for CMU

Angelus Block manufactures its products to meet or exceed applicable standards of the American Society for Testing and Materials (ASTM). Their standards define characteristics of strength, tolerances, and quality.

All hollow and solid cmu comply with:

ASTM C90 Standard Specification for Loadbearing Concrete Masonry Units

NOTE: beginning in 2000, ASTM C90 no longer contained Grade or Type designations. Therefore, specifications calling for Grade N, Type I (or Grade N-I), "moisture-controlled" units are no longer valid. This change was made in recognition that producers simply did not manufacture the other grade, Grade S, which was restricted in its use. And in recognition that "moisture-controlled" was not a function of manufacturing, but of testing.

Further, relying on such specifications as a basis for control joint design was inexact at best. The California Department of the State Architect (DSA) issued a document, DSA IR 21-4, to address this.

The current IBC and CBC refer to and incorporate ASTM C90 without modification, so proper specification of cmu for new projects should not include Grades or Types. Guide specifications are available.

CMU Basics - Standards