- published: 27 Feb 2015
- views: 8619833
Occupancy in building construction and building codes is the use or intended use of a building or part thereof for the shelter or support of persons, animals or property. A closely related meaning is the number of units in such a building that are rented or leased, or otherwise in-use. The lack of occupancy in this sense is a vacancy.
It is possible to have multiple occupancies (or building uses) within one building. For instance, one may have a high-rise building, where the lower levels are occupied by retail stores, whereas the upper levels could be residential. Different occupancies within one building are separated by a fire barrier with a defined fire-resistance rating. It is common for a penetration, such as a fire door, to have a fire protection rating lower than the wall fire resistance rating in which it is installed. For example, a two-hour fire separation normally requires fire doors rated at 90-minutes.
For some high challenge occupancies the code requirements for an occupancy separation are more stringent than for other fire-barriers, even with an identical fire-resistance rating. In this case, an occupancy separation with a two-hour fire-resistance rating may not be able to de-rate its closures, such fire doors or firestops. For example, a two-hour rated high challenge fire wall requires 2 hr rated fire doors.