Bricks & Pavers Technical Manual
Section 1.1 Brick Properties
1.101
Section 1.1 relates to the properties of bricks made to meet the requirements of Australian Standard AS4455 Part
1 Masonry Units. This information is provided as a guide only to the properties of interest to a masonry designer
or builder.
Brick Dimensions
The work size of a standard brick is: 76 mm high x 230 mm long x 110 mm wide.
Some bricks are made with different work sizes. For example brick heights of 119 mm and 162 mm to match 1.5
and 2 standard size brick heights, including mortar joint, respectively. 50 mm and 90 mm high bricks, 90 mm wide
bricks and 290 mm long bricks are made for different structural and aesthetic effect. Larger bricks are often used
for more economical laying and as a design feature either on their own or combined with smaller bricks.
In cyclonic areas larger (140 mm wide x 90 mm high x 290 mm long) hollow bricks are used to allow for
reinforcement and grouting in the wall. Wider (150 mm wide) bricks can also be used in walls requiring lower
sound transmission, higher fire resistance levels and higher load bearing capacity depending on the specific brick
properties.
Clay brick sizes may vary after they are fired but size variation between units averages out when blended properly
during laying. Brick dimensions are measured by dry stacking 20 units, measuring the total length, width and
height and comparing that measurement to 20 times the work size.
Bricks are classified according to how much 20 bricks together deviate from 20 times the work size.
•
For standard bricks, Dimensional Category DW1 means the height and width will differ by less than plus or
minus 50 mm from 20 times the work size, and the length will differ less than plus or minus 90 mm.
•
For standard bricks, Dimensional Category DW2 means the height and width will differ by less than plus or
minus 40 mm from 20 times the work size, and the length will differ less than plus or minus 60 mm.
•
Dimensional Category, DW0 means there are no requirements. This is usually reserved for non-standard
shaped bricks and bricks that have been rumbled or otherwise distorted during the manufacturing process
for aesthetic reasons. ■
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