Jonathan Waldman’s fascination with the destructive properties of rust came to him while living aboard a 40-foot sailboat in San Francisco for a year, according this author bio. A frequent contributor to Slate, Waldman wrote in his article “The Rustiest Place in America”
The most destructive natural disaster in the history of the modern world is not very scary. Snowpocalypses and arctic vortices steal our attention, and hurricanes and supertornadoes freak us out, but rust just nags, constantly, like a swarm of mosquitoes. To an enormous rogue wave, it’s a steady trickle. This persistence, combined with corrosion’s ubiquity, lends it familiarity, which in turn allows us to dismiss it.
Tim Heffernan, reviewing Waldman’s book Rust: The Longest War, mentions that in our modern, digital world, we often overlook how old embedded devices and systems allow us the use of Wi-Fi, cell phones; and how old infrastructures are still used for transportation, shipping—commerce, in general. Heffernan writes:
_Our mobile, personal, wireless world is utterly reliant on a massive, interwoven, mechanical counterpart. And lots of that big stuff is rusting. Every four years, the American Society of Civil Engineers releases its Report Card for America’s Infrastructure. The latest, from 2013, gives the country a D+ overall. Broken down by category, our ports get a C; energy gets a D+; aviation, dams, drinking water, hazardous waste, roads, transit, and wastewater all get D’s; inland waterways and levees, each a D–. Rail manages a C+, as do bridges. Solid waste leads the class with a B–.
Both the review and the book itself relay an important, yet often overlooked truth: “even though we live in a world of constant technological advances, we can only slow corrosion.” We remain unable to fully stop it outright, which means renewed focus and attention must be paid to outfitting existing systems with new anti-corrosive measures. Experts argue that if companies and engineers concern themselves with replacement instead of renovation, not only is the cost greater (affecting the entire supply chain), but there is a great slow-down of productivity and longer periods of lost time in the process. Not to mention, though it is perhaps more important, that the longer a corroded piece of conduit or fitting is in use, the less capable it is of maintaining safe functionality—this endangers workers, systems, et cetera.
In his article, Waldman describes a scenario where he and a photographer walk through Bethlehem Steel—at one time the world’s foremost producer of raw and finished steel, but which has been defunct since 1995. He remarks upon the structural integrity of the building where corrosion has deeply set into the remaining metal around him:
On the streaked wall of an enormous gas stove, Csuk found a patch of metal she’d never seen before, exposed now that a layer of pipes had been removed. While she set up her tripod a couple of feet back, I tried to watch how she worked—but the occasional echo of things falling from who-knows-where distracted me. It felt a bit like standing at the base of a crumbly cliff with no helmet. Csuk was unfazed, as she’d long ago grown accustomed to the rain of metal junk—and had indeed learned to avoid much worse.
This is a vivid, real-time depiction of how rust and corrosion has gutted a once prominent, state-of-the-art facility in the span of mere decades. Imagine then, what it must be like for buried conduit underground, or small-town bridges, big city tunnels. Expert Waldman speaks in the book and leaves a warning for civil engineers, project planners, and anyone else interested in protecting their company or structure from rust: “it is a moral AND an economic concern, for which ignorance is no excuse for proper protection when it means that money and health can be compromised if nothing is done about this constant problem”.
Stainless steel is the safest and most economical conduit option in environments where corrosive materials are processed and/or present, period. The lifespan of stainless steel is often parallel to the lifespan of the facility, making the need for replacement rare. The basic resistance of stainless steel occurs because of its ability to form a protective coating on the metal surface. This coating is a "passive" film that resists further oxidation or rusting. The formation of this film is instantaneous in an oxidizing atmosphere such as air, water, or other fluids that contain oxygen.
There are two types of stainless steel conduit available. The first is type 304Lwhich is approximately 18% chromium and 8% nickel, allowing for use in a wide range of atmospheric environments. The second is type 316L stainless which is approximately 16% chromium, 12% nickel, and 3% Molybdenum. Molybdenum and increased nickel content enhance the resistance to many industrial chemicals and solvents with specific resistance to chloride pitting. For example, stainless steel is recognized as the premium material for marine applications where it used for its excellent corrosion resistance, aesthetic appearance, strength, and ease of installation. Though no metal aside from gold and platinum is completely corrosion proof, stainless steel is the most widely used and economical solution.
Installation of stainless steel is simple. Due to its high ductility, stainless steel can be bent to equally small bend radii, gauge for gauge, as galvanized steel. Dies should be given a high polish and must be free from all surface blemishes to prevent marring the finish of the stainless steel parts. The power necessary to bend annealed stainless steel is 50 to 60% more than is needed for carbon steel. All metal has a certain amount of spring-back, also known as elastic recovery, and 300 series stainless conduit has approximately 5% more than its galvanized steel counterparts. Minimal amounts of cutting and threading stainless conduit in the field with standard field equipment will suffice on smaller to moderate sized jobs or modifications. For larger applications we recommend purchasing stainless steel threading dies and threading oil for better results and to reduce the chance of possible machinery malfunctions.
The corrosion resistance of stainless steel actually improves with routine maintenance. Planned maintenance of plant equipment to avoid failure by corrosion is essential. Planned maintenance consists of scheduled shutdown periods in order to inspect all equipment and refurbish or replace equipment that has failed due to corrosion or other failure mechanisms. Other materials, such as aluminum and galvanized steel, require more frequent intervals of equipment testing for corrosion. Companies that use reliable stainless steel throughout their facilities are able to “plan ahead” for scheduled maintenance closures and sustain consistent financial returns despite the periods of inactive production.