> ## 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.

## 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       |