P P P P RFunctionCode O O O O O O O O O O O PSourceProdServiceCode O O O O O O O O O O O OProdServiceCode O R R O R O O R R R R P P RMaxActuTempC P P P P P P P P P P P PMinActuTempC P P P P P P P P P P P PMaxOperTempC R R R R R R R R R R R RMinOperTempC P P P P P P P R P P P PMaxActuPressureBar P P P P P P P P P P P PMinActuPressureBar P P P P P P P P P P P PMaxOperPressureBar R R R R R R R R R R R RMinOperPressureBar R R R R R R R R R R R RComment OPoFcomment O O O O O O O O O O O OCoFcomment O O OReference P P P P P P P P P P P P P RScope P P P P P P P P P P P P P PStatus P P P P P P P P P P P P P PRepairCategorySmall R R ORepairCategoryMedium R R ORepairCategoryLarge R R ORepairCategoryRupture R R OProdAffectedName R R PGradeOfRedundancy O O OProdLossProfileSmall R R OProdLossProfileMedium R R OProdLossProfileLarge R R OProdLossProfileRupture R R OCalcReport A A A A A A A A A A A A A ACO2H2ScalcPressureBar RCO2inGasMole% R


DET NORSKE VERITAS

Field

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CO2fugacity PCO2scaling PPhactual PCO2condensationRateGm3s PGlycolWeight% PCO2inhibitor% PWaterWetting RSandErosion RTotalMassFlowKgPerS RMassFlowSandGramPerS RVolumeFractionGas RWaterPresent RFlowRateMs R RChlorideConcWt% R R

5.3.3 Degradation mechanisms

DataDegradation Mechanisms

This table presents the results of analyses. It shows the same data as the Parts view, only the partdata is preceded by the degradation mechanisms, probability of failure and consequence of failuredata, and the results of inspection planning calculations.

This table is most useful when reviewing the results of the inspection planning calculations, andentering manual data for inspection planning. If manual data is entered, you must close this tableand return to the Parts table (with the same filtering) to rerun the risk calculations.

The data fields are:

Field DescriptionXpartID Part identification the same as in the Parts tableDegMechName Name of the degradation mechanismManualRateMean Manually entered corrosion rate mean of the distributionManualRateSD Manually entered corrosion rate standard deviation of the distributionManualRateCoV% Manually entered corrosion rate Coefficient of Variation of the

KeyA Automatically assignedP Allows more precise calculation of degradation, but not essentialR Required for the model to work; missing data gives PoF = 1.00O Optional; may be useful for information purposes

Empty cell: No data entry required


DET NORSKE VERITAS

Field Descriptiondistribution

ManualPoF Manually entered probability of failure valueManualPoFinspection Manually entered probability of failure value following inspectionPoF Probability of failure value at present timePoFinspection Probability of failure value at present time following inspectionConseqUnignited Unignited economic consequenceConseqFatalitiesIgnited Safety consequences following ignition. In no. of deathsConseqAssetsIgnited Economic consequence as a result of damage to the installation &

equipmentConseqProdLossIgnited Economic consequence as a result of production loss / downtimeConseqOther Other consequencesPLLgivenLeak PLL assuming a leak occursCalcRateMean Calculated mean corrosion rateCalcRateSD Calculated standard deviation of corrosion rateCalcManualXcalcReport Calculation report. Advises of what calculations performed and error

messages.Conseq Total economic consequenceConseqCatNo Economic consequence category number. Refer to matrix definitionConseqCat Economic consequence category name. Refer to matrix definitionPLLConseq Total safety consequence as PLLPLLConseqCatNo Safety consequence category number. Refer to matrix definitionPLLConseqCat Safety consequence category number. Refer to matrix definitionProb Probability of failure in analysis yearProbCatNo Probability category number in analysis year. Refer to matrix definition.ProbCat Probability category name in analysis year. Refer to matrix definition.Risk Total economic risk in analysis yearRiskCatNo Economic risk category number in analysis year. Refer to matrix

