Coordination Drawing
An overlay drawing that combines multiple trades' rough-in plans, plumbing, ductwork, electrical conduit, into a single view, used to catch physical conflicts between trades on paper before anyone actually installs pipe, duct, or conduit in the field.
Why it matters
Plumbing, HVAC, and electrical rough-in all compete for the same limited space inside a wall or ceiling cavity, and each trade's drawings are usually produced separately. A coordination drawing is the step where someone actually overlays all of them together and finds the conflicts before they become a physical collision in the field. The same idea done digitally in a 3D model is what [[concept-clash-detection|Clash Detection]] covers.
On a real project
Before rough-in begins in a tight mechanical room, a project team overlays the plumbing, ductwork, and electrical conduit drawings for that space onto a single coordination drawing, catching a spot where a duct run and a pipe run were both planned to occupy the same physical space.
Who this matters most to
A Project Engineer often runs the coordination drawing process, since it requires actively comparing multiple trades' plans against each other rather than reviewing any single trade's drawings alone.
Where this goes wrong
A project skips coordination drawings for a tight mechanical space, assuming each trade's own drawings are sufficient. Two trades show up on the same day to rough in through the exact same physical space, and one of them has to reroute its work in the field instead of on paper.