Streamlining Design-to-fabrication With VDC and Constructible BIM

Owners, contractors and fabricators are recognizing that VDC and BIM create advantages for more efficient design and fabrication, making the technologies well worth the upfront investment.
By Brett Stacks
October 16, 2017

The introduction of the integrated project delivery (IPD) project cycle is putting more of the onus on general contractors, mechanical contractors and specialty contractors to have a larger stake in the game when it comes to design.

While general contractors have long been some of the most advanced users of BIM technology for its ability to facilitate collaboration among design teams, architects, engineers and contractors, traditionally the mechanical electrical plumbing (MEPs) and specialty contractors have limited their BIM adoption. That’s because, in general, industrial components and connections are more technical than those in the built environment and therefore more complex. More challenging is that, historically, there’s been a lack of data from MEP manufacturers that is readily usable by most BIM applications.

Other barriers to BIM adoption generally center around perceived high investment costs and the time required to learn new workflows. Thankfully, that’s all changing.

Owners, contractors and fabricators are recognizing the advantages that virtual design and construction (VDC) and BIM create for more efficient design and fabrication are well worth the upfront investment. In fact, a report from the National Institute of Building Sciences found that 93 percent of respondents in the architecture, engineering and construction (AEC) industries had used offsite fabrication methods to some degree over the past year. Of that share, respondents said the main benefit of offsite fabrication was its ability to reduce project timelines and its cost effectiveness.

With greater BIM adoption, MEP contractors now have a significant opportunity to drive deeper collaboration and engagement which correlates directly with improved ROI.

BIM evolved

To better leverage content-rich models, MEP contractors need to continue to drive the end-to-end BIM process. With a BIM-based design and fabrication workflow, project collaboration and project coordination improve internally as well as with partners, clients and other stakeholders. Consider moving toward full BIM adoption to gain even greater value across the fabrication, manufacturing and assembly workflow. Here’s how to do it:

Develop Fabrication-ready Models

When all project stakeholders work from the same model, it becomes the de facto standard for everything involved in the project. Not only that, when all parties are working from the same platform live project collaboration is possible. With a traditional federated BIM workflow, as with CAD design for example, everyone is working on individual files, meaning the process can become fragmented because there is no parallel workflow between modeling and documentation.

However, a centralized or integrated BIM workflow rectifies this because there are built-in dependencies in the platform where changes made to the model are bidirectional and updates are made automatically. This supports real-time, live collaboration because the information in the model is always up-to-date. When everyone is working from the same platform, this also eliminates problems caused by model conversions and file exports.

Hiccups around trying to make disparate platforms "play nicely together" can delay the coordination of each contractor's model and eventually delay the contractor's own planning for procurement, fabrication and installation.

Communication is also streamlined with 3-D visualization of the model which allows for quicker decision making during design and pre-construction phases. When CAD or Revit models include real-world information about MEP components and ductwork, including levels of development 400-level detail, contractors not only have a sharper understanding of design intent, but also the model is suitable for fabrication, assembly and installation of components. Fabrication-ready models that have the actual system components included, based on manufacturer name and part number, allows fabricators to produce pipes, fittings and hangers much more quickly and accurately.

A critical step to full BIM adoption for prefabrication should include a "one BIM model" mentality. This means that when the model changes relating to MEP racks, metal studs, ductwork, conduits, pipes or electrical components, schedules, costs and materials requirements update automatically. With greater BIM adoption, all stakeholders have the correct views and updated timelines. This can save significant time in the prefabrication process and on-site assembly process.

The dynamic BIM model also addresses design issues before construction begins, which means labor and material costs are reduced and design accuracy is improved.

Greater Adoption, Greater Value

The higher adoption of BIM, the higher value delivered when the model is the basis of fabrication and assembly. The next chapter of BIM adoption starts with the creation of more intelligent, constructible 3-D models, where one model includes real-world manufacturing-specific content that ready for fabrication. This way, MEPs can provide input into the design based on their own construction specifications and experience. When the model can be used to fabricate pre-manufactured components such as ductwork and cable trays that can be delivered in racked systems or modules, this is significant potential for productivity gains and cost savings.

Interstates Companies, Sioux City, Iowa, is an example of a leading electrical contractor that has evolved to full BIM adoption strategy, with impressive results. Adam Jeninga, a planner who works on Interstates Companies’ product development process team, explains, “We’re in the process of virtually modeling the entire system down to the smallest conduit. This gives us the ability to identify problems early on and plan out our installation in stages. By going the extra mile and more fully leveraging BIM, we're able to plan much more carefully, reduce errors and conflicts and use our team much more efficiently. On our recent job, we are showing three times labor savings compared to our traditional way of doing things."

Deliver on Real ROI Potential

Because typical fabrication of hangers, pipes, ductwork and electrical components requires very technical cut sheets consisting of dozens of pieces, elevations and fittings, the fabrication process has traditionally been somewhat error-prone and inefficient. This is also why a more automated and accurate fabrication workflow has the greatest potential for ROI. BIM is an incredibly powerful tool for validating spatial coordination, but it needs to be taken to a higher level to support fabrication.

When the design-intent model literally becomes the fabrication model, there is a significant reduction in risk quality as well as accelerated project schedules. One full-service mechanical system solutions provider established a new fabrication workflow for producing piping spools and fabricated skids. The team developed the fabrication workflow first for the fabrication of hangers, and then for pipes and components. The Indianapolis-based contractor then applied the revamped workflow to a large molecule research facility build.

The company knew it wanted to eliminate manual steps for fabricators and improve the accuracy and efficiency of everything from fabrication through installation and was soon able to fabricate approximately 90 percent of components offsite. This reduced their footprint on the job and allowed for increased efficiency among partners, giving them more time and access to complete their work.

By validating the install in the BIM model first, the contractor increased savings and reduced rework and change orders required dramatically. The company is now achieving nearly 10 percent shared cost savings with its improved spooling and fabrication process— resulting in $1 million savings.

While BIM modeling is nothing new in the AEC industry, it’s more evident than ever that a significant opportunity still exists for MEPs to deliver greater value through full BIM adoption and the further implementation of VDC principles. Advantages of greater BIM adoption are many, including improved collaboration, greater communication of the design intent of each component, less rework, labor savings, productivity gains and overall higher quality design.

At the heart of the shift is the adoption of more information-rich models which MEPs can extend into the offsite prefabrication process. Those MEP contractors that can most effectively leverage a BIM-based design and prefabrication workflow will have greater understanding throughout the design process as well as the largest competitive advantage.

by Brett Stacks
Brett Stacks, segment manager, MEP Solutions at Trimble, got his start as a sheet metal worker over 20 years ago and has since then been passionate about improving the technologies and processes for virtual design and BIM through his management positions at companies including TSI, Autodesk, QuickPen and Trimble. He currently oversees product development of Trimble’s BIM and 3-D CAD detailing solutions for MEP contractors.

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