NCC 2019 Volume One Amendment 1
2.2 Design scenario (UT)

2.2 Design scenario (UT)

Fire in normally unoccupied room threatening occupants of other rooms

Design scenario in brief

A fire starts in a normally unoccupied room and can potentially endanger a large number of occupants in another room.

Required outcome

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

2.2.1 Design scenario description

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

A fire starting in an unoccupied space can grow to a significant size undetected and then spread to other areas where people may be present or where people are young, elderly or have a disability and will take longer to evacuate. This design scenario is intended to address concern regarding fire starting in a normally unoccupied room and then migrating into space(s) potentially holding occupants.

The analysis must assume that the target space containing occupants is filled to capacity under normal use or otherwise contains occupants with longer evacuation times.

For analysis, select a design fire for the applicable occupancy. Active and passive fire safety systems in the building must be assumed to perform as intended by the design.

2.2.2 Typical method or solution



carry out ASET/ RSET analysis to show that the occupants within target spaces are not exposed to untenable conditions, or


include separating elements or fire suppression to confine the fire to the room of origin.