Mechanics hands examining a worn component, described on an equipment bill of materials (EBOM), in order to assess the severity of a machine’s condition.

An equipment bill of materials (EBOM) is extremely useful for asset-intensive organizations that rely heavily on proper asset and spare part management. However, creating an EBOM requires time, money, expertise, and a commitment from management, any of which may be lacking in a given organization. Further complicating the issue, valuable asset data is often scattered across several locations, in various electronic and hard copy formats, rather than stored in one place and format.

Despite these challenges, organizations must make a choice: either invest in the resources needed to build an effective EBOM and improve operations, or continue to suffer the consequences that arise from poor asset management.

This article is intended for organizations practicing robust asset management. It guides you through the process of creating, managing, and maintaining equipment bills of materials (EBOM). Organizations that require a simple bill of materials, such as one that will primarily be used for maintenance purposes, should read our companion article, How to Create a Maintenance Bill of Materials.

Note that throughout this article, we refer to an equipment bill of materials as an equipment bill of materials, EBOM, or equipment BOM interchangeably.

What is an Equipment Bill of Materials (EBOM)?

Within your organization, there may be a number of bills of materials (BOMs) that serve different audiences, such as engineering, asset management, manufacturing, and maintenance management. Each of these contains varying levels of detail, depending on who uses the information and how it will be used.

Typically, an equipment bill of materials (EBOM) defines the design or make up of an asset, such as a piece of equipment. The EBOM lists every part and material used on an asset, including specification, stocking level, and other features or characteristics.

Questions to Ask Before Creating an Equipment Bill of Materials (EBOM)

Creating an equipment bill of materials can take considerable effort, but is well worth it. There are many long-term benefits a proper EBOM brings, ranging from decreased downtime to simplified parts reordering and optimized stock management. Therefore, a systematic approach to EBOM creation ensures your time and effort are used efficiently.

The following questions prepare you for EBOM creation and make the process more manageable when the “real work” begins.

Who needs to use the EBOM?

Many parties throughout the organization may use the equipment bill of materials. Therefore, effective EBOMs contain relevant information for all stakeholders.

Think about which stakeholders will interact with the EBOM and how they will use it. Some examples are provided below. Keep in mind that a stakeholder’s role and responsibilities are unique to each organization.

Stakeholder EBOM Can Help Stakeholder…
Maintenance manager
  • Identify assemblies, subassemblies, and other components that may require maintenance
  • Identify inventory items required to complete maintenance work
  • Plan and schedule maintenance based on part availability
Maintenance planner
  • Identify assemblies, subassemblies, and other components that may require maintenance
  • Identify inventory items required to complete maintenance work
  • Centralize part information
  • Identify which parts to stock
  • Simplify information gathering
  • Plan and schedule maintenance based on part availability
  • Gather accurate purchasing data
  • Anticipate changes to inventory based on demand or obsolescence
  • Query and identify on which assets parts are used in the maintenance management system
  • Identify obsolete parts
Maintenance technician
  • Identify parts that require repair or replacement
  • Identify and obtain parts from existing stock
  • Identify and procure parts during off hours, including night and weekend shifts
  • Query and locate an asset’s parts within the maintenance management system
Inventory management staff
  • Associate critical spares with their related assets
  • Create part “kits” based on asset, planned maintenance, or redundant tasks
  • Centralize part information
  • Gather accurate purchasing data for parts procurement
Operations and reliability engineers
  • Review the makeup of assets
  • Identify possible alternative or substitute parts
  • Identify opportunities to standardize parts across assets or locations

Conduct an informal interview with each stakeholder to better understand what information they desire to see. Their responses will also help you identify the appropriate EBOM structure, as described in the next section, as well as what data should be included on the EBOM, discussed later.

How Should the EBOM be Structured?

Depending on the level of detail required, an equipment bill of materials may take many forms. Typically, EBOMs follow either a single-level or indented multi-level structure.

A single-level EBOM simply lists an asset’s components and spare parts. Each part is listed only once along with its total quantity for the asset.

quipment bill of materials (EBOM) created using a single-level structure.

