EN ISO 17556:2012

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Test environment
6 Materials
7 Apparatus
8 Procedure
9 Calculation and expression of results
10 Validity of results
11 Test report
Annex A (informative) - Principle of a manometric
        respirometer (example)
Annex B (informative) - Example of a system for
        measuring the amount of carbon
        dioxide evolved
Annex C (informative) - Examples of methods
        for the determination of evolved
        carbon dioxide
Annex D (informative) - Theoretical oxygen
        demand (ThOD)
Annex E (informative) - Example of a determination
        of the amount and the molecular mass
        of water-insoluble polymer remaining at
        the end of a biodegradation test
Annex F (informative) - Examples of long-term
        tests
Annex G (informative) - Round-robin testing
Bibliography

ISO 17556:2012 specifies a method for determining the ultimate aerobic biodegradability of plastic materials in soil by measuring the oxygen demand in a closed respirometer or the amount of carbon dioxide evolved. The method is designed to yield an optimum degree of biodegradation by adjusting the humidity of the test soil.If a non-adapted soil is used as an inoculum, the test simulates the biodegradation processes which take place in a natural environment; if a pre-exposed soil is used, the method can be used to investigate the potential biodegradability of a test material.This method applies to the following materials:natural and/or synthetic polymers, copolymers or mixtures of these; plastic materials which contain additives such as plasticizers or colorants; water-soluble polymers. It does not necessarily apply to materials which, under the test conditions, inhibit the activity of the microorganisms present in the soil. Inhibitory effects can be measured using an inhibition control or by another suitable method. If the test material inhibits the microorganisms in the soil, a lower test material concentration, another type of soil or a pre-exposed soil can be used.