Quick-Service Restaurant (QSR) projects are booming across the U.S., with strong market expansion and continued investment in restaurant construction — the industry reached an estimated $9.1 billion in 2025.
Yet even as demand grows, many QSR projects face permit drawings — especially MEP (Mechanical, Electrical & Plumbing) sets — getting rejected during plan review, leading to costly permit delays, redesigns, and stalled openings for architects and developers.
Below, we break down the real reasons Illinois authorities reject QSR MEP plans, answer architect-driven questions, and explain how to avoid these delays.
Many architects ask: Why do QSR MEP drawings get rejected in Illinois?
The answer starts with code compliance, incomplete details, and coordination gaps.
Primary reasons include:
These can lead to multiple corrective submissions, which expand approval timelines and increase costs.
This isn’t unique to restaurants — nearly 98 % of U.S. construction projects face delays, often extending 37 % longer than expected due to workflow and review challenges.
Architects sometimes wonder: What Illinois building codes apply to QSR MEP plans?
In Illinois (including Chicago and Cook County), plan reviewers expect:
Errors here can trigger rejections because reviewers interpret codes strictly at the permit stage — especially around kitchen exhaust, makeup air, and grease control.
Learn more about grease trap sizing and installation requirements from industry guidance that details minimum retention and interceptor volumes for commercial kitchens.
Architects often ask: Why do hood and HVAC plans fail review?
Common issues include:
Misalignment between HVAC layouts and architectural plans is one of the most frequent causes of plan comments, because it affects indoor air quality, comfort, and code compliance for commercial kitchens.
In restaurant environments, plumbing systems are under extra scrutiny because of grease, water waste, and sanitation.
Architects frequently face questions like:
Issues that trigger comments or rejection include:
Proper integration of plumbing with kitchen layouts is essential to avoid resubmissions.
A common architect concern is: Do electrical load calculations impact permit approval?
Yes — and they’re often scrutinized.
Key problems include:
These issues force reviewers to request revisions, slowing down approvals.
Architects repeatedly ask: How can we reduce mep permit delays?
Here are proven strategies:
Bundling accurate details helps reviewers approve plans quickly, reducing repeated comments.
Successful QSR projects start with early coordination between architects and engineers specializing in restaurant MEP design, ensuring permit-ready submissions.
Need help with integration? Check out our related blog Three Problems You Can Avoid by Working with Qualified MEP Designers that covers how early engineering involvement speeds approvals.
Many architects wonder: When should we bring in a local MEP engineer for QSR projects?
Best time:
During schematic or early design development.
Bringing in specialists early prevents:
Local MEP engineers experienced with Illinois codes speed approvals and ensure your project avoids unnecessary resubmissions.
For project consultation, see our comprehensive services at QSR MEP Design Services in Illinois
Don’t let permit comments delay your QSR project. Our Illinois-based MEP engineers specialize in:
Request a QSR MEP Design Proposal Today
MEP plan rejection is common, but avoidance is predictable. By understanding what reviewers expect — from HVAC load calculations to electrical coordination and grease interceptor sizing — you can significantly reduce permit delays in Illinois.
The restaurant construction market continues to evolve, and with restaurant construction projected at billions in 2025, efficient design and compliance will be key to staying ahead of competitors.
If you’re planning a QSR or fast-food restaurant project in Illinois, Nearby engineers can help you move faster with code-compliant, coordinated MEP design.