Know Your Conduit Options for Corrosive Applications
Chuck Ross
When it comes to metal conduit, the choice for electrical contractors can often boil down to three options: galvanized steel, aluminum or stainless steel. However, in particularly challenging environments, stainless steel offers advantages the other two materials can’t match. This is particularly true in corrosive settings, such petrochemical plants or food-processing facilities where washdowns are a regular necessity. Aluminum gets closer than galvanized in protecting against corrosion, says Maggie Gibson, executive vice president of Gibson Stainless & Specialty, Inc., but stainless steel is more inherently corrosion-resistant.
“Yes, it means a higher investment up front in material cost; however, installing it once and forgetting about it proves more cost-effective than tearing out and reinstalling inferior, failed conduit systems,” she says. “The growth of the stainless steel market, we believe, has been the recognition of this value.”
Aluminum, Gibson notes, is softer and more ductile, which makes it easier to machine than stainless steel. And both materials resist corrosion through the formation of a thin oxide layer on their surfaces. But for aluminum, that protection can have its limits.
“Aluminum provides good corrosion resistance in a general outdoor environment,” Gibson says. “But it is more susceptible to galvanic corrosion and does not match stainless steel’s corrosion resistance in harsh environments.”
Gibson also counters what she says is a misperception regarding the workability of stainless steel conduit. “That is not the case,” she says. “It may be little harder to work with than galvanized (not drastically, though. And the same standard benders and threaders can be used with some precautions.”
“Yes, it means a higher investment up front in material cost; however, installing it once and forgetting about it proves more cost-effective than tearing out and reinstalling inferior, failed conduit systems,” she says. “The growth of the stainless steel market, we believe, has been the recognition of this value.”
Aluminum, Gibson notes, is softer and more ductile, which makes it easier to machine than stainless steel. And both materials resist corrosion through the formation of a thin oxide layer on their surfaces. But for aluminum, that protection can have its limits.
“Aluminum provides good corrosion resistance in a general outdoor environment,” Gibson says. “But it is more susceptible to galvanic corrosion and does not match stainless steel’s corrosion resistance in harsh environments.”
Gibson also counters what she says is a misperception regarding the workability of stainless steel conduit. “That is not the case,” she says. “It may be little harder to work with than galvanized (not drastically, though. And the same standard benders and threaders can be used with some precautions.”
Photo courtesy of Gibson Stainless & Speciality
