How do I split a footwear factory's emissions across different styles?
Total the factory electricity at 0.710 kg CO2 per kWh and generator diesel at 2.68 kg per litre, then split by standard minutes per style rather than pairs, since a boot takes much longer to make than a sandal. State the rule beside each per-pair figure.
Why pairs alone mislead
Dividing by pairs gives every style the same energy. Styles with more operations, such as boots with lasting and stitching, use more machine and lighting time.
Rules that work
- Standard minute value (SMV) per style, from industrial engineering data.
- Machine hours per line, if lines are dedicated to styles.
- Pairs, only when styles are similar.
Materials stay separate
Allocation covers factory energy. Leather, soles and components are added per style from the bill of materials.
Worked example: pairs versus standard minutes (one month, illustrative inputs)
- Electricity: 70,000 kWh x 0.710 = 49,700 kg CO2
- Diesel: 900 litres x 2.68 = 2,412 kg CO2
- Factory total: 52,112 kg CO2 for 40,000 pairs
- By pairs: 52,112 / 40,000 = 1.303 kg CO2 per pair
- By standard minutes (boots 30, sandals 12; 10,000 boots, 30,000 sandals): boot 2.369 kg, sandal 0.947 kg
Inputs and minutes are illustrative; use your SMV data.
What Senseible does here
Senseible reads the energy invoices behind the making stage into a fingerprinted Scope 1 and 2 record, and keeps material invoices on the Scope 3 trail. Material factors come from your supplier or a named database and are labelled with their source, so the product figure can be traced line by line.
Sources: GHG Protocol Corporate Value Chain (Scope 3) Standard, IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults), CEA CO2 Baseline Database, version 21.0
Last reviewed 2026-10-21.