Residential Buildings on Sloping Sites

 

Where dwelling units in a building are completely separated from other dwelling units by a vertical fire separation having a fire-resistance rating of not less than 1 h, each dwelling unit may be considered as a separate building for the purpose of determining building height, provided that each dwelling unit is not more than four storeys in building height and that the unobstructed path of travel for a firefighter from the street to an entrance of each dwelling unit is not greater than 45 m (147 ft.) (NBC Sentence 1.3.3.4.(2) of Division A).

The fire separation has to be complete, extending through all storeys and service spaces from the basement or crawl space (or from the floor assembly immediately above the basement where the basement conforms to NBC Article 3.2.1.2.) up to the underside of the roof deck.

Accordingly, the stepped building on a sloping site shown in Figure 9.1.-5 can be considered as being three storeys in building height instead of six storeys in building height and is, therefore, covered by NBC Part 9. (See also NBC Note A-1.3.3.4.(2) of Division A.) 

Quoted from Illustrated User's Guide - NBC2015

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