Advancing the Standards of Functional Polymers
ASTM D5338 (ISO 14855)
Standard Test Method for Determining Aerobic Biodegradation* of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures
Significance and Use (This test method is equivalent to ISO 14855)
Biodegradation of a plastic within a composting unit is an important phenomenon because it may affect the decomposition of other materials enclosed by the plastic and the resulting quality and appearance of the composted material. Biodegradation of plastics will also allow the safe disposal of these plastics through large, professionally-managed composting plants and well-run residential units, where thermophilic temperatures are achieved. This procedure has been developed to permit the determination of the rate and degree of aerobic biodegradability of plastic products when placed in a controlled composting process.
During composting, thermophilic temperatures are most readily achieved in large-scale, professionally-managed facilities. However, these temperatures may also be reached in smaller residential composting units, frequently referred to as “backyard” or “home” composting.
Limitations
Because there is a wide variation in the construction and operation of composting facilities and because regulatory requirements for composting systems vary, this procedure is not intended to simulate the environment of any particular composting system. However, it is expected to resemble the environment of a composting process operated under optimum conditions where thermophilic temperatures are achieved. More specifically, the procedure is intended to create a standard laboratory environment that will permit a rapid and reproducible determination of the aerobic biodegradability under controlled composting conditions.
* Disclaimer: Biodegradation metrics for plastic materials enhanced with EcoPure® masterbatches are determined strictly according to standardized laboratory test methods (including applicable ASTM and ISO protocols) specific to controlled, biologically active waste environments. Actual real-world biodegradation outcomes[or behavior] vary significantly based on the structural characteristics characteristics of the finished product, material thickness, mass configuration, and localized environmental variables including microbial population density, solid content, temperature, and moisture levels.
In accordance with international advertising and environmental marketing standards, product performance claims must be confined strictly to the exact numerical results achieved within the specific test duration and shall not be used to substantiate unqualified “biodegradable” or “eco-friendly” claims. Testing documentation must explicitly disclose the net percentage of gaseous carbon evolution achieved by both the test sample and the control reference sample at the formal conclusion of the test. Data shall not be extrapolated, projected, or modeled beyond the actual, completed timeline of the laboratory test.
California: (Public Resources Code § 42357): California completely prohibits selling any plastic product or packaging labeled with the terms “biodegradable,” “degradable,” or “decomposable.” It bars any text, imagery, or scientific references—including specific ASTM or ISO test numbers—that imply the item will break down in a landfill or any other environment when directed at consumers. This applies to all sales within or into the state, including internet sales.
Maryland: (Environmental Code § 9-2101): Maryland completely bans express or implied degradation language on plastic products or packaging sold into the state. Citing laboratory test protocols to consumer audiences is restricted and treated as an illegal implied degradation claim.
Minnesota: (Minnesota Statutes § 325E.94): Minnesota bans the manufacture or sale of any plastic product labeled “biodegradable,” “degradable,” or “decomposable,” or relying on implied breakdown mechanisms, unless it meets an authorized, active state-approved standard for rapid environmental assimilation. Citing standard soil or landfill test protocols on consumer packaging does not bypass this ban.
Washington: (Revised Code of Washington § 70A.455): Washington restricts degradability claims on plastic products strictly to items that meet certified compostability standards (such as ASTM D6400 or D6868). All unqualified “biodegradable” claims and implied laboratory-test marketing on non-compostable plastics are prohibited on commercial consumer goods.