The term "storey" is defined in the National Building Code of Canada (NBC) as meaning: "that portion of a building that is situated between the top of any floor and the top of the floor next above it, and if there is no floor above it, that portion between the top of such floor and the ceiling above it.” As such, a rooftop enclosure is a storey. However, there are several applications in the Code where a rooftop enclosure is exempted from being considered a storey, such as when determining the building height in Sentence 3.2.1.1.(1) of Division B of the NBC.

Sentence 3.5.4.1.(1) stipulates that if one or more elevators are provided in a building, at least one elevator on each storey with access to an elevator is required to have inside dimensions capable of accommodating a patient stretcher (excluding limited-use/limited application elevators).

Sentence 3.5.4.1.(1) means that if a storey is served by an elevator, such elevator should comply with the requirement to accommodate the specified stretcher size. If more than one elevator serves a storey, at least one elevator should meet that specification.

The 2015 edition of the NBC required that all storeys be served by at least one elevator that met the stretcher size specification. The intent statement for Sentence 3.5.4.1.(1) is the following: 

To limit the probability that an elevator will not be of sufficient size to accommodate a person in a stretcher in a prone position, which could lead to delays in providing medical services to the person, which could lead to harm to the person.

This provision was never intended to require an elevator to serve certain rooftop enclosures, nor to require such elevator to meet the car dimension requirements stated in Sentence 3.5.4.1.(1) on the basis that such rooftop enclosure was solely provided for elevator machinery, a stairway or a service room used for no purpose other than for service to the building and would not be occupied on a regular basis. As such, the specified rooftop enclosure should not be considered a storey for the application of Sentence 3.5.4.1.(1). Misinterpretation of the requirements has led to confusion in enforcement and resulted in an inconsistent level of performance across different regions.

To ensure designers and authorities having jurisdiction apply the requirements as intended and to avoid further confusion between this provision in different editions of the NBC, this proposed change exempts such rooftop enclosures from being considered a storey for the application of Sentence 3.5.4.1.(1). Misinterpretation of the requirement could also result in overdesigned building elements, which could lead to increased building costs.

This proposed change clarifies whether or not rooftop enclosures are intended to be considered as a storey in the application of Sentence 3.1.5.4.(1). This proposed change would eliminate confusion among Code users and ensure that the requirements are applied and enforced as intended. As well, this proposed change mitigates the risk of inconsistent levels of performance occurring across different regions.

The introduction of Sentence 3.5.4.1.(4) provides an exemption to Sentence (1) that clarifies when rooftop enclosures are not required to be considered as a storey when applying the requirements for elevator car dimensions. The proposed exemption has the same justification as the existing exemption provided in Sentence 3.2.1.1.(1). That is to say, it is provided because certain rooftop enclosures are normally only briefly and intermittently occupied by persons and thus do not pose an undue safety risk to persons.

This proposed change clarifies Sentence 3.5.4.1.(1) by introducing an exemption that does not change the intent of the existing Code requirements. As such, no cost increases are anticipated. There may be cost savings for Code users in jurisdictions that interpreted the application of Sentence 3.5.4.1.(1) more conservatively than intended.

Code users (including designers and regulators) would need to consider whether their previous interpretation of Sentence 3.5.4.1.(1) was aligned with the intended Code interpretation, as this could affect their subsequent design work and expectations. This proposed change could result in potential cost savings by requiring a less stringent application of the dimension requirements for elevators serving certain rooftop enclosures and whether or not an elevator is required to service certain rooftop enclosures.

The proposed change enables consistent enforcement of Code requirements, which contributes to improving harmonization and consistent levels of performance across regions.

This proposed change clarifies for regulators and designers whether rooftop enclosures should be considered as a storey when applying the requirements of the NBC. As a result, this proposed change would facilitate the enforcement of Code requirements.

Regulators, builders, consumers, manufacturers and designers.