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Selecting the Proper Unistrut Channel and Fittings for Corrosive Applications

Although many of our customers associate Unistrut Service Company with design, fabrication, and installation, we also operate a service center that sends channel, fittings, and hardware worldwide.  When it comes to materials sales, folks don’t rely on to us due to our competitive pricing, incredible selection, and prompt delivery schedules; our customers recognize our ability to help them select the right materials for even the most challenging applications.  Some of the more common Unistrut questions involve corrosion resistance and proper finish selection.

Many Unistrut customers mistakenly assume that corrosion resistance is primarily a function of finish.  This consideration is important, but finish alone does not tell the entire story.  Selecting the proper Unistrut channel for a corrosive application begins with material selection.  For corrosive applications where weight is a consideration, Extruded Aluminum, and Fiberglass Channel are common selections.  As the chart below suggests, Fiberglass Unistrut Channel offers superior resistance to corrosion, but this material lacks the strength of steel.                                                                               

Unistrut Materials

     Material Duty Weight Corrosion Application
Carbon Steel (PL) Indoor/Outdoor Standard Some resistance (depending on finish) Most common; can be painted or coated
Extruded Aluminum (EA) Indoor/Outdoor Lightweight Some resistance Enclosures, perimeter guarding, machine guarding
Stainless Steel (SS-304, ST316) Ideal Outdoor Standard High Resistance Chemicals / Saltwater Applications
Fiberglass (E, P, V, PU, and N) Indoor/Outdoor Lightweight Superior Resistance Common in water treatment plants

 It is important to remember that stainless steel (another common choice for corrosive environments) is a material rather than a finish-style in the Unistrut world.  Stainless steel is well-suited for corrosive applications, but it is also your most expensive option.  For many applications, coated carbon steel Unistrut channel is a viable alternative to stainless.                                                 

Carbon Steel Unistrut Finishes

Finish Duty Corrosion Application
Plain (PL) Indoor and outdoor with proper finish or coating Retains the oiled surface applied to raw steel Jobs that require welding or parts that have to be painted a specific color
Pre-Galvanized Zinc (PG)Perma Green III (GR) Indoor/Outdoor Both are well-proven, time tested performers Make up 80% of the specs
Hot Dip Galvanized Zinc (HG) Some indoor, mostly outdoor Better Corrosion Resistance Street guardrails, highway signs.
Unistrut Defender (DF) Indoor/Outdoor Superior Corrosion Resistance Water treatment and desalinization plants, drilling platforms, cell phone towers

Until recently, contractors seeking corrosion resistant Unistrut channel had two main options:  a galvanized finish or stainless.  Hot-Dip Galvanized Channel (HG) is significantly less expensive than stainless steel, but it also more susceptible to corrosion than stainless steel. Unistrut’s new Defender™ finish bridges the performance gap between galvanized and stainless, offering performance characteristics similar to stainless steel at a fraction of the price.  Specifically designed for corrosive applications, Unistrut Defender utilizes two proprietary material coatings conforming to ASTM standards A1046 and A1059. According to independent lab testing, the end-result of this coating process is a finish three times more corrosion resistant than hot-dip galvanized products.

Unistrut Defender Lab Results

Contractors seeking Unistrut Channel improved performance over Hot-Dip Galvanized while avoiding the high cost associated with stainless steel will find Unistrut Defender provides an excellent mix of value and performance. Remember, when selecting a Unistrut product for a corrosive application, care must be taken to consider both the material style and the finish.  Although stainless steel has long been considered the gold standard for corrosive Unistrut applications, Hot-Dip Galvanized and Defender coatings are cost-effective, viable alternatives that may meet your requirements.  To learn more about selecting the right Unistrut products for your corrosive application, or to request pricing information or a quote, contact Unistrut Service Company for more information.