definition.RiskCat Economic risk category name in analysis year. Refer to matrix definition.PLLRisk Total safety risk in analysis yearPLLRiskCatNo Safety risk category number in analysis year. Refer to matrix definitionPLLRiskCat Safety risk category name in analysis year. Refer to matrix definitionCurrProb Probability of failure in current yearCurrProbCatNo Probability category number for current year probability of failure. Refer

to matrix definition.CurrProbCat Probability category name for current year probability of failure. Refer to

matrix definition.CurrRisk Total economic risk for current year.CurrRiskCatNo Economic risk category number for current year. Refer to matrix

definition.CurrRiskCat Economic risk category name for current year. Refer to matrix definition.CurrPLLRisk Safety risk for current year.CurrPLLRiskCatNo Safety risk category number for current year. Refer to matrix definition.CurrPLLRiskCat Safety risk category name for current year. Refer to matrix definition.InspProb Probability of failure after inspection calculated for analysis yearInspProbCatNo Probability category number for probability of failure after inspection

calculated for analysis year. Refer to matrix definition.InspProbCat Probability category name for probability of failure after inspection

calculated for analysis year. Refer to matrix definition.InspRisk Economic risk after inspection calculated for analysis yearInspRiskCatNo Economic risk category number after inspection calculated for analysis

yearInspRiskCat Economic risk category name after inspection calculated for analysis

yearInspPLLRisk Safety risk after inspection calculated for analysis yearInspPLLRiskCatNo Safety risk category number after inspection calculated for analysis year


DET NORSKE VERITAS

Field DescriptionInspPLLRiskCat Safety risk category name after inspection calculated for analysis yearTimeToRiskLimit Time from current year to economic risk limitTimeToRiskLimitStatus Status message regarding the time to risk limitPLLTimeToRiskLimit Time from current year to safety risk limitPLLTimeToRiskLimitStatus Status message regarding the time to risk limitManualTimeToInspect Manual choice of time to inspection, measured from the current year.ManualInspTask Manual choice of inspection task, according to pull-down menu from

Inspection Effectiveness tableTimeToInspect Shortest time in years from current year until the risk meets the first

acceptance criteria.InspTask ORBIT Offshore calculated choice of inspection taskInspTimeToRiskLimit Time from current year until the second inspection for economic risk,

assuming that the first inspection found the expected damage.InspPLLTimeToRiskLimit Time from current year until the second inspection for safety risk,

assuming that the first inspection found the expected damage.MinInspTimeToRiskLimit Smallest of the two times to second inspectionExpectedDamageMeanMm Calculated wall loss, mean valueExpectedDamageSDmm Calculated wall loss standard deviationPressure Max actual or operating pressure, in bargDiameter Outer diameter of partYieldStrength Material yield strength in MPaRequiredWallThick Wall thickness required, in mm, to withstand the above pressure given

the diameter and yield strength, calculated according to ASME B31.GWallThick Actual wall thickness, in mmRemainingLife Time remaining for the wall thickness to reduce from current thickness to

required wall thickness, in years

5.3.4 Objects table

DataObjects

This table defines the Objects in the database, and allows the results of the RBI to be summarisedinto an Inspection Plan. This works on the assumption that the Parts are components of the Objects,so typical objects are individual pressure vessels, Pipe, and similar. Parts related to a pressure vesselwould then be the shell, heads, and nozzles; parts related to Pipe would be the individual tagnumbers, but there is no reason why these should not also be defined in more detail as reducers,elbows, tees, and similar. The table can also be completed by use of the Analyse->Object Dataform view (see 5.4.10).

The data given in this table are printed in the report Inspection Plan by Object. The data requiredis:

Field DescriptionObject Name The name of the object. Typically used is the equipment tag number when equipment

is to be analysed in separate parts. Forms pull-down menu in Parts tableMax 20 characters.

