ISO 14855-2:2018

Overview

ISO 14855-2:2018 specifies a laboratory-scale method for determining the ultimate aerobic biodegradability of plastic materials under controlled composting conditions by gravimetric measurement of evolved carbon dioxide (CO2). The standard describes how to control humidity, aeration and temperature in small composting vessels to achieve optimum biodegradation, and how to capture and quantify CO2 using absorption columns and gravimetric analysis. This method is suitable for natural and synthetic polymers, blended materials, additives-containing plastics and water‑soluble polymers that do not inhibit microbial activity.

Key topics and technical requirements

• Test principle: Mix test material with mature compost inoculum and inert carrier (sea sand) and measure CO2 evolved by absorption in soda lime/soda talc, weighing traps on an electronic balance.
• Controlled composting conditions: Maintain specified humidity, aeration (CO2‑free, water‑saturated air) and temperature to promote aerobic microbial activity.
• Gravimetric CO2 measurement: Use absorption columns filled with soda lime (2–4 mm) and soda talc (2–3 mm) and periodically record mass increase to determine CO2 evolved.
• Materials and reagents: Sea sand (20–35 mesh), silica gel or CaCl2 for moisture control, TLC‑grade microcrystalline cellulose (<20 µm) as positive reference.
• Apparatus: Small composting vessels, air‑supply with CO2 trap and humidifier, flow controllers, and electronic balance; closed system enables isotopic‑labelling studies.
• Test design and validity:
  • Typical setup uses triplicate vessels for test, blanks and reference material.
  • Standard termination is 45 days, but tests may extend up to 6 months until a biodegradation plateau is reached.
  • Inoculum activity criteria (e.g., CO2 production range after incubation) and other validity checks are specified.
• Safety note: Compost and inocula can contain pathogens - follow appropriate biosafety precautions.

Applications and who uses it

ISO 14855-2:2018 is used by:

• Materials and polymer manufacturers to substantiate biodegradability claims for compostable plastics.
• Third‑party test laboratories performing compliance and certification testing.
• R&D teams developing biodegradable formulations and additives.
• Regulators and standards bodies assessing environmental performance and labeling.
• Waste management and composting operators evaluating material behavior under composting conditions.

Practical uses include product validation, regulatory compliance, life‑cycle studies, and comparative performance testing of biodegradable plastics.

Related standards

• ISO 14855-1 - General method for biodegradability by analysis of evolved CO2 (alternative analytical techniques).
• ISO 11721-1 - Soil burial/biodegradation test methods (relevant for textile/biodegradation assessment).
• ISO 14855 series - Additional parts provide context and complementary methods.

Keywords: ISO 14855-2:2018, biodegradability test, composting, gravimetric CO2 measurement, plastic materials, laboratory-scale biodegradation.