The Unifom Building Code (UBC) and American Society for Testing and Materials (ASTM) contain criteria for prism testing methods to determine the strength properties of pre-construction, construction and in-place masonry. Successful prism test results verify that a masonry building system meets the design standards, but prism failures do not necessari1y mean that the system does not meet the design criteria. In the event of prism failures, it is important to review the prism construction process and the test procedures to determine obvious errors. It is also significant to understand that other tests can be performed to determine the strength of the masonry in the event of prism test failures.