PLQ 3.3 – Understanding Uniclass 2015

Hello BIMfans,
Before I calculate the costs associated with my preventative maintenance schedule, I need to ensure each object is correctly classified.  So, let’s take a good look at Uniclass 2015.

A few weeks ago I had the pleasure of sitting down with Sarah Delaney, head of classification at NBS, to talk about Uniclass 2015.  It turns out that the way I have used classification isn’t exactly how it should be used, so I wanted to share with you why and what changes I needed to make.

NOTE:  Sarah has written an article on Uniclass 2015 which really helped me understand Uniclass 2015.


Ok, a quick bit of context, what is a classification system?  Basically, classification is a method of categorizing ‘things’ into classes, ‘things’ that share the same characteristics. Classification impacts on everything (everything? EVERYTHING!), from the Tree of Life,  the age-old debate around Whether Jaffa Cakes are in fact Biscuits? (Fun fact: A debate based on avoiding VAT), to how we decide what parts of a design are the responsibility of which professionals.

Note:  I have no idea where Jaffa cakes sit on this diagram

In construction, there is an International standard for producing classification systems, ISO 12006-2.  It suggests how classification tables should be broken up as well as their relationships to each other. Uniclass 2015 is the UK’s latest in a series of UK classification systems (CI/SfB, CAWS, Uniclass, Uniclass 1.4, Uniclass 2,…) aligned to this standard.

Note:  Before any QS/Estimators kick-off comment, I will point out that the RICSNew Rules of Measurement (NRM) is NOT a classification system; more on that in a future blog post.

Uniclass 2015:

As explained by Sarah in her article, Uniclass 2015 consists of several tables which are based on the following number series:

Group Title
10 Preparatory*
15 Earthworks
20 Structural
25 Wall and barrier
30 Roof, floor, and paving
32 Damp-proofing, waterproofing and plaster finishing
35 Stair and ramp
37 Tunnel, shaft, vessel and tower
40 Signage, FF&E, and general finishings
45 Flora and fauna
50 Waste disposal
55 Piped supply
60 Heating, cooling, and refrigeration
65 Ventilation and air conditioning
70 Electrical
75 Communications, security, safety and protection
80 Transport
85 Process engineering
90 Circulation and storage

Note:  While under Products(Pr) preparatory work is covered under Pr_15; in Activities(Ac) however, it is under Ac_10. So, as 15 has been taken by Earthwork in Systems(Ss), I have opted to use 10.

So, where did I go wrong?  Put simply, I hadn’t fully understood the relationship between the tables.  Which is as follows:

  • Pr, Products:  Things you buy (Bricks, wall ties, and Mortar)
  • Ss, Systems: An element (or part of an element) made of products (Brickwork)
  • EF, Elements/functions:  Main building components (Walls and Doors)
  • SL, Spaces/locations:  Place where activities happen (Living Room and Kitchen)
  • Ac, Activities: Exercising, Sleeping, Eating, Working etc. (Cleaning and Cooking)
  • En, Entities:  Individual assets (Just the house)
  • Co, Complexes:  Group of Assets (House and Garden as ‘Ty Crempog’)

What I had done was incorrectly use the Systems(Ss) table when I should have used the Elements/function(EF) table for my doors.  Each of my doors were classified as Ss_25_30_20_25: Doorset systems, but this isn’t correct as they are not doorsets.  As such, I have now re-classified them as EF_25_30: Doors and windows.

To remind myself, I drew this diagram.

This feels like one of those Mensa questions.  If all Systems include products, and some elements include systems, are all Elements Systems?  Answers on a postcard!

Using classification:

For classification to work within Revit when exporting an IFC, each object’s classification code and description needs to be placed onto the defined property specified in the classification settings window; written as ‘Code: Description’ to comply with BS 1192-4 & COBie.  As you can see from the image below I have opted for the property ‘ClassificationForObjects’.  I chose this as it is the most appropriate field I could find within the IFC Schema as it is listed within IfcClassification.

The default value is ‘ClassificationCode’, I was just being awkward changing it…

This information is then exported into an IFC file and passed through to COBie so that it is ready to be exchanged and used to manage my home.


And there we have it.  By using Uniclass 2015 in the way that it was intended to be used, I have now improved the quality of the information I have produced and are using to manage my home; fantastic!

Operation and Maintenance
3.1 What are the sizes and condition of the windows & doors?
3.2 What assets are in a poor condition?
3.3 What costs can be attributed to my assets?
3.4 What are the most cost effective thermal improvements that could be undertaken?

Now that I classified my objects correctly, I wonder how classification will relate to costing up my preventative maintenance schedule?…

8 thoughts on “PLQ 3.3 – Understanding Uniclass 2015

  1. Morning Dan, excellent post once again!

    We’ve been crunching through this recently and thankfully came to a similar understanding. I wish I could of held off as this so clearly explains the nuances of Uniclass.

