The role of a schematic model for system design ... - AVEVA Gmbh

The role of a schematic model for
system design coordination
An AVEVA White Paper
Henrik Hultin
Per-Olof Nilsson
Per-Ola Åkesson
AVEVA AB Sweden

The role of a schematic model for system design coordination - an AVEVA White Paper
Introduction
Pressures on plant designers and operators are constantly growing.
Projects have become increasingly larger, but with compressed time
schedules. Large projects are often executed using multiple
contractors at multiple locations and with multiple applications.
Similarly, in the shipbuilding industry designs are becoming ever
more advanced and thereby incorporating a growing number of
increasingly complex onboard systems. This, in combination with an
often flexible approach to project implementation, such as the use
of subcontractors and system suppliers, makes the proactive
management and consolidation of data from different sources an
absolute requirement.
In this paper, we describe an approach to meet these requirements
through the creation of a common schematic model, with related
application functions to represent and manage relevant system
design information for plant design and shipbuilding projects.
‘Pressures on plant designers and operators are
constantly growing. Projects have become increasingly
larger, but with compressed time schedules. Large
projects are often executed using multiple contractors
at multiple locations and with multiple applications...’
Page 2

The role of a schematic model for system design coordination - an AVEVA White Paper
1. Plant and Ship System Design Challenges
Designs in both plant and shipbuilding are increasingly challenging.
Apart from the increased demands made by the design, there is also
a requirement for a more collaborative environment for the design
and development of these systems.
Many major EPCs and shipyards have globally distributed and
collaborating design locations. They are making more use of 'High
Value Engineering Centres' in the case of plant design, design
agents and subcontractors for ship system design, and specialist
system suppliers for turnkey and integration system solutions. Due
to time constraints and compressed schedules, this work is also
often carried out concurrently.
The challenge for the designer, whether an EPC or a shipyard, is how
to efficiently coordinate and handle the plant or ship system design
data. Data from several sources must be consolidated, and design
changes properly managed.
In shipbuilding, the growth in the complexity of ship designs is a
result of the need to better support their transportation functions,
and to offer operational, economical and performance advantages
to their owners and operators. The number of systems aboard
modern ships, especially the more advanced vessels such as
offshore, naval and special ships, is increasing.
These systems are also becoming more complex, in order to provide
faster operation and greater capacity, more automation, less
maintenance and, finally, a better performance for the Owner
Operator.
For large projects split between different engineering companies,
the P&IDs can be created with different authoring tools to minimize
the potential disruption to the companies working practises.
As a result, developing a consistent set of P&IDs for a complete
project as the design evolves is a complex task for project engineers
and designers. Approval of the latest versions of P&IDs and
highlighting of inconsistencies takes considerable time and, if not
carried out correctly, can lead to major design rework.
‘The challenge for the
designer, whether an EPC
or a shipyard, is how to
efficiently coordinate and
handle the plant or ship
system design data...’
Page 3

The role of a schematic model for system design coordination - an AVEVA White Paper
2. Schematic model vs. 3D model
In plant design as well as in shipbuilding, the use of a 3D product
model (see Figures 1a and 1b) currently provides an accepted way of
working. For shipbuilding, a common product model for hull and
outfitting is normally used. In some cases, separate models for hull
and outfitting are still used, with the data being transferred in
various ways.
This offers many advantages, including space management with
collision checks, collaboration between different disciplines such as
hole management, and a common and distinct source for various
derived data, for example, production information.
The concept of the 3D product model is commonly used and
accepted, but it is not usual to treat schematic data in the same
way. By this, we mean having a common database, usable by all
schematic designers and disciplines, to create a continuous,
consolidated and complete schematic model, closely integrated
with the 3D model. Not only could such a schematic model offer
advantages and benefits in the system design area similar to those
provided by a common 3D design product model, but it also offers a
collaborative environment for different engineering disciplines to
better support some of the design challenges described above.
AVEVA has been researching and developing this concept and has
created a Schematic Model Database with related functions.
Our initial approach involved adding the schematic data to the
existing 3D product model database using existing hierarchies and
structures, thereby extending the scope of the product model to
include, not only the 3D spatial representation, but also the
functional schematic representation. However, as the organisation
is system oriented rather than space oriented, we found that the
database schema would need to be structured accordingly.
It was clear from the beginning that, for some items, such as
pipelines, a separate representation was needed, due to the
structural difference from corresponding 3D items.
We wondered whether, in cases where there is a one-to-one
relationship between the schematic and 3D objects, (e.g.
equipment items and cables), the existing 3D objects could be used
and extended to support both the 3D and the schematic design. This
was a tempting approach, since it would reduce the frequency of
redundant objects. However, after careful evaluation, we proved
that having separate objects for the schematic and 3D instances
offered greater advantages in concurrent working, change
handling, workflow and data management.
