5 Red Flags in a BIM Model That Tell You Coordination Wasn’t Done Right

RED FLAG 01

Elements modeled outside the project extents or at elevation zero

Open a 3D view and orbit to the underside of the model. If you see ductwork, pipes, or equipment sitting at elevation 0’-0” — or floating hundreds of feet from the building — the model has orphaned or misplaced elements that were never cleaned up.

This happens when families are loaded and accidentally placed, when linked files are detached without cleanup, or when imported geometry from DWG files is not properly managed. The elements do not affect the views the modeler was working in, so they go unnoticed.

Why it matters: orphaned elements corrupt clash detection results. Navisworks reports clashes between these ghost elements and legitimate geometry, inflating the clash count and making the report unreliable. Quantity takeoffs are also affected.

What to check: In Revit, use a 3D view with section box disabled. Run a schedule with no filters applied to each MEP category. Any element with an elevation or location that doesn’t match a building level is a candidate for review.

RED FLAG 02

No clash detection report exists or cannot be produced

Ask the BIM team for the Navisworks clash detection report. If they cannot produce one — or produce one that shows hundreds of unresolved hard clashes with no resolution notes — coordination was not completed.

A clash report is not proof that coordination happened. It is a starting point. The proof is a clash report with resolution status: which clashes were resolved, which were accepted as soft clashes with justification, and which are pending. Without resolution tracking, the report is just a list.

On a well-coordinated project, the final clash report before construction document issue should show zero unresolved hard clashes between MEP disciplines and structure. Soft clashes (clearance violations, access space) may remain with documented owner acceptance.

What to check: Request the Navisworks .nwf file with saved clash results. A project with legitimate coordination will have multiple saved clash sets, timestamped, with resolution notes in the comments field.

RED FLAG 03

Generic family placeholders throughout the model

Generic MEP families — boxes labeled “Air Handling Unit” with no real dimensions, or “Pump” with no connection points — are appropriate at LOD 200 during schematic design. They are not appropriate in a model submitted for construction coordination.

Generic families do not clash correctly. A real AHU with service clearances, piping connections, electrical disconnects, and a concrete housekeeping pad takes up significantly more space than a labeled box. A model built around generic families will appear coordinated until the equipment shop drawings arrive — at which point the actual equipment dimensions reveal conflicts the model never caught.

This is one of the most common causes of field coordination problems on MEP projects. The model was coordinated against the wrong geometry.

What to check: Open an equipment schedule and look at the dimension fields. Generic families will show uniform placeholder dimensions (e.g., every AHU is 48” x 48” x 48”). Real equipment families show manufacturer-specific dimensions that match the equipment schedule.

RED FLAG 04

Inconsistent LOD between disciplines

Clash detection between a LOD 300 mechanical model and a LOD 100 structural model produces unreliable results. If the structural model shows only schematic beam locations without actual member sizes, MEP routing that appears clear of structure will conflict with real members when the structural model is developed to LOD 300.

This happens when the BEP LOD matrix is not enforced, or when one discipline falls behind and the coordination proceeds anyway. The coordination looks complete in the federated model — but it was done against incomplete data.

The same problem occurs between MEP disciplines. A LOD 300 mechanical model coordinated against a LOD 200 plumbing model will have unresolved conflicts in any area where plumbing routing was only schematically defined.

What to check: Review the LOD matrix in the BEP and compare it to the actual model content. In the federated model, look for areas where one discipline has detailed geometry and another has schematic boxes or centerline-only routing.

RED FLAG 05

Missing system data and parameters

Open an MEP equipment schedule. If the fields for system classification, flow data, equipment tags, and manufacturer information are empty — or filled with placeholder text like “TBD” — the model was built for geometry, not for data.

A model without data is not a BIM model. It is a 3D CAD drawing. The data — system assignments, flow values, equipment specifications — is what enables automated schedules, COBie export, facility management handover, and commissioning verification. Building it in after coordination is complete is significantly more expensive than building it in correctly from the start.

Missing system assignments also affect Revit’s built-in coordination tools. Duct and pipe systems that are not properly assigned to system types do not flow-check correctly and do not export to IFC with the right property sets.

What to check: Run a duct system schedule and a piping system schedule. Every duct and pipe segment should have a system classification. Run an equipment schedule for each MEP category. Flow fields, tag fields, and specification fields should be populated for all placed equipment, not just some.