specsandcodes

BIM Bubble Bursts

Last week, Engineering News-Record (ENR) reported on a lawsuit centered on the use of building information modeling/management (BIM) for a university life-sciences building (ENR: A Cautionary Digital Tale).  Although construction lawsuits appear almost every day, this one has greater significance because it could well be the first case where the use of BIM was determined to be the mitigating factor that created the problem—in other words, this is new legal ground for the design and construction industry.

The facts, as they are currently made available, indicate that the design team—the architect, along with their mechanical, electrical, and plumbing consultants—used BIM to integrate the building’s systems in a plenum space under very tight tolerances.  In order to make it all fit, the contractor would need to install the systems in a specific sequence; however, the contract documents did not convey that sequence.  When the contractor attempted to install the work as indicated in the contract documents, the systems would not fit.  The contractor sued the owner and the owner sued the architect.  That’s the situation in a very tight nutshell.

There are two items that strike me as being very significant about this lawsuit: 1) the delivery method was design-bid-build, so the contractor had no involvement in the development of the model, and 2) design professionals are generally warned against specifying means and methods. 

I’ll start with the latter item.

Specifying means and methods in a set of construction contract documents puts additional risk on the preparer of the documents—the design professional—thus, the practice is usually avoided.  The theory behind that position, which is supported by many professional liability insurers, is that if the contractor follows the means and methods indicated in the contract documents, and subsequently the work fails, then the contractor is covered by the implied warranty established under the Spearin Doctrine (United States vs. Spearin, 248 U.S. 132, 1918).  Therefore, the contract documents typically indicate what the final results of the construction should be and leave it to the contractor to determine how to get there.

In the context of this lawsuit, the design team was working with a double-edged sword.  We know the result of not specifying the means and methods for installing the systems, but let’s assume the design team did specify the exact installation sequence.  If the contractor followed the installation as specified and it still did not work, whether great or small, then the contractor would have been covered by the Spearin Doctrine and the design team would still be responsible for the error.

Let’s step back and take a look at this from another perspective.  What if BIM was not used on the project and the design team increased the plenum depth to allow greater tolerance for installing the building’s systems?  Wouldn’t the building have to be taller, thereby adding construction cost?  Wouldn’t the increase in interior volume of the building require additional cooling and heating, thereby increasing construction and operation costs?

There are many buildings constructed that are much more complicated than a university life-sciences building.  Yet, rarely on those complex projects does the design team specify the construction sequence.  The design team’s responsibility is just that—design.  Design professionals have a basic knowledge of constructability issues; that is why owners hire contractors—contractors are supposed to know how a building goes together and in what sequence.  Why should the design team tell the contractor to “install pipe ‘A’ before duct ‘B,’ but only after installing conduit ‘C’”? 

The ENR quotes the architect’s liability insurer as saying, “If you don’t use BIM correctly, you can get into trouble.”  That could be said for any tool, whether it is CADD or the old pencil-and-paper method.  From the details presented, it appears the design team did use BIM properly; they made efficient use of space to reduce cost of the project.  What happened is the contractor failed to analyze the contract documents and coordinate the installation by consulting with the applicable subcontractors to establish the best approach for installing the work as indicated in the contract documents.  Did that coordination take place?  We don’t know.  Did the contractor attempt to communicate with the design team to discuss possible installation strategies?  Again, we don’t know.  This leads to the first item I mentioned:  the delivery method.

The best design environment for using BIM on a project is when the project is developed using a collaborative approach—when all project team members (owners, designers, contractors, and suppliers) are involved in the decision making.  The design-bid-build delivery method is definitely not a collaborative approach.  Bidders on a project are not privy to the multitude of decisions that are made during the design of a building.  They only have what’s in front of them: a set of bidding documents and a short period of time to put together a price and construction team, which most likely has never worked together before on a project.

Negotiated, design-build, CM-at-risk, and the latest, integrated project delivery (IPD), are delivery methods more suited to a collaborative approach to building design and construction.  They bring each of the project teams together early in project development.  Then, when the permits are pulled and construction begins, everyone involved understands the project in great detail with very few unknowns remaining.  The collaborative approach is even more enhanced when the contractor utilizes BIM as a tool for constructing the project, such as for shop drawing integration, scheduling, and costing.

The details on the lawsuit are few (we don’t even know the parties involved), so a true critical analysis of the lawsuit’s impact on the construction industry and BIM probably will not be coming any time soon.  In addition to the questions I mentioned earlier, there are many others that need answers in order to better formulate an honest criticism of BIM.  These questions include:

• Did the owner require the use of BIM to design the project?
• Why was the design-bid-build delivery method selected?
• Did the contractor have the capability to use the model?
• Did the design team provide any guidance to the contractor during installation?
• Were there errors in the model that would have prevented the installation of the work as indicated in the contract documents?

