Corrosion Resistant Paint Grades for Industrial Fans: C3, C4, C5 and CX
When selecting a fan for a corrosive environment it is important to have some knowledge of how corrosive atmospheres are categorised, this ensures that a selected fan is deemed suitable for use in harsh environments that are at risk of steelwork corrosion, coating failures, and a reduction in the life span of the components ability to perform to its required function.
ISO 12944 in particular part 5, known as ISO 12944-5:2018(En) Paints and varnishes — Corrosion protection of steel structures by protective paint systems — Part 5: Protective paint system, is a globally recognised standard for corrosive environments and details the categories, durability options and paint protection coating requirements for steel structures in atmospheric, immersed, and buried environments.
ISO standard 12944-21 classifies corrosivity severity according to the mass loss of unpainted steel or zinc exposed one year on the site and can be seen in the table below.
In line with the demand for corrosive resistant fans in harsh environments, special requests are regularly made for enhanced paint protection on our range of industrial fans. As standard we supply fans manufactured from rolled sheet steel or Fe360 steel finished in a RAL 5010, qualicoat polyester powder coating stoved at 200 degrees. Stainless steel or marine grade finishes C3, C4, C5 and CX increase the corrosion resistance of these fans making them suitable for use in harsh environments. Some products, such as the Prextur, are C3 as standard given the nature of their regular application use.
Our Prextur medium pressure centrifugal fans with direct coupling and reinforced steel housing are ATEX certified and protected against corrosion with powder coating polyester resin and a C3 finish. They have a high efficiency rate up to 84% and are suitable for a wide range of applications including dusty environments. The Prextur has several beneficial features including a self-cleaning turbine and reinforced impeller with high performance backward blades made of carbon laminated steel dynamically balanced to minimise noise and vibrations.
Typical applications include paint booths, dust collection, food industry dryers, food processing, pollution control and the manufacture and treatment of chemical products.
C3 Environments
Typically, external C3 environments consist of urban and industrial atmospheres with moderate sulphur dioxide pollution and coastal areas with low salinity. Typical internal environments include production rooms with high humidity and some air pollution. Examples include food processing plants, laundries, breweries and diaries.
C4 Environments
Typical internal applications classified as C4 environments include swimming pools, chemical plants, coastal ship and boat yards. Exterior applications include industrial areas and coastal areas with moderate salinity.
C5 Environments
C5 internal environments include buildings or areas with high contamination and constant condensation. External environments are typically aggressive atmospheres with high humidity.
CX Environments
Category CX replaced C5M in the new standard for extreme offshore environments, closing a previous loophole with the C5M category which allowed unsuitable corrosive coating selections for extreme environments leading to coating failures. For more information on our axial fans suitable for offshore environments click here.