PLQ 3.3 – Measured Maintenance

Hello BIMfans,

Now that my COBie has been validated during COBie Culmination, it is time to put that information to use.  When Configuring Costs, I mentioned Jonathan Hewitt of Hewitt Consult Limited had kindly offered to put my information into CostX to produce a preventative maintenance schedule.


Not only has he produced my schedule, but by dealing with the interoperability issues, I have managed to get some useful insights into how my cost information should be managed.  Included below are the steps taken to produce my preventative maintenance schedule.

Review of Pre-embedded Costs

When producing COBie, I made a point of including as much information as I could, which included Type.ReplacementCost.  However, there is a problem; costs change.  Using services like CamelCamelCamel, this becomes clear.

Camel camel camel camel camel … chameleon?

For example, over four years, the Nest Learning Thermostat’s price fluctuated from £312 to £99; who knows what the replacement cost will be in 15-20 years’ time?  Jonathan told me that Quantity Surveys/Estimators normally use schedules of rates when producing cost plans; typically agreed at the start of a project.  For the purposes of this exercise, Jonathan produced a schedule of rates using my replacement costs and uploaded it to CostX as a rate library.

Review of Uniclass

After I spent some time Understanding Uniclass, I applied Uniclass 2015 to all of my manageable assets.  I thought that this information would be useful when calculating my maintenance schedule, as the respective NRM3 codes could have been applied based on the Uniclass 2015.  However, we came across a problem, when the DWFX was exported it was missing my Uniclass 2015 classifications.


While my assessment information, BS 8541-1 aligned object names, IfcGUIDs and IfcNames were all exchanged without an issue, ClassificationForObjects was blank.  Now luckily, because I had named my objects following ISO 4157-1 as outlined in Naming Omnibus, Jonathan was able to work without Uniclass 2015 (Phew!).  This problem didn’t occur when we tested this afterward using my IFC files. Perhaps CostX should recommend IFC over DWFx instead?

Model Mapping

ModelMappingWhen I asked for this preventative maintenance schedule, I was quite clear that I wanted it structured by AssessmentCondition.  My plan is to deal with all poor items this year, and then move on to less critical elements over the next three to five years.  To do this, Jonathan had to apply model mapping, which he explained as:

 “[Model mapping is] a powerful tool that allows you to dictate what information is extracted from the model by creating “dimension groups”.  Using conditional formulas, I was able to sort information based on each of the possible assessment ratings:  Adequate, AsNew, Good, Poor or Very Poor.  This provided the breakdown required, and formed clear groupings that could be calculated independently.  This could only be achieved thanks to the consistency within Dan’s information, as the use of element GUIDs”

Jonathan stressed to me the importance of having a globally unique identifier (GUID) within CostX for each element to enable the use of rate libraries and systems.  As such, I asked that for the IfcGUID to be used.  However, this posed a problem initially as I had exported the DWFx before my IFC, meaning that some IfcGUIDs were missing (oops!).  Once I had resolved this, each element had a unique identifier.

Completing the workbook

Finally, now that the information had been structured, my preventative maintenance schedule could be produced.  Luckily, due to the efficient file sizes I maintain, this process took no time at all.  As you can see the information has been summarized based on the assessment rating and then itemized in full.

This document is exactly what I need to consider what maintenance to undertake first.  I really enjoyed working with Jonathan and apparently, he did too as I he was kind enough to leave me a Testimonial:


And there we have it.  Thanks to the help of Jonathan and Hewitt Consult Limited, I now have a fully costed preventative maintenance schedule.  This exercise has been really educational and has changed my perspective of how I plan to manage my graphical models.  Increasingly I have been putting more information in, but this isn’t the ideal solution.  For example, Jonathan told me that:

CostX is designed for Quantity Surveys/Estimators to do what they’ve always done; take off quantities and undertake cost planning using rates built up from first principles but in a quicker, digital way.  Through tools like CostX, rate libraries could be shared for benchmarking purposes.  Static cost information is OK when you have agreed a target cost on a project and you want to use it for valuing work done or negotiating change control. Those same static costs are useless later down the line when the asset is in operation; costs change!  If a dynamic cost link could be made, this would be useful and powerful for asset management”

If tools like CostX are being produced to empower estimators, then there isn’t much of a benefit in the exchange of static, and often out-of-date cost information.  So from now on when it comes to costs I will do what I always use to do, just leave it to the Quantity Surveys/Estimators!

Note:  As a result of this insight, I have now removed all cost information from my information model.

As you can see, as we have now attributed costs to my assets, I have completed another Plain Language Question.  Fantastic, PLQ 3.3 is complete!

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 my preventative maintenance schedule is complete, it is time to look at my final Plain Language Question, can I use this information to inform how to improve the energy efficiency of my home?

Note:  If you have any comments regarding my preventative maintenance schedule, then please let me know either on Twitter, or by commenting below.

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