In the construction of electrical infrastructure, cable trays are essential components for supporting and protecting cables. Their durability and reliability are critical. To ensure that cable trays perform well under diverse and challenging environmental conditions, selecting the right surface treatment and coating system is vital. The ISO 12944 standard provides valuable guidelines for this purpose. This article will explain how to use the ISO 12944 standard to choose the appropriate surface treatment for cable trays.
01｜What is the ISO 12944 Standard?
The ISO 12944 standard is an international standard for corrosion protection of steel structures and iron components using paint and coating systems. Since its release, it has become a crucial and widely recognized standard in the coating and anti-corrosion industry worldwide. China’s GB/T 30790, “Paints and Varnishes – Corrosion Protection of Steel Structures by Protective Paint Systems,” is based on the ISO 12944 standard. The ISO 12944 standard covers the classification of corrosive environments, selection of coating systems, application, inspection, and maintenance of coatings, providing comprehensive technical guidance for designing anti-corrosion systems for steel structures. By referencing the ISO 12944 standard in the selection of cable trays, you can ensure that the chosen products can withstand various environmental conditions and meet usage requirements.
02｜Importance of Surface Treatment for Cable Trays
Cable trays face varying degrees of corrosion risk in different environmental conditions:
– Outdoor environments: Prolonged exposure to sunlight and rain can cause material aging, discoloration, and corrosion.
– Industrial environments: Acidic and alkaline gases, chemicals, and particulates can accelerate corrosion.
– Humid environments: High humidity can lead to rusting, affecting aesthetics and mechanical properties.
– Extreme climates: High temperatures, low temperatures, and strong winds can cause material deformation and cracking.
Thus, surface corrosion protection for cable trays is crucial. Suitable surface treatment can enhance corrosion resistance, mechanical performance, and extend service life. In practical applications, selecting the appropriate surface treatment method based on specific environmental conditions and requirements ensures the stable operation and long-term use of cable trays.
03｜How to Use ISO 12944 to Choose Surface Treatment for Cable Trays
– Identify the Type of Environmental Conditions
Before selecting the surface treatment for cable trays, it is essential to understand the corrosion levels of different engineering environments. The ISO 12944-2 part categorizes environmental conditions:
Corrosion Level | External Environment | Internal Environment |
C1 Very Low | – | Heated buildings with clean air, such as offices, shops, schools, and hotels |
C2 Low | Low pollution levels in the atmosphere, mostly rural areas | Unheated buildings where condensation may occur (such as warehouses and sports halls) |
C3 Medium | Urban and industrial atmospheres, moderate sulfur dioxide pollution and coastal areas with low salinity | High humidity and some air pollution inside production rooms, such as food processing plants, laundries, breweries, and dairies |
C4 High | Medium pollution levels in industrial and coastal areas | Chemical plants, swimming pools, coastal ship and boat yards |
C5 Very High | High humidity and aggressive atmospheres in industrial and coastal areas with high salinity | Buildings and areas where condensation and high pollution levels are continuous |
CX Extreme | Areas with high salinity, such as offshore environments, and areas with extreme humidity and polluted atmospheres in hot and subtropical industrial zones | Areas with extreme humidity and aggressive atmospheres in industrial zones |
Atmospheric Corrosion Classification and Typical Environmental Examples According to ISO 12944
– Determine the Durability of Protective Coatings
The ISO 12944 standard specifies four durability categories:
Low (L): Up to 7 years
Medium (M): 7-15 years
High (H): 15-25 years
Very High (VH): Over 25 years
– Select the Required Coating System for the Project
Vichnet Technology offers cable trays made from carbon steel and stainless steel, with surface treatments such as electro-galvanizing, hot-dip galvanizing, powder coating. Here is a guide to their suitability in various environments:
Electro-galvanized: Suitable for dry indoor environments, with lower corrosion resistance.
Hot-dip galvanized: Offers long life and high corrosion resistance, ideal for high-temperature and moderately polluted environments.
Powder-coated: Provides vibrant color management for modern cabling systems, best for indoor, dry environments like data centers.
Stainless steel: Exceptional corrosion resistance, though more expensive, suitable for demanding corrosion resistance needs.
– Conduct Coating Performance Tests
Typically, the corrosion resistance and durability range can be roughly determined through environmental and design factors, followed by performance tests as specified by the standard. The neutral salt spray test is a common accelerated corrosion test to assess a product’s resistance to corrosion. In this test, a 5±0.5% saline solution with a pH of 6.5-7.2 is sprayed in a controlled chamber, and the corrosion state of the test piece is observed over time. Vichnet cable trays have passed this test, meeting the standards.
By following the ISO 12944 standard, selecting appropriate surface treatments and coating systems for cable trays ensures enhanced durability and reliability, enabling them to perform effectively in diverse and challenging environments.
