NCC 2019 Volume Two
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Part 3.7.2 Fire separation of external walls

Part 3.7.2 Fire separation of external walls

Appropriate Performance Requirements

Appropriate Performance Requirements

Where an alternative fire separation design is proposed as a Performance Solution to that described in Part 3.7.2, that proposal must comply with—

  1. Performance RequirementP2.3.1; and
  2. the relevant Performance Requirements determined in accordance with A2.2(3) and A2.4(3) as applicable.

3.7.2.1 Application

Compliance with this acceptable construction practice satisfies Performance Requirement P2.3.1 for fire separation.

3.7.2.2 External walls of Class 1 buildings

An external wall of a Class 1 building, and any openings in that wall, must comply with 3.7.2.4 if the wall is less than—

(a)

900 mm from an allotment boundary other than the boundary adjoining a road alignment or other public space; or

(b)

1.8 m from another building on the same allotment other than a Class 10 building associated with the Class 1 building or a detached part of the same Class 1 building.

State and Territory Variations

State and Territory Variations

In South Australia delete 3.7.2.2(b) and insert SA 3.7.2.2(b) and (c) as follows:

  1. (b) 1.8 m from another building on the same allotment other than an appurtenant Class 10 building associated with the Class 10 building or a detached part of the same Class 1 building; or
  2. (c) 3 m from a brush fence.

3.7.2.3 Measurement of distances

(a)

The distance from any point on an external wall of a building to an allotment boundary or another building is the distance to that point measured along a line at right angles from the allotment boundary or external wall of the other building which intersects that point without being obstructed by a wall complying with 3.7.2.4.

(b)

Where a wall within a specified distance is required to comply with 3.7.2.4, only that part of the wall (including any openings) within the specified distance need be constructed in that manner.

(see Figure 3.7.2.1, Figures 3.7.2.2a and Figure 3.7.2.2b)

(c)

Where the distance measured is between attached or detached buildings of different heights, the distance must be taken from the external wall with the highest elevation measured at right angles to a point that intersects the nearest part of a vertical projection above the adjacent building, excluding any eave overhang (see Figure 3.7.2.2b).

State and Territory Variations

State and Territory Variations

In South Australia after 3.7.2.3(c) insert SA 3.7.2.3(d) as follows:

  1. (d) The distance from any point on an external wall of a building to a brush fence is measured in any direction from the external wall.
Figure 3.7.2.1 Walls at right angles to the boundary
v2_Fig37201_2019.svg

Notes to Figure 3.7.2.1 :

  1. No protection required for the wall at right angles or more to the boundary.
  2. For protection of encroachments refer to 3.7.2.7.
Figure 3.7.2.2a Measurement of distances (Plan view)
Diagram a Full wall protection
v2_Fig37202aa_2019.svg
Figure 3.7.2.2a Measurement of distances (Plan view)
Diagram b Part walls protection
v2_Fig37202ab_2019.svg

Note to Figure 3.7.2.2a: Setback distance is measured at right angles to the boundary.

Figure 3.7.2.2b Measurement of distance—Buildings of different heights
Diagram a Class 1 buildings on same allotment
v2_Fig37202ba_2019.svg
Diagram b Attached Class 1 buildings on same allotment
v2_Fig37202bb_2019.svg

3.7.2.4 Construction of external walls

(a)

External walls (including gables) required to be fire-resisting (referred to in 3.7.2.2 or 3.7.2.5) must—

(i)

commence at the footings or ground slab, except where the external wall commences above a separating wall complying with 3.7.3.2 (see Figure 3.7.2.2b); and

Explanatory information:

Explanatory information:

A Performance Solution must be used where an external wall required to be fire-resisting does not commence at the footings or ground slab.

(ii)

extend to—

(A)

the underside of a non-combustible roof covering, except that a wall may terminate not more than 200 mm from the underside of a non-combustible roof covering, where the area between the external wall and underside of the roof covering is sealed with a non-combustible fascia, gutter or flashing; or

(B)

the underside of a non-combustible eaves lining (See Figure 3.7.2.3); and

(iii)

be constructed in accordance with (b).

(b)

A wall required by (a) must—

(i)

have an FRL of not less than 60/60/60 when tested from the outside; or

(ii)

be of masonry-veneer construction in which the external masonry veneer is not less than 90 mm thick; or

(iii)

be of masonry construction not less than 90 mm thick.

