Pre-Galvanized steel tube is commonly used in the construction of Greenhouses. The steel coil is protected by a hot dip zinc coating, applied during rolling, after which the coil is used to cold form the steel tube. Although zinc is self-sacrificial in nature the external weld on the steel tube can be seam sprayed for additional protection.
The Greenhouses as a whole are intended for agricultural production, cultivation and horticulture and galvanised steel tubing is perfect for this industry which is more corrosive than most industries using structural steel tube.
The tubular frames of these various greenhouses are made out of thin walled galvanized steel tube, usually with a coating thickness of 275g/ square meter which is then assembled together with then with the arch rod, longitudinal bar, film slot, film spring, roof head, door and side ventilation device.
There are many reasons why Galvanised tube is used in greenhouse manufacturing and erecting:
| Lifespan | Normal Z275 pre galvanised steel has an expected life span of 15 years if placed between 40-100km from a high water mark. Steel tube in dry interior areas can have a life span of more than 25 years | |
| High Strength | Galvanised steel tube can be bought in grades with increased yield and tensile strengths to the norm. This could increase the amount of weight and wind resistance the structure can take and therefore engineers would be able to use less steel in their design, providing a more competitive steel structure to the market. | |
| Cost | In particular in inland areas the cost of pre galvanised tube is much less than the option to have normal mild steel tube hot dip galvanised. | |
| Design | Due to the flexibility within the cold forming process engineers and designers can creatively design cold formed closed or open profiles to increase load bearing capacity and reduce the total volume of steel and steel tube used within structures. |
