NCC 2019 Volume Two Amendment 1
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Part 3.10.4 Construction in alpine areas
Appropriate Performance Requirements
Appropriate Performance Requirements
Where an alternative alpine area egress design is proposed as a Performance Solution to that described in Part 3.10.4, that proposal must comply with—
- Performance RequirementP2.7.4; and
- the relevant Performance Requirement s determined in accordance with A2.2(3) and A2.4(3) as applicable.
Explanatory information:
Explanatory information:
Buildings constructed in alpine areas need special consideration because of sub-zero temperatures which can create elements which restrict free movement to and from the building. The additional measures in this Part include—
- having external doorways open in a way that is not impeded by snow and ice outside; and
- for external trafficable structures forming part of the means of egress, being constructed so that they remain useable under snow conditions, and
- minimising the impact of snow build up between and around buildings.
Part 3.0 (structural provisions) and Part 3.12 (energy efficiency) also contain specific additional requirements for a building located in an alpine area.
Acceptable Construction Practice
3.10.4.1 Application
(a)
Compliance with this acceptable construction practice for buildings that are located in alpine areas satisfies Performance Requirement P2.7.4.
(b)
The Deemed-to-Satisfy Provisions of this Part apply in addition to other Deemed-to-Satisfy Provisions of the Housing Provisions.
(c)
Where any Deemed-to-Satisfy Provisions are in conflict, the provisions of this Part take precedence.
3.10.4.2 External doors
External doors that may be subject to a build-up of snow must—
(a)
open inwards or slide; and
(b)
be constructed so that the threshold is not less than 900 mm above the adjoining surface; and
(c)
in a Class 1b building, be marked "OPEN INWARDS" on the inside face of the door in letters not less than 75 mm high and in a colour contrasting with that of the background.
3.10.4.3 External trafficable structures
External stairways, ramps, access bridges or other trafficable structures serving the building must have—
(a)
a floor surface that consists of expanded mesh if it is used as a means of egress; and
(b)
any required barrier designed so that its sides are not less than 75% open; and
(c)
for a stairway, goings (G), risers (R) and slope relationship quantity (2R + G) in accordance with—
(i)
Table 3.9.1.1; or
(ii)
Table 3.10.4.1; and
(d)
for a ramp serving an external doorway, a gradient not steeper than 1:12.
3.10.4.4 Clear spaces around buildings
A building must be constructed so that—
(a)
for any external walls more than 3.6 m above the natural ground level, the distance of that part of the building from the allotment boundary (other than a road alignment) must be not less than 2.5 m plus an additional 100 mm for each 300 mm or part by which that part of the external wall exceeds a height of 3.6 m (see Figure 3.10.4.3a); and
(b)
if an external doorway discharges into a court between wings of a building and that area may be used for vehicle access to the building, the clear distance between wings must be not less than 4 m (see Figure 3.10.4.3b); and
(c)
where an external doorway discharges opposite a feature that could trap snow or an embankment that is more than 900 mm above the threshold of that doorway, a minimum clear distance of not less than 4 m must be provided between the door and the feature (see Figure 3.10.4.3c).
Figure 3.10.4.3a Clear spaces around buildings—Set-back from allotment boundary where wall exceeds 3.6 m
Figure 3.10.4.3b Clear spaces around buildings—External doorway discharging into a court between wings of a building
Figure 3.10.4.3c Clear spaces around buildings—Embankments adjoining buildings
Figure 3.10.4.3d Clear spaces around buildings—Use of a threshold where clear space is not available
Explanatory information:
Explanatory information:
Snow build-up around buildings
The design and construction of a building in an alpine area must not aid dangerous levels of snow build-up between and around buildings. This control—
- assists with egress in an emergency; and
- helps vehicle access around the buildings, both for snow clearing and emergency situations; and
- minimises the risk of snow or ice falling from the roof onto adjoining lots or egress routes.
1. Set-back distances
1. Set-back distances3.10.4.3(a) prescribes set-back requirements for external walls from the boundary of adjoining allotments. The aim is to ensure that a reasonable distance is created between buildings to reduce the amount of snow build-up between properties. 3.10.4.3(a) applies only to the area adjacent to that part of the wall that is more than 3.6 m in height.
2. Distance between wings of buildings
3.10.4.3(b) prescribes a minimum distance between wings of a building or attached buildings where external doorways may discharge into this area. This requirement only applies where the court or wings are able to be accessed by vehicles.
3. Embankments adjoining buildings
3.10.4.3(c) applies where features adjacent to an external doorway could trap snow and complicate access and egress to and from the building.