The 7 MEP Plan-Check Comments I Wrote on Almost Every Set
From the reviewer's chair to co-founding CoreX — the seven comments I wrote on almost every plan set that crossed my desk, and how to keep them off yours.
Before I co-founded CoreX, I spent a good part of my career on the other side of the table. Not just designing MEP systems — reviewing them. Third-party peer reviews. City plan reviews. Code-compliance evaluations. Across a portfolio north of 900 projects, I've read a lot of sets the way a reviewer reads them: fast, skeptical, and looking for the reason to send it back.
Here's the thing nobody tells you in school. A reviewer usually knows within the first few minutes whether a set is going to be clean or painful. Not because they've checked every calculation yet — because the tells are everywhere. A missing schedule. A note that doesn't match a plan. An energy form that isn't there. Those tells decide whether your set clears in one cycle or bounces three times and costs you a month.
So let me give you the reviewer's view. These are the seven comments I found myself writing on almost every set that came across my desk — and, more usefully, how to keep them off yours.
The seven most common MEP plan-check comments are: undocumented energy-code compliance, ventilation that doesn't trace to ASHRAE 62.1, an electrical load calc that disagrees with the panel schedule, life-safety/floor-plan mismatches, plumbing fixture counts that don't match occupancy, generic details with no local amendments, and cross-discipline contradictions. Eliminate all seven and a set clears review dramatically faster.
1. The energy-code path isn't documented
This is the most common one, and the most avoidable. The drawings are fine, the systems are sized, and then there's… nothing tying it to the energy code. No COMcheck. No Title 24 forms. Or there's a COMcheck, but the lighting power density on it doesn't match the lighting schedule three sheets over.
A reviewer isn't going to reverse-engineer your compliance. If the energy path isn't handed to them — the right form for the jurisdiction, matching the drawings — it's an automatic comment.
Keep it off your set: finalize the energy-compliance package with the design, not after. Confirm which document your jurisdiction actually accepts (COMcheck won't fly in California — that's Title 24), and cross-check every value on it against the schedules before you submit.
2. Ventilation rates don't trace back to the code
I'd see a mechanical schedule with outdoor-air CFM on it and no way to check where the number came from. ASHRAE 62.1 (the standard that sets minimum ventilation for acceptable indoor air quality) gives you a defined path — occupancy category, people component, area component. If your OA numbers don't visibly trace to it, the reviewer either takes it on faith or writes the comment. Most write the comment.
Keep it off your set: show the ventilation basis. A short table or a referenced calculation that lets the reviewer follow the number from occupancy to CFM turns a question into a check-mark.
3. The electrical load calc doesn't match the panel schedule
Classic. The service is sized to one number in the load calculation, and the panel schedules add up to something else. Or the calc uses demand factors the schedules don't reflect. When the two documents disagree, the reviewer can't tell which one is real — so both get flagged. I've flagged a load calc totaling to a service the panel schedules didn't add up to — a five-minute reconcile on paper, a correction cycle if it ships.
Keep it off your set: reconcile the electrical load calculation and the panel schedules as a pair, every time, before issue. They're two views of the same system; they have to agree.
4. The life-safety plan and the floor plan disagree
Egress path on the life-safety sheet doesn't match a wall on the architectural. An exit sign in a location the plan doesn't support. Occupant loads that don't line up with the fixture count or the ventilation. Reviewers read life safety carefully because it's life safety — and inconsistencies here erode their confidence in the entire set.
Keep it off your set: coordinate the life-safety plan against the current architectural background, not last month's. When the reviewer sees life safety line up cleanly, they trust the rest of the drawings more.
5. Plumbing fixture counts don't match the occupancy
The plumbing sheets show a fixture count; the occupancy on the code plan implies a different one. Under the IPC/UPC, required fixtures are driven by occupant load and use group — so when those two don't agree, it's a comment, and sometimes a redesign.
Keep it off your set: pull the fixture count straight from the same occupant load the code plan uses. One source of truth, carried through.
6. The details are generic — no local amendments
A set full of manufacturer-standard details and national-code notes, with zero acknowledgment that the project is in a jurisdiction with its own amendments. Reviewers notice immediately when a set was clearly produced without opening their code. It reads as "this team doesn't know where they are."
Keep it off your set: check the local amendments and reflect them — in the code notes, the details, the energy path. It's a small effort that signals you did your homework, and it heads off a whole category of comments.
7. The set contradicts itself across disciplines
This is the coordination tell, and it's the one that tells a reviewer the most. Mechanical shows a unit where electrical shows nothing to feed it. Plumbing routes through a beam. A curb on the roof plan that mechanical doesn't know about. Each contradiction is a comment — but collectively they signal that the disciplines weren't coordinated, and now the reviewer is going to look harder at everything.
