Scan-to-BIM for Manufacturing Plants

A manufacturing plant is the building where the drawings are least likely to be right. The pipe racks carry systems added by different contractors over decades, the cable trays run three ways, the equipment pads have moved with every machine swap, and a mezzanine was added for a cell that is long gone. When a capital project is planned on that floor, an equipment move, a new line, a dust collection or compressed-air retrofit, an electrical expansion, the design starts from prints nobody has field-verified. This guide explains how scan-to-BIM records a plant as it stands, what the scan captures on a working floor and what it cannot, what the model is used for, and what it costs.

What the scan records on a plant floor

A terrestrial scanner of the Trimble X7 class, by its datasheet, measures up to 500,000 points a second over a range of 0.6 to 80 m, with a 3D point accuracy of 2.4 mm at 10 m and 3.5 mm at 20 m (one standard deviation). Set on a tripod on the floor and on the mezzanines, it records every surface in its line of sight: the columns and the bay widths, the crane rails and the roof structure, the pipe racks with every line and its hangers, the cable trays and conduit, the ductwork and the air handling units, the sprinkler mains, the equipment with its pads and anchor bolts where they are exposed, the trenches, the drains and the panels. All of it lands in one registered point cloud, in which any dimension can be taken afterwards: the clearance under a header, the elevation of a crane rail, the distance from a column line to a pad.

A plant needs many stations, because every rack, machine and screen hides what stands behind it, and each hidden face needs a station with a view of it. Open assembly bays go quickly; a dense mechanical room or the space under a rack is scanned from between the obstacles. The stations are registered to each other in the field, and the registration is checked before we leave the plant, so a missed aisle is rescanned the same day; the registration report delivered with the cloud lists the error of each station and the overlap between scans.

Scanning a plant that is running

The scanner stands on a tripod, is quiet, uses a class 1 eye-safe laser by its datasheet, and works around people, so fixed structure, racks and overhead systems are scanned during production. Forklifts, people and moving loads leave stray points that are removed from the cloud, and a station is simply repeated if a load passed through its view. Machinery that moves while it is scanned, a conveyor or a crane in motion, cannot be recorded in one position, so the areas around active equipment are scanned in a maintenance window or between cycles. Equipment that vibrates heavily can disturb a station set up next to it; those stations are planned for a quiet moment. The site preparation checklist covers access, escorts and the lock-out and safety orientation a plant requires before the visit.

What the scanner cannot see is not in the cloud. The inside of a closed enclosure, the pipe inside an insulated jacket, the conduit behind a panel cover, the bolts under a machine’s base plate: those are documented from openings the plant makes, from the equipment drawings or from a separate survey, and the model marks them as taken from those sources. Dark and reflective surfaces, painted steel and stainless, are scanned in the high sensitivity mode the datasheet lists for them, which takes about twice as long for the same point spacing.

What the model is used for

In a plant the point cloud itself is often the first deliverable, for an equipment move or a new line, and the model follows for the areas that change. The model is built against the cloud at the level of development the scope names, per element category, in the BIMForum Level of Development Specification’s terms: LOD 200, where an element is “generically and graphically represented within the Model with approximate quantity, size, shape, location, and orientation”, for a feasibility study of a move; LOD 300, where it is represented “such that its quantity, size, shape, location, and orientation can be measured”, for the design; LOD 350, which adds the element’s “interfaces with adjacent or dependent Model Elements”, for the elements new work has to meet. The accuracy of the model is stated in the U.S. Institute of Building Documentation’s Level of Accuracy terms, as a standard deviation at the 95 percent confidence level, and a typical model is represented at LOA30, a deviation between 15 mm and 5 mm.

The uses follow from that. For an equipment move, the model shows the overhead systems along the move path at their real elevations, so a header that was never drawn is rerouted on paper rather than discovered by the rigging crew. For a new duct run or a compressed-air loop, the designer routes the new system in Revit against the existing one and runs clash detection in Navisworks before anything is fabricated; the MEP BIM page describes that scope. For the structural engineer, the columns, bay widths and member sizes are in the model as measured, for the engineer’s own analysis. For a packaged skid or a prefabricated module, the cloud of the landing area goes to the vendor so the connections are checked against the plant before the unit ships.

The delivery is the Revit model in your version, or IFC or an ArchiCAD file when the design is done elsewhere, with the registered cloud in E57, the ASTM exchange format for 3D imaging data, and in RCP/RCS for Revit, the registration report and the panoramic images from each station, which on a plant floor are a labeled record of what stands where. Plans, sections and elevations are cut from the model when they are in scope. The scan-to-BIM page describes the whole scope and the scan-to-Revit workflow guide the sequence.

Price and time

A plant is priced on its area, the stations it needs, which are many, and what is built on the cloud. Large buildings run from $12,000 and are quoted on their own; the point cloud alone of a single bay or a mechanical room starts at about $1,200, and a model built from a point cloud you already have is quoted on that cloud. The exact price comes in a quote within one business day of your sending the address, the area, the systems and categories in scope and the LOD. The scan is scheduled as soon as the project needs it, often within days of the order, around the plant’s maintenance windows; a bay is usually scanned in a day and a whole plant over several. The model usually follows in four to eight weeks depending on the categories and the LOD. We scan in all 50 states.

Sources

• Trimble X7 3D laser scanning system datasheet: scan speed, range, 3D point accuracy, laser class, high sensitivity mode, registration report.
• BIMForum, Level of Development Specification 2023, Part I: the LOD 200, 300 and 350 definitions.
• USIBD Document C120, Level of Accuracy Specification Guide, version 2.0 (2016): the LOA levels as standard deviations at the 95 percent confidence level.
• Autodesk Navisworks help: overview of the Clash Detective tool
• ASTM E2807, Standard Specification for 3D Imaging Data Exchange: the E57 file format.