Before you start: This article follows the definitions and rules set out in EN15804+A2. Many other methods are built on it — including the Dutch Bepalingsmethode, which the NMD database is based on — so this is a good general reference even if you're working under one of those. That said, if your method publishes its own end-of-life scenarios, default distances, or definitions, check that guidance first wherever it differs from what's described below.
Modeling end-of-life correctly means assigning the impacts of dismantling, transporting, processing, and disposing of a product to the right modules, and understanding how those impacts connect to Module D. Getting this right matters: misplacing a process — for example, modeling a mid-life replacement as Module C instead of Module B — skews your results and makes it harder to compare your EPD with others built the same way.
This article covers:
- What counts as waste, and when the end-of-life stage actually starts
- Modules C1–C4 of EN15804+A2
- How Module D relates to the C modules
When does the end-of-life stage start?
The end-of-life stage starts at the end of a product's service life — when it's replaced, dismantled, or deconstructed from the building and no longer provides any further function.
Dismantling, deconstruction, and demolition at the end of the product's life fall under Module C. Maintenance, repair, replacement, and refurbishment carried out during the product's life — and any waste those activities generate — are part of Module B (B2–B5), not Module C.
Waste can also come from earlier life cycle stages, and it's modeled within those stages rather than in C1–C4. For example:
Production offcuts and manufacturing waste → Module A3
Installation losses and packaging waste on the construction site → Module A4–A
Waste generated during maintenance, repair, replacement, or refurbishment → Module B (B2–B5)
Only output generated once the product itself reaches true end-of-life belongs in Modules C1–C4.
When does output stop being "waste"?
Recovered output stops being classified as waste once it meets all of the following criteria:
The recovered material is commonly used for specific purposes after collection.
A market or demand, with positive economic value, exists for the recovered material.
The material fulfils the technical requirements for the specific purpose and meets existing legislation and standards.
Using the recovered material won't lead to adverse environmental or human health impacts.
You'll mainly use these criteria to check whether output has left the product system boundary and can be credited in Module D. Landfilled material, for example, never meets these criteria — it stays part of the product system as disposal, reported in Module C4.
Modeling Tip: if a material meets all four criteria, it exits the product system as a secondary material or fuel, and its downstream benefits are captured in Module D. If it doesn't, it stays within the product system and is modeled through C1–C4 as described below.
C1
Deconstruction & Demolition
All impacts from dismantling or demolishing the product from the building — including the initial on-site sorting of materials — are included in Module C1.
What to include: energy use of demolition equipment (e.g., diesel for excavators, electricity for cranes or handheld power tools), and the initial sorting of materials on-site.
How to model: use standard industry averages or proxy datasets for mechanical deconstruction based on material mass if specific demolition data isn't available.
C2
Transport
This transport represents moving the discarded product, as part of waste processing, to the gate of the recycling site and/or the final waste disposal plant.
What to include: transport by truck, rail, or barge to the gate of a recycling yard, sorting facility, incineration plant, or landfill site.
How to model: apply standard scenarios (e.g., national default transport distances) if the exact location of the waste processing facility is unknown. If you're working under a national method such as the Dutch Bepalingsmethode, check whether it publishes its own default distances for this.
C3
Waste Processing
This is where the impacts of further processing and separating waste into its various streams are attributed — for example, sorting mixed waste into recyclable fractions like plastics or metals, and incinerating materials with energy recovery.
Only incineration with an energy recovery efficiency above 60% counts as energy recovery here. This 60% threshold comes directly from EN15804 and lines up with the EU's R1 formula for energy efficiency. If a process falls below that threshold, it's no longer treated as energy recovery — the material and its impacts are reported in Module C4 instead (see below). That doesn't mean the energy is wasted in the model, though: any heat or power exported from the process can still be credited as an avoided-impact benefit in Module D. More info about Module D in the following article.
Landfilling itself is not part of Module C3 — it's always reported in Module C4.
If any product materials contain biogenic carbon, the release of that carbon back into the atmosphere during processing here is accounted for in this module. Note that biogenic carbon in materials that leave the building earlier — packaging released during installation, like pallets (Module A5), for example — is accounted for within that earlier module instead.
C4
Disposal
Module C4 covers the final destination for materials that are landfilled, or incinerated without qualifying energy recovery (i.e., below the 60% efficiency threshold).
What to include: landfilling of inert or organic waste, and incineration where energy recovery efficiency is below 60% (including when there's no energy recovery at all).
Long-term emissions: for landfills, this includes modeling long-term emissions such as methane generation from decomposing organic waste over time, plus any other long-term emissions relevant to the landfill type and applicable local regulations.
Even though everything in C4 is treated as disposal, any usable heat or power exported from incineration or landfill gas can still be credited in Module D — see below.
Looking Beyond: The Relationship with Module D
While Modules C1–C4 capture the impacts of waste treatment, Module D captures the net environmental benefits or loads that happen after material passes the end-of-waste boundary — or, for energy, whenever usable heat or power is exported, even from processes classified as disposal in Module C4.
Whenever a material is successfully recycled, reused, or incinerated with high efficiency (above 60%), it substitutes the need for primary virgin materials or conventional grid energy in the next product lifecycle. Because C4-classified processes can still export usable energy, incineration below the 60% threshold and landfill gas recovery can also generate a Module D credit, even though they're modeled as disposal — not recovery — within Module C.
Documenting these net credits and avoided impacts in Module D gives a holistic view of your product's circular economy performance.
Read more about Module D in the next article coming soon
Feel like you're missing information? Check out the rest of our help center articles for more information on EPD modules and EN15804+A2