Leading on from this design consideration, we found that the
related management tools would need to provide a high level of
functionality, and offer powerful features for the handling of the
relations between schematic and 3D manifestations.
The AVEVA Marine and AVEVA Plant design product model can,
through the addition of this data, be considered to include both a
schematic and a 3D model section in a single repository. The design
of the database schema for the schematic section was also adapted
to use as much of the concept and design philosophy from the
existing 3D model database as possible, thereby enabling the use of
common data management functions.
We also worked to ensure that the supporting data sources in the
form of Catalogues and Specifications could be referenced from the
schematic data as well as from the 3D design data. This ensures data
consistency and enables a flexible work process whereby Catalogue
selection can take place at the schematic stage and be reused, or
directly added, on the 3D side.
Figure 1a: Ship machinery arrangement as part of 3D model Figure 1b: The third module for Shell/Esso's Fife Natural Gas Liquids Plant,
Mossmorran, designed by Costain Oil, Gas & Process Limited, using PDMS
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2.1 DB Organisation
The schematic model database is organised using two main
hierarchies (see Figure 2). These are the schematic group hierarchy
and the system hierarchy. The schematic group hierarchy can be
viewed as a user-defined folder structure in which the schematic
items can be categorised and organised in an arbitrary way.
In parallel to this, there is a system hierarchy which represents the
design systems of which the schematic items are members.
The database also includes references between schematic items and
the drawings on which they are represented, and this can be used as
a third hierarchy.
2.2 Schematic Objects
The role of a schematic model for system design coordination - an AVEVA White Paper
The database can store and represent a number of base object types
(see Figure 2) including those listed below:
❚ Equipment items having sub-equipment, nozzles (pipe
connection pieces) and electrical connections
Equipment
Schematic Group
Nozzle Branch
System
❚ Pipelines with branches, valves and fittings
❚ Inline and offline instruments
❚ HVAC lines with branches and HVAC fittings
❚ Cables
❚ Diagram drawings, drawing templates and symbol libraries.
The diagrams are represented by proxy objects, which enable the
database to manage the corresponding diagram documents and
their relation to the schematic items which appear on them.
In addition to the base objects, users can extend the data model
with user-defined hierarchies, object types and attributes. Such
user-defined items are still fully recognised, displayed and handled
by the standard application functions.
Topological information, such as connections from pipelines, HVAC
lines or cables to equipment items, and offline instrument
connections to various fittings, is captured and represented in the
data model. The offline instruments can also provide a link between
a main process system and a related control system.
Diagram
Pipeline/
HVACline Offline Instrument Cable
Valve & Fitting Instrument
Figure 2: Simplified overview of schematic model DB schema
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2.3 Data Management
The role of a schematic model for system design coordination - an AVEVA White Paper
To fulfil the data management requirements of the intended
collaboration support for the schematic model database, we used a
data management platform developed in house. This platform
provides support for distributed databases, transactions,
versioning, traceability, and so on.
Such features enable the distribution of the schematic model
database globally between different collaborating parties and
subcontractors. Systems can be designed and consolidated into a
single model, even if design teams are working in different
geographical locations.
‘...Information about major
items, as well as estimates
for pipe lengths and types/
numbers of fittings, can
be obtained by using
the .NET APIs or the
import/export functions...’
2.4 Open Model
A set of functions for importing and exporting data is provided,
allowing a flexible choice of P&ID authoring tools. Line lists,
equipment lists, valve lists, etc., can be imported using ordinary
spreadsheet files, or more advanced XML formats such as ISO 15926
(used in the plant design and offshore industries) can be used to
import pipeline network topology.
Drawings can be imported in different formats, but conversion to
the XML-based SVG format will provide a higher level of
functionality, such as the identification and highlighting of the
related schematic items. Corresponding spreadsheet format export
functions are also available.
For the import of pipeline networks and drawings, the AVEVA P&ID
Manager application is used. This application makes it possible to
check each batch of data for consistency and, when a complete
model has been created, this can be consolidated and further
checked for overall consistency. By establishing the schematic
model and using the related tools, this task is much easier than
checking a large number of separate P&ID sheets and making sure
the interconnections are correct.
In addition to the import and export interfaces, the schematic
model database provides a set of public .NET APIs which enable
custom developed software to interface with it for online reading
and writing of data. This can be used to extend existing
applications, for the custom development of applications operating
directly on the schematic model data, for analysis tools, or for ERPtype
system integration.
Information about major items, as well as estimates for pipe lengths
and types/numbers of fittings, can be obtained by using the .NET
APIs or the import/export functions. This information is useful for
early ordering and material planning.
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3. Connection to 3D
The role of a schematic model for system design coordination - an AVEVA White Paper
The Schematic Model applications include a number of features to
manage the release of information to 3D. This includes a flexible
function for design managers to approve and set release status for a
system, a diagram, or parts thereof. Setting the release status
provides a signal to the 3D designers that the schematic
information is now ready to be used as a base for the 3D design.
