What happens when iron and oxygen interact?
Corrosion.
The most familiar form of corrosion is rust. That red-brown stain that is seen on unprotected iron-based metals everywhere. It is a major problem with many spare parts.
Maritime industries such as shipping and offshore oil and gas platforms spend a lot of time and money on the battle with corrosion. Not only do they use paint as a barrier but they may also use cathodic protection (with sacrificial anodes or a technique known as ‘impressed current protection’), as well as other means to reduce or eliminate the effect of this natural phenomenon.
Equipment suppliers, and the companies that use their products, fight corrosion with their operating assets – be that specialist equipment or just routine assets such as such pumps, chillers, valves, or compressors.
But what about the spare parts?
Too often when I visit storerooms around the world I see components that are held as spare parts but where corrosion has, in some cases, ruined the part. Or at least made it unfit for use – which in practical terms is the same thing. In far too many storerooms, corrosion is largely ignored and it may only be when someone comes to need the part that the corrosion gets any attention.
The best case here might be that the part can be cleaned up and used – which might have the effect of extending the equipment downtime while this extra task is completed. The worst case is that it may be too late and the part is not usable. This has the effect of both extending the downtime and making the investment in that spare part a complete waste of money.
The Problem with Managing Corrosion
The problem of course is that, as already mentioned, corrosion is a natural phenomenon. You can’t stop it happening. The best you can do is fight it. Sometimes this involves mechanically protecting the surface, such as with galvanizing. Sometimes it involves fighting back with natural processes such cathodic protection. But these solutions are not always practical.
You can’t galvanize moving parts and, in cases where a mix of materials are used, cathodic protection may damage some materials. This is a real problem with complex equipment such as pumps, motors, chillers, and compressors.
Corrosion Protection for Spare Parts
The good news is that there is a range of solutions that can be applied for the corrosion protection of spare parts. These can be sorted into categories such as:
- Environmental protection – this may require keeping items in an environmentally controlled space or just simply out of the rain!
- Cathodic protection – some solutions incorporate a type of cathodic protection in wrapping materials.
- Barrier technology – generally these create a barrier between the metal surface and the air or moisture. Solutions in this category include anti-corrosion paper and wraps, liquid films, and oils that are applied to surfaces.
These solutions come in all manner of shapes and sizes and I am assured by those in the industry that there is a paper, bag, film, sheet, box, or liquid, for almost all situations.
The Benefits Should Be Obvious
Nothing is more frustrating for users of spare parts than to locate the required part for the task at hand, only to find that it is not suitable for use. From a company perspective, this represents a waste of not only the funds spent on the part but also all the labor and time spent procuring and managing the part plus the maintenance time and effort. In addition, you may now need to spend more time and money on expediting a replacement!
If you have made the decision to stock a spare part in your inventory, and presumably this involved consideration of the impact of the part not being available, then it makes sense that you should also make sure that the part is maintained in a suitable environment and condition.
Ensuring that the spare parts that you purchase are fit for use when needed is a fundamental responsibility of those tasked with managing the warehouse/storeroom. It is these personnel who, with the advice of the maintenance team, need to ensure that steps are taken to prevent corrosion being the reason that a spare part is not usable.
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Posted by: Phillip Slater