TO BE CONTINUED - UNDER CONSTRUCTION

ISO 15926 part 4 is the ISO-standardized part of the Reference Data Library (RDL). ISO 15926 part 4 is also called the "Core Library". An RDL is like a class library which also contains reference individuals. A class in the RDL is the definition of a type, a kind. Individuals are not classes, they are unique. But an individual is member of one or more classes. To be a member of a class in ISO 15926 is called "to be classified as". The RDL contains classes and a few reference individuals. A reference individuals is an individual that is referenced so often that it makes sense to store it in the RDL. Examples of reference individuals are: London (city), Germany (country), Shell (company).

The currently being developed RDL can be viewed from the online system Reference Data System (RDS). See also RDS. It is available through http://rds.posccaesar.com . You have to wait until the Java Applet is installed, then click Login at the right upper corner.

Start by typing an expression in the search box. The * is used as wildcard. For instance type *pump* to find any class short name containing the word pump.

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(text courtesy RDS help)

The RDL Browser allows the user to search the RDL for classes, relationships and individuals.

1. Search & search results - The user is able to do a basic search on predefined attributes of the RDL Object. More advanced searches on multiple criteria can also be done by checking off the advanced search checkbox.
2. Details - Once the user has selected an RDL object (class, relationship or individual), its details can be viewed here. More information on the details can be found under the topic View details and View relationships
3. Search configuration - The user configures the advanced search by selecting which fields to search on. A user can also limit the ISO 15926-2 entity types that are to be searched and finally the user can also select which fields to display as part of the results.
4. Relationship - On an RDL Object there can be many different types of relationships. The user can expand the relationships he/she is interested in and view it as a tree hierarchy.
5. Support documentation - The documentation for ISO 15926-2 is made available here along with the context sensitive help which you are now using. Export sets are also stored here which allows the user to export the data in P21, P28 or CSV.

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For more help refer to the help window in RDS; this tutorial will focus more on the content of ISO 15926 part 4.

As soon as anybody starts browsing through the ISO 15926 part 4 data, remarks and comments come up and a need arises to improve the set. Albeit this set was subject to the (more than 40 manyears) work of maybe a hundred domain matter experts of dozens of companies since 1992, many obvious improvements come to mind. The set will never be finished; it will always grow and will always be subject to improvement.

Right now the comments have to be sent by email to the RDS, IDS and IIP team. Refer to Contact. It is the intention to setup a good forum where issues can be addressed, maybe on this knowledge base, but it needs to be decided yet.

In the future an organization will be set up to deal with these improvements. They need to be addressed in a timely matter, and subject to certification. For more details on this see ISO 15926 Single Global Source.

To find the subject areas of the RDL, in the RDS screen search for:

Then in the Second Relation windows open the SPECIALIZATION.superclass relation, showing the subject areas. It is possible to select the list and to copy paste them into another application like your text editor. They are:

ACTIVITIES

BASICS

CLASS OF CLASS

CONNECTION MATERIAL

ELECTRICAL

ENCODED INFORMATION

HEAT TRANSFER

INFORMATION

INSTRUMENTATION

MATHEMATICAL OBJECTS

PIPING

PROPERTIES

PROTECTION

ROTATING EQUIPMENT

SOLID HANDLING

TRANSPORT

UOM

VALVES

Clicking one such subject area, then choosing CLASSIFICATION.classifier relation, brings you down in the taxonomy (tree) hierarchy. So each class has (one or more) parent class relation(s) through CLASSIFICATION.classified and can have children through CLASSIFICATION.classifier relations.

See here the structure provided by the ISO 15926 part 2 data model. It comprises of objects like classes or individuals, and relations like the one described here; CLASSIFICATION.

You see there are two types of setting the type of an object; classification and specialization. Classification in the ISO 15926 is not the same as in the OWL sense. Here are the official definitions:

Thinking this through, classification is non-transive and specialization is transive. This means for the use of it, for specialization all definitions, and also relations, of the superclass also all go for the subclass. In the case of classification some or all of the classifier may go for the classified.

So in a simplified view, the taxonomy paths are given as specialization and classifications give aspects of type. See this hydraulic motor as an example.

Note that taxonomy does not come in single superclasses; there can be more.

