Specification 4 Design of buildings in cyclonic areas
S4C1
Scope
2019: Spec B1.2: 1
WA S4C1 Scope2019: Spec B1.2: 1
S4C2
Roof cladding
2019: Spec B1.2: 2
Test for strength: Metal roof cladding, its connections and immediate supporting members must be capable of remaining in position notwithstanding any permanent distortion, fracture or damage that might occur in the sheet or fastenings under the pressure sequences A to G defined in Table S4C2.
Sequence | Number of cycles | Load |
---|---|---|
A | 4500 | 0 to 0.45 Pt |
B | 600 | 0 to 0.6 Pt |
C | 80 | 0 to 0.8 Pt |
D | 1 | 0 to 1.0 Pt |
E | 80 | 0 to 0.8 Pt |
F | 600 | 0 to 0.6 Pt |
G | 4500 | 0 to 0.45 Pt |
Table Notes
- Pt is the ultimate limit state wind pressure on internal and external surfaces as determined in accordance with AS/NZS 1170.2, modified by an appropriate factor for variability, as determined in accordance with Table B1 of AS/NZS 1170.0.
- The rate of load cycling must be less than 3 Hz.
- The single load cycle (sequence D) must be held for a minimum of 10 seconds.
- The floor area of the “strengthened area” is to be calculated at the rate of 1.2 m2 per person normally accommodated within the building.
- The design wind pressure for the overall “strengthened area” is for an Importance Level 3 building.
- The minimum standard of debris protection to walls, floors and ceilings (or roof) bounding the "strengthened area" shall be that which resists (without complete penetration) the impact loading specified in AS/NZS 1170.2, using a regional wind speed associated with an Importance Level 3 building.
- All doors, windows, vents and the like in walls bounding the “strengthened area” are to be protected against windborne debris with permanently installed screens in accordance with (c).
- Consideration must be given to the selection of materials and fittings to ensure doors, windows and vents can withstand the required design wind pressures.
- All doors serving as required entries/exits to a “strengthened area” are to be inward opening with locking devices suitably noted for use in a cyclone emergency.
Strengthened area