The applications also contain functions for visualising the releaseand
3D-usage status, as well as warning or restraining the user from
modifying released data. Already released design information can
be revised and re-released in a controlled way, allowing revisions to
be implemented and released while parallel work is continuing on
the 3D side.
P&ID Authoring Tools
P&ID Manager
Schematic 3D
Integrator
Schematic Model
Viewer
Product Model DB
Schematic
Data
3D Design
Data
Figure 3: The schematic model as part of the complete product model DB, together with related functions
‘Already released design
information can be revised and
re-released in a controlled way,
allowing revisions to be
implemented and released while
parallel work is continuing on
the 3D side...’
Global
Synchronisation
Spreadsheet
Import/Export
Customisation APIs
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4. Schematic Model Viewer
The role of a schematic model for system design coordination - an AVEVA White Paper
Given the schematic model database and its capability to represent
a continuous schematic model for the whole ship design, the next
question was whether it would be possible to view and visualise the
contents of the database in an intuitive and easily understandable
way. As this data can originate from a number of different P&IDs
and other diagrams, as well as being imported from various sources,
there is no single drawing that illustrates the complete schematic
model.
Although the connectivity can be seen in the various P&IDs and
other diagrams, these documents are most often organised in such
a way that a single diagram only shows a single system or even part
of a single system and does not provide a complete overview of
interconnected systems. In ship design there are many cases of
equipment items that are related to more than one system. The
most obvious example in shipbuilding is perhaps the main engine
which is connected to a number of supporting systems, including a
cooling water system, a fuel oil system and a lubrication system
(see Figures 4 and 5).
Figure 4: The schematic model viewer can show a view of all systems connected to
an equipment item, in this case, the main engine in a ship
A set of main goals for a visualisation tool was defined as follows:
❚ It should illustrate the connectivity of items in the database in a
neutral way not related with the subdivision and layout of
individual P&IDs
❚ It should provide a consolidated view of multiple systems
❚ It should provide a navigable view and not a static picture
❚ It should be possible to start with a limited view in scope as well
as detail, and then expand and drill down on request
❚ It should be easy and intuitive to use.
Based on these goals, research was done in the area. We quickly
found that a traditional 'tree' view (Explorer) control is suitable for
showing predefined hierarchies, but cannot illustrate the full
connectivity of the model. It must be considered that the topology
of the piping network includes such features as loops.
After examining different alternatives, we decided to look more
closely at the Mind Map® style of diagram and a variant, known as a
'wheel' diagram. When investigating existing applications of this
style of diagram, we found that inspiration could be taken from
computer network administration applications which, in many
cases, exhibit features similar to what we wanted to accomplish.
Figure 5: A closer view showing one of the systems to the engine
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4.1 Creating an initial layout
The role of a schematic model for system design coordination - an AVEVA White Paper
We decided that the navigation should start with an equipment item
selected by the user. From this item, the system would automatically
find all connections in the database and display each connection as
a graphical subtree. Each subtree would then be traversed through
all branches until other equipment items or branch ends were
encountered.
Branching points (such as tees, olets or three-way valves) were
represented by a generic branching point symbol. For the
equipment items, a set of customer definable rules have been
created. By using these rules, the application can select and display
an appropriate graphical symbol for each equipment item. As the
Schematic Model Viewer is a dynamic viewer tool and is not
displaying a static P&ID layout, we decided not to use the
traditional P&ID symbols, but to go, instead, for a more illustrative
style.
The pipeline network can also contain circular layouts. To handle
this, we introduced an algorithm by which the connected items were
placed in a primary subtree, and the looping connection was
illustrated by a diagonal line to a member of another subtree, or at
another location in the same subtree.
If the layout generated by this mechanism is not what the user
wants, they can easily reverse the link, so that the item in question
will move and become a member of the other subtree, or the other
part of the same subtree.
Figure 6: The initial view created by the viewer shows the selected item together
with all connected items and generic branching points
The process described above results in an initial view with the
selected equipment item in the middle and connected equipment
items around it, and the branching topology visible in the
interconnecting lines and branch points (see Figure 6).
4.2 Navigation and drill-down
From the initial view it is possible to navigate interactively along the
connection network, expanding and collapsing subtrees and recentring
on other equipment items. By this process, the user can
proceed from system to system and explore the complete schematic
model.
In the initially generated overview layout, only equipment items
and generic branching points are shown. To go into more detail, and
see inline parts such as valves, reducers and other fittings, the user
needs simply to press one button (see Figure 7). Alternatively,
right-clicking on an item in the Schematic Model Viewer allows the
user to list the diagram drawing(s) on which this item exists, and to
open and view the selected drawing(s). This provides another form
of drill-down.