Explanatory information:

Explanatory information:

The intent of the typical construction details shown in Figure 3.7.2.3 is to ensure that combustible materials (external or internal) are not directly exposed to fire at the junction of the wall and non-combustible roof, eaves lining, guttering and the like. Other forms of construction may also be acceptable provided that they achieve this intent.

See Figure 3.7.2.1 and 3.8.6.4 for internal separating wall construction under one common roof.

(c)

Openings in external walls required to be fire-resisting (referred to in 3.7.2.2 or 3.7.2.5) must be protected by—

(i)

non-openable fire windows or other construction with an FRL of not less than –/60/–; or

(ii)

self-closing solid core doors not less than 35 mm thick.

(d)

The requirements (c) do not apply to a window in a non-habitable room that is located adjacent to and not less than 600 mm from the boundary of an adjoining allotment or 1200 mm from another building on the same allotment provided that—

(i)

in a bathroom, laundry or toilet, the opening has an area of not more than 1.2 m2; or

(ii)

in a room other than one referred to in (i), the opening has an area of not more than 0.54 m2 and—

(A)

the window is steel-framed, there are no opening sashes and it is glazed in wired glass; or

(B)

the opening is enclosed with translucent hollow glass blocks.

(e)

Subfloor vents, roof vents, weepholes, control joints, construction joints and penetrations for pipes, conduits and the like need not comply with (c).

Figure 3.7.2.3 Typical construction of external walls
v2_Fig37203_2019.svg
v2_Fig37203e_2019.svg

Notes to Figure 3.7.2.3 :

  1. The external wall is deemed to extend to the underside of non-combustible roof covering, or non-combustible eaves lining, when constructed as shown.
  2. Where sarking is installed it must be located so that ponding of water is avoided between the fascia and the first roofing batten.
  3. The location of flashing and framing is indicative only.

3.7.2.5 Class 10a buildings

(a)

A Class 1 building must be protected by a method in—

(i)

Figure 3.7.2.4 where a Class 10a building is located between or adjacent to a Class 1 building and a boundary alignment that is not a boundary with a road alignment or other public space; or

(ii)

Figure 3.7.2.5 where a Class 10a building is located between or adjacent to a Class 1 building it is associated with and another building on the same allotment; or

(iii)

Figure 3.7.2.6 where two or more Class 10a buildings on the same allotment are located between and are associated with different Class 1 buildings.

(b)

A Class 10a building must not significantly increase the risk of spread of fire between Class 2 to 9 buildings.

Explanatory information:

Explanatory information:

3.7.2.5(a) ensures that when a Class 10 building is located between an allotment boundary and a Class 1 building or another building on the same allotment, either directly or indirectly, that the Class 1 building be protected by a wall with an FRL.

The intention is to prevent the spread of fire from an allotment boundary (fire source feature) to a Class 1 building via a Class 10a building. Where a Class 10a building is not sited directly and wholly between the allotment boundary and the Class 1 building (see Figure 3.7.2.4 diagrams f. to i.), the potential of fire spreading from the allotment boundary to the Class 1 still exists. Therefore fire separation would be required.

3.7.2.5 does not apply to a boundary that adjoins a road or public space such as parklands, lakes, rivers and the like where the construction of buildings is unlikely.

State and Territory Variations

State and Territory Variations

In South Australia after 3.7.2.5(b) insert SA 3.7.2.5(c) and (d) as follows:

(c)

A carport or verandah may have timber posts and timber roof support beams regardless of the distance from the boundary.

(d)

A Class 10b brush fence must not be constructed within 3 m of a Class 1 building unless any part of the building within 3 m of the brush fence complies with the fire-resisting requirements of 3.7.2.2, 3.7.2.3, 3.7.2.4 and 3.7.2.7.

Figure 3.7.2.4 Protection of Class 1 buildings—Class 10a between Class 1 and the allotment boundary

a.

900 mm from allotment boundary

The Class 10a building is not less than 900 mm from the allotment boundary, other than the boundary adjoining a road alignment or other public space.
v2_Fig37204a_2019.svg

b.

External wall to Class 10a building with FRL

An external wall of the Class 10a building which is less than 900 mm from an allotment boundary, other than the boundary adjoining a road alignment or other public space, complies with 3.7.2.4.
v2_Fig37204b_2019.svg

c.

External wall to Class 10a building with FRL

An external wall of the Class 10a building, which is less than 900 mm from the Class 1 building, complies with 3.7.2.4.
v2_Fig37204c_2019.svg

d.

