NCC 2019 Volume Three Amendment 1
2.3 Design scenario (CS)

2.3 Design scenario (CS)

Fire starts in a concealed space

Design scenario in brief

A fire starts in a concealed space that can potentially endanger people in another room or in the room of fire origin.

Required outcome

Demonstrate that fire spread via concealed spaces will not endanger occupants located in other rooms / spaces; and

Demonstrate that the proposed level of safety is at least equivalent to the Deemed-to-Satisfy Provisions.

2.3.1 Design scenario description

This design scenario only applies to buildings with rooms or spaces that could be threatened by a fire occurring in a concealed space. Such rooms or spaces must include those rooms or spaces physically adjacent to the concealed space as well as rooms or spaces that are a farther distance and are not fire separated; or rooms or spaces where slower evacuees have to pass through a potentially threatened room or space adjacent to the concealed space. It does not need to be satisfied for any other rooms or spaces in the building.

A fire starting in a concealed space can develop undetected and spread to endanger a large number of occupants in another room. This design scenario addresses concern that a fire originating in a non-separated concealed space without either a detection system or suppression system could spread into a room within the building potentially holding a large number of occupants.

Assume that active and passive fire safety systems in the building perform as intended by the design.

Explanatory information:

Explanatory information:

Fire spreading in concealed spaces may also compromise the ability of firefighters to assess the threat to themselves whilst undertaking rescue and firefighting operations.

2.3.2 Typical method or solution

If a calculation approach using this Verification Method is used, the expected solution will most likely be to—


use separating elements or suppression to confine fire to the concealed space, or


include automatic detection of heat or smoke to provide early warning of fire within the concealed space, or


a combination of (a) and (b).