STATEMENT OF PROBLEM:
A coordination meeting between structural/civil/mechanical was held for the outdoor air rotation units which sit on concrete pads. In the meeting JEG gave the required dimensions of the pad and stated the ARU & pad should be centered within the building column bay. The pads were then designed by IBI Civil and CCC installed. However when the structural engineer went to design the stairs for the units, it was realized that in the mechanical 3D model the base of the unit was actually not centered in the bay. Only the top of the unit (supply duct) was centered in the bay.
The units had always been 3D modeled by JEG in the correct location. Contributing factors to this error include:
1) The civil & structural engineers did not reference the mechanical 3D model for the actual unit locations when they completed their pad design.
2) The pad design was not incorporated into the master model when it should have been, due to the need to expedite the installation.
3) In the coordination meeting the mechanical engineer communicated in a way that was contrary to what they had designed in 3D. The team went off of what they said, as opposed to what the actual design condition was.

COURSE OF ACTION:
The units could not be shifted over. As such, CCC directed IBI to provide a pad extension detail so the unit could fit, and was released in Engineering revision #8. CCC then excavated and installed the (3) pad extensions prior to setting the ARUs.


LESSON LEARNED:
1) Make the subcontractor that is providing the equipment provide a dimensioned sketch, or in writing what the pads for their equipment need to be sized to, and where located. Do not build off of a verbal statement.
2) Make sure the engineer responsible for designing the pad for the equipment designs it in 3D and coordinates it with the mechanical equipment 3D model. The pad cannot be built until this coordination is complete.
3) The model manager must also look at the matchup to ensure that the coordination is sound.