BCAB 1966 - Fire separation and fire-resistance rating requirements for floor assemblies within a house

Fire separation and fire-resistance rating requirements for floor assemblies within a house

Project Description

The project is the design and construction of a new, sprinklered, house containing a single dwelling unit.  The house is four storeys in building height and the distance between the lowest floor level and the uppermost floor level within the dwelling unit is more than 6 m.

Applicable Code requirements (BCBC 2018)

Article 3.2.2.51., Division B, Group C, Up to 4 Storeys, Sprinklered

(3) In a building that contains dwelling units that have more than one storey, subject to the requirements of Sentence 3.3.4.2.(3), the floor assemblies, including floors over basements, which are entirely contained within these dwelling units, shall have a fire-resistance rating not less than 1 h but need not be constructed as fire separations.

(4) In a building in which there is no dwelling unit above another dwelling unit, the fire-resistance rating for floor assemblies entirely within the dwelling unit is waived.

Sentence 3.3.4.2.(3), Division B, Fire Separations

(3) Floor assemblies within a dwelling unit need not be constructed as fire separations provided

(a) the distance between the lowest floor level and the uppermost floor level within the dwelling unit is not more than 6 m, and

(b) the dwelling unit is separated from the remainder of the building by a fire separation having a fire-resistance rating not less than

(i) 1 h if the building is not sprinklered throughout,

(ii) 45 min if the building is sprinklered throughout and it is not more than 3 storeys in building height, or

(iii) 1 h if the building is sprinklered throughout and it is more than 3 storeys in building height.

Decision being appealed (Local Authority’s position)

The floor assemblies within the dwelling unit are required to be fire separations.  The floor assemblies within the dwelling unit do not require a fire-resistance rating.

Appellant's position

The floor assemblies within the dwelling unit are not required to be fire separations.  The floor assemblies within the dwelling unit do not require a fire-resistance rating.

The waiver provided in Sentence 3.2.2.51.(4), Division B, supersedes the requirements of Sentence 3.3.4.2.(3)., Division B.

Appeal Board Decision #1966

The Board confirms the decision of the local authority.

It is the determination of the Board that floor assemblies are required to be fire separations that do not require a fire-resistance rating.  Unrated fire separations must be provided in accordance with the prescriptive acceptable solution or the requirement might be addressed by an alternative solution.

Reason for decision

Sentence 3.2.2.51.(3), Division B, indicates that the floor assemblies do not need to be constructed as fire separations, but that permission is subject to the requirements outlined in Sentence 3.3.4.2.(3), Division B.  This has the result that, in some circumstances, floor assemblies within a dwelling unit are required to be fire separations.

Sentence 3.2.2.51.(4), Division B, which waives the requirement for fire-resistance ratings in some circumstances, does not supersede the requirements in Sentence 3.3.4.2.(3), Division B, related to fire separations.

Don Pedde
Chair, Building Code Appeal Board

Dated:  May 29, 2025