> ## Documentation Index
> Fetch the complete documentation index at: https://docs.variable.global/llms.txt
> Use this file to discover all available pages before exploring further.

# Life-cycle stages explained

> Understanding EN 15804+A2 life-cycle stages

Life-cycle assessment (LCA) breaks down a product's environmental impacts across distinct stages, from upstream material production through end-of-life. Variable follows the **EN 15804+A2** standard, which defines a comprehensive framework for these stages.

<Info>
  EN 15804 calls each A1-D stage an **information module**. We use **life-cycle stage** throughout Variable - the two terms mean the same thing.
</Info>

## Stage overview

EN 15804+A2 organizes the product life-cycle into four main phases:

```mermaid theme={"system"}
flowchart TB
    subgraph CradleToGate["Cradle to gate (A1-A3)"]
        subgraph Upstream
            A1[A1: Materials]
            A2[A2: Transport to factory]
        end
        subgraph Direct
            A3[A3: Manufacturing]
        end
    end
    subgraph Downstream
        subgraph Distribution["Distribution (A4-A5)"]
            A4[A4: Distribution]
            A5[A5: Installation]
        end
        subgraph UsePhase["Use (B1-B7)"]
            B[B1-B7: Use phase]
        end
        subgraph EndOfLife["End of life (C1-C4)"]
            C[C1-C4: End of life]
        end
    end
    subgraph Optional["Optional benefits (D)"]
        D[D: Beyond system]
    end
    A1 --> A2 --> A3 --> A4 --> A5 --> B --> C --> D

    style A1 fill:#d1edff,stroke:#d1edff,color:#003540
    style A2 fill:#d1edff,stroke:#d1edff,color:#003540
    style A3 fill:#d1edff,stroke:#d1edff,color:#003540
    style A4 fill:#ede5ff,stroke:#ede5ff,color:#003540
    style A5 fill:#ede5ff,stroke:#ede5ff,color:#003540
    style B fill:#e8f2a1,stroke:#e8f2a1,color:#003540
    style C fill:#f7edcf,stroke:#f7edcf,color:#003540
    style D fill:#f3f0ed,stroke:#f3f0ed,color:#003540

    style CradleToGate fill:transparent,stroke:#BDB8B2
    style Distribution fill:#F8F5F2,stroke:#DDD9D5
    style UsePhase fill:#F8F5F2,stroke:#DDD9D5
    style EndOfLife fill:#F8F5F2,stroke:#DDD9D5
    style Optional fill:transparent,stroke:#BDB8B2

    style Upstream fill:#F8F5F2,stroke:#DDD9D5
    style Direct fill:#F8F5F2,stroke:#DDD9D5
    style Downstream fill:transparent,stroke:#BDB8B2
```

<Info>
  Module **D** (benefits beyond the system boundary) is reported separately and **does not count toward a product's total footprint**. It captures potential benefits - reuse, recycling, energy recovery - that happen outside your system boundary.
</Info>

## Detailed stage reference

| Stage | Name | Phase | Description |
| :- | :- | :- | :- |
| A1 | Materials | Upstream | The materials and components that go into your product, including their upstream production from cradle to the supplier's gate |
| A2 | Transport to manufacturing | Upstream | Transportation of materials and components to the manufacturing facility |
| A3 | Manufacturing | Direct | All manufacturing and assembly processes, including energy consumption, waste, and packaging |
| A4 | Transport to customer | Downstream | Distribution of the finished product to the customer or construction site |
| A5 | Installation/assembly | Downstream | On-site installation, assembly, or construction activities |
| B1 | Use | Downstream | Emissions during normal product use (e.g., off-gassing, refrigerant leakage) |
| B2 | Maintenance | Downstream | Regular maintenance activities throughout the product's service life |
| B3 | Repair | Downstream | Repair activities to restore product functionality |
| B4 | Replacement | Downstream | Replacement of components that have a shorter lifespan than the product |
| B5 | Refurbishment | Downstream | Major refurbishment or renovation activities |
| B6 | Operational energy use | Downstream | Energy consumed during product operation |
| B7 | Operational water use | Downstream | Water consumed during product operation |
| C1 | Deconstruction/demolition | End of life | Dismantling or demolition of the product at end of service life |
| C2 | Transport to processing | End of life | Transportation of waste materials to processing facilities |
| C3 | Waste processing | End of life | Recycling, recovery, or other waste treatment processes |
| C4 | Final disposal | End of life | Landfilling or other final disposal methods |
| D | Benefits beyond boundary | Optional | Potential benefits from reuse, recycling, and energy recovery outside the system boundary |

## What to include in each stage

<Note>
  These are non-exhaustive examples to get you started. Your product's **PCR (Product Category Rules)** is authoritative - always follow it where it differs from the guidance below.
</Note>

### A1: Materials

The materials in your model. Each input is a quantity of a Material - whether unprocessed (ore, timber), processed (steel sheet, plastic pellets), or pre-formed (a steel pipe, a molded housing). The Dataset behind each Material covers its upstream production from cradle to the supplier's gate, including mining or harvesting, refining, and any supplier processing. It does **not** include transport to your factory - that's A2.

Packaging can fall into different stages depending on what it is: packaging on incoming supplier materials commonly sits in A1, manufacturing or product packaging in A3, and distribution packaging in A4. When in doubt, default to A1 - but always follow your PCR, which is authoritative on where each kind of packaging belongs.

### A2: Transport to manufacturing

* All transport modes from suppliers to your factory
* Consider supplier location and transport distances

### A3: Manufacturing

* Electricity and fuel consumption
* Direct emissions from a process (e.g., welding, curing, calcination, clinkering)
* On-site waste generation and treatment
* Water consumption and wastewater treatment

### A4-A5: Distribution and installation

* Transport to distribution centers and final customers
* Installation energy and consumables
* Construction site waste
* Temporary works and scaffolding

### B stages: Use phase

* Energy consumed during operation (B6) - typically the largest use-phase contribution
* Maintenance schedules and replacement cycles

### C stages: End of life

* Demolition and dismantling energy
* Transport to waste facilities
* Recycling processes
* Landfill or incineration

## Bundling and unbundling nested models

When a line in your bill of materials points to another product you've modeled in Variable (a *nested* model), you can choose how its stages appear:

* **Bundled** (the default) — the nested model contributes as a single line carrying its cradle to gate (A1-A3) total, wherever the line sits in your model.
* **Unbundled** — the nested model's own stages are broken out and laid out individually, so its detail flows into your product across the matching stages.

Unbundling is available for every stage group: cradle to gate (A1-A3), distribution (A4-A5), use (B1-B7), end of life (C1-C4), and optional benefits (D). For the multi-stage groups this is how you pull a separately-modeled phase — for example a child end-of-life model with its own C1-C4 lines — into a parent product with the stages kept intact. Optional benefits (D) is a single stage: bundled, it imports the source's cradle to gate (A1-A3) total; unbundled, it imports the source's own module D credit (its recycling or recovery benefit) into stage D.

Open a line's actions menu and use the **Bundling** options to switch between bundled and unbundled; each option shows what it imports. Switching changes how the nested model's detail is grouped into your product's stages; it doesn't change what the nested model itself contains.

Through the API, set `bundled` on a model input to make the same choice.

Bundling also decides which stage the nested model's own lines are reported under in your export. Bundled, they are reported at the stage the parent line sits in — a carton model bundled into A1 has its board and its ink listed under A1, matching the single A1 total the calculation books. Lines the parent's stage doesn't cover are left out rather than moved: that same carton's C3 disposal line doesn't appear at all, because the calculation doesn't count it there either. Unbundled, and with no bundled line above it, a line keeps its own stage, because that is how the calculation counts it.

The model page shows the same thing: under a bundled line, a nested row's Stage cell is a read-only chip carrying the stage it inherits, and hovering it names the bundled line the stage came from. Unbundle that line to give the row its own stage back — editing the stage on the nested model's own page won't change what the chip reports while the line above stays bundled.

Bundling also changes how the nested model's weight appears in your materials breakdown. Bundled, it shows as a single line carrying the sub-model's own total. Unbundled, that line carries no weight of its own and the individual materials underneath it carry theirs instead. Either way the total is the same — but don't add the two together, because the sub-model line and its materials describe the same weight.

One case is not yours to choose: when a line sources a model published by another company on Variable, it always appears as a single line. Their bill of materials is theirs, so your export shows that single line rather than breaking it down into their materials. Supplier records you created in your own account aren't affected — those are yours, and their detail flows through normally.

## Examples by product type

### Electronics (laptop)

| Stage | Example inputs |
| :- | :- |
| A1 | Semiconductors, metals, plastics, battery cells |
| A2 | Component shipping from Asia |
| A3 | Assembly, testing, packaging |
| A4 | Air freight to retailers |
| B6 | Electricity during 5-year use phase |
| C3-C4 | E-waste recycling, circuit board processing |

### Construction materials (steel beam)

| Stage | Example inputs |
| :- | :- |
| A1 | Iron ore mining, coking coal |
| A2 | Rail transport to steel mill |
| A3 | Electric arc furnace, rolling |
| A4 | Truck delivery to site |
| A5 | Crane operation, welding |
| C1 | Cutting for demolition |
| C3-C4 | Steel recycling |

### Consumer goods (furniture)

| Stage | Example inputs |
| :- | :- |
| A1 | Wood harvesting, foam production |
| A2 | Truck from suppliers |
| A3 | Cutting, assembly, finishing |
| A4 | Delivery to customer |
| B2 | Cleaning products, reupholstery |
| C3-C4 | Wood recycling or landfill |


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