e-News #84: Building Information Modeling

February 1, 2012
 
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Building Information Modeling:
A Holistic Approach to Facility Design and Planning

What is Involved?

Industry practice has been for architects and engineers to use Computer Aided Design (CAD) software for planning and designing a new facility or retrofit project. Sets of two-dimensional drawings are produced and used to construct the building. From these sheets, Scopes of Work are developed to be bid and completed by various trades, changes to the design are tracked on site, and a post construction "As-built" revision of the original design is recorded and left with the building Owner for their records. Due to the static nature and hierarchy of this process, there is increased risk for common coordination issues to arise, and for information to be missed, resulting in schedule delays while RFI's are answered.

Figure 1: Using a 3D modeling program to design all systems within the building, design disciplines can work together to more effectively coordinate space requirements, designing a leaner, more efficient building.

Figure 1
click to enlarge

Clash detection can occur during design, reducing RFI's once the project gets to the construction phase. For example if a light fixture is placed in the path of a supply duct, this could be a problem during construction, wasting time and money, and could result in the electrician having to return to the site to move the light fixture, or an RFI to the design team to redesign the duct work. A project using BIM can identify the conflict during design, saving the owner time and money before those issues arise during construction.
Photo courtesy of RLF

With advances in computer technology, there is a change moving through the building design and construction industry. The Architectural and Engineering (A/E) community, as well as many general contractors, is increasingly implementing Building Information Modeling (BIM). BIM is the process of building a 3D data rich model of all architectural, structural, mechanical and electrical systems in the building. The model is not only used to design the building and document it for construction, it's also used as the primary tool to create and coordinate design solutions. "It really is a game changer," says Keith Holloway, a Project Manager with RLF. "A lot of companies are trying to treat it like a traditional drafting tool, but doing it that way just adds extra steps that aren't necessary and are counter productive to the end deliverable."

When using BIM on a project, early involvement of all parties responsible for final completion of the facility is recommended. Everyone including the owner, architect, design engineers, general contractor, and associated trades have input in the process from the beginning. This early input means combining field experience with vision and the BIM model helps merge real-world with design-world. Much of the reason that there is a need to create as-built documentation following construction is the fact that adjustments are made in the field, whether it be for constructability, cost savings, etc. It is often the case that 'rules of thumb' may be applied during the early stages of design and will remain unless and until they are vetted out by the design team and owner. On large projects it is possible that these items, especially if small by relative significance, go unnoticed until the tradesman is trying to route equipment or apply a finish that can't be done to specification.

In addition to creating and detailing design solutions, BIM increases coordination among the many disciplines involved in the building delivery process. As mentioned before, the more typical practice is for A/E firms to produce electronic drawings for a project that include two dimensional 'floorplan' layouts on a by-floor or by-section basis. The architectural views within this electronic CAD file act as the background and layout for spacial reference of the engineering systems and other infrastructure. Layers are then placed over top of this reference to view mechanical, electrical, structural, plumbing, fire protection, and any assortment of other specialty systems or details that need be applied. Working in 2D means that many calculations and measurements are done outside the CAD model, to ensure everything will fit above the specified ceiling height, or to do area take offs for cost estimating. This process leaves a lot of room for error, as the structural engineer who is planning beam depths is simultaneously doing their calculations with the mechanical engineer who is sizing ductwork.

Verticality is Key

Applying a third dimension to the drawing set is not a new idea, but allows for greater detail and understanding of the building. Architects have applied three dimensions to their projects throughout history to allow greater representation of the intended finished product to the client. Models began as cutouts and handmade structures to demonstrate orientation within surroundings or proximity to other buildings within a campus. Naturally these have progressed to simulated BIM renderings through programs like Revit or Navisworks to review external finish work and perspectives of the intended facility. What this provides is a greater depth of understanding and analysis to members of the design team and support staff. Being able to 'walk' through a hallway virtually, see how daylighting plays across the room, what fixtures hang from the ceiling above, to the detail of how ductwork will run from the air handler to interior offices. This model is about reviewing and ensuring that the owner's criteria and basis of design are met efficiently while providing a look at the final result. The author of 'Engineering-centric BIM' states that "Creating a multidisciplinary 3D integrated model of a building is a valuable tool…but if it does not enable interoperability, then it is not truly BIM."

Advantageous to the Owner

However, increased coordination and better modeling are not the only advantage of using BIM tools on a project. The following benefits can also result from creating a 3D model before construction begins:

  • Promotes sustainable design through less material use and integrated tools for energy and daylight simulation.
  • Provides better information for cost estimating purposes. This is very important when it comes to access issues and timing for installation of critical, large, or specialty components.
  • Promotes efficient scheduling; reducing costs associated with rework in the field.
  • Reduces materials being stored on site; creating a safer site and less chance for items to be damaged prior to install.
  • Allows analysis of alternative design options to resolve conflicts early in the process and increase value.

BIM Still Improving: ASHRAE Headquarters Remodel

Ultimately the goal of the BIM method is to create a single packet of data referring to the building. This should include energy modeling and performance analysis, even at the basic level, to provide the owner with operational cost projections and trade-offs from design decisions. The challenge lies in formatting the data set to be compatible with the most appropriate energy/ daylight modeling software for the building type and proposed systems. During a recent test of the BIM method by the American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE), researchers conducted a trial using imported information from a BIM model for their headquarters renovation and found that the "models produce impressive graphics" but "BIM has been overhyped" when it comes to the transition between different programs to perform the needed tasks. Instead of being able to directly transition the design data from the BIM program to the energy analysis software, it became apparent that it would take less time (and thus be less costly) to re-build the geometry and systems in the energy model from scratch. These results were reported in an article 'BIM Test at ASHRAE HQ'.

Despite its noteworthy advantages, BIM software has been widely available for many years, without significant market adoption. Only 50% of the industry is using BIM, though it has been gaining momentum since 2007. Whether it's because of software issues like the one described above, firms can't afford the training or expertise needed, or project budgets aren't structured to accommodate the early effort, BIM seems to still be up and coming. But for the design and construction firms that have embraced BIM, the benefits far outweigh the costs. Seventy percent of BIM users who measure ROI see positive returns.

Case Study: Veterans Affairs Medical Center, Orlando Florida

The reason BIM users are such proponents is because BIM has advantages for every member of the design, construction and operations teams. Figure 1 below shows how each member of the Veterans Affairs Medical Center Team has a stake in the planning process and is able to retrieve the specific data they require from a central repository.

Figure 2click to enlarge

Figure 2: Process and data flows in a project utilizing the BIM approach.
Figure courtesy of RLF

Using BIM on a large and complicated project such as a medical campus provided the team with the data necessary to conduct analysis in other useful software packages, and in some cases, export data back into the BIM model. This "streaming data concept" allowed for increased coordination, and for each team member to have the final information needed to complete their project responsibilities. In addition, from the project initiation phase, the BIM model was intended to be used by the contractor and eventually the owner for facility management purposes.

Not only did the software provide a 3D model of the building for design coordination purposes, but data was also extracted to manage program, equipment counts and other information important to project stakeholders. For example, Figure 2 below shows a data table generated by the BIM program that compares client programming requirements to those achieved by the final design solution. This information was used to illustrate accomplishment of project goals to the client, and it was used by medical planners during design to develop an optimal solution.

The following benefits that were attributed to the use of BIM were identified for the VA Medical Center project:

  • Ability to manage costs and budgets
  • Streamline the workflow
  • Improve team communication
  • Resolve conflicts
  • Analyze design options
  • Calculate lifecycle usage

These benefits were recognized by some of the key players in the project, represented by these statements:

Architect:

"Due to the enormous scale of the project,...the use of BIM and associated technologies has been key to providing an integrated medical campus…"

Owner:

"The use of BIM has assisted the owner in numerous ways including showing a three -dimensional fly-over… and developing lists of equipment items. Information directly from BIM is used as…procurement planning and preliminary equipment budgets"

Contractor:

"As construction began…it was extremely evident that the use of BIM enabled the entire project team to identify and resolve potential issues that may have had a substantial impact to the future phases of the project."

In the Industry

As it stands currently, there is no formal oversight committee or group that defines and manages what BIM entails and the extent of its use. However, there are groups such as GSA, DOD and the VA who are currently working to establish standards for BIM solicitation and contract language, constructing BIM toolkits and publishing BIM Guides. In addition, the buildingSMART Alliance, part of the National Institute for Building Sciences (NIBS) is developing a standard, dubbed NBIMS-US that is scheduled for release in December 2011. There are many options for BIM software available and appropriate software must be chosen carefully to ensure accurate data sharing between software packages when necessary. For example, AutoCAD, Revit or Navisworks, Radiance or AGI32 (for lighting), and Design Builder or eQUEST (for energy analysis) may be used on a single project. The selection of software will also determine up front licensing costs and training needs for the individuals utilizing the software.

Figure 3: Example Data Table Generated by BIM
Figure 3
click to enlarge

For references and resources there are many networking and professional groups that can provide lessons-learned about the BIM process. Trade groups like the American Institute of Architects (AIA) post articles and resources for designers. Multiple user-groups have formed on sites like LinkedIn to network design and construction individuals.

The exciting truth of BIM is that the concepts are not necessarily new in and of themselves. Where the innovation comes is the application of those same tools that we rely on for proper design and construction to new points in the process and including additional trained personnel to ensure quality design and delivery becomes a reality. We design all manner of retail products in this virtual environment to be reviewed and approved before the first generation is off the line. Many of the same concepts apply to the buildings we construct today. The result is one chance to build it right and the effects of mistakes early on only compound time, cost, and stress in team relationships. With the increasing use of the BIM approach to facility design and planning, additional advances will be made in modeling software integration and centralization of project data. Trained professionals can also begin to establish best-practices for use in the years to come.

Training Highlights

California utilities offer outstanding educational opportunities that focus on the design, construction and operation of energy-efficient buildings. Listed here are a few of the many upcoming classes and events; for complete schedules, visit each utility's website.

Financial Analysis of Energy-Efficiency Projects
This workshop will expand the definition of "owner-occupied", overcoming myths and organizational inertia, find opportunities for energy-efficiency improvement, and quantifying the benefits of contemplated upgrades.

Friday February 10,
8:30 am to 4:30 pm
San Francisco - PEC
register >

EnergyPro Software for Beginners
EnergyPro computer training is designed for architects and others involved in documenting Title 24 compliance. This class introduces the basic input and modeling requirements used to document commercial building envelope, lighting, and mechanical systems with Title 24 Standards.

Thursday February 6,
8:30 am to 4:30 pm
Irwindale - Energy Education Center
register >

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e-News is published by Energy Design Resources (www.energydesignresources.com), an online resource center for information on energy efficiency design practices in California.

Savings By Design (www.savingsbydesign.com) offers design assistance and incentives to design teams and building owners in California to encourage high-performance nonresidential building design and construction.

Energy Design Resources and Savings By Design are funded by California utility customers and administered by Pacific Gas and Electric Company, Sacramento Municipal Utility District, San Diego Gas and Electric, Southern California Edison and Southern California Gas Company, under the auspices of the California Public Utilities Commission.

EDR_eNews_084.pdf

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