How do I get emissions data from tier-2 suppliers I don't buy from directly?
Mostly through your tier-1 supplier. Ask them for a cradle-to-gate footprint of what they sell you, which already includes their own suppliers, and ask them to request material-level data from their key sub-suppliers. Go to tier 2 directly only for a few high-impact materials, such as steel, aluminium, resins or chemicals.
Why tier 2 is already inside a tier-1 footprint
Under the GHG Protocol Scope 3 Standard, Category 1 covers the cradle-to-gate emissions of what you buy: everything from extracting raw materials to the product leaving your supplier's gate. A tier-1 product footprint done properly therefore includes tier 2, tier 3 and beyond. If you add tier-2 emissions on top of it, you count them twice.
Find where tier 2 matters
- Rank your purchases by spend and mass, then by material carbon intensity.
- For the top items, ask the tier-1 supplier what the main input material is, how much they use per unit, and which mill, smelter or plant it comes from.
- Focus on the few materials that make up most of the footprint. Basic metals, cement, plastics and chemicals usually dominate; packaging and consumables rarely do.
Three ways to get the data
- Cascade: tier 1 asks its key sub-suppliers for product-level figures and builds them into its own footprint, then passes the total to you. The PACT Pathfinder Framework sets out how product footprints are calculated and exchanged along a chain so each tier can reuse the one before.
- Hybrid: tier 1 gives you its own allocated Scope 1 and 2 plus the quantity of each main input; you multiply inputs by the producer's published intensity or a sourced factor.
- Direct: for a large, concentrated input, such as steel from one mill, ask the producer for its plant-specific intensity, or use what it publishes, and record that you did.
Making it stick
- Put a data clause in tier-1 contracts that requires them to pass on requests to key sub-suppliers.
- Give one template and one deadline across all suppliers, and accept estimates first, with a plan to replace them.
- Record for each figure whether it is primary from tier 1, primary from tier 2, or a secondary factor, so data quality is visible.
- Revisit yearly; a change of mill or resin grade can move the footprint more than any process change.
Worked example: hybrid footprint for forged parts (illustrative)
- Purchase: 100 t of forgings from a tier-1 forging supplier
- Tier 1 own Scope 1 and 2, allocated: 0.35 t CO2e per t x 100 t = 35 t
- Steel bar input at 91% yield: 110 t, from a mill reporting 2.2 t CO2e per t
- Tier 2 steel: 110 x 2.2 = 242 t
- Cradle-to-gate total: 35 + 242 = 277 t, or 2.77 t CO2e per t of forgings
All factors are illustrative. Here tier 2 is almost 90% of the total, which is why the mill's figure matters more than the forging shop's.
What Senseible does here
A tier-1 supplier can build a document-backed emissions number from its own invoices and bills in Senseible and pass it on, and Senseible's enterprise offer supports supplier programmes. It does not reach tier-2 suppliers on your behalf or exchange data automatically along the chain.
Sources: GHG Protocol Corporate Value Chain (Scope 3) Standard and Scope 3 Technical Guidance, Category 1, WBCSD, PACT Pathfinder Framework and Technical Specifications for PCF data exchange
Last reviewed 2026-10-15.