Technical Alert!

Ambient Temperature Biodegradation Lab Reports are Not Accepted for Industrial Composting Certification

The Compost Manufacturing Alliance is committed to maintaining the highest standards for compostable products. As part of this commitment, we require that all products show acceptable laboratory verification under the latest version of ASTM D6400 or D6868.

We see a significant increase in laboratory reports where disintegration and mineralization or biodegradation is performed at ambient (20C +/-) temperatures rather than industrial composting temperatures (60C +/-). These temperatures are measured in the compost medium rather than outside the vessel or pile. While some certifications may accept ambient temperature results to satisfy their requirements, CMA does not.

CMA strictly applies the D6400 and D6868 criteria. These standards require:

6.1 In order to be identified as compostable in municipal or industrial aerobic facilities, products must pass the requirements of 6.2, 6.3, and 6.4 using the appropriate laboratory tests, representative of the conditions found in aerobic composting facilities, which reach thermophilic temperatures. ASTM D6400-26, 6.1 (Emphasis added.)

Thermophilic temperatures range from 55 to 70 C.[1] Therefore, disintegration and biodegradation testing must be performed at this temperature range to comply with the requirements of ASTM D6400 and D6868.

There is an assumption that if a product biodegrades or disintegrates at one temperature, such as ambient temperatures, it naturally follows that it will biodegrade at a higher temperature. This is simply not true!

Composting requires microbial activity to perform the work of degrading material. Microbial activity varies at different temperatures. Different microbial populations thrive at higher or lower temperatures. It is primarily this microbial activity that affects disintegration of material or products. Some microbes break down one material better than another. Therefore, the different microbes at different temperatures will not break down all materials – natural or manufactured – at the same rate.[1]

Reference

[1] Robert Rynk, Jeff Ziegenbein, Cary Oshins, Nanci Koerting, James Hardin, and Jeff Gage, “Process Management,” in The Composting Handbook: A How-To and Why Manual for Farm, Municipal, Institutional and Commercial Composters, ed. Robert Rynk et al. (Cambridge, MA: Academic Press, 2022), 505, Table 11.2.

If you are planning to apply for CMA certification, please confirm that your laboratory testing has been performed at the appropriate temperature.

If you have questions about our certification requirements, please reach out to Janet Thoman at janet@composterapproved.com.