Level of Development (LOD) BIM Specifications for Metal Buildings

When designing and constructing metal buildings, an increasing number of professionals are using a computerized building information model (BIM) as their primary tool. This allows for detailed, three-dimensional computer models to be created, not only to develop the design, but to identify material lists, coordinate details, avoid conflicts between building systems and streamline the design and construction process.

Problem: BIM Coordination

Of course, design is a process that requires some back-and-forth between multiple parties to arrive at the best final solution. So, when a metal-building supplier or manufacturer is asked to provide their information to be incorporated into a BIM process, the question that naturally comes up involves the level of detail. This is common across all trades, and fortunately, there is an organization that is addressing this issue. Known as the BIMforum (www.BIMForum.org), is is the not-for-profit United States chapter of buildingSMART International, and its mission focuses on improving BIM technology, collaboration, education, innovation and open information exchange. As they describe themselves, “Co-sponsored by the Associated General Contractors of America (AGC) and the American Institute of Architects (AIA), BIMForum seeks to lead by example and synchronize with counterparts in all sectors of the industry to jointly develop best practice for virtual design and construction.”

Solution: Level of Development (LOD) Specification

A flagship publication of BIMForum is the 2016 version of Level of Development (LOD) Specification. Having evolved over several years, this publication is “a reference that enables practitioners in the AEC Industry to specify and articulate with a high level of clarity the content and reliability of Building Information Models (BIMs) at various stages in the design and construction process.” Coordinated with other industry standards, it “defines and  illustrates characteristics of model elements of different building systems at different Levels of Development.”

Essentially, it defines and standardizes how much detail is expected in a building information model at different stages of design development. Therefore, if a metal-building manufacturer or any other trade is asked to supply its BIM information, then it needs to ask “What Level of Development?” so that is it providing the right amount of information to coordinate with the larger computer model for the building.

How LOD Works:

The LOD Specification is based first on the familiar Uniformat specification sections used by most spec writers. Metal Buildings commonly fall under Special Construction in Section F1020.40 in the Uniformat approach, or 21-06 10 20 40 in the Omniclass approach, and are found that way in the LOD Spec. From there, five levels of detailing are described by the numbers 100, 200, 300, 350 and 400, as described further below.

  • LOD 100 – This is the most basic of model, described as “Generic mass of special structure with system typically noted with a design narrative for conceptual pricing.” It is likely that this level of BIM is already developed by an architect or engineer and given to a manufacturer or supplier as a starting point.
  • LOD 200 – This level calls for basic primary structural member sizing, generic representation of secondary framing, and general cladding and exterior trim to be provided, including openings.
  • LOD 300 – More-specific sizing of all needed primary frame structural members, web tapers, frame connections and similar details are called for at this level. Similarly, secondary framing needs to be shown, including purlins and bridging, girts, subframes and base conditions. Exterior panel and trim with actual profiles, actual openings and all significant trim and accessories are shown here.
  • LOD 350 – This level starts to show coordination with other elements or building systems. Therefore, for the primary structure, things like base plate locations, bracing/gussets, clips and any reinforcement all need to be included. Secondary framing elements need to include similar details, such as nested members, connections to primary structure, any miscellaneous or secondary steel members, bridging, etc. Cladding and exterior trim would include all actual profiles, closures, downspouts and all minor trims shows at least generically.
  • LOD 400 – This is the full-fabrication level equivalent to shop-drawing level of detail. As such it includes all final details, including welds, bolts, holes, cinching and all other details of fabrication and assembly for primary and secondary framing, plus all cladding and trim.
Level of Development (LOD) Specification Example – image courtesy of BIMForum.org

By using these standardized Levels of Development, all design and construction professionals can proceed in an orderly sequence to provide the appropriate information, receive coordination feedback and then move on accordingly to the next level.

The full 2016 LOD Specification can be downloaded for free at http://bimforum.org/log/. The specific information for Metal Building Systems can be found on pages 177–186. For information on how to work with a manufacturer to provide the appropriate BIM information, contact your local MBCI representative.

BIM: Has it Lived Up to the Hype?

Five years ago, I remember people talking all about Building Information Modeling, or BIM, and how it was going to change the construction industry forever. Furthermore, if you were a building product manufacturer and didn’t have an established presence in in the BIM space, your products were going to become obsolete overnight. Shortly afterwards, a giant Alaskan Bull Worm (Yes, I just dropped a Spongebob Squarepants reference on you) was going to devour your manufacturing facility, destroy your employees’ neighborhoods, and you would spend the rest of your days huddled under a bridge and eating food you grow in a ditch.

