Classification and BAP

As already mentioned some time ago in the article on BIM and classification classifications are always necessary when the elements in a BIM model are grouped together according to certain classes - which is always the case in practice sooner or later.

BIM authoring software such as Revit structures the model according to internal classes, such as walls, doors, etc., as soon as it is created. This is also already a classification, albeit a very rough one - which is why many clients may require other classification systems depending on the planning phase or purpose of the model. There is often a desire for a universal classification system, but I think this is utopian - depending on the application, it must be possible to filter the components according to other rules. For example, a calculator has a completely different view (and requirement!) of the model than a facility manager.
In this context, the "BIM elephant" is often used as a humorous metaphor - if you only look at one part of "the whole", the interpretation depends very much on your own expectations and personal experience.

A very common and usual classification in building construction is, for example, DIN276, which divides elements into cost groups - a uniform parameter must be defined and the corresponding cost group entered for all components. In practice, of course, this should not be done manually, as this is not only cumbersome, but the risk of typing errors is quite high. Ideally, the correct classification can be selected from a prepared list. In Revit, for example, it can also work quite well via the assembly identifiers - see also the article Cost groups according to DIN276 in Revit on the Autodesk BIM Blog. The assembly identifiers can also be customized to cover other classification systems.

However, as mentioned at the beginning, it may also be necessary to cover several classifications in one model, e.g. for 4D/5D simulation or building operation. Other parameters must be used for this, but these can also be filled automatically in Revit - using the Classification Manager from the BIM Interoperability Tools.
The Classification Manager is even more convenient than the assembly identifiers, as it accesses an Excel spreadsheet (instead of a text file), which can therefore be edited and customized more easily. The tool comes with international and established classifications such as UniFormat, MasterFormat or OmniClass. In one of the next articles, we will take a look at what needs to be considered when adapting these classifications and how the Classification Manager can be used in practice.

So how do you know which classification system to use? In principle, BIM projects should always have a BIM execution plan (BAP), which is developed by the project team based on the requirements of the client / building owner. Unfortunately, this is still often neglected in practice, which diminishes the benefits of BIM processes, as the models often have to be subsequently adapted at great expense.
If your client requires a BIM model, they must define exactly what this means as part of the BIM specifications (also known as client information requirements or AIA) - including whether and which classification should be used, as well as which BIM objects should be defined and under which parameters.

The book BIM Manager by Mark Baldwin describes these requirements in great detail and also explains them using practical examples, which is why the book is definitely worth recommending (especially as the 2nd and revised version has only recently been published).

Image: "The BIM Manager"

 

2 comments
  1. Your blogs on classification are still highly topical! It's good that the correct IFC classes (e.g. IfcDamper for the fire damper) can be assigned to the entities for export in Revit via the Classification Manager. In cooperation with the CAFM ring, a standard Revit-CAFM mapping can be defined.
    Uni/MasterFormat and OmniClass are important in Anglo-Saxon countries. In D-A-CH, however, CAFM-Connect (also known as "DIN 276 x" key) and AMEV key are required. This is because CAFM systems can use these two keys to automatically create templates for maintenance planning. If not "only" the data transfer to the operating phase is required, but also a cost estimate (AVA, 5D), it is advisable to use the DBD BIM plugin. DBD BIM already assigns all the classification keys mentioned in this commentary today (2023) and thus opens up a wide variety of content. With the increasing integration of CAFM in BIM, new procedures such as the high-quality ECLASS classification are coming into focus.
    A good overview of current possibilities for successful AVA/CAFM mapping in D-A-CH can be found in the book BIM - einfach machen!, published by Beuth-Verlag in 07/2023.

  2. Thanks for the addition Christof, tools like DBD BIM make classification according to DACH standards much easier!

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