Understanding ABC Classification of Inventory for Maintenance Spare Parts
Examples from HVAC, Thermal Power Plants, Aviation and Oil & Gas Industries
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If you’ve been working in maintenance department of any industry, you might have heard the term ABC classification of inventory. Our purpose in this article is to explain in a practical way (with examples) about how ABC classification of inventory works on maintenance spare parts.
Our focus will be to first explain the concept of ABC classification with emphasis on maintenance spare parts and then give examples from different industries to ensure better understanding of the topic.
The first thing to understand about the ABC classification of MRO inventory is that it is not like the categories were made first and then items were put into those categories. It is as if the categories were discovered.
What is that supposed to mean?
In any maintenance facility, there are some parts and materials that are used frequently while some that are not used frequently. It is not like the runner of a Francis turbine in a hydel power plant fails as often as a 16-ampere circuit breaker installed in plant’s switchgear.
A Francis Turbine Runner
Hydel Power Plants around the world use a type of turbine known as Francis turbine. At the heart of Francis turbine is what is called a “runner”. It is a giant impeller-like part of the turbine (Image Credit: Wikimedia Commons)
What is another statistical fact is that the parts that are used rarely are generally the parts that are quite expensive. The runner of the Francis turbine will cost several thousand USD while the 16-ampere circuit breaker will cost USD 10-20.
The above two statistical commonalities form the two ends of the spectrum of ABC inventory classification.
Category-A inventory comprises parts that are rarely used and are very expensive like the runner of a Francis turbine mentioned above.
Category-C inventory comprises parts that are frequently used and are not expensive like the 10-ampere circuit breaker installed in plant’s switchgear.
Between these two ends of the spectrum is Category-B inventory i.e., the inventory falling in between the rarely used expensive parts and the frequently used inexpensive parts.
An example for the Category-B inventory is a ball bearing of a pump in the same power plant. It may need replacement after 5 years and cost a thousand dollars. Therefore, it falls between the Francis turbine runner and the
Let us expand on this ABC inventory classification by giving examples from different industries.
Let us first present some examples of Category-ABC inventory spare parts in HVAC industry i.e., Heating, Ventilation & Airconditioning Industry.
Category-A Inventory Spare Parts in HVAC
Category-B Inventory Spare Parts in HVAC
Category-C Inventory Spare Parts in HVAC
Now let us give some examples from thermal power plants.
Category-A Inventory Spare Parts in Thermal Power Plants
Category-B Inventory Spare Parts in Thermal Power Plants
Category-C Inventory Spare Parts in Thermal Power Plants
Now, let us give examples of ABC inventory spare parts in Aircraft Maintenance.
Category-A Inventory Spare Parts in Aviation Industry
Category-B Inventory Spare Parts in Aviation Industry
Category-C Inventory Spare Parts in Aviation Industry
Now, let us give examples of ABC inventory spare parts in Oil and Gas industry.
Category-A Inventory Spare Parts in Oil & Gas Industry
Category-B Inventory Spare Parts in Oil & Gas Industry
Category-C Inventory Spare Parts in Oil & Gas Industry
Now, let us give examples of ABC inventory spare parts in Water Treatment Plant.
Category-A Inventory Spare Parts in Water Treatment Plant
Category-B Inventory Spare Parts in Water Treatment Plant
Category-C Inventory Spare Parts in Water Treatment Plant
So, that is it from our side.
We hope you found our explanation and examples helpful. If yes, do share our work with someone likeminded.
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