    Did Sarah have any news as to when Uniclass2015 was to be implemented in NBS create? As this is currently a sticking point for us, our concern being that the old implementation of NBS Create to a previous version of Uniclass, but with a similar format of codes, could be rather confusing once supersede by the new NBS/Uniclass specification definitions that have been in development for some time.

    With our clients asking us to categorise model elements against NRM1, Uniclass 2015; ourselves using an legacy in-house classification system of Ci/Sfb, then further specifying elements with Revit keynotes using the CAWS system; which are then also mapped within Revit model categories and IFC – I feel like we’re in a world of excessive classification!

    Dave David Brook for Nicholas Hare Architects LLP

    3 Barnsbury Square London N1 1JL Tel +44 (0)20 7619 1670

    Member of the UK Green Building Council CHAS and Constructionline accredited BS EN ISO 9001:2008 and BS EN ISO 14001:2004

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    • Hi David, thank you. I’m glad we have came to the same conclusions. From memory a separate team deals with NBS create.

      Yes I agree, there does seem to be a lot of confusion. For example, I know of FM providers who want information classified to NRM to align with their annual operational cost models, while we (supply) are told about Uniclass. While it is possible to include multiple classification properties in Revit, only one will get transferred to COBie under the ‘category’ field. Making the whole thing less simple than it seems


  2. Thought provoking as always… thanks for posting!

    I’m not sure I agree with your take on the doors.

    Your EF classification would apply to every door in the building regardless of type e.g. EF_25_30. This is a high level classification and I don’t disagree that this is correct.

    However I would argue that your assembled door, albeit an existing one, is still a doorset. It has all the components of a doorset, frame, leaf, architrave etc so therefore it’s a doorset in my mind and should be classified as such e.g. Ss_25_30_20_25 Doorset systems. The individual components that then make that doorset up would be the products, e.g. Pr_35_90_43_87 Wood architraves

    Having worked through this this morning following your post, this is how I understand a more complex element to work, in this case walls, which I think tallies with your example above. I’m assuming that your plaster is not just plaster but is in fact something like lath and plaster thus making it a ‘system’ in it’s own right. The example below is me just trying to get my head straight…

    With walls every wall would fall under EF_25_10 (Wall Elements). This Element is then made up of a number of systems. e.g. External Wall External Leaf, cavity wall insulation, external wall internal leaf. Each of these systems is then made up of a number of Products.. So it would look something like this..

    EF_25_10 : Wall Element

    Ss_25_13_50_50 : Masonry external wall external leaf systems
    Pr_20_93_52_15 : Clay bricks
    Pr_20_31_53_32 : Mortar

    Ss_25_13_50_11 : Cavity wall insulation systems
    Pr_25_57_06_97 : Wood fibre batt insulation
    Pr_20_85_84_19 : Cavity wall ties

    Ss_25_13_50_51 : Masonry external wall internal leaf systems
    Pr_20_93_52_05 : Autoclaved aerated concrete (AAC) blocks
    Pr_25_71_52_63 : Plasterboard panels


  3. Hi Dan,

    Very useful, thank you.

    I have been looking at the possible use of Uniclass 2015 for our BIM projects, rather than NRM3 which we currently use to set our information requirements. There seem to be benefits using the NBS toolkit definitions/RIBA Toolkit Responsibility Matrix however, in the definitions section on their website there is no LOD or LOI information published for EF / Elements and Functions. Assuming one chooses to use the LOD / LOI info and manufacturer templates kindly provided by the NBS to produce a Responsibility Matrix, one would need to use either a system or a product instead. So, it looks like assigning an EF code to a door would not suffice to produce requirements. I also wonder whether SFG20 core PPM schedules are applied to systems, products or elements or to a mix of all? This could be confusing. What are your thoughts on this?

    Many Thanks,


    • Thank you Elena,

      That is a good (and difficult) question.

      The problem with NRM is that it is not a classification system, NRM is meant to be applied to a classification system to determine how to measure classes assigned to that NRM code, which is why I don’t use it. The problem with SFG20 is that it doesn’t include many of the tables required in ISO 12006-2 (The ISO of writing classification systems), which is why I don’t use that either. Uniclass 2015 is the only UK implementation of ISO 12006-2 which, to me, means that Uniclass 2015 should be the default.

      Yes, it is disappointing that only the Ss and Pr table have been comprehensively defined; the toolkit is still a work in progress. I would structure my responsibility matrix so that any elements/products are listed under a parent system. Any elements/products not defined could then use the parent system as a basis of their requirements. For example door elements would fall under Ss_25_30_20_25 (Doorset Systems). I haven’t done this to my own DRM, but I will soon (Thank you).


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