BIM is for design engineers and architects.

Well, that’s true. Building information modeling has become an essential item in the toolbox for those professions. The modeling software’s ability to identify and eliminate spatial conflicts before construction ever starts in the field is significant.

It’s also true that using BIM is far less common among mechanical contractors — in part because it wouldn’t make much sense for residential contractors, and in part because it hasn’t been an essential investment for contractors doing business in the commercial arena.

That much is a sort of 2-D picture of BIM. Walk around the situation, though, and a 3-D image starts to emerge. All of that initial stuff is still true, but gaining the information in that “third dimension” adds the depth of understanding that can influence some meaningful financial decisions for contractors.

See what some mechanical contractors who have embraced BIM have to say about their experiences and what advice they would give to companies considering taking the leap.



The design and architect community has been relying on BIM for a good while, but BIM inherently provides a bigger payoff as it gets used more widely within the project team. So after a while, gravity kicks in: Some general contractors start using it for tighter coordination with the engineer and architect. Then a lot of general contractors are using it, and then they start looking at the other end of the sequence of construction events and wondering about the possibilities.

In 2013, PGA Inc., a multidisciplinary mechanical firm in Weston, Wisconsin, saw what was happening and implemented BIM into its workflow. William Burton, the company’s director for CAD/BIM/EST, said the decision was made as requests for coordination and BIM deliverables became a prerequisite to be considered as a bidder.

Burton confirmed the commonly assumed upside of BIM: costly fixes or adjustments in the field go way down, and that saves money and time. The third dimension of benefits also begins to reveal itself, too.

“Not only eliminating unforeseen clashes,” Burton said, “but it has the ability to allow subs to prefabricate parts of their work at their shop, under indoor conditions, to speed up the process on the job site.”

Going a step further, Burton said that requiring full BIM coordination prior to any mechanical subcontractor starting work has proven to be valuable to all participants.

That’s something he has seen from various perspectives, since Burton coordinates the BIM work for not just the mechanical but also the company’s electrical and plumbing responsibilities.

Justin Ross, project manager, Kahn Mechanical in Dallas, shares that assessment. Having that tangible, visible plan, he said, contributes to an orderly installation and enforces a level of contractor accountability. BIM coordination gives everyone confidence that what is intended to fit can actually fit, he noted.

Before anyone gets to the site, though, Ross said that BIM has already helped the team visualize theories and designs without spending exorbitant amounts of resources with mock-ups or trials and errors.

As for stereotypical change order avoidance, Ross pointed out that time in the field isn’t the only thing getting saved when BIM avoids a clash. The owner and rest of the team also dodge the need for a new change to be created, distributed, priced, negotiated, and released.



Ross participated in this article while working on a 46-floor office project in downtown Dallas. He reported that coordination started in 2017, ground was broken in September 2017, and they were now modeling the upper floors on a trade-by-trade basis. For that project, Kahn’s scope of work covers the air conditioning, including condenser water piping, air conditioning and heat exchange equipment, and air distribution/ductwork.

Kahn and PGA represent how the choice to embrace BIM can serve a contractor well. They also represent the fact that  contractors have another choice in how they bring the software modeling into their existing business models.

PGA expanded its staff and created a dedicated leadership position. Burton guides that team, and that suited PGA’s sensibilities.

On the other hand, Ross acknowledged that a BIM startup process for a contractor has its costs: “Software, training, personnel, computers, etc. … If the capacity to sustain this type of addition is there, it would make a lot of sense to go that route,” he said. “But if that’s not an option, there are plenty of third-party BIM modelers/coordinators to subcontract. That’s what we did for our current project.”

As a result, Kahn is supervising a team similar to Burton, but the two modelers — one focusing on piping and the other on ductwork — aren’t Kahn employees. The trio would call into a weekly meeting that could last anywhere from 90 minutes to a half-day.

“Due to so many trades being involved in the coordination, an intense focus is required to ensure that all fitment and access meets codes and designs,” Ross said.

He can do some rudimentary navigation through the software to evaluate things, but the modelers bring years of experience and can “fly through” the model. On the current job, Kahn employed BIM not only for field coordination between trades but also, as Burton had pointed out, for piping prefabrication.

Ross reports that his team uses Navisworks and Revit for recent work. Similarly, Burton’s team at PGA also uses Revit MEP and Navisworks, along with BIM 360 Glue.



Having taken different paths to developing BIM as an asset, the two men have picked up some different nuggets of advice to offer contractors who are contemplating making a move.

“Research software carefully,” Burton said. “Talk to the architects and firms you collaborate with. Find a solution that is compatible with them, not just what seems to work from your perspective.”

Some contractors may be using CAD but not BIM, and Burton recommended building in some time for that transition.

“The parametric 3-D world is a bit of a hurdle from 2-D,” he said. “Give yourself three to six months … find a smaller ‘pilot project’ to work on to work out the kinks.”

Then, it’s a matter of setting up BIM office standards, workflows, and expectations for the team.

Working from Ross’ particular role has its challenges as well. He singled out “scope creep” as a serious hurdle to efficiency.

“Keep a firm grip on what’s being modeled,” he warned, “and define boundaries very clearly from the start.”

BIM does entail some financial upkeep along the way. Ross pointed out that software licenses have to be maintained, personnel beyond the hired modelers will spend some time in the software, and there are the aforementioned meetings.

And to be fair, it’s not like using BIM is a 100 percent change order avoidance mechanism. Those changes can come in for any number of reasons, and when they do, a redraw will be needed, and the redraw will represent an owner expense.



Speaking of the owner who may be weighing the investment for a project, Ross brought up a few considerations. Is it a situation where a rigid schedule will make delays especially painful? Is some of that time-saving prefabrication a necessity or not so much? Does the space involve those classic highly congested areas where it could pay dividends to sort out issues on a screen rather than in the field?

That said, he observed yet another dimension to the possible upside.

“A fully modeled BIM system will also allow the software to produce a bill of lading, so more accurate material quantities can be known,” Ross said.

That advantage has a ripple effect that naturally translates to better labor and materials estimates and thus a more accurate overall budget. Everyone tends to like those.

Overall, this is a technology that will create a spike on the coordination side of things but then frequently save a significant amount of time on the execution side. The reduced time on-site can have at least one unexpected but logical consequence. When Dodge Data & Analytics talked to a group of architects, engineers, and larger contractors in 2016, over 40 percent of them reported at least a 5 percent reduction in reportable safety incidents as a result of BIM use.

A more frequent benefit of deeper BIM coordination for contractors? The same Dodge study found that 70 percent reported a decrease in requests for information during the process, saving additional organizational labor.

Of course, for contractors focused on the commercial side, there won’t be any project headaches avoided or money saved if someone else won the work in the first place. That’s an area where the experiences of Burton and Ross dovetail smoothly into the same sense of the market.

“When I started in construction in 2010,” Ross recalled, “it was a cool new toy that had to be sold. Now, not having BIM capability can disqualify a contractor from a project.”

Publication date: 1/21/2019

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