Article Ref: F-038

Weights and Measures Connection, Vol. 6, Issue 2 Page 1

February 24, 2015

The Office of Weights and Measures

Proposes Revisions to the

Method of Sale for Animal Bedding and Recommends 

New Test Procedures and Test Measures for Use in 

Verifying the Quantity Declarations on Packages of Peat 

Moss and

Animal Bedding

Byline: Kenneth Butcher

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 procedures in 

NIST Handbook 133, Checking the Net Contents 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 

container, 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, draft procedures were developed for testing 

both the compressed and uncompressed volumes declared on packages 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 volumes 

of animal bedding, leading to the conclusion that the requirement for compressed volume statements 

on the package label is unnecessary. The full text of the proposal is posted on the OWM website under 

“Topic Areas” at www.nist.gov/pml/wmd/pubs/hb133.cfm and includes recommended changes to the 

method of sale for animal bedding in NIST Handbook 130, Uniform Laws and Regulations in the Areas of 

Legal Metrology and Engine Fuel Quality, a revised test procedure for NIST Handbook 133 relating to the 

verification of the compressed volume of Peat Moss (which has been used with animal bedding), new 

test procedures for measuring the compressed and uncompressed volumes of animal bedding, 
Article Ref: F-038

Weights and Measures Connection, Vol. 6, Issue 2 Page 2

suggested test equipment, and a gravimetric auditing procedure that allows inspectors to avoid 

destroying all of the packages. 

The complete proposal at www.nist.gov/pml/wmd/pubs/hb133.cfm provides background information 

to the proposed amendments to the Method of Sale of Commodities Regulation in NIST Handbook 130 

and the recommended test procedures in NIST Handbook 133. 

For more information please contact the Technical Advisors for the NCWM Laws and Regulations 

Committee: Lisa Warfield, at lisa.warfield@nist.gov, (301) 975-3308, or David Sefcik, 

david.sefcik@nist.gov, (301) 975-4868.

Office of Weights and Measures, owm@nist.gov or (301) 975-4004