Module D: beyond system boundaries — claiming the recycle credit correctly

Module D is the most contested section of the EN 15804+A2 modulary table. Titled "net benefits and loads beyond the system boundary", it measures the net environmental benefit a product provides after leaving its system, by being reused in secondary markets. This positive value (displayed as negative emissions) is a competitive advantage between categories. But A2 sharply limits optimistic claims.

What does the end-of-waste criterion require?

A2 requires the material to reach "end-of-waste" status before any Module D claim. This criterion is derived from Article 6 of the EU Waste Framework Directive 2008/98/EC: the material must enter a tangible market as feedstock for another product, meet demand and application conditions, and pose no threat to environment or human health. Being "recyclable" is not enough; the material must have an actually-recycled market.

Avoided burden vs cut-off — two different mindsets

EN 15804+A2 uses cut-off allocation: recycled material enters A1 as virgin-burden-free; Module D simultaneously credits the substitution of virgin material in the second market. This is the "avoided burden" approach. Under the older A1 the distinction was more flexible; A2 tightens the boundaries. Practical implication: the Module D credit calculation requires evidence-backed answers to "how much virgin do you actually substitute?".

Defensible Module D rates by sector

• Steel (structural) — recycle rate 85-95%; Module D is genuinely large (-30% to -50% of GWP)
• Aluminium — recycle rate 75-90%; Module D yields a meaningful credit
• Copper — recycle rate 40-60% (in construction); moderate Module D
• Concrete — recycle rate 30-50% (CDW as aggregate); but virgin aggregate substitution is limited, credits are modest
• Glass wool — cullet recycling 20-40% by country; Module D is moderate
• EPS — energy recovery (incineration) 50-70% in EU; Module D carbon credit is small
• PVC — recycle rate 15-25%; Module D is moderate
• Wood — energy recovery 60-80%; Module D claimable as renewable-fuel substitution

Quality downgrading of secondary materials

Recycled material is not always a 1:1 substitute for virgin. In plastics, polymer chains shorten during recycling and mechanical properties drop; a PVC window profile cannot meet structural needs at 100% post-consumer recycled (PCR) content. The Module D substitution factor in such cases is 0.5-0.8, not 1.0. Verifiers expect this "down-cycling" factor to be reported explicitly.