Aluminium
Types and Durability
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Description Aluminium (Infill Panels) |
Expected Lifespan (Years) |
Adjustment Factors
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General
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| Aluminium alloy to BS EN 485. Anodized to BS 3987, minimum 25 micron coating. |
30 (10 years warranty for coating) |
1st stage adjustment factor:
In industrial areas (heavy polluted): -15% years In urban areas: -10% years In suburban areas: -0% years 2nd stage adjustment factor: Within 20m from express way: -20% years Within 20m from major arterial road: -10% years Within 20m from light traffic road: – 5% years Within 20m from sea water/ area prone to salt spray: -15% years Test certificate from approved local testing authority : +15% years |
| Aluminium alloy to BS EN 485. Liquid organic coating to BS 4842 after all fabrication, minimum 40 micron thickness. |
25 (10 years warranty for coating) |
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| Aluminium alloy to BS EN 485. Polyester powder coating to BS 6496 after all fabrication, minimum 40 micron thickness. |
25
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| Aluminium alloy to BS EN 485. Mill finished. |
15
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| Unclassified, ie aluminium alloy, not to BS EN 485. |
< 15
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None |
Combination of adjustment factor (1st stage and 2nd stage) should be added to obtain the durability values. Refer to durability calculator.
Notes: The micron thickness should be measured in accordance with ASTM B 244-97 (2002) or equivalent. The life of metal coatings is influenced by the colour of the coating, the orientation of the building, and by the environmental conditions. Detailed guidance on lives and on any guarantee or warranty schemes is available from manufacturers. Proprietary products are available for the re-coating of factory applied coatings. When using aluminium panels with mill finish surface which are neither protected by lacquer nor by anodising against atmospheric influence, a change in the appearance of the aluminium surface is to be expected.
The untreated mill finish aluminium surface which does not meet any decorative requirements, generates a natural oxide layer of which the thickness gradually increases under the influence of outside atmosphere until reaching a thickness of about 0.1µm. The surface covered by reaction product has a strongly reduced reflectivity compared to the new surface which means that it will lose its metalic gloss and get a dull light grey appearance. This impression is intensified by dirt deposits in and on the surface. However this greying effect is often considered to be positive.
It is true that the reactions of the plain aluminium to atmospheric influences change the appearance of the surface, but do not affect the stability of the aluminium panel itself, since it is only the surface that reacts while the oxide layer protects the material below against further corrosive attack.