Difference between hollow brick and perforated brick

Overall, the perforatged brick is dense,

1 .both of this two kinds of brick s' porosity requirements are equal to or greater than 15%;
 

2 . perforated brick has small hole size and large hole numbers, while  hollow brick has big holes but with small quantities;
 

3 .perforated bricks are commonly used in load-bearing parts, while hollow bricks are commonly used in non-load-bearing parts.
 

Block: Main specifications of length, width or height of one or more than one respectively, greater than 365 mm, 240 mm or 115 mm seperately. But the height is not more than six times the length or width, length does not exceed three times the height.