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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
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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.
New
Pro
ject
Ope
n ex
istin
g pr
ojec
t
Prin
t cur
rent
win
dow
Prin
t Pre
view
Cop
y
Pas
te
Inse
rt re
cord
Del
ete
reco
rd
Sea
rch
Rep
lace
Vie
w F
ield
s
Vie
w a
ll fie
lds
Filte
r by
Sel
ectio
n
Rem
ove
Filte
r
Sor
t
Ref
resh
Wor
king
pro
cess
win
dow
Exp
lore
r win
dow
Hel
p
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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)
Check for errors /inconsistencies & fix
Check for errors /inconsistencies & fix
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.
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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
Atm
os-C
orr
CO
2
CS-
In-W
ater
CU
I-C
S
CuN
i-In-
Wat
er
ESC
C
Loc
al-C
orr-
SS
MIC
Mis
c-In
sign
ifica
nt
Sand
-Ero
sion
SS-L
ocal
-In-
Wat
er
CoF
Ign
ited
CoF
Uni
gnite
d
Insp
ectio
n Pl
anni
ng&
Upd
atin
g
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
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Field
Atm
os-C
orr
CO
2
CS-
In-W
ater
CU
I-C
S
CuN
i-In-
Wat
er
ESC
C
Loc
al-C
orr-
SS
MIC
Mis
c-In
sign
ifica
nt
Sand
-Ero
sion
SS-L
ocal
-In-
Wat
er
CoF
Ign
ited
CoF
Uni
gnite
d
Insp
ectio
n Pl
anni
ng&
Upd
atin
g
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
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Field
Atm
os-C
orr
CO
2
CS-
In-W
ater
CU
I-C
S
CuN
i-In-
Wat
er
ESC
C
Loc
al-C
orr-
SS
MIC
Mis
c-In
sign
ifica
nt
Sand
-Ero
sion
SS-L
ocal
-In-
Wat
er
CoF
Ign
ited
CoF
Uni
gnite
d
Insp
ectio
n Pl
anni
ng&
Upd
atin
g
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
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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
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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
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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
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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
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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.
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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.
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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.
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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:
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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