6 May

Architects: Make Specified 3D Coordination The Norm

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Looking back at my biggest C.A. headaches as a designer,  a third would have been relatively painless to solve with BIM clash testing.

Commercial architects really are letting low hanging fruit rot on the tree. If a designer builds a model to produce bid docs there are few reasons not to require 3D trade coordination. Digital clash detection is a magnitude better than typical 2D lightbox/overlay coordination. The consequences of that difference are measurable in review time, change order money, and headaches for architects and their clients. In practice it’s one of the most cost effective requirements you can specify. The model assets are largely already there for the taking–GCs just need a push to reap benefits for all stakeholders.

Owners. The client receives a tremendous benefit from BIM clash detection. Any institution of  significant size likely has a Risk Manager, and the cost for BIM should be understood and explained in that same spirit.
  • Risk-Management. BIM clash detection is fundamentally a risk control tool focused on the most volatile segments of construction. Its value is in sussing out potentially catastrophic liabilities.
  • Pre-planning. Most dramatically, the model provides an intuitive tool to reify ambiguous assumptions and tighten project planning.
  • Verification. The model allows the GC or CM to test a virtual mock-up of the most delay- and change order-causing trades before they get anywhere close to fabricating.
As an analogy, your client might grumble about their insurance and the cost of the premium but they can not responsibly consider going without. Push-back on the cost of 3D coordination is tied to it’s novelty; its only their unfamiliarity that prevents owners from pushing for it. Architects. The cost is clearly worth it for the owner. But my experience is the biggest benefit is actually for the designer.
  • Foresight. The most useful result is that errors are found weeks, if not months, before a competent superintendent could discover them. Real sleep-ruining troubles increase exponentially in proportion to how late in the process they have been discovered.
I’d like to give a real world example to illustrate. Right before I left my old firm for our company full-time, I had an ugly problem at one of the schools on which I had lead. The main supply and return ducts from the roof mounted OAU had been routed down a chase near the elevator. Unfortunately that chase was also occupied by a K-brace. It was discovered right as the sub was measuring to fabricate the duct and the only tenable option was to annex a portion of a neighboring elevator lobby in an awkward manner.
  • Opportunity Cost. The earlier a problem is brought to light, the more elegant/less-costly the eventual solution is likely to be.
Though the duct issue should have been caught in design, the complexity of modern buildings means that there will always be significant problems. Spatial intuition fails even the most methodical design team. In our current project in Baton Rouge, we identified most major MEPFP issues while our client was pouring grade beams.
  • Low Cost Solutions. Coordination wont’t solve scope being left out of the documents, but caught earlier enough many other problems can be resolved for little to no money.
We’ve been able to shake out and visualize the major concerns of 8 or 10 months down the line at a time when the foundation or steel could actually be modified to address them. With the duct/brace issue, we could have relocated the brace and the enlarged caps that go with it, or adjusted the position of the elevator.
  • Relationships. Avoiding tense conversations about change orders helps you save face wth the owner. Minimizing obstacles is also going to save the GC and subs money in  management and rework they can’t make stick. Profitable contractors are easy contractors to work with.
Context. Most commercial project manuals already include a boilerplate specification (Section 01 31 00) requiring coordination drawings, though many architects are unaware of the specifics. It outlines the minimum requirements to produce project specific drawings to demonstrate that the GC has coordinated tight/troublesome areas. This stems from A201, which firmly puts coordination on the contractor as being a part of their means and methods.
  • Engineering Drawings. MEPFP service engineering designs are schematic in nature. So though the design team must describe a building that works, there is a great deal of responsibility on the contractor. The have to adapt these service layouts to the structural and architectural condition.
  • Verification. Requiring the use of BIM processes and delivery of evidence of a clash-free coordination model is as valid as detailing the requirements for the project schedule. If you’ve gone through the trouble of laying out the details of a critical path schedule, you should detail advanced clash detection for proof of coordination.
  • Novelty. Though my feeling is the primary reason 3D clash detection has not yet been widely required is due to its relative novelty and therefore the profession’s ignorance of it, there have been some objections raised as to the cost for the service borne by the owner. More on the cost in a bit.
Opposition. BIM coordination largely isn’t required in specifications because its value isn’t widely understood. I’d like to address some other objections.
  • Higher Hard Bids. Many think that this will add a tremendous amount to bids. But steel detailers already model to LOD 400 in order to shop fabricate and most MEPFP detailers do the same for their own coordination. Add in the design model and all the cost-intensive assets are already provided for. There will be some added-cost in a hard bid, but it’s minimal compared to the benefits.
  • Liability. With a properly tight hold harmless release, I have heard or read of very few real problems arising from transmission of the model to the contractor.
  • Size. There are arguments that it is only cost effective on large projects, but I’d say most ground up construction is a candidate, varying by typology. $1 million is probably the cut-off for a medical project, but for a school it might be $3 million, and residential much more.
  • Familiarity. There’s a case that if GCs knew more about BIM, they would actually be doing this on their own as cost savings and risk-management. One of the goals of including BIM specs is to make the industry better.
  • Documents. Due to its novelty, there aren’t widespread access to good specifications detailing requirements, To that end, I’ve synthesized some I have seen and flushed them out into a non-proprietary specification, which can be downloaded below:

013113_fl – Project Coordination via BIM (PDF) 013113_fl – Project Coordination via BIM (DOC)

I’m curious to hear other designers’ and architects’ horror stories during construction. What’s the biggest heartburn you’ve had from flubbed coordination, and what frustration could you have avoided with better forwarning?
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