Object Type Description of the object. This is a pull-down menu from pre-defined object typesDescription Text description of the object. Max 50 charactersInspection_Internal_Comment Memo field where internal inspection requirements based on the RBI can be entered

as text, also findings from inspections.Inspection_External_Comment

Memo field where external inspection requirements based on the RBI can be enteredas text, also findings from inspections


DET NORSKE VERITAS

Field DescriptionPoF_Internal_Comment Memo field where evaluations relating to internal PoF estimation can be summarised.PoF_External_Comment Memo field where evaluations relating to external PoF estimation can be

summarised.CoF_Comment Memo field where the CoF evaluation can be summarised.MaxDesigntempC Information field. Maximum design temperature for the Object.MinDesigntempC Information field. Minimum design temperature for the Object.MaxDesignpressBar Information field. Maximum design pressure for the Object.MinDesignpressBar Information field. Minimum design pressure for the Object.InternalLiningCladding Yes/No field (0 for No, 1 for Yes). For information onlyLiningCladdingType Text field where the internal lining or cladding type can be specified. For information

only, not yet used in ORBIT evaluations.

5.3.5 Area table

DataAreas

This table defines the areas or modules forming the installation. An area is typically a module of theinstallation bounded by fire and blast walls, or similar type of boundary. The data allows thesimplified QRA in ORBIT Offshore to calculate the branch probabilities for ignition, fire andexplosion, leading to installation damage and loss of life. The table contains data on what can causean ignited event, and the extent of the consequences of that ignition in terms of the scale of damageto the installation and personnel on it. The data required is:

Field DescriptionAreaName Area name. Max 20 charactersDescription Area description. Max 50 charactersComment Memo field allowing comment regarding the area dataVolumeM3 Volume of space within the area floor area x height in cubic metresNumberOfPersons Average number of persons located within the areaAreaM2 Area floor area in square metresPressWallDesignBar Design pressure for blast walls around the AreaPressEquipDesignBar Design blast pressure for major equipment within the areaPressExplMaxBar Max. anticipated blast pressure usually taken from QRAVentChange1Hr Number of air changes per hourHotWorkHrYear Number of hot work hours per yearFireWater Yes / No field is fire water present?NumberOfPumps Number of pumps located within the areaNumberOfCompressors N umber of compressors located within the areaNumberOfGenerators Number of electrical generators located within the areaNumberOfPersonsNbour Average number of persons within neighbouring areasMaterialCost Optional. Cost of materials of construction for the areaWtElectTon Optional. Tonnes weight of electrical equipmentWtHvacTon Optional. Tonnes weight of HVAC equipmentWtInstrTon Optional. Tonnes weight of instrumentation equipmentWtPipingTon Optional. Tonnes weight of piping equipmentWtMechTon Optional. Tonnes weight of mechanical equipmentWtStructTon Optional. Tonnes weight of structural itemsWtFireSafeTon Optional. Tonnes weight of fire & safety equipment


DET NORSKE VERITAS

Field DescriptionWtArchiTon Optional. Tonnes weight of architectural itemsWtOther1Ton Optional. Tonnes weight of user-defined other equipmentWtOther2Ton Optional. Tonnes weight of user-defined other equipmentTotalWtTon Optional. Total tonnes weight of all the aboveProdDownTimeDays Optional. Production downtime expected during repairs and replacement of the aboveAll fields below the double = line are optional, and can be left blank. These are used if the optionCostRBIQRA is selected Yes in the Segments table, in conjunction with the cost per tonne ofthese items that is given in the window that pops up following the sequence DataSegments;select the relevant segment, then AnalyseRisk calculations and click on the Cost Parametersbutton.

In the case where an external QRA is to be used to estimate consequence, then it is only necessaryto define the area name. No other data is required for ORBIT to assign CoF.