900 mm separation between buildings

The Class 1 building is not less than 900 mm from the Class 10a building.
v2_Fig37204d_2019.svg

e.

Class 1 building with FRL to external wall

An external wall of the Class 1 building, which is less than 900 mm from the Class 10a building, complies with 3.7.2.4.
v2_Fig37204e_2019.svg

f.

External wall of adjacent Class 10a building with FRL

An external wall of the Class 10a building which is less than 900 mm from an allotment boundary other than the boundary adjoining a road alignment or other public space, complies with 3.7.2.4.
v2_Fig37204f_2019.svg

g.

External wall of an adjacent Class 10a building with FRL

An external wall of the Class 10a building, which is less than 900 mm from the external wall of the Class 1 building, complies with 3.7.2.4.
v2_Fig37204g_2019.svg

h.

Class 1 building with FRL to external wall

An external wall of the Class 1 building, which is less than 900 mm from a Class 10a building that is situated less than 900 mm from an allotment boundary, complies with 3.7.2.4.
v2_Fig37204h_2019.svg

i.

External wall to Class 10a building with FRL

The external wall of the Class 1 and Class 10a building which are less than 900 mm from an allotment boundary, other than the boundary adjoining a road alignment or other public space, complies with 3.7.2.4.
v2_Fig37204i_2019.svg
Figure 3.7.2.5 Protection of Class 1 buildings—Class 10a between Class 1 and other buildings on allotment

a.

1.8 m from other building on allotment

The Class 10a building is not less than 1.8 m from the other building.
v2_Fig37205a_2019.svg

b.

External wall to Class 10a building with FRL

An external wall of the Class 10a building, which is less than 1.8 m from the other building, complies with 3.7.2.4.
v2_Fig37205b_2019.svg

c.

External wall to Class 10a building with FRL

An external wall of the Class 10a building, which is less than 1.8 m from the Class 1 building, complies with 3.7.2.4.
v2_Fig37205c_2019.svg

d.

1.8 m separation between Class 1 and 10a

The Class 1 building is not less than 1.8 m from the Class 10a building.
v2_Fig37205d_2019.svg

e.

Class 1 building with FRL to external wall

An external wall of the Class 1 building, which is less than 1.8 m from the Class 10a building, complies with 3.7.2.4.
v2_Fig37205e_2019.svg

f.

External wall of adjacent Class 10a building with FRL

An external wall of the Class 10a building, which is less than 1.8 m from the external wall of the other building, complies with 3.7.2.4.
v2_Fig37205f_2019.svg

g.

External wall of adjacent Class 10a building with FRL

An external wall of the Class 10a building, which is less than 1.8 m from the external wall of the Class 1 building, complies with 3.7.2.4.
v2_Fig37205g_2019.svg

h.

Class 1 and 10 building with FRL to external wall

An external wall of the Class 1 and 10a building, which is less than 1.8 m from the external wall of the other building, complies with 3.7.2.4.
v2_Fig37205h_2019.svg
Figure 3.7.2.6 Protection of Class 1 buildings—separation of Class 10a buildings on an allotment

a.

1.8 m between Class 10a buildings

Each Class 10a building must be separated from each other by a distance of not less than 1.8 m.
v2_Fig37206a_2019.svg

b.

External wall to Class 10a building with FRL

Each Class 10a building must be separated from each other by external walls complying with 3.7.2.4.
v2_Fig37206b_2019.svg

c.

900 mm separation between Class 10a and Class 1 buildings

Each Class 10a building must be separated from each Class 1 building by a distance of not less than 900 mm.
v2_Fig37206c_2019.svg

d.

External wall to Class 10a buildings with FRL

Each Class 10a building must be separated from each Class 1 building by external walls complying with 3.7.2.4.
v2_Fig37206d_2019.svg

e.

Class 10a buildings with FRL to separating wall

Each Class 10a building must be separated by a wall complying with 3.7.3.2.
v2_Fig37206e_2019.svg

f.

External wall to adjacent Class 10a buildings with FRL

Each Class 10a building must be separated from each other by external walls complying with 3.7.2.4.
v2_Fig37206f_2019.svg

g.

External wall to adjacent Class 10a buildings with FRL

Each Class 10a building must be separated from each Class 1 building by external walls complying with 3.7.2.4.
v2_Fig37206g_2019.svg

h.

