Plain English:
Project Basis Gate
This article explains the 2024 IMC model-code path. Before project use, confirm the adopted code edition, local amendments, controlling administrative provisions, permit-application date, and current AHJ procedures. The locally adopted requirements control.
Approval (107.1): After required tests and inspections show full compliance with the IMC and the approved plans, the code official issues a notice of approval. Each inspection phase (underground, rough-in, final) generates its own approval - passing underground inspection does not approve rough-in. You need a separate notice for each phase.
Revocation (107.2): That approval can be suspended or revoked in writing if it was issued in error, based on incorrect/incomplete information, or if the work is later found in violation of code or ordinances. An approval issued months ago does not protect work that is subsequently altered.
Notice of Approval vs. Certificate of Occupancy: The Notice of Approval is a mechanical system approval, not the final CO. The CO is issued by the building official after all trades (mechanical, electrical, plumbing, fire protection) have received final approval. Mechanical approval is required before CO issuance.
On Plans: Why It Matters in Design & Construction
An approval is not a shield - it confirms compliance at the time of inspection, but it's revocable if facts change or defects surface. This makes truthful submittals, traceable test reports, and strict change control essential. If you alter the installed work after approval, you risk losing the approval and triggering rework, delays, and added inspections. The phased approval sequence (underground → rough-in → final) means every stage needs its own sign-off before the next phase begins.
Code Path: What to Show
M-001 or closeout sheet: Include a commissioning and closeout checklist noting required tests, inspections, and the approval sequence.
Annotate inspection hold points directly on affected sheets - not just on the cover sheet.
Identify all required test reports that must be assembled before final inspection.
Check: Before Requesting Final Approval
Confirm which inspections require AHJ witness and which can use third-party approved agency reports.
Verify all test reports are signed and on file before requesting final approval.
Confirm no work was concealed before required inspections were passed.
Review Risk:
Don't conceal ductwork, piping, or equipment before the required inspection - this is the most common approval delay.
Don't treat a prior approval as permanent - it is revocable if defects or violations emerge.
Don't request final approval with incomplete or unsigned test reports.
Field Tip:
Before requesting approval, run a closeout huddle: verify you're building to the stamped set, assemble signed test reports (e.g., pressure/leakage/startup/functional tests), and confirm O&M pages match what's installed. After approval, freeze field changes-any deviation goes through RFI + revised submittal + permit revision before work proceeds. Keep the notice of approval and the approved set on site for inspector verification.
Masterbuild QA Lens
Work that is concealed before the required inspection will fail. Confirm which inspections require work to remain visible before scheduling any rough-in cover. Sequence the project schedule to allow mechanical rough-in inspection before ceiling, wall, or slab closes. Put the inspection sequence on the drawings.
Drawing / Submittal Check
The permit set should include a commissioning and closeout checklist on M-001 or a dedicated sheet, listing required inspections, who requests each inspection, and the sequence relative to rough-in cover dates. If the project has phased inspections, show the phase boundaries on the plan.
Common Review Risk
The most common approval delay is work that was concealed before the required inspection - ductwork in walls before rough-in inspection, equipment behind ceilings before equipment inspection, or piping in slabs before underground inspection. The fix requires opening and re-inspection. Coordinate the inspection schedule with the construction sequence before mobilization.
When To Escalate
Escalate when an AHJ suspends or revokes a previously issued approval - triggering contract, insurance, or construction timeline consequences that cannot be resolved at the field or project-manager level.