Keep it off your set: coordinate before you submit, not after the city does it for you. A federated model or even a disciplined manual overlay catches these. Most building departments or authorities having jurisdiction (AHJs) will catch every one of them; better that you find them first.
What This Looks Like in Practice
None of these seven are exotic. They're the boring, preventable stuff — and that's exactly why they matter. A set that eliminates all seven doesn't just avoid comments; it changes how the reviewer reads the whole submission. They can spend their time verifying compliance instead of hunting for avoidable inconsistencies. A clean set doesn't get a lighter review — it gets a faster one. If you want to see what that discipline looks like on the sheet itself, how to read MEP drawings walks through the same permit drawings and construction documents a reviewer works from.
That reviewer's checklist is baked into how we work at CoreX, carried through SD, DD, and CD rather than bolted on at the end. Before anything goes to a building department for review, we run an internal design review and code compliance review against this exact list — the same scrutiny I used to apply from the review chair. It's a big part of why so many of our sets reach permit approval on the first submission, without a second cycle (a resubmittal) or a round of correction comments, and with far fewer construction-phase RFIs once the job is underway.
We started CoreX to be the engineering partner I'd want on my own projects — the one that treats your deadlines and your reputation as our own.
The Checklist I'd Run Before Submitting
If I were reviewing my own set before it went in, these are the checks that head off the seven comments above — the same seven, turned into questions I'd ask myself before a reviewer has to ask them for me:
- Energy compliance documentation matches the drawings — the forms and the set agree.
- Ventilation basis traces to ASHRAE 62.1 — the outdoor-air numbers are shown, not implied.
- Panel schedules reconcile with the load calculations.
- Life-safety plans match the architectural life-safety sheet.
- Plumbing fixture counts match the occupant load used in the code analysis.
- Local amendments incorporated for the specific jurisdiction.
- Cross-discipline coordination complete — mechanical equipment shown on structural, power on electrical, and so on.
Read that list against the seven comments above and you'll notice it's the same information, just asked as a question instead of written as a correction. That's the whole difference between a set a reviewer flags and a set a reviewer waves through.
None of it is hard engineering. It's the discipline of checking — which is exactly what a reviewer is about to do for you. Run it the day before you issue, not the day you're rushing to meet a deadline — the checks take an hour; the resubmittal costs a month.
Related: Why MEP Sets Bounce at Plan Check · What Clients Get Wrong Before a Project · MEP Coordination Best Practices
Common Questions
The seven that show up most often are an undocumented energy-code path, ventilation rates that don't trace back to ASHRAE 62.1, an electrical load calculation that disagrees with the panel schedule, a life-safety plan that doesn't match the floor plan, plumbing fixture counts that don't match the occupancy, generic details with no local amendments, and a set that contradicts itself across disciplines. Eliminating all seven changes how a reviewer reads the whole submission and gets a set through review faster.
Cross-discipline contradictions — a mechanical unit with nothing feeding it electrically, plumbing routed through a beam, a roof curb mechanical doesn't know about — are the coordination tell reviewers notice fastest. Each contradiction is its own comment, but together they signal the disciplines weren't coordinated before submission, so the reviewer starts scrutinizing everything else in the set more closely.
Finalize the energy-compliance package with the design rather than after, show the ventilation basis so outdoor-air numbers trace to ASHRAE 62.1, reconcile the electrical load calculation against the panel schedules before issue, coordinate the life-safety plan against the current architectural background, pull plumbing fixture counts from the same occupant load used on the code plan, reflect local code amendments in the details and notes, and coordinate across all three disciplines before you submit rather than letting the city find the conflicts.
The Authority Having Jurisdiction — the building department, agency, or official responsible for enforcing the adopted codes and approving the permit set for a given project location. On a given project, that might be a city building department, a county, or in some cases a state fire marshal's office — whichever entity is actually named on the permit.
It varies widely by jurisdiction and workload; the reliable way to shorten it is to avoid a second cycle (a resubmittal) entirely by resolving the common comment causes before the first submission. A set that clears in one round moves faster than one that needs two or three, no matter how the individual cycle length is measured.
An internal quality check run before a set is submitted — confirming coordination across disciplines, that code and energy documentation match the drawings, and that calculations and schedules reconcile — the same scrutiny a plan examiner applies, done earlier. It's the same discipline described in the checklist above, run before the reviewing authority ever sees the set.
No. It significantly reduces the number and severity of comments, but the reviewing authority always makes the final call on approval. What it does guarantee is a cleaner conversation with the reviewer — fewer comments to negotiate, and a shorter path to yes.
A plan-check comment comes from the reviewing authority during permit review, before construction; an RFI (Request for Information) is typically raised during construction when the field needs a clarification. Both exist to resolve open questions, but a comment can usually be prevented with a more thorough design review; an RFI often can't.
Senior electrical design engineer with 6+ years designing MEP systems for 900+ U.S. projects. Experienced third-party peer reviewer and city plan reviewer.
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