5.3.6 Segments table

DataSegments

This table defines the isolatable segments in hydrocarbon-containing pressure equipment, in termsof their location, contents, and potential for blowdown, and is used in ignited consequencecalculations. The table contains data allowing the size and duration of any ignited event to beestimated. The data required is:

Field DescriptionSegmentName Segment name. Max 20 charactersDescription Description of segment. Max 50 charactersComment Memo filed for consequence of failure analysts comments regarding definition of

the segmentsTempC Max operating temperature of segment contentsPressureBar Max operating pressure of segment contentsVolumeM3 Internal volume of the segmentCalcRBIQRA Yes / No field: Set to Yes if the ORBIT internal QRA is to be used to calculate

the segment consequences of failure. Set to No if an external QRA will be usedto estimate consequence. Data must be edited manually into tables Segment LeakSize, Segment Extent and Segment Leak Size Extents. See 5.4.7.

CostRBIQRA Yes / No field: Set to Yes if the ORBIT Internal QRA is to be used to calculatethe the repair costs. This requires that weights and costs per tonne of equipmentetc. to be supplied. See 5.4.7. Set to No otherwise, also if an external QRA isto be used for CoF estimation.

AreaNameRBIQRA Area name where the segment is located. Pull-down menu referring to table AreaFluidType Fluid type in segment. Pull-down menu to select.BlowDown Yes / No fieldLowerExplLimit Lower explosive Limit for segment contentsSpreadEquip Yes / No field. Is spread to equipment possible in the Area?SpreadRiser Yes / No field. Is spread to risers possible in the Area?SpreadArea Yes / No field. Is spread throughout the Area possible?EquipFluid What fluid is in the equipment? Pull-down menu.EquipPFP Yes / No field. Is the equipment protected by passive fire protection??EquipBD Yes / No field. Is the equipment protected by blowdown?RiserFluid What fluid is in the riser? Pull-down menu


DET NORSKE VERITAS

Field DescriptionRiserPFP Yes / No field. Is the riser protected by passive fire protection?RiserBD Yes / No field. Is the riser protected by blowdown?KappaGas The kappa value for the hydrocarbon gasMoleWeightGas The molecular weight for the hydrocarbon gasFlashFracOil The flash fraction of the oilMassBurningRateOil The mass burning rate of the oilDensityOil The density of the oilMaterialCost Optional. Cost of materials of construction for the areaWtElectTon Optional. Tonnes weight of electrical equipmentWtHvacTon Optional. Tonnes weight of HVAC equipmentWtInstrTon Optional. Tonnes weight of instrumentation equipmentWtPipingTon Optional. Tonnes weight of piping equipmentWtMechTon Optional. Tonnes weight of mechanical equipmentWtStructTon Optional. Tonnes weight of structural itemsWtFireSafeTon Optional. Tonnes weight of fire & safety equipmentWtArchiTon Optional. Tonnes weight of architectural itemsWtOther1Ton Optional. Tonnes weight of user-defined other equipmentWtOther2Ton Optional. Tonnes weight of user-defined other equipmentTotalWtTon Optional. Total tonnes weight of all the aboveProdDownTimeDays Optional. Production downtime expected during repairs and replacement of the

aboveNbourMaterialCost Optional. Cost of materials of construction for the neighbouring areaNbourWtElectTon Optional. Tonnes weight of electrical equipment in the neighbouring areaNbourWtHvacTon Optional. Tonnes weight of HVAC equipment in the neighbouring areaNbourWtInstrTon Optional. Tonnes weight of instrumentation equipment in the neighbouring areaNbourWtPipingTon Optional. Tonnes weight of piping equipment in the neighbouring areaNbourWtMechTon Optional. Tonnes weight of mechanical equipment in the neighbouring areaNbourWtStructTon Optional. Tonnes weight of structural items in the neighbouring areaNbourWtFireSafeTon Optional. Tonnes weight of fire & safety equipment in the neighbouring areaNbourWtArchiTon Optional. Tonnes weight of architectural items in the neighbouring areaNbourWtOther1Ton Optional. Tonnes weight of user-defined other equipment in the neighbouring

areaNbourWtOther2Ton Optional. Tonnes weight of user-defined other equipment in the neighbouring

areaNbourTotalWtTon Optional. Total tonnes weight of all the above in the neighbouring areaNbourProdDownTimeDays Optional. Production downtime expected during repairs and replacement of the

above for the neighbouring area

All fields below the double = line are optional, and can be left blank. These are used if the optionCostRBIQRA is selected Yes in the Segments table, in conjunction with the cost per tonne ofthese items that is given in the window that pops up following the sequence DataSegments;select the relevant segment, then AnalyseRisk calculations and click on the Cost Parametersbutton.

