NCC 2019 Volume Two
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Part 3.4.4 Structural steel members
Appropriate Performance Requirements
Where an alternative structural steel member system is proposed as a Performance Solution to that described in Part 3.4.4, that proposal must comply with—
The following described terms are used in this Part:
Design member
Member 1
Member 2
Effective member spacing
0.5 x Span 1
0.5 x (Span 1 + Span 2)
Design Member
Member 1
Member 2
Member 3
Effective member spacing
0.4 x Span 1
0.6 x (Span 1 + Span 2)
0.5 x (Span 2) + Span 3
Steel member abbreviations are as follows:
Performance RequirementP2.1.1 is satisfied for structural steel sections if they are designed and constructed in accordance with one of the following:
Steel structures: AS 4100.
Coldformed steel structures: AS/NZS 4600.
Design requirements for other materials used in combination with structural steel members are described in Part 3.4.2 — Steel framing, 3.4.3 — Timber framing or Part 3.0 — Structural provisions.
Compliance with this acceptable construction practice satisfies P2.1.1 in respect to structural stability, provided—
the building is located in an area with a design wind speed of not more than N3; and
the first dimension of steel sections is installed vertically; and
all loads are uniformly distributed (unless otherwise noted or allowed for); and
the building is one for which Appendix A of AS 1170.4 contains no specific earthquake design requirements; and
There are certain limitations on the application to domestic structures such as Class 1a and 1b buildings in Appendix A of AS 1170.4. These limitations include building height, roof slope, etc. For additional information refer to Appendix A of AS 1170.4.
the structural steel member is not subject to snow loads.
Structural steel members may be used as follows:
Bearers supporting a timber floor or nonloadbearing stud wall — in accordance with Figure 3.4.4.1, Table 3.4.4.1a and Table 3.4.4.1b.
Strutting beams supporting roof and ceiling loads — in accordance with Figure 3.4.4.2 and Table 3.4.4.2a to Table 3.4.4.2b.
Lintels supporting roof, ceiling, frame and timber floor — in accordance with Figure 3.4.4.3 and Table 3.4.4.3a to Table 3.4.4.3b.
Columns — in accordance with 3.4.4.3.
Structural steel members described in this Part must be protected against corrosion in accordance with 3.4.4.4.
Joists, bearers and lintels must be restrained from lateral movement or twisting along their length by fixing rafters or joists to the top flange of the member so that it prevents that member from moving laterally.
End supports for joists, bearers and lintels must transfer loads to the footings and have a bearing distance as follows:
For single spans, the bearing distance must not be less than the width of the member.
For continuous spans, internal bearing must be not less than two times the width of the member.
Steel Section 
1.8 EBS 
2.4 EBS 
3.0 EBS 
3.6 EBS 
4.2 EBS 
125TFB 
4.1 m 
3.8 m 
3.6 m 
3.4 m 
3.2 m 
180UB16.1 
5.1 m 
4.7 m 
4.5 m 
4.3 m 
4.1 m 
200UB18.2 
5.6 m 
5.2 m 
5.0 m 
4.7 m 
4.6 m 
250UB25.7 
6.8 m 
6.4 m 
6.0 m 
5.8 m 
5.6 m 
250x150x9.0 RHS 
7.7 m 
7.1 m 
6.7 m 
6.4 m 
6.2 m 
250x150x5.0 RHS 
6.8 m 
6.3 m 
5.9 m 
5.7 m 
5.5 m 
310UB32.0 
7.9 m 
7.3 m 
7.0 m 
6.7 m 
6.4 m 
125x75x2.0 RHS 
3.1 m 
2.8 m 
2.6 m 
2.5 m 
2.4 m 
125x75x3.0 RHS 
3.5 m 
3.2 m 
3.0 m 
2.8 m 
2.7 m 
150x50x2.0 RHS 
3.4 m 
3.1 m 
2.8 m 
2.7 m 
2.5 m 
150x50x3.0 RHS 
3.7 m 
3.4 m 
3.2 m 
3.0 m 
2.9 m 
100TFC 
3.2 m 
2.9 m 
2.7 m 
2.6 m 
2.4 m 
150PFC 
4.8 m 
4.5 m 
4.2 m 
4.0 m 
3.9 m 
180PFC 
5.4 m 
5.1 m 
4.8 m 
4.6 m 
4.4 m 
200PFC 
5.9 m 
5.5 m 
5.2 m 
5.0 m 
4.8 m 
250PFC 
7.2 m 
6.7 m 
6.4 m 
6.1 m 
5.9 m 
300PFC 
8.1 m 
7.6 m 
7.2 m 
6.9 m 
6.6 m 
Notes to Table 3.4.4.1a :
EBS = Effective bearer spacing (m).
