Laser Scanning vs. Field Mockups: Practical Lessons for Retrofit Projects

Retrofit projects are a nontrivial part of our engineering work at Hallam-ICS.  Our clients often need new systems installed in and around existing infrastructure rather than in a new building.

Sometimes this work is straightforward, such as routing a few small-diameter pipes and an electrical conduit across a mechanical room. Other projects involve larger equipment and utilities in crowded spaces. At Hallam-ICS, we relish the more difficult projects.

Understanding existing conditions before design begins is also an important part of avoiding unexpected project costs. Wayne Catucci explores this in Why Laboratory and Pharmaceutical Projects Go Over Budget Before Design Even Starts.

Using Laser Scanning to Document Existing Conditions

For some retrofit projects, we use laser scanning to document existing conditions. The process generates a point cloud, creating something similar to a three-dimensional photograph of the space. A scanning contractor provides the point cloud model, and we use specialized software to navigate through it and measure existing elements, including diameters, lengths, and angles.

 It's a powerful tool, and it still feels very modern. 

In 2021, on a West Coast project, the owner engaged a specialty firm to scan approximately 10,000 square feet of an existing building. The scanning took less than a day and produced 1,845,245,677 “triangles, lines, and points.” That's 1.8 billion objects.

The resulting file was 132 gigabytes, too large to reliably transfer over the internet at the time. Instead, the firm shipped us an external hard drive. My colleague Leigh had to copy the file to his computer before we could begin working with it.

Once we had the file and became familiar with the software, the model became a valuable tool for planning an expansion to an existing helium recovery system.

The owner was considering installing a triaxial liquid helium line to convey liquid helium to a new phase separator serving two semiconductor research tools. We had completed the process engineering for the original liquefier installation in 2019, and the project architect used the laser scan to guide the layout of new equipment within the existing building.

We appreciate the capabilities of modern tools like laser scanning and modeling. However, not every project's size or complexity justifies the cost and effort involved.

Choosing the right approach to existing conditions can also influence the overall project strategy, as illustrated in this example of laboratory retrofit planning 

Two projects in 2023 illustrated this point. Both involved adding relatively large piping within existing, crowded spaces.

Observing the feasibility of passing two 16” process cooling water pipes through an existing wall.

Using Full-Scale Mockups to Plan Pipe Routing

One project involved adding new 16-inch process cooling water piping and 12-inch insulated chilled water piping in the ceiling of an existing semiconductor fabrication facility to reinforce the existing process cooling systems.

The subfab (industry slang for the level below the cleanroom) measured approximately 550 feet by 300 feet and contained literally thousands of conduits, cable trays, pipes, tubes, and stretches of ductwork.

A laser scan of this space and its systems would have taken days to complete, producing an unwieldy file. Breaking the scan into smaller zones could have reduced the file size, but that approach wasn't practical because our piping needed to extend to nearly every corner of the space.

Instead, I created full-scale (1:1) drawings of the different piping configurations, and our colleague Jen printed them on our plotter. She used her craft skills to mount the prints on cardboard and carefully cut out the shapes.

My colleague Tori and I brought the cardboard templates into the subfab and carried them around to see what was feasible and what wasn't for pipe routing. 

Planning a route for a parallel set of process cooling water pipes, 14" and 10".

Evaluating Pipe Clearances in an Existing Utility Tunnel

Another project involved routing a new 130 psig, 12-inch steam pipe approximately 1,000 feet through an existing utility tunnel to a boiler room. With 5 inches of insulation, the pipe's overall diameter was nearly 24 inches.

The tunnel appeared spacious when walking through it and imagining the pipe route. But appearances and reality are often different, especially when installing welded carbon steel piping in existing spaces.

We created a set of full-scale (1:1) cardboard mockups of different pipe sizes and brought them into the tunnel to evaluate the available space. Thanks again to Jen and her skills with scissors!

Spotting the location of a 12” 130 psig steam pipe with insulation.

After a few hours of walking around (and under, and behind) existing piping systems, we found a route that appeared to work. While the cardboard mockups helped us plan the route, we also considered laser scanning the tunnel and existing supports rather than spending two to three days taking measurements to the nearest millimeter.

Considering the route of a 12” 130 psig steam pipe and 4” condensate pipe, both with insulation. We discovered this particular location is nonviable, there is an existing pitched drain line that crosses perpendicularly.

Part of why I enjoy my career at Hallam-ICS is the variety of projects, clients, and tools we work with. There's fun in selecting the right tool for the job, bringing together the right colleagues, and ultimately designing the right systems to safely serve our clients' needs.

Sometimes we use lasers, powerful software, and teams of colleagues and subcontractors. Other times, two of us walk around a hospital basement carrying big discs of cardboard.

Tools of our trade, a 12” steam pipe, with pair of 8” steam pipes (equivalent for our conditions as a single 8”), and a 4” condensate line.

About the Author

Bill has been a mechanical engineer since 1995 and with Hallam-ICS since 2010. His career has brought him to the top of the Transamerica Pyramid Center, chemical plants, underground mines, paper mills, and semiconductor fabrication facilities. He has experience designing, specifying and installing mechanical and electrical systems in the built environment covering industrial, institutional and commercial facilities.

Read  My Hallam Story  

About Hallam-ICS

Hallam-ICS is an engineering and automation company that designs MEP systems for facilities and plants, engineers control and automation solutions, and ensures safety and regulatory compliance through arc flash studies, commissioning, and validation. Our offices are located in Massachusetts, Connecticut, New York, Vermont, North Carolina, Texas and California and our projects take us world-wide.