The National Building Code (NBC) is organized into three Divisions, which are distributed across two volumes.
Division A: Compliance, Objectives and Functional Statements
Division A defines the scope of the NBC and presents the objectives that the Code addresses and the functions the building must perform to help to satisfy those objectives.
Division A cannot be used on its own as a basis for designing and constructing a building, or for evaluating a building's compliance with the Code.
Division B: Acceptable Solutions
The term "acceptable solutions" refers to the technical provisions contained in the Code. It reflects the principle that building codes establish an acceptable level of risk or performance and underlines the fact that a code cannot describe all possible valid design and construction options. The term provokes the question "To whom are these solutions considered acceptable?" Acceptable solutions represent the minimum level of performance that will satisfy the NBC's objectives and that is acceptable to an authority that adopts the NBC into law or regulation.
The requirements in Division B-the acceptable solutions-are linked to at least one objective and functional statement found in Division A. These linkages play an important role in allowing objective-based codes to accommodate innovation.
It is expected that the majority of Code users will primarily follow the acceptable solutions presented in Division B and that they will consult Division A only when seeking clarification on the application of Division B's requirements to a particular situation, when considering an alternative solution, or to read the definition of selected terms in the context of the NBC.
Division C contains administrative provisions relating to the application of the Code. Many provinces and territories establish their own administrative provisions upon adopting or adapting the NBC; having all the administrative provisions in one Division facilitates their customization to suit jurisdictional needs.
Relationship between Division A and Division B
Sentence 1.2.1.1.(1) of Division A is a very important sentence: it is a precise statement of the relationship between Divisions A and B and is central to the concept of objective-based codes.
1) Compliance with this Code shall be achieved by a) complying with the applicable acceptable solutions in Division B (see Note A-1.2.1.1.(1)(a)), or b) using alternative solutions that will achieve at least the minimum level of performance required by Division B in the areas defined by the objectives and functional statements attributed to the applicable acceptable solutions (see Note A-1.2.1.1.(1)(b)).
Clause (a) makes it clear that the acceptable solutions in Division B are automatically deemed to satisfy the linked objectives and functional statements of Division A.
Clause (b) makes it clear that alternative solutions can be used in lieu of compliance with the acceptable solutions. However, to do something different from the acceptable solutions described in Division B, a builder, designer or building owner must show that their proposed alternative solution will perform at least as well as the acceptable solution(s) it is replacing. The objectives and functional statements attributed to the acceptable solution(s) identify the areas of performance where this equivalence must be demonstrated.