Steel is base grade.
Load must be evenly distributed along the member.
See 3.4.2.3 for provisions that apply to suspended floors in singlestorey and ground floor construction of suspended steel floor frames.
Effective bearer spacing is a measure of the width of the load area being supported by the member (for single span members see Table 3.4.4.0a and Figure 3.4.4.0a).
Steel Section 
1.8 EBS 
2.4 EBS 
3.0 EBS 
3.6 EBS 
4.2 EBS 
125TFB 
4.7 m 
4.3 m 
3.8 m 
3.5 m 
3.2 m 
180UB16.1 
5.9 m 
5.5 m 
5.2 m 
5.0 m 
4.7 m 
200UB18.2 
6.5 m 
6.0 m 
5.7 m 
5.5 m 
5.3 m 
250UB25.7 
7.9 m 
7.4 m 
7.0 m 
6.7 m 
6.4 m 
250x150x9.0 RHS 
8.8 m 
8.2 m 
7.8 m 
7 m 
7.1 m 
250x150x5.0 RHS 
7.8 m 
7.2 m 
6.8 m 
6.5 m 
6.3 m 
310UB32.0 
9.1 m 
8.5 m 
8.1 m 
7.7 m 
7.4 m 
125x75x2.0 RHS 
4.0 m 
3.7 m 
3.5 m 
3.3 m 
3.1 m 
125X75X3.0 RHS 
4.4 m 
4.1 m 
3.9 m 
3.7 m 
3.5 m 
150x50x2.0 RHS 
4.2 m 
3.9 m 
3.7 m 
3.5 m 
3.4 m 
150x50x3.0 RHS 
4.6 m 
4.3 m 
4.1 m 
3.9 m 
3.7 m 
100TFC 
3.7 m 
3.2 m 
2.8 m 
2.6 m 
2.4 m 
150PFC 
5.5 m 
5.1 m 
4.9 m 
4.7 m 
4.5 m 
180PFC 
6.3 m 
5.9 m 
5.6 m 
5.3 m 
5.1 m 
200PFC 
6.8 m 
6.3 m 
6.0 m 
5.7 m 
5.5 m 
250PFC 
8.4 m 
7.8 m 
7.4 m 
7.1 m 
6.8 m 
300PFC 
9.4 m 
8.8 m 
8.3 m 
8.0 m 
7.7 m 
Notes to Table 3.4.4.1b :
Steel Section 
1.8 SBS 
2.4 SBS 
3.0 SBS 
3.6 SBS 
4.2 SBS 
125TFB 
5.7 m 
5.4 m 
5.1 m 
4.9 m 
4.6 m 
150UB14.0 
6.4 m 
6.0 m 
5.7 m 
5.4 m 
5.1 m 
200UB18.2 
7.9 m 
7.4 m 
7.1 m 
6.8 m 
6.5 m 
250UB31.4 
10.0 m 
9.4 m 
9.0 m 
8.7 m 
8.4 m 
310UB46.2 
11.9 m 
11.3 m 
10.8 m 
10.5 m 
10.1 m 
100TFC 
4.6 m 
4.4 m 
4.2 m 
3.9 m 
3.7 m 
150PFC 
6.7 m 
6.3 m 
6.0 m 
5.8 m 
5.6 m 
200PFC 
8.2 m 
7.7 m 
7.4 m 
7.1 m 
6.8 m 
250PFC 
10.0 m 
9.4 m 
9.0 m 
8.7 m 
8.4 m 
300PFC 
11.1 m 
10.5 m 
10.1 m 
9.7 m 
9.4 m 
Notes to Table 3.4.4.2a :
SBS = Strutting beam spacing (m).
