Compostability Admissibility Boundary
Compostability claims are valid only if packaging fully exits the recoverable fragment spectrum under realistic home compost conditions. Residual microfragments render consumer-facing disappearance claims non-admissible.
A packaging item is non-admissibly compostable under home conditions if any recoverable fragment at or above the defined detection threshold remains after the stated consumer timeframe.
No fragment at or above 1 mm remains after 12 weeks in realistic home compost conditions.
Any recoverable packaging fragment ≥1 mm remains within the screened compost fraction.
Residual fragment persistence under consumer-realistic home composting, not label language or average degradation narrative.
Disappearance within consumer time
Packaging labeled compostable fully disappears in home compost within a reasonable consumer timeframe.
This claim is admissible only if disappearance is confirmed by residual fragment exclusion, not visual impression or partial breakdown.
Home-compost boundary conditions
- Home compost bin under ambient conditions
- 12-week composting interval
- Typical moisture and turning frequency
The claim is bounded to realistic household composting. No industrial compost assumptions are admissible within this test.
Recoverable fragment spectrum
Compost is dried, sieved through 5 mm and then 1 mm screens, and inspected under stereomicroscopy.
Any packaging-derived fragment at or above 1 mm is counted as persistent.
Visual disappearance is non-admissible if recoverable fragments remain.
Persistence, not narrative decay
- Residual fragment presence or absence
- Fragment size threshold: ≥1 mm
- Time-bounded home compost interval: 12 weeks
The governing variable is recoverable persistence. Partial disintegration does not override retained material identity at the detection threshold.
Binary falsification condition
Presence of any packaging fragment ≥1 mm after 12 weeks constitutes failure.
A single surviving fragment is sufficient to invalidate full disappearance under the defined regime.
Absence of gross visibility is not evidence of compostability.
Residual persistence invalidates consumer meaning
Consumer-facing compostability claims often rely on apparent breakdown, texture loss, or partial fragmentation. These are non-admissible proxies if material persists within the recoverable fragment spectrum.
- Surface disappearance is non-admissible
- Average degradation language is non-admissible
- Partial disintegration is non-admissible as full compostability
Compostability, under this boundary, means exit from detectable residual fragment form within the stated home-use regime.
What this test does and does not establish
- Whether residual fragments remain at ≥1 mm
- Whether full disappearance occurred within 12 weeks
- Whether the claim holds under home compost conditions
- Industrial compost performance
- Ecotoxicity or downstream environmental fate
- Policy or compliance conclusions outside the test regime
PASS
No packaging-derived fragment ≥1 mm remains after 12 weeks under realistic home compost conditions.
FAIL
Any packaging-derived fragment ≥1 mm remains after 12 weeks. The full home-compost disappearance claim is non-admissible.
Fragment persistence overrides label intent.
If recoverable material remains within the defined fragment spectrum, disappearance has not occurred. Compostability claims must resolve to residual absence, not optimistic interpretation.