Common MEP Design Mistakes and How to Avoid Them
-Kaleb Markey Project Manager | Mechanical Engineer
When I first started designing MEP systems, I thought that if the drawings looked good on paper, everything would work in the field. I quickly learned that’s rarely the case. Small oversights can turn into big headaches once construction begins. Over the years, I’ve noticed the same mistakes keep popping up, so here’s what I tell fellow engineers—straight from experience.
1.Verify Existing Conditions
I’ve lost hours designing duct runs only to find that the ceiling height in the field was lower than the drawings indicated.
Before laying out anything, I check photos, walk the site, or get notes from the surveyor.'
This simple step ensures accuracy and helps avoid costly rework — especially when connecting to existing equipment like RTUs, exhaust fans, or VAV boxes.
2.Double-Check Equipment Fit and Connections
Even if the design looks fine on paper, new equipment can clash with existing ductwork, piping, or sprinklers.
I’ve had to move supply grilles or reroute ductwork after spotting tight coordination issues. I also ask questions like: “Can we tie into existing ducts?” “Is the RTU providing enough CFM for the new space?”
Checking clearances and airflow early avoids redesigns and field headaches.
3.Coordinate Across Trades
Mechanical, electrical, plumbing, and architectural elements all compete for space. I make sure everyone’s work is coordinated – for example, ensuring ductwork doesn’t interfere with electrical panels or lighting.
Early coordination saves rework and prevents conflicts during construction.
4. Think About System Routing Early
It’s easy to design equipment in the right location but forget how the ductwork or piping will run. I try to plan routes early to minimize long runs, sharp turns, or tight bends that could be hard to build.
Thinking about routing ahead of time keeps the design practical and easier for contractors to install. Even the small things, like how the supply or return connects to the RTU, make a big difference in buildability and performance.
Key Takeaways
-Check what’s there, including ceiling heights, demo items, and existing equipment.
-Make sure equipment fit, connections work, and airflow or CFM is adequate.
-Coordinate with all trades early, including electrical service and plumbing.
-Plan system routing before finalizing the design.