A block unit measuring 7 5/8 inches wide, 7 5/8 inches high, and 15 5/8 inches long is commonly referred to by which nominal size?

A block unit measuring 7 5/8 inches wide, 7 5/8 inches high, and 15 5/8 inches long is commonly referred to by which nominal size?

• A. 8 x 8 x 16
• B. 6 x 6 x 12
• C. 4 x 8 x 16
• D. 10 x 12 x 16

Answer: (A)

The important idea is that masonry blocks are named by nominal sizes, which are larger than their actual dimensions because walls include mortar joints. A standard block labeled with a nominal size uses full inches, while the actual block you measure is slightly smaller. Here, the block measures 7 5/8 inches wide, 7 5/8 inches high, and 15 5/8 inches long. Those actual dimensions match the common standard where an 8 x 8 x 16 inch nominal block has an actual size of about 7 5/8 x 7 5/8 x 15 5/8. So the nominal size you’d usually refer to for this block is 8 x 8 x 16. The other nominal sizes would produce different actual dimensions (for example, a 6 x 6 x 12 nominal would be about 5 5/8 x 5 5/8 x 11 5/8 actual), which doesn’t match the measurements given.

The important idea is that masonry blocks are named by nominal sizes, which are larger than their actual dimensions because walls include mortar joints. A standard block labeled with a nominal size uses full inches, while the actual block you measure is slightly smaller.

Here, the block measures 7 5/8 inches wide, 7 5/8 inches high, and 15 5/8 inches long. Those actual dimensions match the common standard where an 8 x 8 x 16 inch nominal block has an actual size of about 7 5/8 x 7 5/8 x 15 5/8. So the nominal size you’d usually refer to for this block is 8 x 8 x 16. The other nominal sizes would produce different actual dimensions (for example, a 6 x 6 x 12 nominal would be about 5 5/8 x 5 5/8 x 11 5/8 actual), which doesn’t match the measurements given.