Another way of looking at it is to see specialization as the essence of a thing, and classification as aspects or designation.

Currently, in the RDL, the most often used properties and relationships are:

• Short names
• Definitions
• Superclass relations
• Entity Data Types

Other properties and relations will follow, but they will be part of the Object Information Models (OIM).

Examples:

ID: THERMOWELL
Entity data type	class_of_inanimate_physical_object
Short name	thermowell	English
Superclass	physical object
Definition	A physical object that is a pressure-tight receptacle adapted to receive a temperature sensing element, provided with external threads or other means for pressure-tight attachment to a vessel or pipe.	English
Subclass	flanged thermowell
Subclass	screwed thermowell
Subclass	socket weld thermowell
Subclass	stepped stem thermowell
Subclass	straight stem thermowell
Subclass	tapered stem thermowell
Subclass	van stone thermowell
Subclass	welded thermowell

ID: FLANGED_THERMOWELL
Entity data type	class_of_inanimate_physical_object
Short name	flanged thermowell	English
Superclass	Thermowell
Definition	A pressure-tight receptacle adapted to receive a temperature sensing element, provided with flange for pressure-tight attachment to a vessel or pipe.	English
Subclass	solid forged flanged thermowell
Subclass	welded flange thermowell

ID: SOLID_FORGED_FLANGED_THERMOWELL
Entity data type	class_of_inanimate_physical_object
Short name	solid forged flanged thermowell	English
Superclass	flanged thermowell
Definition	A flanged thermowell where the flange is made in one piece with the shank/stem.	English

Above is shown the taxonomy thermowell - flanged thermowell - solid forged flanged thermowell.

The ID's are in capitals with underscores. That is the way the RDL's ID's are currently set up. They could also be numbers or follow the ISO standard for ID's. This way is for convenience. If you follow this way of making ID's in your Facade, you will eventually run into trouble. There is no way of continuously making unique naming when specializing classes. That is why equipment vendors use serial numbers; uniquely naming all types of equipment, with all their special extensions and features, would be impossible.

The short names are stored as properties to the objects. They can be stored in various languages and to those synonyms will be added too.

The superclass - subclass relations make out the taxonomy. An object can have multiple superclasses.

The definitions can be stored in various languages.

Classes, once part of the ISO 15926 RDL, cannot be changed any more, because there is no way of knowing how many parties are using the class as a reference in data integration. When a change needs to be made, a new class must be added. If this new class has the same ID, the version number will be added (currently unresolved how this will be executed).

Examples of objects stored in the RDL:

object short name	entity data type	count
zero power-factor test	class_of_activity	2157
yearly average temperature environment	class_of_arranged_individual	85
zirconium-93	class_of_atom	181
wood fibre	class_of_biological_matter	5
document description	class_of_class_of_description	3
workshop equipment class	class_of_class_of_individual	294
clad metal	class_of_composite_material	10
zinc alloy	class_of_compound	370
instrument process connection	class_of_direct_connection	39
actual completion date	class_of_event	46
wing fastener head	class_of_feature	406
acos function	class_of_functional_mapping	78
abandoned well	class_of_functional_object	936
turbine	class_of_inanimate_physical_object	6868
zero sequence voltage component	class_of_indirect_property	2332
yellow colour	class_of_individual	16
log	class_of_information_object	9
as built	class_of_lifecycle_stage	4
(2-(2-methoxymethoxy)m ethoxy)-ppopan-2-ol	class_of_molecule	1542
forest	class_of_organism	1
accreditation company	class_of_organization	22
sand	class_of_particulate_material	6
thrustee	class_of_person	13
waste matter	class_of_relationship_with_signature	111
adjacent	class_of_relative_location	39
wire diameter	class_of_shape_dimension	556
unstable	class_of_status	15
proton	class_of_sub_atomic_particle	13
cause and effect chart	document definition	481
ac generator special support and test equipment class	enumerated_set_of_class	472
swedish	language	16
viscosity liquid at t and p	multidimensional_property_space	35
avogadro constant	property	10
voltage range 18 - 35 vdc	property_range	27
value space	role	31
m3/h	scale	7
youngs modulus of elasticity	single_property_dimension	543
zero suppression	status	18

TO BE CONTINUED - UNDER CONSTRUCTION