If point load applied, then it must be located within the middle third of the strutting beam span.
Top and bottom flanges of strutting beam must be laterally restrained at the loading point.
Strutting beam must be tied down at the support point, in the case of steel sheet roofs.
Steel is base grade.
Steel Section 
1.8 SBS 
2.4 SBS 
3.0 SBS 
3.6 SBS 
4.2 SBS 
125TFB 
4.9 m 
4.6 m 
4.4 m 
4.2 m 
4.1 m 
150UB14.0 
5.5 m 
5.2 m 
4.9 m 
4.7 m 
4.5 m 
200UB18.2 
6.9 m 
6.4 m 
6.1 m 
5.8 m 
5.6 m 
250UB31.4 
8.8 m 
8.2 m 
7.8 m 
7.5 m 
7.2 m 
310UB46.2 
10.6 m 
10.0 m 
9.5 m 
9.1 m 
8.8 m 
100TFC 
4.0 m 
3.7 m 
3.6 m 
3.4 m 
3.2 m 
150PFC 
5.8 m 
5.5 m 
5.2 m 
5.0 m 
4.8 m 
200PFC 
7.2 m 
6.7 m 
6.4 m 
6.1 m 
5.9 m 
250PFC 
8.8 m 
8.2 m 
7.8 m 
7.5 m 
7.3 m 
300PFC 
9.8 m 
9.3 m 
8.8 m 
8.4 m 
8.2 m 
Notes to Table 3.4.4.2b :
SBS = Strutting beam spacing (m).
If point load applied, then it must be located within the middle third of the strutting beam span.
Top and bottom flanges of strutting beam must be laterally restrained at the loading point.
Steel is base grade.
Steel Section 
1.8 ELW 
2.4 ELW 
3.0 ELW 
3.6 ELW 
4.2 ELW 
125TFB 
3.7 m 
3.4 m 
3.2 m 
3.0 m 
2.8 m 
150UB14.0 
4.1 m 
3.9 m 
3.7 m 
3.5 m 
3.3 m 
200UB25.4 
5.6 m 
5.3 m 
5.0 m 
4.8 m 
4.7 m 
250UB31.4 
6.6 m 
6.2 m 
5.9 m 
5.7 m 
5.5 m 
100TFC 
2.8 m 
2.6 m 
2.4 m 
2.3 m 
2.1 m 
150PFC 
4.4 m 
4.1 m 
3.9 m 
3.7 m 
3.6 m 
200PFC 
5.4 m 
5.0 m 
4.8 m 
4.6 m 
4.4 m 
250PFC 
6.6 m 
6.2 m 
5.9 m 
5.7 m 
5.5 m 
75X75X5EA 
1.3 m 
1.2 m 
1.1 m 
N/A 
N/A 
90X90X6EA 
1.9 m 
1.6 m 
1.5 m 
1.3 m 
1.2 m 
100X100X6EA 
2.0 m 
1.8 m 
1.6 m 
1.5 m 
1.4 m 
125X75X6UA 
2.3 m 
2.0 m 
1.8 m 
1.7 m 
1.5 m 
150X100X10UA 
3.9 m 
3.6 m 
3.2 m 
2.9 m 
2.7 m 
Notes to Table 3.4.4.3a :
ELW = Effective load width (m).
Top flange of lintel must be laterally restrained at the loading points.
Load must be evenly distributed along the member (e.g. joists).
Angle lintels  first dimension corresponds to vertical leg (e.g. 100x75x6UA, 100 mm leg is vertical).
For lintels supporting masonry walls, see Part 3.3.3.
