Summary of CAP
With increasing utilization of compost, testing compost for quality is on the increase. The publication of the Test Methods Manual for the Examination of Composting and Compost (TMECC), benchmark compost methods now exist for the testing lab industry. To ensure accurate and precise analysis and meet ISO 9001 requirements, a laboratory proficiency program is needed to provide testing labs with an external means of quality control evaluate laboratory performance, and evaluate inter-lab method performance.
The CAP program:
CAP is a laboratory quality assurance program which is conducted as tri-annual exchanges of three [3] compost materials, each submitted in blind triplicate (3 × 3 × 3 = 27) for each of two testing tiers. Tier I. Inorganic; and Tier II. Inorganic plus Biological. Refer to Compost Analysis Proficiency Program Test Parameters.
With the completion of each exchange, participating laboratories will be provided a statistical report with data as to their individual performance on each analysis. Statistical results of each exchange and list of participating laboratories are accessible as Acrobat Reader pdf files.
Work Plan
The project will include the collection of up to nine [9] reference compost materials from across the United States, corresponding to the diversity of feed stocks and composting technologies employed by Participating STA Facilities.
Tier I:
Each Tier I reference sample material is air dried, pulverized to pass a 1.0-mm screed and blended in a Patterson-Kelley V shell blender. Samples are packaged in 600 gram HDPE bottles. Three [3] air dry samples are submitted in blind triplicate [3] to the participating laboratories using regular mail.
Tier II (REQUIRED FOR STA LABS):
Each Tier II reference sample represents a biologically active, moist compost. Individual samples are packaged in 600 gram HDPE bottles. quantities at wet ice temperature using chemical ice packs. Three [3] as-received moist samples are submitted in blind triplicate [3] to the participating laboratories using overnight express delivery. The STA Chain of Custody Form is used to track sample condition, timeliness of delivery and laboratory sample preparation.
All USCC Seal of Testing Assurance Laboratories (STA) are required to enroll in the Tier II CAP Program. Each lab receives advance notice of sample delivery; notification is made by E-mail and fax one week prior to sample shipment. Confirmation of scheduling with CAP Project Leader is required.
Lab Proficiency Evaluation:
Selected test methods from TMECC will be utilized in the CAP program. Results for each of the three compost sample exchanges will be statistically analyzed using median and MAD (median absolute deviation statistics), and measures of intra-laboratory repeatability and inter-laboratory reproducibility will be calculated. Laboratories providing data exceeding a 90% confidence interval of the median of each analysis parameter will be flagged as an outlier. Within 30 days of completion of an exchange, labs will be receive a report on proficiency.
Project budget is based upon the enrolment of laboratories in the Tier I program, and laboratories enrolled in the Tier II program. The CAP program was first implemented in 2001.
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The Composting Council Research and Education Foundation
