Mild Steel
Types and Durability
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Description Mild Steel (Framing Members) |
Expected Lifespan (Years ) |
Adjustment Factors
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General
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| Hot dip galvanized steel to BS EN 10142 or BS EN 10147, minimum 275g/m² zinc coating weight. PVC/Plastisol coating, 200 microns nominal thickness. |
25
|
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 |
| Hot dip aluminium-zinc coated steel to BS EN 10215, minimum 150g/m² zinc coating weight. PVDF/PVF2 coating, 25-50 microns nominal thickness. |
20
|
|
| Hot dip aluminium-zinc coated steel to BS EN 10215, minimum 150g/m² zinc coating weight. Acrylic/polyester/silicone polyester coating, 25-50 microns nominal thickness. |
20
|
|
| Hot dip galvanized steel to BS EN 10142 or BS EN 10147, minimum 275g/m² zinc coating weight.PVDF/PVF2 coating, 25-50 microns nominal thickness. |
15
|
|
| Hot dip galvanized steel to BS EN 10142 or BS EN 10147, minimum 275g/m² zinc coating weight. Acrylic/polyester/silicone polyester coating, 25-50 microns nominal thickness. |
15
|
|
| Hot dip galvanized steel to BS EN 10142 or BS EN 10147, minimum 350g/m² zinc coating weight. |
10
|
|
| Unclassified, ie mild steel not to relevant BS, or coating/surface protection less than above specifications. |
< 10
|
None
|
Combination of adjustment factors (1st stage and 2nd stage) should be added to obtain the durability values. Refer to durability calculator.
Note: 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 manufactures. Proprietary products are available for the re-coating of factory applied coatings.
Corrosion of unprotected cut edges is a common problem which can occur within a relatively short space of time. This process can be delayed by the application of additional edge protection at the time of installation (eg latex system or other products recommended by sheet supplier).
Some fading and chalking of coatings may occur within the life quoted.
Key durability issues
- Hot rolled steel: tested in accordance with BS EN 10002-1, has an ultimate tensile strength in the range 355 to 510 MPa.
- Base metal, type/thickness of surface protection, maintenance frequency, exposure conditions, colour of coating.