Steel Section 
1.8 ELW 
2.4 ELW 
3.0 ELW 
3.6 ELW 
4.2 ELW 
125TFB 
3.6 m 
3.3 m 
3.0 m 
2.9 m 
2.7 m 
150UB14.0 
4.0 m 
3.7 m 
3.5 m 
3.3 m 
3.2 m 
200UB25.4 
5.4 m 
5.1 m 
4.8 m 
4.6 m 
4.5 m 
250UB31.4 
6.3 m 
6.0 m 
5.7 m 
5.4 m 
5.2 m 
100TFC 
2.7 m 
2.5 m 
2.3 m 
2.1 m 
2.0 m 
150PFC 
4.2 m 
3.9 m 
3.7 m 
3.6 m 
3.4 m 
200PFC 
5.1 m 
4.8 m 
4.6 m 
4.4 m 
4.2 m 
250PFC 
6.3 m 
6.0 m 
5.7 m 
5.4 m 
5.3 m 
75X75X5EA 
1.3 m 
1.1 m 
N/A 
N/A 
N/A 
90X90X6EA 
1.7 m 
1.5 m 
1.4 m 
1.3 m 
1.2 m 
100X100X6EA 
1.9 m 
1.7 m 
1.5 m 
1.4 m 
1.3 m 
125X75X6UA 
2.2 m 
1.9 m 
1.7 m 
1.6 m 
1.4 m 
150X100X10UA 
3.7 m 
3.3 m 
3.0 m 
2.8 m 
2.6 m 
Notes to Table 3.4.4.3b :
ELW = Effective load width (m).
Top flange of lintel must be laterally restrained at the loading points.
Load must be evenly distributed along the member (e.g. joists).
Angle lintels  first dimension corresponds to vertical leg (e.g. 100x7 x6UA, 100 mm leg is vertical).
For lintels supporting masonry walls, see Part 3.3.3.
Columns may support the area provided for in Table 3.4.4.6a to Table 3.4.4.6b provided—
the effective height of the column is determined in accordance with Figure 3.4.4.4 and Table 3.4.4.4; and
the floor area to be supported is determined in accordance with Figure 3.4.4.5 and Table 3.4.4.5; and
the load eccentricity between the centre of the column and the applied vertical loading complies with Figure 3.4.4.6.
Base detail
Fully braced ^{(1)}construction
Unbraced construction (cantilever columns) ^{(2)}
Cast into footing
1.00
2.60
Fixed by bolts to footing or slab
1.20
must not be used
Fixed by intermediate floor or bracing in both directions
1:20
2.60
Notes to Table 3.4.4.4 :
To determine the column effective height, the actual column height (H) in Figure 3.4.4.4 must be multiplied by a column height factor (F1) in Table 3.4.4.4.
H = Distance measured from the top of footing to underside of supported beam or bearer, or between intermediate lateral bracing points.
The flooring system must be fully braced to footing level by—
a combination of column bracing sets, and timber or masonry bracing walls; or
the provision of cantilever steel columns only (i.e. no column bracing sets, timber or masonry bracing walls).
Column descriptor (as shown in Figure 3.4.4.5 )
Total area supported
C1
0.375L1 x 0.375LA
C2
0.625(L1 + L2) x 0.375LA
C3
0.375L1 x 0.625(LA + LB)
C4
0.625(L1 + L2) x 0.625(LA + LB)
C5
0.375L1 x (L cant + 0.5LC)
C6
0.625(L1 + L2) x (L cant + 0.5LC)
Note to Table 3.4.4.5: The total area supported depends on the position of the column in the structure as shown in Figure 3.4.4.5. To calculate the correct area supported by a column, match the column’s position with those shown in Figure 3.4.4.5. which shows a plan view of a floor and then calculate the total area supported from Table 3.4.4.5.