Class 10a buildings with FRL to separating wall

Each Class 10a building must be separated by a wall complying with 3.7.3.2.
v2_Fig37206h_2019.svg

3.7.2.6 Open carports

(a)

A Class 10a carport is exempt from complying with 3.7.2.5(a) if—

(i)

it has two or more sides open and not less than one third of its perimeter open; and

(ii)

for the purposes of (i), a side is considered to be open if the roof covering adjacent to that side is not less than 500 mm from another building or allotment boundary; and

(iii)

it has a polycarbonate or non-combustible roof covering; and

(iv)

any ceiling lining and wall cladding, including gables, is non-combustible(see Figure 3.7.2.7); and

(v)

it does not provide direct vertical support to any part of the Class 1 building; and

(vi)

in the case where it has a common roof structure with the Class 1 building and the carport does not have a ceiling (See Figure 3.7.2.8), the opening between the top of the wall of the Class 1 building and the underside of the roof covering is infilled with—

(A)

a non-combustible material; or

(B)

construction clad with non-combustible material on the carport side.

Explanatory information:

Explanatory information:

A side of a carport enclosed by a vehicle access door is not considered to be an open side.

Figure 3.7.2.7 Identifying an open carport
v2_Fig37207_2019.svg

State and Territory Variations

State and Territory Variations

In South Australia delete 3.7.2.6(a) and insert SA 3.7.2.6(a) as follows:

  1. A carport or verandah is exempt from 3.7.2.5(a) if—
    1. it has—
      1. two or more sides open and not less than one third of its perimeter open and, for the purpose of this clause, a side is considered to be open if the roof covering adjacent to that side is not less than 500 mm from another building or allotment boundary; or
      2. any part of the external wall of the Class 1 building located less than 2 m from the allotment boundary or less than 4 m from another Class 1 building on the same allotment is fire-resisting to the underside of a non-combustible roof covering or to the underside of a non-combustible ceiling lining (see Figure SA 3.7.2.7a, Figure SA 3.7.2.7b and Figure SA 3.7.2.7c); and
    2. it has polycarbonate or non-combustible roof covering and any ceiling lining and wall cladding, including gables, is also non-combustible (see Figure 3.7.2.7); and
    3. it does not provide direct vertical support to any part of the Class 1 building; and
    4. in the case where it has a common roof structure with the Class 1 building and the carport or verandah does not have a ceiling (see Figure 3.7.2.8), the opening between the top of the wall of the Class 1 building and the underside of the roof covering is infilled with—
      1. a non-combustible material; or
      2. construction clad with non-combustible material on the carport or verandah side; and
    5. in the case where two carports or verandahs have a common roof structure with two different Class 1 buildings and the carports or verandahs have a ceiling, the roof space or ceiling space between the top of the ceiling and the underside of the roof covering is infilled as follows—
      1. vertically between the two Class 1 buildings and between the two appurtenant carports of verandahs in accordance with SA 3.7.2.6(a)(iv) (see Figure SA 3.7.2.6d); or
      2. vertically between the two Class 1 buildings and between the two appurtenant carports or verandahs in accordance with SA 3.7.2.6(a)(iv), except that the construction must be clad with non-combustible materials on both sides and must not be crossed by timber or other combustible building elements except for roof battens with dimensions of 75 × 50 mm or less, roof sarking-type material or a timber gutter board not less than 20 mm thick.

Figure SA 3.7.2.7a

Fire-resisting requirements for carports or verandahs without a ceiling

v2_FigSA3727a_2019.svg

Figure SA 3.7.2.7b

Fire-resisting requirements for carports or verandahs with a non-combustible ceiling

v2_FigSA3727b_2019.svg

Figure SA 3.7.2.7c

Fire-resisting requirements for external walls in carports and verandahs that share a common roof space

v2_FigSA3727c_2019.svg

Figure SA 3.7.2.7d

Fire-resisting requirements for roof space openings in carports and verandahs with a ceiling that share a common roof space

v2_FigSA3727d_2019.svg
Figure 3.7.2.8 Requirements for non-combustible infill panels to carport
v2_Fig37208_2019.svg

3.7.2.7 Allowable encroachments

(a)

An encroachment is any construction between—

(i)

the external wall of the building and the allotment boundary other than a boundary adjoining a road or other public space; or

(ii)

the external walls of two buildings on the same allotment; or

(iii)

the external wall of the building and the vertical projection of an adjoining building on the same allotment.

(b)

For the purposes of (a), an encroachment relates to any external wall of—

(i)

a Class 10a building required to comply with 3.7.2.5; or

(ii)

a Class 1 building.

