# How do I calculate the carbon footprint of stainless steel surgical instruments?

Canonical: https://senseible.earth/answers/surgical-instrument-carbon-footprint-per-piece

Multiply the stainless steel per instrument, including forging and machining scrap, by your steel supplier's per-kg figure. Add forging fuel, heat treatment, machining, polishing and passivation, cleaning and packing, then divide plant energy by instruments passed.

## Materials

- Martensitic or austenitic stainless bar or blanks by weight.
- Tungsten carbide inserts, where used.
- Pouches and cartons.

## Process

- Drop forging and trimming, with furnace or induction heating.
- Hardening and tempering.
- Grinding, polishing, passivation and ultrasonic cleaning.

## Per piece

Report per instrument type, since a scalpel handle and a retractor differ widely in steel weight.

## Worked example: instrument unit per piece (one month)

- Electricity: 25,000 kWh x 0.710 = 17,750 kg CO2
- LPG: 500 kg x 2.98 = 1,490 kg CO2
- Instruments passed: 50,000
- Plant total: 19,240 / 50,000 = 0.385 kg CO2 per instrument
- Add stainless steel 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)
- [Forging footprint per tonne](https://senseible.earth/answers/forging-carbon-footprint-per-tonne)
- [Heat treatment emissions per tonne](https://senseible.earth/answers/heat-treatment-emissions-per-tonne)

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 2026-10-20.