Mitigating corrosion in humid environments

All conventional ventilation systems are subject to atmospheric corrosion. This occurs due to interaction between the chemical components in the surrounding air and the metal part which results in changes in the metal’s properties by means of visual and/or functional impairment.


Lauris Rezgals

Research & Development Manager

In general, there are 3 necessary requirements for atmospheric corrosion to take place: a conducting metal, an electrolyte (water), and oxygen. Other factors determine the speed of corrosion. Key factors include temperature-humidity complex, pollution by sulfur dioxide, and chlorides (atmospheric salinity). Corrosion effects of other pollutants (ozone, nitrogen oxides, particulates) can also influence the corrosion rate. To avoid these issues, conventional ventilation systems require thermal insulation (requiring additional material, transportation, and labor that results in rising costs) and special treatment (galvanization or painting), which can be extremely costly. However, the HVAC industry has had an alternative for half a century that is becoming increasingly popular in corrosive environments.

Corrosion-resistant solutions

Fabric-based air distribution solutions are ideal for highly corrosive environments. Specifically, fabric ducts can be permeable, and thus, they do not sweat. Because no condensation forms on the ducts, they remain dry and corrosion-free, avoiding a variety of detrimental issues.

The first and most obvious problem is damage to the ducts themselves. Rusted ducts will eventually need to be replaced, as they are no longer safe to use in crowded areas. In addition, in applications like swimming pools, rust could flake into the water and affect the health of visitors. These types of harmful issues are easily avoided by using fabric ducts.

Additionally, there are a wide variety of suspension types with different materials and part treatments to fit specific applications and corrosion-resistant requirements. This means that fabric ducts can be installed in corrosive environments with suspensions that are made from anodized aluminum, galvanized parts, stainless steel, or hot dip galvanized parts. Plastic components that are not susceptible to corrosion can also be used depending on the project.

Benefits to buildings

One of the most definitive examples of a corrosive environment is pools or natatoriums. Indoor pools are warm, humid environments and condensation tends to collect on exposed metal, windows, and walls, especially in cooler months. Condensation results in the oxidation of metal parts which is unsightly, unsanitary and may compromise structural integrity.

Fabric duct systems are not only highly corrosion resistant but are the best choice to protect other metal elements from corrosion. Fabric air dispersion offers linear air dispersion and completely customizable throw and volume of the supply air in any direction, benefiting the occupants and the building structure.

Get valuable content first

Enter your email and be among the first to get tips and articles from our experts about HVAC industry topics.