Where an external QRA is to be used, only the segment name and corresponding Area name shouldbe entered. The fields CalcRBIQRA and CostRBIQRA should be set to No.


DET NORSKE VERITAS

5.4 Running the analysis

Once the data is entered in mandatory fields in the tables, the detailed analysis is executed as listedbelow. The probability of failure and consequence of failure calculations can be done separately asthe work progresses, it is only when progressing to risk and further, that the order below must befollowed.

5.4.1 Probability of failure for parts

Allocate the degradation mechanisms to the Parts. Open the Parts table, set filters as desired,and follow the sequence AllocateAll, or select the individual mechanism group you wish toallocate instead.

After this is complete, follow the sequence Calculateprobability of failure

5.4.2 Consequence of failure for Parts

Open the Segments table, and follow the sequence ToolsRisk Analysis for Segments.Segments where CalcRBIQRA is s set to No will not be calculated. Close the Segmentstable.

Open the Parts table, set the filters, and follow CalculateConsequence of failure

5.4.3 Risk calculation for Parts

After calculating probability of failure and consequence of failure, the parts table should beopened, filters set as desired, and CalculateRisk followed to calculate the risk values for theParts.

5.4.4 Time to Risk Limit

Open the Parts table and set the filters as desired. This allows the calculation of the time to thesafety and economic risk limits for all Parts in the filter. This is an iterative process, and maytake a little time. Follow CalculateTime to Risk Limit

5.4.5 Inspection Plans

Open the Parts table and set the filters as desired. Follow CalculateInspection Plan tocalculate the inspection plan for the parts. The software reviews all applicable inspection tasksfor each degradation mechanism for each part, and selects the one with the greatest riskreduction per cost unit. It then calculates the second time to the risk limit. This is a lengthyprocess, made longer if you have created a large list of potential inspection tasks for eachdegradation mechanism.

After calculating the inspection plan, open the Degradation Mechanisms table, set the viewFields to view those columns that are of interest, and review the inspection plan selection. Thistable allows manual selection of inspection task (from those specified in the InspectionConfiguration) and timing. After selecting the manual inputs, re-run the inspection plancalculations and the manual input is included in the plan, together with its effect on the risklevels.


DET NORSKE VERITAS

5.4.6 Calculate All

The use of CalculateCalculate All follows the above sequence in the above order, with theexception of Allocating the degradation mechanisms.

To allocate and calculate all in one process, follow ToolsAllocate and Calculate All.

5.4.7 Consequence of failure analysis

When the areas and segments have been defined by name, a combined form view for these can beused to complete the filling-out of the tables by opening the segments table and following the menusequence:

AnalyseRisk Calculations

This data entry form (AnalyseRisk Calculations) can be available only when the Segment table isactive. A form view is given where tabs are used to show input data and results of calculations.

Segment data: This allows input of data into the Segments table in a manner that iseasier to follow than direct input to the table.

Area and Installation data: This allows input of data into the Area table in a manner that is easierto follow than direct input to the table. It also contains one field notgiven elsewhere, being the total personnel count for the installation.

Calculation results: This shows an event tree for each segment and hole size combination.To change the hole size: Click on a radio button,To change segments: Close the form and select another segment.

Conseq costs input: To be used where the CostRBIQRA is selected Yes. Allows inputof the cost data in relation to segment and area in several ways.Either:

1. Material cost Input the replacement / repair costs for equipment, area, neighbouring areaand entire installation. Exclude cost of deferred production whilst these repairs are ongoing.Costs can be estimated from the sum of the cost of replacement of these items. Precise valuesare not required.

2. Per weight Input the weight of each discipline as listed. This requires that the cost pertonne is entered into the Area and Segments tables.

