AS 4055:2021 pdf Wind loads for housing
1.1 Scope
This document specifies site wind speed classes for determining design wind speeds and wind loads
for NCC Class 1 and 10a buildings within the geometric limits given in Clause 1.2. The classes are for use in the design of housing and for design, manufacturing and specifying of building products and systems used for housing.
Wind loads for NCC Class 1 and 10a buildings that are not within the geometric limits given in Clause 1.2 and other NCC building classes, i.e. Class 2 to 9 buildings, are outside the scope of this document.
NOTE 1 Commentary on the clauses of this document is given in Appendix A.
NOTE 2 A worked example for the determination of topography is given in Appendix B.
NOTE 3 Worked examples for the determination of terrain category and shielding class are given in Appendix C.
NOTE 4 A worked example for racking forces is given in Appendix D.
NOTE 5 Refer to AS/NZS 1170.2 for buildings that are outside the geometric and other limitations of this document.
1.2 Geometric limits
For the purpose of this document, the following conditions (geometric limits) shall apply (see
Figure 1.2):
(a) The distance from averaged ground level to the underside of eaves shall not exceed 6.0 m.
(b) The distance from averaged ground level to the highest point of the roof, not including
chimneys, shall not exceed 8.5 m.
(c) The width (W) including roofed verandas, excluding eaves up to a maximum of 0.9 m, shall
not exceed 16.0 m. The length (L) shall not exceed five times the width.
(d) The roof pitch shall not exceed 35°.
NOTE 1 The tables in Section 5 are based on a floor to ceiling height of 2.4 m and a floor depth of 0.3 m (floor level down to ceiling below).
Where wind loads on houses are determined using this document, design parameters shall be derived from this document only. Where wind loads on buildings are determined using AS/NZS 1170.2, design parameters in that Standard only shall be used.
NOTE 2 Clause 3.2.3 refers to pressures on solar panels given in AS/NZS 1170.2. These parameters are referenced in this document.
1.3 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document.
NOTE Documents referenced for informative purposes are listed in the Bibliography.
AS/NZS 1170.2, Structural design actions, Part 2: Wind actions
1.4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
1.4.1 averaged ground level
natural ground level excluding earthworks where earthworks are minor, or averaged ground level
through modified land where the earthworks are major
Note 1 to entry: Where minor earthworks have changed the level of the land over less than 50 m 2 , see lower cross-section in Figure 1.2(a).
Note 2 to entry: Where major earthworks have changed the level of the land over more than 50 m 2 , see upper right cross-section in Figure 1.2(a).
1.4.2 bottom of hill, ridge or escarpment
area at the base of the hill, ridge or escarpment, where the average slope is less than 1 in 20
1.4.3 height
distance from ground level to the underside of eaves or to the highest point of the roof neglecting
chimneys; or the height of each storey at external walls
Note 1 to entry: See Figure 1.2.
1.4.4 house
NCC Class 1 or 10a building with the geometric limitations specified in Clause 1.2
1.4.5 length
maximum overall distance between outside edges of the external walls of a house or shape
Note 1 to entry: See Figure 1.2.
1.4.6 may
indicates the existence of an option
1.4.7 obstruction
natural or man-made objects that generate turbulent wind flow, ranging from single trees to forests
and from isolated small structures to closely spaced multi-storey buildings
1.4.8 plan
basic rectangular, square or L-shaped layout, or simple combinations of these layouts
Note 1 to entry: See Figure 1.2.
AS 4055:2021 pdf Wind loads for housing