A multi-level EBOM shows the hierarchy between an asset’s assemblies, subassemblies, and components. These parent-child relationships are usually visualized through indentation, showing which components “belong” to – or are organized “under” – each other. Unlike a single-level EBOM, parts in a multi-level EBOM are listed every time they are used by their parent item.

Equipment bill of materials (EBOM) created using a multi-level, indented structure.

The feedback you receive from stakeholder interviews will help you determine which structure to use.

What System Will Be Used to Create the EBOM?

Due to the amount of information that will be included, think carefully about the best way to document and create the equipment BOM. Using paper and pencil will not work, as handwritten information is not easily edited and will likely need to be entered electronically to be useful anyway. Spreadsheet programs such as Microsoft Excel are popular and great for data collection and organization, but have limited collaboration capabilities, lack automation, and are cumbersome to use.

Many organizations build EBOMs using a computerized maintenance management system (CMMS). In fact, many CMMS solutions provide automatic EBOM creation, which streamlines some aspects of EBOM creation, maintenance, and management. Further, the speed, accuracy, and convenience of using a CMMS for EBOM management are far superior to other methods. Enterprise asset management (EAM) software may also be used.

Further Reading: What’s the Difference between CMMS vs. EAM Software?

EBOM Creation

The process of creating an equipment bill of materials involves multiple steps. When done in a systematic fashion, such as the process described below, EBOM creation is efficient and produces high quality results.

1. Determine which Assets need an Equipment Bill of Materials

In this first step, identify which assets need an equipment BOM and in what order you will create them. If you find that a large number of assets will benefit from an EBOM, you must prioritize EBOM creation. Start with the most critical assets. Critical assets are those that are integral to business operations and cost the most when they fail. Therefore, you will make the most impact by focusing efforts here first.

Once completed, you can repeat the EBOM creation process for similar assets, and assets that share the same assemblies, subassemblies, and parts. Depending on your organization, industry, and type of assets you own, one EBOM may cover multiple identical assets.

2. Decide what Items to Include on the EBOM

Set the parameters of what will and won’t be included on the EBOM. For example, if EBOM is created for the sake of making the maintenance team more efficient, you don’t need to list every nut and bolt that makes up the asset. In this case, only regularly serviced and replaced components may be listed, along with critical spares. EBOMs in highly specialized or heavily regulated industries may be required to contain more detail than in a standard maintenance organization.

At a minimum, include the following:

  • Critical spares
  • Anything that is reasonably expected to be repaired or replaced
  • Anything for which it is beneficial for usage history to be tied to the asset

Stakeholder interviews also provide guidance as to what items are necessary to include.

You may have noticed that absent from this list are consumables such as towels, rags, gloves, and other supplies. While these items are used to perform maintenance, they are not part of assets themselves, and are therefore omitted from the EBOM. Work orders are a more appropriate place to identify what is needed to complete maintenance jobs.

Learn what should be included on a work order.

3. Determine what Data to Include on the EBOM

Finding the right amount of detail to include is important to the success of the EBOM. There is a delicate balance between providing enough information that the EBOM is useful, but not so much that is causes confusion. Conversations with key stakeholders should shed light on what information is important to have available.

At the most basic level, identify the part or component being used. This usually includes the item number and item name. Based on your organization’s needs, other information may be included. Below is a list of commonly used categories of information:

  • CMMS part number
  • Part number
  • Part name
  • Description
  • Revision number
  • Unit of measure
  • Size
  • Length
  • Weight
  • Quantity required by the asset
  • Manufacturer
  • Manufacturer part number
  • Authorized substitutes/alternatives
  • File availability (e.g., availability of drawings, CAD files, etc.)
  • Other specifications or features

Information that is not available on the EBOM should be easily accessible in the CMMS. CMMS software centralizes maintenance data, and links important asset and inventory information together. This makes it quick and easy for users to navigate to appropriate records to find accurate information.

4. Collect Inventory Item Data

Effective equipment bills of materials rely on comprehensive, accurate data. Unfortunately, many organizations struggle with their data tracking practices. They either don’t track maintenance activities, have some data but don’t know if it’s accurate, or have data but lack the resources to do anything with it. Additionally, maintenance teams often do not reliably enter data in a CMMS or other maintenance management system.

