Durability of steel structures
The corrosion protection added to steel is a crucial aspect that determines the service life and reliability of steel constructions.
When installing a lattice tower there are a number of guidelines and regulations that manufacturers must provide to extend and estimate the life of a structure.
On the one hand, Eurocode 1, in its Annex B of EN 1990:2002 provides detailed guidance on the design service life for various structures that the designer should be aware of. Table 2.1 of this annex classifies structures into different categories according to their recommended service life:
- Category 1: Temporary structures with a useful life of up to 10 years.
- Category 2: Structures with replaceable parts or with medium service life, designed to last between 10 and 25 years.
- Category 3: Extended durability structures, with a useful life of 15 to 30 years.
- Category 4: Long-lasting structures, designed to last 50 to 100 years or more.
Ferroval’s structures for the wind energy sector use steel with hot-dip galvanized protection, providing a coating of 85 microns of zinc. In addition, these towers are painted with category C3 epoxy powder according to ISO 12944. The combination of these protection methods ensures remarkable resistance against corrosion and significantly extends the service life of the structures, even above category 3 of EN1990:2002 in environments with moderate humidity and pollution.
The estimation of durability of a structure is not easy to determine and depends largely on the environment where it is exposed such as humidity, salinity, contamination, etc. Based on the compliance with the ISO 14713-1:2009 standard that provides recommendations for corrosion protection of zinc and its alloys, we can assure that for a galvanized layer of 85 microns in an environment of moderate humidity and pollution (environment C3), Ferroval towers have a useful life of 20 to 40 years.
In addition, high-rise structures are painted in red and white stripes according to Civil Aviation standards. ISO 12944-2 provides guidelines on the durability of paint systems in different corrosion categories. These categories, defined by the standard, range from dry indoor environments to harsh industrial and marine environments. A category C3 paint system, as used by Ferroval as standard, generally consists of several layers to ensure adequate protection. The total thickness of the C3 paint system can range from 150 to 220 microns. This paint system can offer a durability of more than 15 years in conditions of moderate humidity and medium contamination.
Synergy between Galvanizing and Painting
The combination of galvanizing and painting provides dual protection that significantly improves the overall durability of the structure. In environments of moderate moisture and contamination, this combination is expected to provide a service life of 20 to 40 years, however the paint coating may require attention after 15 years to maintain its effectiveness.
At Ferroval, we can help you make a decision based on your needs or your project, optimizing costs and guaranteeing the functionality and durability you require. You can contact our team of experts on (+34) 962 522 094 or fill in the contact form by clicking on the button below:
