A property of paper or paperboard used in packaging that measures its resistance to rupturing, defined as the hydrostatic pressure needed to burst a paperboard sample when it is applied uniformly across its side. Bursting strength is a function of various processes performed in the papermaking process. The increased use of fillers decreases bursting strength, while the increased use of longer fibers and surface sizing increases a paper's bursting strength.
Bursting strength is measured utilizing a rubber diaphragm that is expanded hydraulically against the paper sample. A bursting test is also known as a Mullen test or pop test, and a minimum bursting strength is required for cartons used for shipping. Bursting strength has little application to printing papers.