Duct Banks: Advanced Feeder Takeoff

I perform many takeoffs for industrial projects. One of the significant differences between commercial and industrial work is the feeders, which can account for more than 80 percent of the time needed to complete the takeoff. In particular, water and wastewater projects can have exceedingly complex feeder layouts. They often consist of hundreds of power and control conduits leaving a central location and then branching out to the various facilities in the plant.

Early in my estimating career, I was content with the paper forms we used for feeder takeoff. When computers came along, I was thrilled with the feeder input modules in the estimating programs I used. However, as I started bidding more complex work, I became dissatisfied with the tools I was using. I needed help organizing and analyzing complex feeder systems. I was regularly bidding projects with well over a thousand feeders. Each feeder could pass through several duct bank segments and above-ground locations.

‘Excel-erating’ your takeoff

Along came the electronic spreadsheet. Even though they had been around for some time, I was mostly using them for data storage and analysis. My first step was to simply recreate the paper feeder schedule as a spreadsheet. There were several immediate benefits. One was not having to use an eraser to make corrections. Another was the ability to create as many columns as I needed. I used this feature to create columns for items more unique to duct banks, such as sand, concrete, ground wires, risers and spoils removal. However, it was not until I received a special request from a customer that I tapped into the organizational power of a spreadsheet.

The customer did a lot of water and wastewater projects. He requested I prepare my estimates in a way that enabled him to see labor and material totals for each segment of every duct bank. At that time, I was using my feeder spreadsheet to sort and total each size and type of conduit and wire. This was required to simplify input into my estimating system. Obviously, I had to find a new approach to comply with my customer’s request for more detail. Here is what I came up with.

The first step is to list all the feeders on your spreadsheet. Most often, feeders for industrial projects are shown in tables on the plans or in the specifications. I usually put headers in the spreadsheet to indicate where the feeder listings came from, such as Table 3, or Plan Sheet 2E-01. Be sure to include all the important information in your listing, including the tag number. When you have finished listing the feeders from all the plans and tables, you will have created a library to draw from when assembling the duct banks.

Duct banks assemble!

Now it’s time to assemble the duct banks in the spreadsheet. Put a header in your spreadsheet describing the first duct bank segment, such as “Duct Bank A: From MH-1 to Junction at Duct Banks B & C.” Then, use your spreadsheet’s search feature to find the first conduit’s tag number. Cut the entire row from where you found it, and then paste it under the header for the duct bank. Continue cutting and pasting until all the conduits required for each duct bank have been transferred.

Be careful when cutting and pasting. Sometimes, a single feeder can appear in several duct banks. When this happens, cut and paste the feeder for the first duct bank. Then, copy (don’t cut) and paste it in each additional duct bank requiring that feeder.

When you have finished all the cutting and pasting required to comply the duct bank profiles, you can start your measurements and takeoff. You can save time here by copying and pasting identical feeders. For instance, if a duct bank has 16 4-inch conduits with a pull rope, you only need to enter the takeoff information once. You can copy and paste the information to the next 15 rows of the spreadsheet.

After the last feeder in the duct bank, add a header for the trenching takeoff. Enter all trenching requirements here, including encasement concrete, rebar, sand, warning tape and ground wires.

When takeoff is finished, input the feeders into your estimating system. Use the software’s organizational features to create separate totals for each duct bank. For instance, my software can create a report with subtotals for each phase, so I enter each duct bank into a separate phase.

If you are really lucky, your estimating software has a feature that allows you to enter the feeder listing directly into the system, skipping the spreadsheet listing step, saving time.

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 steve@electrical-estimating.com, and...

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.