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• #Masonry stack bond in seismic category full

The specifier has the option of permitting a segment of the masonry construction to serve as a sample panel or requiring a separate stand-alone panel.” Construct sample panels within the tolerances of Article 3.3F. Certain elements of sample panels, such as the type of mortar joint, can have structural implications with the performance of masonry. Each procedure, including cleaning and application of coatings and sealants, should be demonstrated on the sample panel.

#Masonry stack bond in seismic category full

TMS 602 Commentary states “Sample panels should contain the full range of unit and mortar color. TMS 602 does not address a viewing distance for sample panels. No there is not a standardized means of assessing workmanship or appearance of completed masonry assemblies as noted by NCMA. Commentary Discussions to ASTM C90-09 Standard Specification for Loadbearing Concrete Masonry Units. One reason that these requirements are applied to a finished assembly is because there are not standardized means of assessing workmanship or appearance of completed masonry assemblies.ĪSTM Standard C90-16a, “Standard Specification for Loadbearing Concrete Masonry Units,” ASTM International, West Conshohocken, PA, 2016, National Concrete Masonry Association. When applying these limits to units that have already been installed, one should note that units may become damaged between the time they were delivered and the time they were installed. While this requirement could be applied as such, its true intent is for assessing units prior to their installation – again, because this is a product standard. It is often interpreted that the 20-foot criterion above applies to the units that are installed. – each of which is necessary for the successful application of a C90-compliant concrete masonry unit. It does not cover design, application, workmanship, etc. NCMA FAQ 11-14 includes the following commentary:ĪSTM C90 is a manufacturing standard – addressing the minimum requirements for block. According to ASTM C90, the CMUs are viewed specifically for non-permitted chips, cracks, and other imperfections.ĪSTM C90 Section 7.2 states “Where units are to be used in exposed wall construction, the face or faces that are to be exposed shall not show chips or cracks, not otherwise permitted in 7.1.2 and 7.1.3, or other imperfections when viewed from a distance of not less than 20-ft under diffused lighting.” Viewing CMUs under direct lighting, and not diffused lighting.Viewing the completed wall assembly and not only the CMUs.The most common ways that the ASTM C90 viewing distance has been misused are: However, this viewing distance is often misused. ASTM C90 specifies a viewing distance of not less than 20-ft.