The 2011 edition of the National Energy Code for Buildings (NECB) is presented in a format called “objective-based code” that is structured in three Divisions (A, B and C). The Code contains an explicitly defined objective and functional statements (see Division A), which are statements on the functions that the components of a building or facility must perform and the objective that these functions must satisfy. Most of the Code provisions in Division B—called acceptable solutions—are linked to the objective and one or more functional statements (referred to as “attributions”).
Objectives and functional statements are developed through a process called “bottom-up analysis,” which involves the analysis of each provision in Division B of the National Model Construction Codes to determine its intent and then derive applicable objectives and functional statements. The bottom-up analysis is carried out by the standing committees of the Canadian Commission on Building and Fire Codes (CCBFC) with extensive support from the staff of the Canadian Codes Centre (CCC).
Intent statements, which are additional, non-mandatory information and not an integral part of the Codes, provide guidance to Code users. The intent statements contain useful information not available elsewhere that helps users understand the rationale behind each requirement. This contributes to a more accurate interpretation and application of acceptable solutions and a clearer understanding of what alternative solutions should achieve.
Only the provisions in Parts 3 to 8 of Division B (i.e. the acceptable solutions not including their Appendix Notes) have intent statements.
Clicking on a Sentence reference in the left-hand portion of the screen brings up an analysis window on the right-hand side, which contains that Sentence's applicable attribution(s) and intent statement(s).
For the most part, entire Sentences are analyzed as units of text. In such cases, only the Sentence number is identified in the analysis window and the actual text of the Sentence can be found in the printed Code. In some instances, however, the analysis applies to only a portion of a Sentence; in such cases, the Clause or Subclause being analyzed is identified in the field entitled “Attribution” or the portion of text being analyzed is quoted or summarized in that field and introduced by the phrase “Applies to.”
The objective attributed to the provisions or portions of provisions in Division B is derived from the bottom-up analysis. Each analysis window contains a tab or tabs displaying the acronym for the objective (OE1). Clicking on a tab reveals a panel containing the information related to that objective attribution.
Some provisions or portions of provisions in Division B have no objective attributed to them. In such instances, the tab will display the symbol “+” rather than the objective.
The specific functional statements and sub-objectives attributed to the text being analyzed are presented in square brackets in the Attribution field. If the attribution(s) and intent statement(s) apply to the entire Sentence, no explanatory text will appear before or after the square brackets; if they apply to only a portion of a Sentence, the square brackets will either be preceded by the Clause or Subclause identifier, or followed by a phrase beginning with “Applies to,” which specifies which portion of the Sentence the attributions and analysis apply to.
An intent statement explains the purpose of a provision or portion of provision found in Division B. It reveals what the standing committee was trying to achieve by introducing the Code provision in the first place or what the Code-user community has come to understand as the reason for the provision's existence.
Generally speaking, intent statements present the consequences of non-compliance with a requirement using a standardized set of phrases and terms. They try to answer the question “What are the undesirable thing(s) that might happen if this provision is not complied with?” In many cases, the initial consequences of non-compliance may lead to a chain of consequences; the link between those consequences and the overall objective of the provision may only become apparent in the description of the latter consequences in the chain. All functional statements and the objective identified in Division A and attributed to the provisions in Division B are derived from the intent statements.
Not all Code provisions are technical requirements; some act as definitions, clarifications, application modifiers or pointers to another provision. In such cases, the intent statement explains the role the provision plays in the Code and there is no chain of consquences. These types of provisions have no objective or functional statements attributed to them. Appendix Note A-18.104.22.168.(1) in Division B of the Code provides information on how these types of provisions are interpreted.
Many of the hazards and undesirable events the National Model Construction Codes address, such as deterioration, spread of fire and heat loss, can only be minimized, retarded or controlled through compliance; other undesirable events such as the ignition of fire or structural collapse can never be prevented with absolute assurance. This is why the phrase “to limit the probability” is used in the intent statements rather than “to prevent.”
Using the phrase “to prevent” would mean that it is possible to comply fully with a requirement but still not meet its intent. The phrase “to limit the probability” was therefore adopted to clearly convey the notion that the Codes do not and cannot provide absolute protection.