The value of 3-D Modelling and record keeping.
The majority of my time on phase 3 has been focussed on working at the London School of Hygiene of Tropical Medicine (LSHTM). LSHTM’s building was opened in 1929 and has undergone several overhauls and extension over the last 80 odd years. This combined with the fact the keeping of record drawings seems to have been considered as an embuggerance as opposed to good practice made working out how I could modify their systems a bit more tricky than it needed to be.
If LSHTM were to be considered as left of arc, I have more recently been working on a project at the right of arc end of the spectrum; the re-modelling of Circle Reading Hospital which I have previously blogged on. The scope has now been expanded slightly. The client now wants to change the use of a waiting /reception area to a group activity (physio) room. This has implications with regards to the level of ventilation required to the space and the cooling load required. Although not contractually completed to a specific BIM level, Circle Reading was designed in Revit with the associated Navisworks models still in existence. This has allowed me to quickly interrogate the model via a desk top study to see what is supposed to be in the ceiling void and work out what space and services we have to play with. The client’s F&M team have also been very good at keeping records, so I have been able to interrogate the original main contractor’s commissioning results and compare them against the original design specification and schedules. From there it has been a case of applying the necessary calculations to work out what the new load is, confirming if the existing system has sufficient spare capacity and in what areas modifications need to be made to allow my proposal to work. Of course all this would have been possible without the information I was given, but it would have required hunting around the building for equipment details, getting airflow velocities and getting into ceiling voids to see what is actually there. The use of 3-D modelling and good record keeping has allowed me to meet the client’s intent of getting a proposal out cheaply and quickly. There will be significant caveats applied to my design note as I’ve not confirmed my design start point on site; however, the client is aware of this risk and happy to proceed.
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Rich,
Sounds like the Circle Reading client had the operation phase of a project in mind when paying for the works completed previously. I would think that a health and safety file with a 3D Revit/Navisworks model included should become the norm. I wonder if there is any stipulation for public projects to keep as built records in this format with the BIM requirements becoming more onerous. Not sure if all of the E and M work in Anemoi will have this level of model, but as the project is likely to extend beyond its 30-year design life this would probably be time well spent when coming to make future modifications.
Damo,
With the 2016 Government mandate for all publicly funded projects to be BIM Level 2 compliant (basic collaboration), then I’d suggest that there is a requirement to keep all as-built information as current as possible.
Damian,
I think the difference in mind set of the two clients I’ve mention is what drives them. Circle, as a private healthcare provider, are all about money. They’ve put money and effort into their records to save money in the future. Conversely LSHTM, although world leaders in what they do, aren’t focussed on making money. Circle have also had the advantage of starting from scratch with a new building (only built in mid 2000s). Without understanding the M & E works involved in Anemoi (I may have just highlighted my lack of reading the Sapper Telegraph) it’s difficult for me to make a comment on what level of detail I think they should be going into. If it’s a relatively simple design without significant physical constraints then a 3-D model might be overkill.
Rich, Damo,
As I learnt from my thesis research, Project ANEMOI does not have a BIM deliverable. This is due to the client, DIO, not requesting it of the Corps.
However, that being said a draughtsman on the job has used his self-taught experience of 3D modelling and to great effect, confirming clash detection between E&M services which have proved invaluable.
Rich,
I too have used Navisworks models from the REVIT files to aid in describing one of my concept designs for underground carpark ventilation.
It’s a great way to interrogate the model to find what you’re looking for and take a cut of it. Then through Blue Beam (Mark-up tool) add your comments and other detail before sending off to the client/architect for review.
On your change of design for the now Physio room, your ventilation strategy should just be increased outside air rates to account for the increase in occupant activity and possibly additional cooling. If the base build indoor unit doesn’t have the capacity can you not add a supplementary unit, a DX split perhaps?
Fran,
Thanks for telling me what the design should be…The preferred solution is currently to utilise the existing AHU and increase the supply and extract flow rates as you’ve mentioned. The spec for the AHU shows that it should be able to handle the increased volume, however, the commissioning results show that the discharge pressure was somewhat higher than anticipated at the original design stage, so I’ve run a simple pressure loss calc to confirm that the new load being placed on the index run will still fall within the fan power curve. It’s then just been a case of confirming that the cooling and heating coils are man enough to deal with the additional load (which they should be). What we want to avoid at any costs is any form of refurbishment to the AHU as this would result in it needing to comply with updated EU regulations regarding AHU efficiency, which we’d undoubtedly fail.
A preferred option to DX units would have been FCUs or Chilled beams for cooling as this would fit in with the rest of the site strategy, however, there aren’t any distribution pipes in the area so that’s a none starter.
If all else fails DX units will be the fall back option.
Historically the challenge was always trying to get contractors to amend the construction drawings to ‘As Built’ status and the H&S file frequently ended up containing the construction drawings. The difference is similar to the difference between a geotechnical report for a site versus the ground truth that emerges when actually digging the hole. When planning works I would suggest that the BIM model has value in showing the original intent and is much better than guess work but you should still anticipate the impact of reality as a risk down the line.
One of the perennial challenges when deciding to put effort into something that may be of value later is knowing how much to invest. Structures have a habit of lasting for about a century before being replaced but E&M is usually replaced three four or five times in the same period. It is not only that use changes and equipment wears out but often these combine with advances in technology and/or standards which render it sensible to rip out and start again and any perceived value of the calculation done twenty five years ago being of value now will be laughed at.
Richard,
In this case the contractor has been pretty good at producing as built drawings. Having interrogated them quickly they do appear to reflect what I have seen in other parts of the building (when I actually visited site for the original remodel) and are not just a carbon copy of the original for construction drawings.
I accept what you are saying with regards to the risk associated between reality and the model, but this has been articulated to the client. Who are happy to accept it in order to get the work done cheaply. I’ve considered myself a sceptic with regards to BIM mainly due to the discrepancies I’ve seen between what is shown in a model and what an operative on a price rate actually installs. However in this instance there is less scope for the reality differing as a huge portion of the works were prefabricated.
Another point I’ve forgotten to mention is that the client aren’t paying to have the REVIT model updated. At the moment it’s accurate and is allowing modifications to be made with relative ease. Circle are about to fall into the same trap as the team at LSHTM. If they continue doing this for the next 10 to 15 years then the model will be pretty useless.
Thanks Rich, plus ça change, plus c’est la même chose! and in those shadows of doubt hides the salvation of engineers.
Richard, good to see some down stream usage of BIM being talked about. Because the protocol is so new, most stuff you currently see focuses on the during build benefits. If Gatwick had been 3D modelled, my life would have been so much easier. The trick of course going forwards is to make sure the models are kept up to date; I imagine the new owners of the LSHTM felt equally pleased with their drawing pack back in the day.