As I talk to people, especially when we are having discussions around EAM issues, there seems to be a fair amount of confusion surrounding the way that individual parts are identified in such software.

I thought I would take some time to try and clarify the terminology and give some advice on what I see as some opportunities for managing these systems.

storeroom 2

Why do we Maintain a Numbering System?

A true numbering system for MRO items (Maintenance Repair and Operations) is the really the only way to differentiate one item from the next.   Many storeroom listings contain tens of thousands of individual items, and it is not uncommon at all to see corporate listings measured in the hundreds of thousands.

The challenge to the maintenance technician is finding just the right item that we need to perform the task at hand.  Numbering each item and recording this number in the right place helps to shorten the time required to identify, locate, and obtain the needed materials.

These unique numbers are used in a variety of ways:

  • On the work order to identify what will be needed to perform the task
  • On the purchase order to indicate exactly what it is we want to purchase
  • On the Bills of Material (BOM) to indicate which parts are associated with which equipment
  • On the storeroom bin location to indicate what is stored in that specific shelf location

Something as simple as a single row ball bearing can have so many variables and features that describing the specific item using only words becomes a monumental challenge.   Thus the need for a numbering system.


The 3 main ways that any item is numbered in your system are listed below (the specific language may vary slightly based on your software and internal terminology – I have included the most common usage).

  • Item Number
  • Vendor Catalog Number
  • Manufacturer Part Number (OEM = Original Equipment Manufacturer)

These numbers are described in the table below:


Tips for Maintaining your Item Numbering System

Consider the following tips for maintaining your item master.

The Fewer People the Better

The fewer the people who can establish a new item number the better.   For some of you reading this you are thinking “of course, I can not create a new item, I must submit a form…”; others are thinking “what’s the big deal?”

I have some organizations that I interact with that are setup so that literally anyone can create a new item number entry, and guess what?  There system is filled with duplicate entries.   Duplicates lead to extra inventory, which leads to higher costs, storage space, and confusion.

For many of you this is not an option, but you may not understand why we go to all of this extra trouble.

         The Pros:

Duplication:  The more controls you place on your item master the less duplication that you will have.  Resources dedicated to this cause will search for duplicate items before adding a new one.

Standard Descriptions: and will make sure that we follow the standard naming convention when filling in the description field.

Accurate Item Attribute Data : Most EAM systems have attribute fields (classifications) that can be filled in for each item that greatly increase your ability to search amongst the hundreds of thousands of items.   Dedicated resources will take the time to research and accurately fill out these attribute fields; people performing this task as a collateral duty likely will not.


          The Cons:     

Time:  Probably the biggest frustration is the time (and follow on questions) that are required to centralize this effort.  You have to fill out a form and submit it to some centralized resource that handles this types of thing.  Usually this resource works for the procurement department, or even for an outside vendor contracted to manage this data for you.

Your request goes into a que where you wait and wait.  Meanwhile you just want to place this part sitting in the box next to your desk in the storeroom and be done with it.

If you are one of those people who have started with a loose set of controls and are looking to clean up and standardize your listing, you are beginning to see that this is a very expensive and nearly impossible situation.    There are people out there who can use software and large databases to search and clean up your sins from the past, but these efforts are time consuming and costly.  Better to manage things up front.

Be patient and follow the process.  You will be glad you did in the end.

Cost:  If somebody is going to manage the data that person will need to be paid.  Additionally, it takes time out of your day to fill out the needed forms and respond to requests.  Time is money, but in this case it is money well spent.

A Note on Construction Projects

Even if you have inherited a listing full of bad descriptions and duplicate items, you still have a chance to do better in the future.

Capital expansion or construction projects are your best line of defense to establish good materials listings for the future.   Most of the contracts that I see contain specific language as to what spare parts data must be supplied at the conclusion of the project, sadly it has been my experience that this language is rarely enforced.

Here is what you need to do to make sure you receive and use this data for the best chance of success:

  • Assign the responsibility for receiving, managing, and submitting this data for addition to the item master. Don’t use someone who is directly responsible for the construction project, make sure it is someone who will have to live with the consequences once the project is completed.
  • Make sure you get the data that you paid for in your contract. It is all about the Manufacturer Part Number (OEM Part Number).  If you have this, a simple Google search will provide you with a dozen different places to purchase it.  Now you can negotiate.   Sadly, this data is often an afterthought, and when it is provided, I see a lot of vendor catalog numbers.  As you would guess, with the vendor number you will have a harder time finding duplicates, and you will only be able to purchase this item from that vendor in the future.  Forget about negotiating. For example, get the SKF bearing number not the Acme Supply catalog number.
  • Build your BOM at the same time. The longer you wait the lower your chances of success become.   You will only find missing data once you start digging, and if you wait too long the people who can provide this data will have been paid and left town.  Get what you paid for before the project is done and all final payments are made.


Inventory data is a funny thing.  Give a person one item, and they will say “no big deal, I can figure this out on the internet!”  Give them the tens of thousands of items that make up a typical storeroom inventory and we quickly realize that this is an effort that is way over our heads.  We give up and move onto something else.  Wishing we had an accurate inventory, BOM, and item descriptions.

Better to strike while the iron is hot, and stay patient.  Follow the process, as painful as it is, and you will end up in a better place.

If you are one of those people who work under a system of rules that enforces these behaviors, perhaps this article has shed some light on why this is all necessary, as painful as it may seem at the moment.

Best of Luck and Mahalo

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5 Responses to Deciphering the Inventory Item Numbering System

  1. Sean Mullan says:

    Another great blog Mike! And timely in that we are currently in a global project to standardize our numbering systems and nomenclature in our EAM system. The project is huge and frustrating, but we will be much better off when the project is complete. Through standardization, we will have better BOMs, the ability to see and compare MRO parts throughout the organization, and the ability to negotiate purchasing agreements for large categories of parts. You’re right…it is painful, but we will end up in a better place.

  2. Hi Mike, nicely written, clear, and great advice. I agree that getting this right, right from the start and keeping the system clean is key. It is painful to build that system while still out there trying to find the right part… yet very much worth the effort.

    Mahola? are you writing from a tropical island by chance?



  3. Khan M. says:

    One method of avoiding item duplication while reducing the time required to put new items on shelf is to employ more item masters.

    You are right that it is not feasible to give everyone the right to add new items (as this would cause duplication).

  4. Thanks Mike – Highly relevant for CMMS, EAM or Asset Management Software Implementation. On the business side, Inventory Management has a direct impact on a balance sheet, so as you say – better to go through a painful process at the start, to reap benefits later.

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