Before the advent of BIM (Building Information Modeling), mechanical contractors relied on tape measures, strings, and printed plans to lay out fittings, pipe hangers, and other elements on a job site. This time-consuming technique was complicated and prone to errors. Now, using a Trimble Robotic Total Station, 3D models with Trimble Points can be uploaded from the BIM office and downloaded at the worksite. Using control points, the Trimble can pinpoint its location within a job, and accurately lay out various MEP points to be marked within an 1/8-inch tolerance. A single Trimble operator can layout a job 5x’s times faster than a 2-person team using manual methods.[i]
First, the operator sets up the Trimble RTS (Robotic Total Station) by delicately placing the robot on top of a tripod, and then leveling the machine to ensure accuracy. The operator proceeds to calibrate the machine by focusing the RTS laser on various control points (reflective foils) around the job site. Usually, after three control points, the RTS machine will be able to locate its spatial relationship within the job site. From there, the RTS communicates with a Yuma II tablet which guides the operator and his prism pole laser over the exact Trimble points for fittings, hangers, etc. The Trimble Operator then uses a permanent marker to paint the laser indicated spot on the slab and note its specific identifying number.
When installers arrive, they create chalk lines for corresponding pipe runs, allowing them to locate various pipe systems, fittings, sleeves, hanger locations etc. By aiming a PLS laser from different Trimble points on the ground to the ceiling, installers see exactly where an installation point lies above.
The Trimble RTS is also capable of recording as built information to the BIM Team. This allows for updates to the collaborative 3D model, while reducing clashes and the time it takes to resolve issues. In a head to head test of Trimble verses Traditional Measuring, 200 Trimble Points were marked in four hours with perfect accuracy. Traditional measuring only marked 97 points in the same time frame with 2 RFI’s required.[ii]
TMC (Tebarco Mechanical Corporation) in Alpharetta, Georgia has been using Trimble since November of 2015. Project Manager, Trevor Barden has seen a huge improvement in the way that mechanical systems are being laid out and installed.
“With Revit, the BIM team can accurately create a virtual representation of a building’s systems prior to any physical installation of its components. By taking this approach, contractors create their own opportunities to utilize efficient layout and installations methods—in our case, Trimble and Pre-Fabrication. These best practices will condense the OPS and help deliver a far superior product to the owner.”
Trevor Barden, TMC Project Manager
Tony Adams, TMC’s Vice President of Pre-Construction, recalls a time when TMC used Trimble on a worksite and discovered that the string and tape measurements of the electrical contractor were totally off. Luckily for the General Contractor, this error was caught before any permanent structures were assembled, saving thousands of dollars in rework.
For more information on TMC’s BIM capabilities, go to www.tebarco.com or call (770) 475-5552
[i] Trimble MEP, Construction Layout with the Trimble Robotic Station, https://www.youtube.com/watch?v=e-BnQH5v7tA&list=PLeXB-DGlqL9An2fePqDLKxiqmUf9ILCob , accessed July 11, 2016
[ii] Trimble vs. Tape, http://mep.trimble.com/products/field-solutions/trimble-mep, accessed July 11, 2016