Column section
Column effective height (mm)
Floor area supported:
5 m ^{2}
Floor area supported:
10 m ^{2}
Floor area supported:
15 m ^{2}
Floor area supported:
20 m ^{2}
Floor area supported:
25 m ^{2}
CHS C250
600
60.3 x 3.6
88.9 x 4.0
101.6 x 5.0
114.3 x 5.4
139.7 x 5.0
CHS C250
1200
60.3 x 4.5
88.9 x 4.0
101.6 x 5.0
114.3 x 5.4
139.7 x 5.0
CHS C250
1800
60.3 x 4.5
88.9 x 4.0
101.6 x 5.0
114.3 x 5.4
139.7 x 5.0
CHS C250
2400
60.3 x 4.5
88.9 x 4.0
101.6 x 5.0
114.3 x 5.4
139.7 x 5.0
CHS C250
3600
76.1 x 3.6
101.6 x 4.0
114.3 x 4.5
139.7 x 5.4
139.7 x 5.0
CHS 350
600
60.3 x 2.9
88.9 x 2.6
101.6 x 3.2
114.3 x 3.6
139.7 x 3.5
CHS 350
1200
60.3 x 2.9
88.9 x 2.6
101.6 x 3.2
114.3 x 3.6
139.7 x 3.5
CHS 350
1800
60.3 x 2.9
101.6 x 2.6
114.3 x 3.2
114.3 x 3.6
139.7 x 3.5
CHS 350
2400
76.1 x 2.3
101.6 x 2.6
114.3 x 3.2
139.7 x 3.0
139.7 x 3.5
CHS 350
3600
88.9 x 2.6
101.6 x 2.6
114.3 x 3.2
139.7 x 3.0
165.1 x 3.0
SHS 350
600
50 x 50 x 2.5
75 x 75 x 2.5
75 x 75 x 4.0
100 x 100 x 4.0
100 x 100 x 4.0
SHS 350
1200
65 x 65 x 2.0
75 x 75 x 2.5
75 x 75 x 4.0
100 x 100 x 4.0
100 x 100 x 4.0
SHS 350
1800
65 x 65 x 2.0
75 x 75 x 3.0
100 x 100 x 3.0
100 x 100 x 4.0
100 x 100 x 4.0
SHS 350
2400
65 x 65 x 2.0
75 x 75 x 3.0
100 x 100 x 3.0
100 x 100 x 4.0
100 x 100 x 5.0
SHS 350
3600
65 x 65 x 2.5
75 x 75 x 4.0
100 x 100 x 3.0
100 x 100 x 4.0
100 x 100 x 5.0
SHS 450
600
50 x 50 x 2.0
65 x 65 x 2.5
75 x 75 x 3.0
100 x 100 x 2.8
100 x 100 x 3.3
SHS 450
1200
50 x 50 x 2.0
65 x 65 x 2.5
75 x 75 x 3.0
100 x 100 x 3.0
100 x 100 x 3.3
SHS 450
1800
50 x 50 x 2.3
75 x 75 x 2.3
75 x 75 x 3.3
100 x 100 x 3.0
100 x 100 x 3.8
SHS 450
2400
65 x 65 x 2.0
75 x 75 x 2.5
75 x 75 x 3.5
100 x 100 x 3.0
100 x 100 x 3.8
SHS 450
3600
65 x 65 x 2.3
100 x 100 x 2.0
100 x 100 x 2.8
100 x 100 x 3.8
100 x 100 x 4.0
Note to Table 3.4.4.6a: Tabulated values are the column sections to be used.
Column section
Column effective height (mm)
5 m ^{2}
10 m ^{2}
15 m ^{2}
20 m ^{2}
25 m ^{2}
CHS 250
600
60.3 x 3.6
60.3 x 3.6
76.1 x 3.6
76.1 x 4.5
88.9 x 4.0
CHS 250
1200
60.3 x 3.6
60.3 x 3.6
76.1 x 3.6
76.1 x 4.5
101.6 x 4.0
CHS 250
1800
60.3 x 3.6
60.3 x 3.6
76.1 x 3.6
76.1 x 4.5
101.6 x 4.0
CHS 250
2400
60.3 x 3.6
60.3 x 4.5
76.1 x 3.6
88.9 x 4.0
101.6 x 4.0
CHS 250
3600
60.3 x 3.6
76.1 x 3.6
76.1 x 4.5
88.9 x 4.0
101.6 x 4.0
CHS 350
600
60.3 x 2.3
60.3 x 2.3
76.1 x 2.3
88.9 x 2.6
101.6 x 2.6
CHS 350
1200
60.3 x 2.3
60.3 x 2.9
76.1 x 2.3
88.9 x 2.6
101.6 x 2.6
CHS 350
1800
60.3 x 2.3
60.3 x 2.9
88.9 x 2.6
88.9 x 2.6
101.6 x 2.6
CHS 350
2400
60.3 x 2.3
76.1 x 2.3
88.9 x 2.6
88.9 x 2.6
101.6 x 2.6
CHS 350
3600
60.3 x 2.3
76.1 x 2.3
88.9 x 2.6
101.6 x 2.6
101.6 x 2.6
SHS C350
600
50 x 50 x 2.0
50 x 50 x 2.5
65 x 65 x 2.5
75 x 75 x 2.5
75 x 75 x 3.0
SHS C350
1200
50 x 50 x 2.0
50 x 50 x 2.5
65 x 65 x 2.5
75 x 75 x 2.5
75 x 75 x 3.0
SHS C350
1800
50 x 50 x 2.0
65 x 65 x 2.0
