Its fire resistance rating is based on the thickness of the block.
So what?s the difference between a class B block and the typical concrete block available at a local lumberyard or home store? It comes down to the required thickness of the walls and the size of the hollow core. Blocks purchased at home repair and maintenance stores typically have large hollow cores and are not adequate in thickness or density for fire resistance.
So how does an inspector know if the block being used is of the correct classification? The construction design will indicate a required classification. Additionally, block shipments usually contain a certificate with its classification and inspectors should ask to see that certificate.
Block classification should be checked routinely and automatically. There are also various issues to consider before application such as the type of mortar used, how to keep the mortar from freezing, what accessories will be used and the bearing conditions and penetrations. All of these components comprise an assembly.
Indeed, masonry construction is solid and serves the construction industry well.
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