Permitting & Codes · Engineering Glossary
A change of occupancy occurs when a building or space is converted from one use classification to another — for example, converting a warehouse to a fitness center, or an office to a healthcare clinic. Building codes require a change-of-occupancy review to verify that the building meets the requirements of the new use.
Under the IBC, each occupancy group (A for assembly, B for business, I for institutional, M for mercantile, S for storage, etc.) has different requirements for fire protection, structural loads, means of egress, ventilation, and accessibility. When a building changes from one group to another, the AHJ evaluates whether the existing construction meets the requirements for the new occupancy — often triggering upgrades to sprinklers, electrical service, accessible routes, and structural systems. A change of occupancy permit typically requires engineering drawings and calculations demonstrating compliance. Apex Grid evaluates existing buildings for change-of-occupancy compliance and provides the required structural, MEP, and civil engineering.
Apex Grid Engineering maintains this glossary as a resource for architects, contractors, developers, and property owners who encounter unfamiliar engineering terminology on their projects.
View All Engineering TermsApex Grid's licensed PEs provide permitting & codes services across multiple jurisdictions — with fast quote turnaround and permit-ready documents.
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