Until answers to these and other questions are revealed about BIM’s involvement in this lawsuit, the jury in the case of Traditional Methods vs. BIM should remain in deliberation.

11th Hour Designing

How many of you, either as an employee or consultant,  worked for, or are working for, design firms that seem to be designing their projects till the last possible moment before sending the drawings and specifications off to the printer or client?  I’m not referring to the preparation of drawings or specifications, which normally continue till the very end.  No, I’m referring to significant design decisions; decisions that could affect a project if not thoroughly researched and analyzed.

Why do architects and engineers do that?  As an architect myself (I cannot speak for engineers), it seems to be in our blood.  The title “architect” could easily be a synonym for “procrastinator.”  A fellow classmate in architecture school once stated during an all-night marathon design session that “Rome may not have been built in a day, but knowing architects, it was designed in one night.”   This “infliction” not only affects your typical design professional, but renowned designers are also known to have no immunity.

Those familiar with Frank Lloyd Wright have probably heard the story (which is fact, by the way) of his last-minute design charrette for Fallingwater.  Edgar Kaufmann, Jr., the client, was in Milwaukee on business and called Mr. Wright to see how the design was coming along for the Kaufmann’s vacation home in Bear Run, Pennsylvania.  Mr. Wright told Mr. Kaufmann that the design was done, when in fact it had not even started.  As Mr. Kaufmann drove the 140 miles from Milwaukee to Spring Green to look at the design, Mr. Wright started putting pencil to paper as apprentices handed him sharpened pencils to keep him going nonstop.  The design was completed in time and Mr. Kaufmann was none the wiser.  Miraculous as that accomplishment was, it was, nonetheless, just preliminary design drawings and not a full set of construction documents.

For years the standard design process for basic architectural services has consisted of three phases:  schematic design, design development, and construction documents.  Each phase adds further detail and refinement to the previous phase.  The schematic design (SD) phase provides preliminary information including floor plans, elevations, and some building sections, to give the client a general overview of the building’s design.  The design development (DD) phase adds more information, including integration of mechanical and electrical systems, building materials, and some details that show how it all goes together.  The construction documents (CD) phase takes the design from its preliminary status to a set of drawings and specifications from which a contractor could construct the building. 

Early in the CD phase, the design work should have stopped so attention can be placed on developing the drawings and specifications.  However, some design work may be required to address some constructability issues that arise late in the CD phase; but overall, the design should be well established by this time—including the selection of materials and finishes.  Unfortunately, from my experience, that seems to be the exception and not the rule. 

As minor as material and finish selection may seem to some people, it appears odd that some designers put off making those selections until late in the CD phase, even though they play a significant role in the visual aesthetic of the building—something that should be high on an architect’s list.  I am not talking about selection of colors or patterns, but actual product types, such as carpet versus vinyl tile, or curtain wall versus storefront.  I have on occasion received specification information from clients within 24 hours of the CD due date.  On a few rare ocassions I have received some information after the due date, which had to be handled by addendum (recently I had one project that required the deletion of one specification section to be replaced by a new section, all handled through an addendum).

It might appear that I am complaining (to some extent I am), but it goes beyond that.  Some materials and finishes have implications on the building design—not just from an aesthetic point of view, but from a performance one, as well.  To delay a decision may have unexpected consequences that create the trickle-down or domino effect.  This may require alteration of completed documents, thus wasting the design team’s time and money.

For example, a late decision to use a vapor-sensitive flooring material over a slab-on-grade may require the addition of a vapor retarder if none was previously indicated in the documents.  This would affect both the drawings and specifications.  Another example would be a change from metal roofing to clay tile.  That change would affect the drawings—architectural as well as structural (for added dead load)—plus the specifications (delete one section and add a new one).

In some cases, procrastination is not the culprit behind changes made late in the CD phase.  Some designers just cannot resist the temptation to continue tinkering with the design until the end.  But at some point the designing must stop so that the construction documents can be completed.  Another reason to stop designing early in the CD phase is that frequent changes near the completion of the CD phase may lead to errors and omissions in the documents.

Change is inevitable, but it does not have to be self-inflicted.  In this period of reduced budgets and staffing, it is irresponsible to re-do work that was essentially complete if it could have been avoided by earlier decision making.   I, too, am guilty of putting things off, but it can be managed through effective prioritization.  Although the construction documents phase is considered one of the phases of design, it does not mean you should continue to make significant design decisions till the very end.

What are your experiences and horror stories involving last minute design decisions?

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Ron Geren