Standard Test Method for Determination of the Degree of Disintegration of Items Under Defined In-Field Composting Conditions Using Containers

Abstract

5.1 This field test method is intended to measure the level of disintegration of compostable items that independently meet Specification D6400, or equivalent specifications, in aerobic composting facilities which are operating under the defined in-field composting conditions. 5.1.1 The test method assesses disintegration only, which is only one of several requirements for determining compostability, and does not determine biodegradability in compost, plant toxicity, heavy metals, or restricted substances (e.g., PFAS). 5.2 The container method is appropriate for facilities where the method of containment can remain intact during testing and be removed and re-loaded as needed. Composting technologies using continuous agitation or that are fully contained (e.g., rotating drum) are examples where the container method may not be suitable. 5.2.1 Compostability standards were developed based on both lab and in-field research at ASTM in the 1990s, establishing tiered testing for biodegradation, disintegration, and plant toxicity. According to the ILS report, lab-based tests are the most conservative, meaning all samples had higher rates of disintegration in the field, making lab tests best suited for claims of compostability. The ILS report concludes that field testing data “provides demonstration and confirmation of compostability, however, this tier (test method) should not become mandatory to demonstrate compostability.” For field testing to best provide confirmation that the lab tests are reliable indicators for the real-world performance, a standardized test method is needed. This field test method provides additional data to supplement tests performed in a laboratory in the compostability specifications, as a means for assessing disintegration at composting facilities that can achieve the defined in-field conditions, regardless of composting technology. Composting can vary based on conditions determined by technology/facility type, feedstocks, management of piles, seasonality, end markets for compost, etc., and therefore field test results will vary, posing challenges for repeatability.