![]() ![]() In 2000, the Type I (moisture-controlled) and Type II (non moisture-controlled) unit designations were removed from C90. The equivalent web thickness was replaced with a normalized web area, a measure of the area of web contact with the face shells per square foot of wall (see Table 2). In ASTM C90-11b, these requirements were replaced with a single minimum web thickness (0.75 in., 19.1 mm), regardless of unit width. Additionally, equivalent web thickness, a measure of the width of web per foot of wall length was used to determine if sufficient web was present to transfer shear loads. 3), there were different minimum web thicknesses based on unit width. In 2011, web thickness requirements were significantly revised. The bulk of these revisions are editorial, although two recent major changes are discussed here. LOADBEARING CONCRETE MASONRY UNITS- ASTM C90Īs the most widely-referenced ASTM standard for concrete masonry units, ASTM C90 is under continuous review and revision. Code officials will commonly accept more current editions of ASTM standards than that referenced in the code, as they represent state-of-the-art requirements. 1), as well as the most current ASTM edition. For this reason, Table 1 includes the editions referenced in the 2006, 2009 and 2012 editions of the International Building Code (IBC) (ref. Also note that it may take several years between publication of a new ASTM standard and its subsequent reference by a building code. ![]() A date in parentheses after the last revision date is the reapproval date.īecause significant changes can be introduced into subsequent editions, the edition referenced by the building code or by a project specification can be an important consideration when determining specific requirements. The number immediately following indicates the year of last revision (i.e., ASTM C55-11 is the version of C55 published in 2011). For example, ASTM C55 is the fixed designation for concrete building brick. The letter and first number of an ASTM designation is the fixed designation for that standard. Currently, seven ASTM standards apply to units intended primarily for construction of concrete masonry walls, beams, columns or specialty applications (see Table 1). These requirements include items such specified component materials, compressive strength, permissible variations in dimensions, and finish and appearance criteria. These ASTM standards contain minimum requirements that assure properties necessary for quality performance. The most widely-used standards for specifying concrete masonry units in the United States are published by ASTM International. ![]()
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