What is an occupancy classification?#
One of the first questions asked during a building permit review is how the building or space will be used. The BC Building Code calls this the occupancy classification.
An occupancy classification groups buildings and spaces according to the activities taking place inside them. This allows the Building Code to apply different safety requirements to different types of buildings.
A hospital, restaurant, office, apartment building and warehouse are all used differently. Because the risks are different, the code requirements are also different.
Why occupancy classification matters#
Occupancy classification affects almost every part of a building design.
It influences fire-resistance ratings, exiting requirements, occupant load calculations, accessibility requirements, washroom requirements, structural design assumptions, ventilation, fire alarm systems and many other Building Code provisions.
Choosing the wrong occupancy classification can result in permit delays, redesign costs and additional review comments.
How occupancy affects permit review#
Municipal reviewers do not simply check drawings. They first try to understand what the building will actually be used for.
Once the occupancy classification is known, the reviewer can determine which parts of the BC Building Code apply to the project.
This is why occupancy classification is usually one of the earliest decisions made during permit review.
The major occupancy groups#
The BC Building Code divides occupancies into several major groups identified by letters.
Group A generally covers assembly occupancies such as theatres, restaurants, schools and places where people gather.
Group B generally covers institutional occupancies such as hospitals and care facilities.
Group C covers residential occupancies including houses, apartments and residential buildings.
Group D covers business and personal service occupancies such as offices and professional clinics.
Group E covers mercantile occupancies including retail stores.
Group F covers industrial occupancies such as warehouses, manufacturing and processing facilities.
Can one building have multiple occupancies?#
Yes.
Many commercial buildings contain multiple occupancies.
For example, the ground floor may contain retail space while the upper floors contain residential apartments.
In these situations the Building Code contains additional requirements for fire separations, exiting, structural design and life safety between the different occupancies.
What is a change of occupancy?#
A change of occupancy occurs when a space begins to be used for a different purpose than originally intended.
For example, converting a retail store into a daycare or converting an office into a medical clinic may create a change of occupancy.
Even when very little construction is proposed, changing the occupancy can trigger significant Building Code review because the safety requirements may change.
Common mistakes#
Many owners assume occupancy simply describes the business operating inside the building.
In reality, occupancy classification is a technical Building Code concept that determines which safety provisions apply.
Another common mistake is assuming a previous tenant's approval automatically applies to a new business. A different occupancy classification can completely change the permit requirements.
Key takeaway#
Occupancy classification is one of the foundations of the BC Building Code.
Before reviewing structure, exits, accessibility or fire protection, building officials first need to understand how the space will actually be used.
Understanding occupancy classification early helps owners avoid costly redesigns and unnecessary permit delays.