Due to these reasons, data collection may be the most time-intensive step in the process. With that said, don’t overexert yourself trying to collect all the data at once. Refer to your prioritized list of assets from earlier and collect information for the most critical assets first. EBOMs for less critical assets can be created later, as long as they are done eventually.

Asset data can be obtained from multiple sources including:

  • Equipment manuals provided by the original equipment manufacturer (OEM)
  • Equipment suppliers or other vendors
  • Drawings, schematics, and catalogs
  • Similar assets and equipment
  • Engineering change notices and redesign documentation
  • Current or planned preventive maintenance (PM) work orders
  • Previous unplanned work orders
  • Work order history records
  • Personal lists or cheat sheets
  • Equipment nameplates
  • Physical asset inspections
  • Veteran employees and other “go to” workers

During data collection it is acceptable to store data in a spreadsheet. This information can be easily transferred into a CMMS after your data collection and review phase.

5. Review EBOM Data

As you collect data, take the opportunity to perform some “clean up”. You are likely to find information that is out of date or obsolete. If you encounter discrepancies, cross-check between multiple sources to ensure the most up-to-date information is being used. It is imperative that data is accurate because after this step, you will enter it into the maintenance management system for use by you and your team.

Read Also: CMMS Data Transfer Best Practices

6. Enter the EBOM Data in the CMMS

In this final step, enter inventory part data into the CMMS or other system. Some CMMS systems can automatically import part data, while others require you to do it manually. Either way, data entry should be performed by someone familiar with the CMMS who can accurately enter data into the required fields.

EBOM Maintenance

Equipment bills of materials are not “set and forget.” There are a number of events that require EBOMs to be updated in order to maintain their accuracy. Consider the events described below:

  • Asset decommissioning and retirement: When assets are taken out of use and/or dismantled, an accurate EBOM identifies which parts are unique and can be sold or scrapped. Parts used elsewhere can be put back into inventory.
  • Asset design changes: Assets that have been redesigned, refurbished, or otherwise modified may use new and different components. These items should be included in the EBOM, along with any alternatives.
  • Part substitution: Due to availability issues, there exists a need to identify alternative parts that are viable substitutes. The EBOM or part record in the CMMS can show this relationship.
  • Part standardization: To streamline inventory procurement and purchasing, parts may be standardized across similar assets or across plants. Amend the EBOM to show these changes, including effective start and end dates of new parts.
  • EBOM review: EBOMs may go through informal or formal review throughout their lifetime. Informal reviews may happen as EBOMs are being used by those with specific knowledge about the asset. More formal reviews may be performed periodically by key maintenance stakeholders.

EBOM Management

To remain effective and accurate, EBOMs require a formal change management process. An out-of-control process – one in which anyone is allowed to make changes, changes are made without approval, or changes are made infrequently – can lead to disaster. Below are some EBOM management tips:

  • Set clearly defined responsibilities and expectations for users. Make sure each person knows their role in using, maintaining, and managing the EBOM.
  • Decide who is responsible for making changes to the EBOM. It is undesirable for everyone to be able to make changes. Limit editing capability to a small number of people.
  • Ensure everyone is using the most up-to-date EBOM. Clearly label the EBOM, including titles, version numbers, and page numbers to reduce problems caused by using out-of-date information.

If your organization requires more intensive file change management, consider the following:

  • Maintain a version history. Keep a copy of all versions of the EBOM in case you need to roll back to a previous version.
  • Use a change log. A change log records what changes were made, by whom, and when. This makes it easy to identify what has changed from version to version. It also holds editors accountable for information added to or removed from the EBOM.

The activities described above are quite manual. A good CMMS automates EBOM maintenance and management activities. Some systems automatically build EBOMs when parts are issued against assets on a work order. In addition, updates to part records only need to be done once for it to be affected throughout the system. Although errors may occur less frequently when using an automated CMMS, EBOMs should still be closely monitored.

Manage Assets with FTMaintenance

FTMaintenance CMMS software is an optimal tool for organizing and tracking asset information, including equipment bills of materials. It provides a platform for tracking robust asset and part information, including the ability to see where parts are used and to what jobs they are assigned. Request a demo today to learn more about how FTMaintenance improves asset management.

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