All channel steels have the same basic composition of iron and carbon, but stainless-steel channel construction also contains a healthy dose of chromium, the alloy that gives stainless steel its famous corrosion resistance.

There are numerous grades under the stainless-steel umbrella, each with slightly different alloy composition and therefore slightly different physical properties.

Stainless steel should contain at least 10,5 per cent chromium. Depending on the grade, it can contain much higher levels of chromium and additional alloying components such as molybdenum, nickel, titanium, aluminium, copper, nitrogen, phosphorus and selenium.

The two most common grades of stainless steel for grooving are 304 and 316. The main difference is the addition of molybdenum, an alloy that greatly improves corrosion resistance, especially for environments exposed to more salt water or chloride. 316 stainless steel contains molybdenum, but 304 does not.

For outdoor and some corrosive channel applications stainless steel is an ideal corrosion-resistant material, but if suitable for the classroom environment, it will only withstand prolonged exposure. 304 is an economical and practical choice for most environments but does not have the chloride resistance of 316. The slightly higher price point of 316 conduit and components may be worth it in high chloride exposure areas or applications. Each application for stainless steel pipework has its unique demands and needs stainless steel that is up to the task.

Stainless steel ducting may cost slightly more than galvanised or aluminium, but there are both commercial and industrial situations where stainless steel is the best option. More often today, design engineers require stainless steel pipework in laboratories and research facilities due to the caustic or hazardous nature of the air being vented. The extreme durability and longevity of stainless steel are among its cost-saving advantages: it resists corrosion from harsh substances such as salts used in food processing and can be used in both indoor and outdoor applications, providing years of use without the need to replace them. Furthermore, stainless steel is stronger than aluminium with the addition of abrasion resistance. Its rigidity makes it an excellent choice for conveying high volumes of air. Using stainless steel can also reduce upfront costs – due to its high malleability, aluminium is a challenge to fabricate and install as ductwork and may require special welding techniques, often leading to higher prices than stainless steel.

Stainless Steel Channel

Environmentally, stainless steel is the better choice, as both withstand moisture and condensation that can cause harmful mould or mildew to build up. This is essential in industries where petrol and other fine “wet” mists are drawn from the air. Due to its high recycling/recovery rate, stainless steel is considered the “green” choice because you reduce energy consumption during production. And stainless steel is 100% recyclable: it can be converted from stainless or carbon steel into new metal at an incredibly high rate. Keeping stainless steel out of landfills reduces the impact on natural resources.

Recycled stainless steel is used in the production of solar, nuclear, geothermal and wave energy and the manufacture of alternative energy equipment. It makes existing power generation technologies cleaner; is used to store and transport potable water to minimise damage to the environment; to clean wastewater; in large public water and sewage treatment plants; for small water storage, treatment or filtration units that clean construction waste and grey water, reducing potable water consumption; and as highly reflective roof surfaces that reflect and dissipate heat to perform air conditioning more effectively.

There are situations where you would choose aluminium duct rather than stainless steel. Where you need to cover exposed spiral ducts; in applications where you need a product with flexibility; or as air ducting in areas around indoor swimming pools or in clean rooms where industrial films are produced.