Monday, December 29, 2008

AIA BIM Protocol (E202)

Despite my recent ranting (aka constructive crticism) about the AIA's communication practices, I would like to discuss one of their newest contract documents - AIA E202-2008: Building Information Modeling Protocol Exhibit.  As recently discussed by Jim Bedrick (Webcor Builders) in a featured article on titled "Organizing the Development of a Building Information Model," the BIM Protocol has evolved from work initiated by Vico Software and Mr. Bedrick which was subsequently presented to the AIA's Integrated Project Delivery (IPD) Task Force.  This document takes an important step towards the effective downstream use of BIM data by a project team.  A free sample can be obtained from the AIA at

In a previous post, I had discussed the use of disclaimers for added protection from liability when sharing native design data with team members outside of the Design Team.  To make the next logical step - from "little BIM" to "BIG BIM" - I have been conducting discussions with my colleagues, peers and our firm's legal counsel about ways to start "chipping away" at the shield (disclaimer) in an effort to establish usable and controllable channels of BIM data.  To that end, the AIA has released E202 to address the issue of integrating BIM data into the contractual environment.  It begins with the general "protocol" in which project teams can define procedural details such as Model Management, Model Ownership and Coordination & Conflicts.  While these areas are important to define, the key part of E202 is the definition of two fundamental concepts:  Level of Development (LOD) and the Model Element Author (MEA).  These two categories are then combined in a matrix for each phase of the project, corresponding to model element assemblies in the Model Element Table described in greater detail below.

Level of Development

There are 5 basic levels of development which do not reflect specific modeling guidelines for any particular software, rather a generic definition of model content and, more importantly, authorized uses of the model for the respective LOD:

SOM_LOD100 LOD 100 - Essentially the equivalent of conceptual design, the model would consist of overall building massing and the downstream users are authorized to perform whole building types of analysis (volume, building orientation, cost per square foot, etc.)

LOD 200 - Similar to schematic design or design development, the model would consist of "generalized systems or assemblies with approximate quantities, size, shape, location and orientation."  Authorized uses would include "analysis of selected systems by application of generalized performance criteria."
SOM_LOD300 LOD 300 - Model elements are suitable for the generation of traditional construction documents and shop drawings.  As such, analysis and simulation is authorized for detailed elements and systems.
Mortenson-Beam Image courtesy of Mortenson Construction LOD 400 - This level of development is considered to be suitable for fabrication and assembly.  The MEA for this LOD is most likely to be the trade contractor or fabricator as it is usually outside the scope of the architect's or engineer's services or would constitute severe risk exposure if such parties are not adequately insured.
FM-lighting LOD 500 - The final level of development represents the project as it has been constructed - the as-built conditions.  The model is suitable for maintenance and operations of the facility.

Note that the above descriptions are merely excerpts from the original AIA E202 document.  Refer to the free sample available from AIA's Contract Documents website for complete details.

MEA's and the Model Element Table

Quite simply, the Model Element Authors (MEA's) are the parties responsible for developing the model content as specified in the Model Element Table.  The Levels of Development are paired with an assigned MEA for each major building assembly as shown in a filled-out sample below:



The AIA E202 Building Information Modeling Protocol Exhibit is a compelling tool for use in the evolving world of virtual design and construction teams.  I have had many conversations with my BIM Specialists as well as project team leaders using it as a basis for development of BIM Management Plans; however, it has not yet become a formal addendum to any of our project contracts.  That will likely change very soon.

The AIA Document E202 is a copyright of The American Institute of Architects and is protected by U.S. Copyright Law and International Treaties.


  1. Did they change the name to Level of Development? I thought it was Level of Detail.

    Does the AGC have anything formal yet on model specifications?

  2. I'm not sure why it was changed to "Level of Development"...maybe to avoid a direct reference to Revit? I don't believe the AGC has anything specific concerning LOD in their ConsensusDocs BIM Addendum other than a line item for the "BIM Execution Plan" which says shall include:

    "The expected content of each Model and the required level of detail at various Project milestones, which content includes:

    - geometric and spatial data;
    - object property data;
    - object constitution data;
    - provision for object parameters as place holders for cost and schedule data; or
    - authoritative source information.

  3. Have you found the need to create a custom version of this document?

    This is something that is being thrown around in our office. Being a contractor who has been creating construction models while the designers are creating design models, our details in LOD descriptions differ. I'm curious if you or anyone else has ran into this.

  4. Dont forget the Vico Software!!

    Webcor Builders tied up with Vico build up the concept and submit it to the technology subcommittee of the AIA California Council’s Integrated Project Delivery (IPD) Task Force. In order to expand the usefulness of the MPS all the opinions of architects, contractors, engineers, subcontractors, owners, and software developers were taken into consideration. The AIA National Documents Committee has approved the approach, provided further development, and included it into the new E202, an exhibit, in the fall of 2008.

  5. One of my clients is already half-way through the building construction and now have his client asking him to quote for an As-Built BIM Model to be produced after completion of the building via Laser to BIM approach. I presume that would fall under the category of LOD 500? They would not have the model grown progessively from LOD 100 to LOD 400 as BIM was no way part of their scope during the design and construction stage. So, how would you propose to integrate the interior elements like Ducts etc. into a LOD 500 model produced from laser that would essentially capture only the "exteriors of the interiors"? Any suggestions?

    Also, suggest if it would be correct to assume that LOD 500 is sort of a unique stage in itself and does not essentially mean that it carries a "further additonal degree" of detail beyond LOD 400 as one would assume it to be?

  6. Something as generalized as a specification by LOD cannot possibly apply in every situation or to every question related to scope of work. The AIA E202 and the associated concept and definitions of LOD levels is a good first step. I have heard rumors that it is under revision. The USACE "M3" has taken another step. Virtual building models are multi-faceted in multi-dimensional space - much like real buildings are. A condensed specification for such a thing is bound to fall short of everything that might be asked of it.

    It's not my blog, but In regard to Mr. Ghullani's question, some of what comes out of a post-completion laser scan may be at LOD 500, but it will only be information which manifests itself as a solid in space, and is visible from someplace an instrument can be placed with its location tied to other scans interior and exterior. A laser scan generates nothing in the way of materials, subsystems, performance, durability, operation and maintenance requirements, (the list goes on). Most Those elements which the laser scan does not touch will be an no greater LOD than they were during construction. This sounds like a case of someone being sold a laser scan as a new way to quickly create an "as-built" document/model. It can only make a start at that.

  7. The 5 basic levels of development are explained clearly.But did they changed the name of level of development ?

  8. For a description of the difference between Level of Development and Level of Detail look at this blog post: