# How do I calculate the carbon footprint of investment castings?

Canonical: https://senseible.earth/answers/investment-casting-carbon-footprint-per-kg

Add the alloy melted per kg of good castings, the wax, ceramic slurry and stucco for the shells, and the melting, shell firing and finishing energy. Divide by kg of good castings, counting rejects and gating as melted metal.

## Material

- Steel, stainless steel or other alloy.
- Pattern wax, partly reclaimed.
- Ceramic slurry, stucco and binder.

## Process

- Wax injection and tree assembly.
- Shell building, dewaxing and shell firing.
- Melting, pouring, cut-off, finishing and heat treatment.

## Per kg

Report per kg of good castings by alloy. The yield from melted metal to good casting is often low, which raises the figure per kg shipped.

## Worked example: plant energy per kg (one month)

- Electricity: 100,000 kWh x 0.710 = 71,000 kg CO2
- PNG: 8,000 SCM x 2.05 = 16,400 kg CO2
- Kg dispatched: 40,000
- Plant total: 87,400 / 40,000 = 2.185 kg CO2 per kg
- Add the alloy for the full figure

Inputs are illustrative; use your own bills and production records.

## What Senseible does here

Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.

- [Product carbon footprint calculator](https://senseible.earth/calculators/product-carbon-footprint)
- [Foundry footprint](https://senseible.earth/answers/foundry-charge-mix-pig-iron-vs-scrap-carbon)
- [Forging footprint](https://senseible.earth/answers/forging-carbon-footprint-per-tonne)
- [Steel industry](https://senseible.earth/industries/steel)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-21.