65 x 65 x 2.5
75 x 75 x 2.5
75 x 75 x 3.0
SHS C350
2400
50 x 50 x 2.0
65 x 65 x 2.0
65 x 65 x 2.5
75 x 75 x 2.5
75 x 75 x 4.0
SHS C350
3600
50 x 50 x 2.5
65 x 65 x 2.5
75 x 75 x 2.5
75 x 75 x 3.0
75 x 75 x 4.0
SHS C450
600
50 x 50 x 1.6
50 x 50 x 2.0
65 x 65 x 2.0
65 x 65 x 2.3
65 x 65 x 2.8
SHS C450
1200
50 x 50 x 1.6
50 x 50 x 2.0
65 x 65 x 2.0
65 x 65 x 2.3
65 x 65 x 2.8
SHS C450
1800
50 x 50 x 1.6
65 x 65 x 1.6
65 x 65 x 2.0
65 x 65 x 2.5
75 x 75 x 2.5
SHS C450
2400
50 x 50 x 1.6
50 x 50 x 2.5
65 x 65 x 2.3
75 x 75 x 2.3
75 x 75 x 2.8
SHS C450
3600
50 x 50 x 2.0
65 x 65 x 2.0
75 x 75 x 2.3
100 x 100 x 2.0
100 x 100 x 2.3
Note to Table 3.4.4.6b: Tabulated values are the column sections to be used.
Structural steel members that are not built into a masonry wall must be protected against corrosion in accordance with Table 3.4.4.7.
Environment 
Location 
Minimum protective coating 
Moderate ^{Note 1} 
Internal 
No protection required in a permanently dry location ^{Note 8} 
Moderate ^{Note 1} 
External 
Option 1. 2 coats alkyd primer Option 2. 2 coats alkyd gloss Option 3. Hot dip galvanised 300 g/m^{2} min Option 4. Hot dip galvanised 100 g/m^{2} min plus—

Severe ^{Note 2} 
Internal 
Option 1. 2 coats alkyd primer Option 2. 2 coats alkyd gloss 
Severe ^{Note 2} 
External 
Option 1. Inorganic zinc primer plus 2 coats vinyl gloss finishing coats Option 2. Hot dip galvanised 300 g/m2 Option 3. Hot dip galvanised 100 g/m2 min plus—

Notes to Table 3.4.4.7 :
Moderate = More than 1 km from breaking surf or more than 100 m from salt water not subject to breaking surf or nonheavy industrial areas.
Severe = Within 1 km from breaking surf or within 100 m of salt water not subject to breaking surf or heavy industrial areas.
Heavy industrial areas means industrial environments around major industrial complexes.
The outer leaf and cavity of an external masonry wall of a building, including walls under open carports are considered to be external environments. A part of an internal leaf of an external masonry wall which is located in the roof space is considered to be in an internal environment.
Where a paint finish is applied the surface of the steel, work must be hand or power tool cleaned to remove any rust immediately prior to painting.
All zinc coatings (including inorganic zinc) require a barrier coat to stop conventional domestic enamels from peeling.
Refer to the paint manufacturer where decorative finishes are required on top of the minimum coating specified in the table for protection of the steel against corrosion.
Internal locations subject to moisture, such as in close proximity to kitchen or bathroom exhaust fans are not considered to be in a permanently dry location and protection as specified for external locations is required.
For applications outside the scope of this table, seek specialist advice.