Defining the 5D of BIM
There have been several interesting developments throughout the last few years relating to 5D BIM (building information modeling): cost estimating. Since the BIM model itself is the 3D (and understandably so) representation of the project, 4D has become the de facto standard for the sequencing (or time) element of the project. The next logical progression of the model has been that of the cost estimate, and being able to take not only all of the objects defined in the model, but also those that are not, and being able to accurately estimate the entire cost of the project.
Architects, engineers, and owners in North America have long relied on the specific cost engineering and cost estimating expertise to produce these estimates for the building industry, represented by the top two organizations that have done so for the cost estimating profession throughout the last 50 years.
Both AACE Intl., Inc. (The Assn. for the Advancement of Cost Engineering) and ASPE (American Society of Professional Estimators) were founded in 1956, well before CAD as we know it today became the industry standard way for producing the graphical representation of a project. Outside of North America, RICS (Royal Institute of Chartered Surveyors) has a very long history in establishing standard rules of measurement for the built environment.
In November 2008, these three leading organizations which were already functioning as a joint task force, along with the U.S. Army Corps of Engineers, the GSA (General Services Admin.), and NIBS (National Institute of Building Sciences), entered into a memorandum of agreement to work together through NIBS in forming a team to “solve cost engineering related problems for the facilities industry” under the auspices of the buildingSMART Alliance, a council of NIBS.
The purpose of which was recognizing that BIM is built on the concept of collaboration, and to coordinate cost engineering and estimating throughout the project lifecycle to improve the value of our products through the use of BIM. It was also anticipated many of the products of this agreement would become candidate standards for MBIMS (National Building Information Modeling Standard).
Also around this time, AIA Document E202– 2008, Building Information Modeling Protocol Exhibit, under paragraph 4.3 Model Element Table, was released. Elements represented by the CSI (Construction Specifications Institute) UniFormat classification system exemplify how the commercial industry is giving specific definition to what is expected in a model.
One of the key components of this exhibit is the definition table (4.3 Model Element Table) for the LoD (level of development) required to identify each model element at the end of each phase (of design) and the MEA (model element author) responsible for developing the model element to the LoD identified.
These model elements are not broken down by the traditional CSI MasterFormat, but rather by the CSI UniFormat, which breaks down the project into systems such as substructure (shell, interiors, etc.) and into subsystems (substructure – foundations, basement construction) as an example. This elemental classification system is also known as UniFormat II, and supersedes UniFormat (I) which was developed in the 1970s by AIA (American Institute of Architects) and the GSA. UniFormat II was adopted and first published by CSI in 1998, and just recently updated in 2010 to coordinate more closely with CSI MasterFormat 2004.
This consortium continues to adjust to, and coordinate with these ever-changing standards, so that the process of extracting and processing the 5D (cost) information from the BIM model is clearly defined, especially as the design evolves.
The momentum of this consortium can also be seen in recent documents such as the VA BIM Guide (v1.0 April 2010), published by the Department of Veterans Affairs which states, “It is also critical that national standards and protocols are used in developing the models, such OmniClass, Uniformat, Masterformat, VA National Standards, National BIM Standards (NBIMS), etc., so that information can be machine read and normalized for VA management purposes. Unique GUIDs (GUID – Globally Unique Identifier, which is a unique code identifying each object/space), assigned in the BIM tools, shall be maintained to support data in workflows.”
Further, the guide goes on to describe the process “to facilitate BIM development, the VA has provided the Object Element Matrix that defines object and element properties and attributes by Uniformat/OmniClass classification and Level of Development (LoD).”
Technical lead for the 5D BIM consortium is Tamera (Tammy) McCuen, LEED AP BD+C
Assistant Professor at the Haskell & Irene Lemon Construction Science Division, College of Architecture, University of Oklahoma. Tammy has been a long time member of AACE and has been an ardent proponent of technical BIM as it relates to cost estimating and project controls. The consortium has benefited from each of its members experiences, work environments, and industry association involvement, and has been coordinating as well as influencing these documents and standards as it relates to 5D BIM and IPD (integrated project delivery) methodologies.
In 2007, the AIA published “Integrated Project Delivery: A Guide”, and also addressed project cost by saying, “The overall project cost is a prime metric that is established at the project inception and tracked throughout the life of the project with agreed upon emphasis on lifecycle and sustainability components. Included are the cost of the actual work, non-incentive based compensation (fees for services), and appropriate contingencies. The potential for a direct connection between the design and quantity survey during all phases creates a powerful tool to determine and manage the project cost. This is one of the prime opportunities to see the efficiency possible with IPD.”
From there, the project schedule was identified as another main potential benefit of IPD, especially as it relates to process improvement.
The consortium will continue to fine tune and coordinate with the industry, as well as communicate, as 5D evolves. Additional areas of refinement that will evolve from the LoD identification process will be more robust cost and scheduling integration, where the BIM model will able to be interpreted very specifically to the quantity, quality, and timing of the resources necessary to facilitate the most expedient and cost efficient way of completing projects.
Philip Larson, CCE CEP CPE PMP PSP FAACE FRICS, has been providing BIM consulting services with Project & Cost Control (PC2) since 1992. He can be reached at email@example.com