AS 4055:2021 pdf free download – Wind loads for housing

AS 4055:2021 pdf free download – Wind loads for housing.
This document specifies site wind speed classes for determining design wind speeds and wind loads for NCC Class I and lOa buildings within the geometric limits given in Clause 1.2. The classes are tor 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 lOa buildings that are not within the geometric limits given In Clause 1.2 and other NCC building classes. i.e. Cbss 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 c.Itcgory and shielding class are given In AppcndixC.
NOTE 4 A worked example for racking forces is given in Appendix 0.
NOTE 5 Refer to AS/MiS 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 rn
(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 3S.
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 (Door 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 sobr panels given in AS/NZS 1170.2. These parameters are relerenced in this document.
2.5 Selection of shielding class
The shielding class is a measure of the effect of surrounding buildings, or similar size obstructions, on the wind speed at the site. It maybe based on the anticipated shielding five years alter design.
NOTE 1 In Regions A and B, trees or groups of trees with similar face area to houses may be considered as shielding elements.
In Regions C and D, trees and vegetation shall not be used as shielding elements.
The shielding class for a housing site shall be identified by the notation FS. PS or NS. and he determined as follows:
(a) Full shielding (FS) — Full shielding shall apply where there are no open areas within 100 m of the site and at least two rows of house’s or similar-sized permanent obstructions surround the house being considered. In Regions A and B, permanent, closely spaced trees with a height greater than the proposed house and extending equivalent to three rows of houses. shall be determined to provide full shielding. Full shielding shall be only for houses within Topographic Classes TO. Ti and T2.
The application of full shielding shall be appropriate for typical suburban development greater than or equal to 10 houses, or similar size obstructions per hectare.
NOTE 2 The effects airoaci reserves or other small open areas with a width of less than 20 m adjacent to the house site may be Ignored.
(b Partial shielding (PS, — Partial shielding shall apply to intermediate situations where there are at least 2.5 houses or sheds per hectare, such as acreage type suburban development. Partial shielding shall be only for houses within Topographic Classes TO, Ti, T2 and T3.
NOTE 3 The second row of houses abutting open parkiand. open water or airfields may he classified as having partial shleldng.
NOTE 4 In Regions A and B, permanent. dosely spaced trees with a height greater than the proposed house and extending equivalent to two rows ot houses provide partial shielding.