9.8.6.2. Required Landings

This Article indicates where landings are required. In general, landings must be used to provide occupants with a level area at the top and bottom of ramps and flights of stairs, where a doorway opens onto a stair or ramp, where a ramp opens onto a stair, and where a stair opens onto a ramp. They can also be used to make changes in direction or to break a long stair or ramp into shorter runs. Excessively long stairs and ramps are psychologically intimidating and physically tiring, and can be a cause of serious falls.

Where a door at the top of a stair within a dwelling unit swings away from the stair, no landing is required between the doorway and stair. A landing may be omitted at the top of an exterior stair serving a secondary entrance to a single dwelling unit or a house with a secondary suite, provided the stair contains no more than three risers and the principal door to the entrance is a sliding door or swings away from the stair (Figure 9.8.-9).

Quoted from Illustrated User's Guide - NBC2015

Ramps in a barrier-free path of travel

Ramps in a barrier-free path of travel must conform to the requirements in NBC Article 3.8.3.5., as shown in Figure 9.8.-7

Quoted from Illustrated User's Guide - NBC2015

#ramps #barrierfree

9.8.8.6. Design of Guards to Not Facilitate Climbing

This Article requires that guards that protect a level located more than 4.2 m (13 ft. 9 3/8 in.) above the adjacent level, except for those in industrial occupancies, be designed so that no member, attachment or opening located between 140 and 900 mm (5 1/2 and 36 in.) above the level protected by the guard facilitates climbing. Such guards must not be constructed with decorative features that young children could use as a foothold.

Some configurations of members, attachments or openings may be part of a guard design and still comply with NBC Sentence 9.8.8.6.(1). Figures 9.8.-21 to 9.8.-23 present a few examples of designs that are considered to not facilitate climbing.

Quoted from Illustrated User's Guide - NBC2015

#openings #guards #climbing

Dimensions for Rectangular Treads

The limits on the run, together with those on the rise, control the steepness of stairs, which is also a factor in accidents. The minimum run, which is equal to the minimum tread depth, is intended to provide sufficient room to accommodate the length of a foot. Insufficient tread depth causes users to walk sideways to get sufficient foot support, increasing the risk of missteps. The maximum run, on the other hand, is intended to prevent users from having to take more than a single stride between steps, which would decrease the speed of travel. The maximum tread depth is intended to prevent excessive nosing projection. 

The dimensional requirements for steps with rectangular treads in private and public stairs are summarized in Figure 9.8.-2. 

Height over Stairs

These clear heights are intended to provide sufficient headroom clearance to prevent a reasonably tall adult from making accidental head contact with the ceiling or other objects at that height (e.g., light fixtures, sprinklers heads, or piping). The lower minimum clear height for stairs in dwelling units is rationalized on the basis of greater occupant familiarity. 

The clear height requirements for stairs are illustrated in Figure 9.8.-1.

Quoted from Illustrated User's Guide - NBC2015

Hallway

 The minimum unobstructed width of a normal hallway within a dwelling unit is 860 mm (34 in.), but this minimum hallway width is permitted to be reduced to 710 mm (28 in.) when certain requirements are met, as illustrated in Figure 9.5.-2. Hallways narrower than 860 mm (34 in.) must serve only bedrooms or bathrooms at the end of the hallway furthest from the living area, and must have an exit at that end of the hallway or an exit in each bedroom served by the hallway.

Parking Garage Considered as a Separate Building

Sometimes several buildings are built over a common basement used as a parking garage. For example, in certain housing designs, separate low-rise buildings are built over a common basement parking garage (Figure 9.1.-8).

Ordinarily, such a structure would be considered a single building, and the building area would be the area of the basement parking garage. Because this area tends to be fairly large, the entire building would normally fall outside the scope of NBC Part 9. If, however, the basement parking garage is separated from the buildings above it by a concrete or masonry slab having a fire-resistance rating of at least 2 h, these buildings can be considered separate buildings (NBC Article 9.10.4.3). 

In Figure 9.1.-8, buildings A and B would be considered as separate buildings having their own building areas and would probably fall within the scope of NBC Part 9. The parking garage, however, would probably fall outside of the scope of NBC Part 9 because of its large area. 

Quoted from Illustrated User's Guide - NBC2015

#building #parking #basement #sepratebuilding

Mezzanines

Mezzanines that are essentially open to view, so that a fire on the mezzanines would be visible from the room below and vice versa, do not have to be counted as a storey if their aggregate area does not exceed 40% of the open area of the room (Figure 9.1.-6) (NBC Sentence 9.10.4.1.(2)).

If, however, the condition for visual communication is not met from above or below the mezzanines, the mezzanines are only permitted to not be counted as a storey if their aggregate area does not exceed 10% of the floor area of the building in which they are located and if the area of each mezzanine does not exceed 10% of the area of the suite in which it is located.

Quoted from Illustrated User's Guide - NBC2015

#building #mezzanine #storey

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

#buildingheight #residential #dewellingunit

Buildings Separated by Firewalls

 Where a firewall divides a building, each portion of the building is considered as a separate building for the determination of building size

Most walls that separate one property from another are required to be firewalls (walls between semi-detached and row houses are exceptions to this rule). Firewalls are fire separations that have special features to ensure their stability in the event of a fire (NBC Subsection 3.1.10.), so that, should the building on one side of the firewall be destroyed, the firewall and the building on the other side will remain.

Firewalls may be voluntarily used to reduce the building area in order to take advantage of certain fire and structural concessions permitted for smaller buildings. Firewalls are frequently used to create buildings of 600 m2 (6 458 ft.2) that fall within the scope of NBC Part 9. For example, in some row houses, ordinary fire separations are used between most units, while firewalls are used at 600 m2 (6 458 ft.2) intervals.

Quoted from Illustrated User's Guide - NBC2015

#building #property #firewall