3. Per total weight Input the total weight of equipment likely to be damaged. This requires thatthe cost per tonne is entered into the Area and Segments tables.

The costs per tonne for options (2) and (3) can be given by clicking on the Cost parametersbutton.

In addition, the downtime and deferred production are required. Two options exist:

a. Input the number of days downtime based on estimates by platform personnel and experienceb. ORBIT can calculate based on the Dow Fire and Explosion Index if (a) is left blank.


DET NORSKE VERITAS

Conseq costs output: This shows the results of the CostRBIQRA as the probability ofdamage, the cost of damage, the extent of production downtime, theproduction affected and the cost per day, the total cost and the totalrisk cost, the last two after the Calculate button is pressed. Theoption used in deriving the costs (1, 2 or 3; a or b) is shown next tothe cost figures.

5.4.8 Consequence Analysis using External QRA

There are many advantages to using an external QRA in RBI, not least the reduction in duplicatedeffort in data collection and analysis, as well as consistency in approach with the other risk studies.However, there are several points to note before following this approach:

A QRA is usually performed to assess all risks to personnel on an installation, not just risksfrom leakage of fluids

A QRA usually is based on defined leak rates as opposed to degradation-based hole sizes, as isORBIT RBI.

These require correction prior to entering the data into ORBIT. The precise method of correctionshould be checked for each case; guidance can be obtained from DNV if required.

The following guidelines are proposed for the use of existing QRAs in RBI analysis, and areapplicable for personnel risk only.

1. Obtain the event trees for the relevant segments.2. Determine the risk level arising from inspectable events3. Remove the generic failure rate component from the event tree the output should be

GIVEN a leak, ORBIT will calculate the PoF.4. Check whether the hole sizes used in the QRA are relevant to RBI by use of release rate

equations. If the QRA hole sizes are close to those required by RP-G 101 then the hole sizesneed not be adjusted and the event tree may be used directly, with correction for leakfrequency only. Otherwise, calculate the probability of ignition based upon corrected holesize.

5. Tabulate corrected personnel CoF per segment with respect to the 4 hole sizes.

The following additional steps should be carried out to use existing QRA results in RBI coveringeconomic consequence assessments:

6. From the safety risk assessment, determine which end events contribute to fire andexplosion for each segment, materials and degradation combination

7. Determine from the QRA the end event probabilities for these events8. Determine the likely extent of damage to equipment and structure, using, for example,

equipment count/value, rebuilding time & cost, referring to RP-G 101 Appendix B where agraph is given from Dow that can assist in this.

9. Multiply the end event probabilities by the cost of that end event, and sum up for thespecific hole sizes for that segment, taking the values in the same distribution as the holesize distribution to give the final economic consequence for that segment & degradationmechanism.

The above method will give values of PLL per segment and hole size combination (step 5), andmaterial loss per segment and hole size (step 9), together with the probabilities for each end event.The data is entered into ORBIT thus:


DET NORSKE VERITAS

Safety ConsequenceOpen the Segment Leak Sizes table (Data->Ignited Events->Segment Leak Sizes). Select the firstsegment by pull-down menu and the smallest leak size name, also by pull-down menu. The holesize field is for information only. Enter the corrected PLL in the field PLLGivenLeak. Repeat for allsegment and leak size combinations.

Economic ConsequenceOpen the Segment Extents table (Data->Ignited Events->Segment Extents). Select the firstsegment by pull-down menu and the damage extent name, also by pull-down menu. The materialcost of damage should be entered in the appropriate currency units for that segment and extentcombination, together with the number of days production downtime and the production affected.Repeat for all segment and extent combinations. This table defines the size of the relevant endevents.

Open the Segment Leak Size Extents table (Data->Ignited Events->Segment Leak Size Extents).Select the first segment by pull-down menu, the leak size by pull-down menu and the damageextent name, also by pull-down menu. The probability of that combination of segment, leak size andextent is then given i.e., the probability of that specific end event. Repeat for all segments, leaksize and extent combinations.

