Atmospheric corrosivity category | ||||
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Designation | C1 | C2 | C3 | C4 |
Description (Refer to AS 4312 and ISO 9223) | Indoor dry Air-conditioned (not ventilated externally) | Most areas of Australia beyond 50 km from the sea but can be as close as 1 km from relatively sheltered waters. | In coastal areas with significant surf, this area extends from around 1 km to 50 km, varying significantly with winds, topography and vegetation. Around sheltered bays it extends from around 50 m to 1 km from the shoreline. | Occurs mainly on the coast in areas with rough seas and surf, extending from around 300 m to 1 km inland. Around sheltered bays it extends up to 50 m from the shoreline. |
Application |
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Components inaccessible for maintenance | ||||
Roof framing system – unventilated | A | A | C | C |
Roof framing system – ventilated | NA | B | C | D |
Wall framing system – unventilated | A | A | C | C |
Wall framing system – ventilated | NA | B | C | D |
Floor bearers and joists including intermediate floors – unventilated | A | A | C | C |
Floor bearers and joists – ventilated | NA | B | D | D |
Decking/balcony – integral (eg cantilevered) | NA | C | D | D |
Ceiling battens | A | C | C | |
Components accessible for maintenance |
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Roof battens | NA | B | C | C |
Stumps and piers supporting main building | NA | C | C | C |
Decking/balcony – independent of main structure | NA | B | C | C |
Verandah beams and rafters | NA | B | C | D |
Verandah posts and stumps | NA | B | C | D |
Carport rafters and beams | NA | C | C | D |
Carport posts | NA | B | C | D |
Lower storey unlined eaves and pergola rafters and beams | A | B | C | D |
Pergola posts | NA | B | C | D |
Hot dip metallic coated strip AS 1397 | ||||||
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Protection designation (Refer to Table B1) | Zinc | Aluminium/Zinc | Aluminium/Magnesium/Zinc | Open sections Zinc/Aluminium AS/NZS 4791 | Hollow sections either: Hot Dipped Galvanised (ZB, ILG, HDG) or Electroplated (ZE) - Zinc AS/NZS 4792 AS 4750 | Post fabrication hot dip galvanised Zinc AS/NZS 4680 |
A | Z275 | AZ150 | AM150 | IZA75 | ZE50/50 | HDG320 |
B | Z275 | AZ150 | AM150 | IZA75 | ZB100/100, ILG100 | HDG320 |
C | Z275 | AZ150 | AM150 | IZA75 | HDG300, ILG140, ZB135/135 | HDG320 |
D | Z450 | AZ150 | AM150 | IZA200 | HDG300 | HDG320 |
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