The Bill of Materials (BoM), as the name suggests, provides a detailed breakdown of the materials used in a product. For multi-component products, this can result in a substantial BoM. However, its primary purpose is to demonstrate a clear understanding of the product’s composition and address any potential risks. Think of it as the skeleton that holds your technical substantiation together. It is not just a list of components, but serves as the foundation for your product, confirming the materials used in each component along with how much is used which is typically expressed as the percentage weight of the product (%w/w).

The BoM is a comprehensive list of components and materials, allowing the reader to identify the corresponding technical substantiation. This ensures that the testing on file addressses the entire product and that no gaps exist, which could pose health or safety risks—for example REACH compliance for coatings or varnishes. Often, it can be a small oversight, such as a banned substance in inks, dyes or finishes that can lead to product recalls.

A Bill of Materials (BOM) is a comprehensive list that details all the components, parts, and materials required to manufacture a complete product. As the substantiation required in CERT Filing is only to address health and safety and market compliance, the minimum criteria for a BoM is:

• Specify the components that make up your product, along with the corresponding materials that each component consists of.
• The packaging component and materials used.
• The Bill of Materials also needs to indicate how much of each material is used, which is commonly reference to as percentge weight (%w/w) of the product. The percentage present based on the whole product and primary packaging combined i.e. what is supplied to the consumer.

 The %w/w needs to account for the whole product and primary packaging that the consumer receives. This needs to add up to 100% content:

Product Component —>	Material/Composition —>	%w/w of the finished product
Primary Packaging Component —>	Material —>	%w/w of the finished product
Overall Percentage Weight (%w/w) =		100%

A BoM can also include the secondary and tertiary packaging, but this additional packaging is not mandatory to declare and should not be included in the %w/w calculation, as it is not considered as part of the product. The primary packaging on a BoM is useful as it aids in confirming calculations on packaging waste for compliance with Extended Producer Responsibility (ERP) requirements.

This is the minimum mandatory requirement. Please see ‘Part 2’ below for a more comprehensive example.

The real added value of a BoM is the assistance it provides with manufacturing and ensuring quality. Clients are welcome to upload a full BoM if preferred as this only helps to reinforce the quality of the product, but as a minimum it needs to address the requirements in Part 1.

It serves as a fundamental blueprint in manufacturing processes, providing crucial information for various stages of production:

1. Components: The BOM includes all raw materials, sub-assemblies, intermediate assemblies, sub-components, and packaging needed for the final product.
2. Quantities: It specifies the exact quantities of each component required for a single unit of the finished product.
3. Hierarchical Structure: BOMs are typically organized in a hierarchical manner, with the top level representing the finished product and lower levels detailing sub-assemblies and individual components.
4. Additional Information: Depending on the type of BOM, it may also include:
   • Part numbers and descriptions
   • Material specifications
   • Manufacturing processes
   • Assembly instructions
   • Packaging requirements – where it is at your discretion how much of the packaging is identified. Some producers specify all packaging including tertiary packaging. This may assist with some distribution and packaging processes, but the key element is ensuring that the packaging provided to the end consumer is specified, as this has legal obligations.

BOMs are essential for various aspects of the manufacturing process, including:

• Production planning and scheduling
• Cost estimation
• Inventory management
• Procurement of materials
• Quality control
• Assembly guidance
• Reporting packaging waste

There are different types of BOMs, such as Engineering BOMs (EBOMs) and Manufacturing BOMs (MBOMs), each tailored to specific needs in the product development and manufacturing process. For formulated products you can rely on the product formulation (which acts as a product BoM) accompanied by a packaging specification. These two combined act as the product BoM.

In electronics manufacturing, BOMs are particularly crucial, detailing components like resistors, capacitors, integrated circuits, and printed circuit boards (PCBs). They play a vital role in ensuring efficient production, accurate sourcing of components, and maintaining product quality throughout the manufacturing process.

What if I have a very large amount of accessories or components?

Official guidance advises listing all components and materials and having testing to support it, as this is the clearest way to substantiate product safety. In practice doing full testing is not always possible, as it can be cost prohibitive. A solution can be to clearly document all components and raw materials and ensure their safety and compliance for use in your product through the use of safety data sheets or raw material supplier test results, using a Declaration of Conformity (DoC) to create the paperwork trail linking it to your product. A final test report for the overall safety of the completed product is always strongly advised…

DoCs from manufacturers and suppliers can be helpful, as they prevent further layers of investigation for you. However, if a DoC is challenged, the issuer must be able to provide testing to substantiate it. This underscores the importance of a clear service agreement with your manufacturer, ensuring that any DoC provided can be readily substantiated. Manufacturers should have screened and obtained supporting documentation from their raw material suppliers to confirm that materials and components used in production are safe and compliant with the markets they target.

Traceability is essential, especially when entering new markets. It ensures that compliance information is readily accessible and any gaps can be addressed through testing or material substitutions. Additionally, updates to legislation, such as new substances added to the Substances of Very High Concern (SVHC) list or changes to REACH requirements, can impact your product.

Are there other options?

Yes, but only if you can clearly account for all materials in the product and provide testing to substantiate their safety and suitability. For example, in an electrical or electronic product where the same components (e.g., circuit boards) are reused across multiple products, you may not wish to retest the same materials each time. The same concept can be extrapolated into other product areas where appropriate.

In this case, you could test the circuit board as a whole, confirming that the materials used in the assembly are safe and appropriate. This could then be listed as a group on the BoM, with the relevant test report name and date. It’s also advisable, as due diligence, to specify the key materials present, as this can help meet surveillance monitoring requirements.

This approach allows the BoM to reference the same testing, allowing it to be specified in other products using the same hardware. As the testing is done at the component level, the BoM will confirm the component’s inclusion in the product, with the material percentages, and the testing will demonstrate its suitability for the product and target markets. Note: This only addresses materials used and not performance testing or mechanical/electrical safety in terms of the application which would be addressed by separate testing.

Always remember – if you are the market introducer, you are liable for the product in its entireity and so initially you will be expected to address any issues raised by market authorities. It is then your responsibilty to deal with the situation internally if another party e.g. manufacturer is at fault.

Every business has their unique way of saving and displaying product development data.

If you are new to the concept of a Bill of Material, CERT can provide a template with detailed example for minimal cost. Please contact the Regulatory Expert in our team who is coordinating your product reviews for more details.

Clear Effective Responses to Technical challenges