A short-cut to creating an empty set of tables so that the event tree data can be quickly entered is tocarry out the following:1. Define area names2. Define segment names, and input the area name for the segment3. Set CalcRBIQRA to Yes4. Complete for all segments and area combinations.5. Open Segments table. Run Risk Analysis (Tools->Risk Analysis for Segments)6. Return to Segments table, and set all CalcRBIQRA to No. Be sure to do this, otherwise

rerunning the risk analysis will erase any manually entered data!7. The tables listed above will have been filled out but with the numerical data missing.

5.4.9 Individual Part analysis

With the Parts table open, all data relating to the part selected can be viewed and adjusted for what-


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if or sensitivity calculations, and the results viewed graphically as probability of failure and riskplotted as functions of time for all degradation mechanisms, showing their relation to risk limits.Probability of failure after inspection is also shown when this has been calculated. Graphs can becopied and pasted into other documents.

This is achieved by selecting AnalysePart data and Calculations

5.4.10 Individual Object Analysis

This is intended to allow quick and easy data input, results analysis and inspection planning forObjects. It is obtained through Analyse->Object Data. The following screen view is obtained:

This view is split into three areas. The top area shows the object name, description and type, andhas a navigation bar. Individual objects can be selected from a pull-down menu that refers to theObjects table.

The middle area shows a sketch of the object type (a separator in this case), and has a few data entryfields for mass data entry and editing. Entry of data into these fields allows all parts for the object tobe updated with the new data. Data entry is effected by clicking on the Edit button, at which pointa new screen is opened to allow the automatic creation of the vessel parts shell, head, nozzles,materials. Press OK when the data is ready for entry and the parts created.

Changes that are required subsequent to the initial creation of the parts should be edited into thetable at the bottom of the screen; the insertion of additional parts (such as new nozzles) or deletionof parts should be made by use of the Insert or Delete buttons to the left of the lower part of thescreen.

The lower part of the screen has three tabs. The first shows basic part mechanical data such asmaterials, dimensions, pressures and temperatures and location; the degradation mechanisms tab


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allows the RBI results and outline inspection plan to be reviewed and manually adjusted asrequired; the Evaluation tab allows the PoF, CoF and Inspection evaluations to be made. Thebuttons with three dots can be used to open the field to a greater size for easier viewing andediting.

6. REPORTING

Report (Choice as below)

The following reports are available, accessed as shown in the screen dump:

Report name DescriptionExecutive Summary Intended as a short summary for management, the report prints the contents of the

Comments field in the Installation table, followed by the contributions of safety andeconomic risk to the whole picture, expressed as pie charts. Also, matrices for the currentyear, analysis year before & after inspection are shown for safety & economic risk

System summary This is a detailed summary of the risk results and the conditions that give rise to them,printed on a system-by-system basis. The probabilities of failure, consequence of failure andinspection comments from the System table are also printed as footnotes to each systempage.

Frame programme The inspection frame program is given for the inspection planning period, and is intended asa general forward planning tool. This shows, for each system and corrosion groupcombination, when inspection should take place for each degradation mechanism, with a Xfor the first inspection and a O for the second.

Parts Simple table of parts including actual diameter and actual wall thickness for each part,grouped by object

Risk distribution The risk distribution, showing risk in current year, analysis year with and withoutinspection, can be printed for each of the following: Degradation mechanisms Areas Systems Segments Objects Groups


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Report name DescriptionInspection plan This is a part-based inspection plan, showing part name, degradation mechanism, risk

before and after inspection, inspection task and timing, expected damage extent. The Plancan be focused by filtering on the desired conditions prior to running the report. The lastpage shows any filter conditions.

Inspection Plan byObject

This prints an inspection plan for all parts forming linked to Objects, based on the filteringset in the Parts table. The descriptive data for the object is listed at the top of the report,together with the risk limits and the inspection planning period, thereafter each part is listedwith the degradation mechanisms, rate(if applicable), PoF category, CoF category andinspection requirement by task and timing.

Risk summary This plots the safety and economic risk matrices

ORBIT Offshore User Manual

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