The Schematic Model Viewer also provides standard features,
including the viewing of database attributes for the selected item,
and the facility to manually rearrange the auto-generated layout by
drag-and-drop.
Figure 7: Schematic Model Viewer showing valves and inline fittings at detail
level
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5. Relation with the 3D model
Clearly, a set of management functions was needed for the data of
the two models, schematic and 3D. These functions would have to
include the creation of 3D data based on the schematic model,
comparison functions including reporting, and functions for
managed updates to existing data following design changes. An
important aspect to this would be to support parallel working and
not restrict it to a predefined sequence of events. For these
purposes, the AVEVA Schematic 3D Integrator application was
developed (see Figure 8). As these functions are, in many cases,
part of a workflow that is handled by existing design applications,
an important design decision was to implement this application as
an add-in, which could be integrated into existing design
applications. This means, for instance, that a 3D piping engineer
does not have to leave the 3D piping design application to compare
the current 3D design with the corresponding schematic design.
5.1 Creating 3D design data
The role of a schematic model for system design coordination - an AVEVA White Paper
The consolidated data in the schematic model database can be used
as a base for the 3D layout design of the related systems. The
Integrator add-in allows the schematic model data to be exploited
as a base for the automatic creation of 3D design data.
A customer-configurable rule-based implementation means that
this creation is adaptable to customer preference and design rules,
including automatic pipe routing. The automatically created data
can then be further elaborated and modified by the 3D piping
engineer, to accomplish a final 3D design. By applying this
procedure, the 3D design can be elaborated quicker and with less
effort, and the logical correctness of the 3D model can be
increased.
5.2 Comparing 3D design data with schematic
data
The Schematic 3D Integrator includes functions to compare the
schematic data with the 3D design data. The comparison can find
missing and unmatched items on both sides, as well as differences
in attribute values, and topology and connectivity (for instance, an
incorrect branching model or incorrect sequence of fittings in a
branch).
Using the Integrator, the user can view the diagram as well as the
related 3D data. If a schematic item is selected, the corresponding
3D item is also selected and highlighted, and vice versa. This makes
it easy for the user to see the relationship between corresponding
items and to understand any anomalies.
It is also important to point out that this comparison can be
performed even if the 3D data has not been created from schematic
data using the Integrator. In many cases, the strict sequential
working procedure between schematic design and 3D design cannot
be applied, and it must still be possible to compare the models.
5.3 Managed updates
If any inconsistencies or anomalies are found by the comparison
between the schematic model and the 3D model, either can be
updated from the other in a controlled way. This forms the basis for
the management of design changes, and ensures that they are
properly applied to both the schematic and the 3D design models.
‘The AVEVA Schematic
3D Integrator includes
functions to compare the
schematic data with the
3D design data...’
Figure 8: The AVEVA Schematic 3D Integrator,
showing a 3D model machinery arrangement,
together with the corresponding diagram, and
tables of related data
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6. Conclusions
The role of a schematic model for system design coordination - an AVEVA White Paper
The schematic model database provides a good platform for
compiling all relevant schematic data for a project. This can be
accomplished by tight online working against the database, where
items are created automatically as they are drafted on the diagram,
or in an offline fashion, where data can be imported from other
authoring tools.
This flexibility can support a distributed way of working with
partners, contractors, subcontractors, vendors and system
suppliers. The resulting set of data in the schematic model database
can be verified and consolidated by using the Schematic Model
Viewer, as well as the checking capabilities of P&ID Manager,
miscellaneous reports and other tools. This makes it possible to
ensure that all related data is complete and consistent.
The schematic model database also provides a base for the 3D
model, where schematic data can be reused on the 3D side.
However, a more concurrent working mode often has to be used
because of time constraints. In this case, the schematic model can
be of use anyway, to retrospectively check that the 3D model fulfils
the system design intent.
If the schematic model database is kept up to date with all changes
introduced, it can also provide a schematic as-built documentation
of the project, which can easily be navigated using the schematic
model viewer. This includes the possibility for other project
reporting functions or in-service and onboard applications.
Looking further, we believe that current developments in this area
have great potential. This concept can be extended and enhanced in
many different ways, only a few of which have been implemented so
far.
‘This flexibility can support a
distributed way of working with
partners, contractors,
subcontractors, vendors and
system suppliers. The resulting
set of data in the schematic
model database can be verified
and consolidated by using the
Schematic Model Viewer, as well
as the checking capabilities of
P&ID Manager, miscellaneous
reports and other tools. This
makes it possible to ensure that
all related data is complete
and consistent...’
This article has been adapted from a paper given at the International Conference on Computer Applications in Shipbuilding (ICCAS 2007), in September 2007, organised
by the Royal Institution of Naval Architects (RINA). It is reprinted with the permission of RINA.
Page 11

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