Well, here we are five years later and I’m looking around and see nothing of the sort. Yes, BIM is a powerful tool and is used on many high-profile projects. Yes, it is very helpful to architects, engineers, and general contractors. Yes, it gives building product manufacturers a new marketing medium. But at the same time, it seems like only a very small percentage of most building product manufacturer’s bread-and-butter work is chained to having BIM content. So what happened? Well, I’ve asked some architects and general contractors who are trusted advisers of mine that question and the answers I received are very interesting and sparked me to write this blog. I’m going to warn you now that this blog is purely my opinion and I’m going to float some theories that are more gut feel than researched fact. If you don’t agree with me, I welcome your opinion and would love to hear from you. I’m a big believer in the concept of a healthy disagreement, so don’t be shy.

First, let me answer the question that is the title of this blog. No, I don’t think it has lived up to the hype. That alone may spark a debate. But to me, it has not and there are a few reasons I think why not:

BIM was over-hyped in the first place – Badly, as in worse than Water World. (Poor Kevin Costner will never live that down, will he?) I work a lot of trade shows in this industry and every one I’ve been to in the last five years had multiple BIM demos from a software company. In between demos, people worked the floor visiting all of the other attendees trying to convince them that they needed to develop BIM content or they were going to go the way of the Dodo, Betamax and cassette tapes. I bought into it and led an effort in my company to get in the BIM space. That process taught me a lot and I’m glad I did it. But in that process, I realized that the software company seemed to benefit a little more from the effort than we did. After all, I was developing content for their software and then paying them to host it for me. Look, hitching your wagon to successful products with a good reputation is smart business, so I’m not saying they did anything wrong. But I do think some of the software suppliers played the fear card to product manufacturers, who admittedly are an excitable bunch, to get that to happen.

BIM Content is not locked down – Anyone can download BIM content from someone else and change it to their heart’s content and the original author will never know. That’s a good thing and I’m NOT saying that BIM content should be locked down. But you can’t put too much work into your content as a manufacturer without quickly realizing that all a competitor has to do is download a copy, change your name to his and he is in the same position you are with less than 1% of the effort. At the same time, to not openly distribute your content for that reason is not really a good idea because there are real marketing advantages to treating it like a business card. However, that advantage is over once the content is in the hands of your competitor and I believe that is a huge reason why many manufacturers have been resistant to make anything but a just a basic, almost token, effort to be a BIM player. Along similar lines, many architects and engineers view digital copies of their work as intellectual assets and (rightfully so) aren’t real wild about turning their models over to the digital space for that reason. At least when it is in print, somebody still has to convert it to digital form.

Liability Concerns– The core benefit to BIM is the ability to have a virtual building. That’s huge. It means you can know exactly where everything goes, what it will look like, how much space it will need, how it will move, etc.  That takes a lot of uncertainty out major questions like how long will it take to build this building? How much will it cost? Will it function as intended? Obviously that’s not just a good thing, it’s a great thing and in theory would reduce liability tremendously.  But that’s IF everything is modeled right…scratch that…perfectly, and that is never going to be the case because the people using the tool are humans. Many architects, engineers and general contractors I’ve talked to are deeply concerned that the amount of time it takes to get everything nailed down to the gnat’s you-know-what will result in an increase in time (and thus fees) that the market simply will not bear. However, that is the owner’s expectation now because the software does have that ability. That perception-reality gap results in an increased liability on engineers, architects and especially the general contractor.  If an unexpected problem happens, the owner is there saying, “You had a BIM model, you should have seen this coming.” This just in: General contractors get sued… a lot.

Let’s be very clear here: I’m a BIM proponent.  I think it is a good thing and will change the construction industry significantly over time. Just not as much as everybody is saying nor as quickly as they are saying it will change.  Of all of those reasons, I think the last reason is the most significant and it actually has nothing to do with BIM; it is really a people issue. To me that says that it is not actually the shortcomings of BIM holding BIM back but instead well-meaning people who might be trying to use BIM out of its natural context.

Here is the point of this blog:  BIM could live up to its hype if it is utilized in a way that addresses the liability issue and provided the entity responsible for the model a direct benefit to having a near-perfect virtual building, which is undoubtedly the strength of BIM. When does that happen? The Design-Build contract, that’s when. In this case, the architect is working for the general contractor, who benefits highly from having the model because of the ability to do clash detection and construction phase modeling, just to name two. With that motivation, he is more than willing to pay the architect and engineer the extra money to do the modeling down to the gnat’s you-know-what.  It’s truly is a win-win.

Say what you will about BIM.  At the end of the day, it is not BIM that is in control of our industry, it’s us. If we all work together to create a favorable playing field to let disruptive technologies take hold, they will. If we don’t, they won’t and our great grandchildren will be building their buildings just like we did while everyone rides around in flying zero-carbon cars that did live up to their hype.

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