(c)

Encroachments allowed within 900 mm of an allotment boundary or within 1.8 m of another building on the same allotment are—

(i)

non-combustible fascias, gutters and downpipes; and

(ii)

light fittings, electricity or gas meters, aerials or antennas; and

(iii)

pergolas, sun blinds or water tanks (see Figure 3.7.2.9); and

(iv)

unroofed terraces, landings, steps and ramps, not more than 1 m in height.

(d)

Encroachments allowed up to but not closer than 450 mm from an allotment boundary or up to but not closer than 900 mm from another building on the same allotment or associated encroachments of another building on the same allotment are—

(i)

combustible fascias, gutters and downpipes (see Figure 3.7.2.9); and

(ii)

eaves with non-combustible roof cladding and non-combustible lining; and

(iii)

flues, chimneys, pipes, domestic fuel tanks, cooling or heating appliances or other services.

(e)

Encroachments allowed between an external wall of a building and the vertical projection of an adjoining building on the same allotment are non-combustible fascias, gutters and downpipes (see Figure 3.7.2.3(e)).

Explanatory information:

Explanatory information:

A deck is not considered an unroofed terrace and is therefore not permitted as an allowable encroachment under 3.7.2.7 whether combustible or not.

The term pergola is a reference to an unroofed structure.

Figure 3.7.2.9 Allowable encroachments for non-combustible construction
Diagram a Combustible fascia up to but not closer than 450 mm to an allotment boundary
v2_Fig37209a_2019.svg
Diagram b Non-combustible fascia and gutter within 900 mm of an allotment boundary
v2_Fig37209b_2019.svg
Diagram c Unroofed pergola within 900 mm of an allotment boundary
v2_Fig37209c_2019.svg

State and Territory Variations

State and Territory Variations

In South Australia delete 3.7.2.7 and insert SA 3.7.2.7 and Figure SA 3.7.2.9a as follows:

  1. An encroachment is any construction between—
    1. the external wall of the building and the allotment boundary other than a boundary adjoining a road or other public space; or
    2. the external walls of two buildings on the same allotment; or
    3. the external wall of the building and a brush fence.
  2. For the purposes of (a), an encroachment related to any external wall of—
    1. a Class 10a building required to comply with 3.7.2.5; or
    2. a Class 1 building.
  3. The encroachments allowed within 900 mm of an allotment boundary or within 1.8 m of another building on the same allotment or within 3 m of a brush fence are—
    1. non-combustible fascias, gutters and downpipes; and
    2. light fittings, electricity or gas meters, aerials or antennas; and
    3. pergolas, sun blinds or water tanks; and
    4. unroofed terraces, landings, steps and ramps, not more than 1 m in height.
  4. Except as permitted by (e) or not permitted by (f), encroachments allowed up to but not closer than 450 mm from an allotment boundary or up to but not closer than 900 mm from another building on the same allotment or associated encroachments of another building on the same allotment are—
    1. combustible fascias, gutters and downpipes (see Figure 3.7.2.9); and
    2. eaves with non-combustible roof cladding and non-combustible lining; and
    3. flues, chimneys, pipes, domestic fuel tanks, cooling or heating appliances or other services.
  5. Eaves with non-combustible roof cladding and non-combustible soffit or lining may encroach within 450 mm of the allotment boundary where the external walls of a building are located not less than 900 mm from the allotment boundary and the walls are positioned at an angle of not less than 20 degrees and not more than 70 degrees to the allotment boundary or other building and the eaves only encroach at the corner of the roof (see SA Figure 3.7.2.9a).
  6. Fascias listed in (d)(i), must not be built within 3 m of a brush fence.

Figure SA 3.7.2.9a

Concession for encroachment of eaves

v2_FigSA3729a_2019.svg

3.7.2.8 Roof lights

Combustible roof lights, skylights or the like installed in a roof or part of a roof required to have a non-combustible covering must—

(a)

have an aggregate area not more than 20% of the roof or part of the roof; and

(b)

not less than—

(i)

900 mm from the allotment boundary other than the boundary adjoining a road alignment or other public space; and

(ii)

1.8 m from any roof light or the like in another building on the allotment other than an associated building or a detached part of the same building. (See Figure 3.7.2.10).

Figure 3.7.2.10 Location of combustible roof lights
v2_Fig37210_2019.svg

Note to Figure 3.7.2.10: Roof lights depicted in Figure 3.7.2.10 are combustible.