Construction and classification

Construction and classification

Sorting buildings into occupancy and building classes

(The information on this page is taken from where additional information can be found on the subject.)

In order to determine which fire safety measures are needed in a building, it must first be sorted into a building class as well as one or more occupancy classes. Section 5 of the BBR provides information about what requirements apply to evacuation routes, fire compartments, sprinkler systems and more.

Building Classes

Buildings should be divided into building classes (Br) based on their need for protection. The assessment should consider probable development and possible consequences of a fire as well as the complexity of the building. Examples of possible parameters include the number of floors and what occupancy classes operate in the building. The building classes are:

  • Br0 – Buildings with a very high need for protection.
  • Br1 – Buildings with a high need for protection.
  • Br2 – Buildings with a moderate need for protection.
  • Br3 – Buildings with little need for protection.

Occupancy Classes

The building space must be divided into one or more occupancy classes (Vk) based on intended activity. The determination of occupancy class depends on the following factors:

  • If people can be expected to have knowledge of the building.
  • If people can be expected to be awake.
  • If people can be expected to evacuate on their own.
  • If there is a high risk of fire.


A building can contain several occupancy classes (Vk) but can only belong to one building class (Br). An educational facility that keeps both preschool and school children can for example be classified into building class Br2 while containing both occupancy class 2B (schools with more than 150 people in a fire compartment) and occupancy class 5A (preschools).

There are gray zones for some businesses where it can be difficult to classify which occupancy class the business belongs to. In these cases, the four criteria mentioned above may be used to motivate why an activity belongs to one occupancy class over another. This guide also provides a number of supportive examples in the assessment of occupancy classes.