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Testing Packages of Animal Bedding and Peat Moss with Compressed and Expanded Volume Declarations



Kenneth S. Butcher


Proposal for a Test Procedure: Animal Bedding (Bedding), also called pet or stall bedding, litter, or simply bedding is generally sold by dry volume in compressed or uncompressed packages. Based on numerous failed inspections of packaged animal bedding the Office of Weights and Measures (OWM)conducted a study in which compressed and uncompressed packages of animal bedding were measured using a variety of procedures and test equipment. The results from those tests indicate that the current procedure in NIST Handbook 133, "Checking the Net Content of Packaged Goods," the dimensional inspection procedure for testing compressed packages (e.g., peat moss); and the volumetric inspection procedure (e.g., mulch); are inadequate for use in testing animal bedding. Uncompressed volume measurements of animal bedding are dependent on a number of factors, including the size and shape of the measuring containers, the method of filling, the measuring container, and the means used to break up the bedding prior to measuring. Based on the findings of this study, a draft procedure was developed for testing the uncompressed volume of animal bedding. OWM also designed and constructed new test measures to be used with the procedure, and then brought these measures to several animal bedding packaging plants for on-site verification of the test methods. Preliminary findings indicate that the draft procedure provides more consistent measurement results. Further, the study shows that there is no correlation between compressed and uncompressed volume statements on the package label is unnecessary.
Handbook (NIST HB) - 133
Report Number


HB133, animal bedding, bedding, litter, method of sale, regulation


Butcher, K. (2015), Testing Packages of Animal Bedding and Peat Moss with Compressed and Expanded Volume Declarations, Handbook (NIST HB), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 28, 2024)


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Created February 19, 2015, Updated February 19, 2017