Promises, Promises

A long time ago, in the early days of AutoCAD, I went to a seminar where an electrical design and estimating system was demonstrated. It was amazing! The system actually did a takeoff while the design was being done in AutoCAD. It also provided specialized tools for electrical design that could be used in AutoCAD. I was very excited and was imagining all the ways this system could cut estimating time. I believed that all the engineers would use this system and then send the files to the estimators so we could extract the quantities in just a few minutes.

Unfortunately, that was where the process stayed; in my imagination. In 30 years of estimating, I have not been able to get an AutoCAD drawing during the bidding process. The designers told me that they were afraid I could change the drawings before the bid. I have heard the real reason has more to do with the designers not wanting to be responsible for counts and measurements.

So now building information modeling (BIM) has come along with a whole new set of promises. Not only are we going to be able to do a takeoff with a push of a button, but also all of our routing and layout problems will be solved in the design. Do I believe it? Well, yes and no.

Let’s explore the possibilities

Three-dimensional building models have been around a long time. What makes BIM different is the “I,” information. It is possible to have these models contain all the information we need to complete an estimate in an extractable form. Push a button and get a completed takeoff in seconds. What used to be just a symbol on a drawing is now an object, which can have properties such as cost, manufacturer’s information and relationships to other objects. That “S” with a line through it can possibly tell you it is a Hubbell No. 1221 mounted 48 inches above finished floor with a stainless steel plate in a 5/8-in. drywall partition. Take note that I wrote “possibly.” Someone has to put that information in the model. The designer could very well just indicate that it is a switch.

It is also possible to have the takeoff automatically entered into an estimating system. There are, however, a number of hurdles to clear before this becomes an everyday thing. I spoke with Kevin Yu at Innovaya about this. His firm—and others like it—has created third-party software to bridge the gap between a BIM application and an estimating application. The software “learns” to interpret the information in the model’s database and translate it into a format the estimating database can understand. Below are some of the hurdles.

And the problems are …

The first hurdle has to do with standards, which are a big problem. Each design firm has its own way of doing things, including the names they use. A specific type of material can be called many different things. For instance, galvanized rigid conduit, galvanized rigid steel, heavy wall conduit, GRC, RSC, and GRS are all names used for the exact same material. If your estimating database calls it GRS, and the model calls it GRC, this could be a problem.

Another hurdle is level of detail. Will the models contain all the information you need to complete a takeoff? For instance, will the model indicate all the fittings and supports needed for a large conduit run? If not, can the software fill in the blanks? How will the model deal with waste and makeup?

The next hurdle: Can you trust that the model is complete? Complete bid documents are not exactly the trend we are seeing these days. Human intervention will still be required to study the model and complete the takeoff.

So, will BIM have an impact on estimators? In the hard bid world, I don’t think so. First, I do not believe designers will ever part with live files before the bid. I imagine they could come up with a type of file that would allow us to extract quantities while locking the design, but I am not holding my breath. Second, I do not believe the designers will be willing to create a complete model for a bid, given the condition of the drawings we are being provided now. 

That being said, I believe BIM will be used for estimating design/build projects in the near future. The tools are maturing, and general contractors are using BIM-based estimating now.

I spent quite a bit of time looking for someone using BIM for electrical estimating and did not find anyone. If you are using BIM for electrical estimating, please contact me.

About the Author

Stephen Carr

Estimating Columnist
Stephen Carr has been in the electrical construction business since 1971. He started Carr Consulting Services—which provides electrical estimating and educational services—in 1994. Contact him at 805.523.1575 or .

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