The coordinating dimensions are a measure of the physical space taken up by a brick together with the mortar required on one bed , one header face and one stretcher face.
A standard metric brick has coordinating dimensions of 225 x 112.5 x 75 mm (9”×4½” ×3“) called nominal size of a brick.
The working dimensions are the sizes to which manufacturers will try to make the bricks.
Working dimensions (actual dimensions) of 215 x 102.5 x 65 mm (8.5“ * 4 *2.5) called architectural size.
Below is the Diagram of the working dimensions of a brick.
Difference between working and coordinating dimensions:
The difference between the working and coordinating dimensions of a brick is 10mm (0.5“)and this difference is taken up with the layer of mortar into which the bricks are pressed when laying.
The difference between working and coordinating size can be elaborated by the diagram below.