If the grout joint width is 1 4 or greater then the allowable warpage is 1 16 plus the allowable inherent warpage of the tile.
Ceramic tile lippage tolerance.
So that means that 2 mm lippage would be acceptable to ceramic tile.
If there is no warpage the lippage should not exceed the value in the table.
Accordingly the tolerance for variation from tile to tile includes the actual warpage of the tile.
The photo at left looks like it shows excessive lippage due to the type of lighting and angle of viewing.
Nearly each tile has at least one adjacent tile that is uneven i e there is lippage throughout the house and i would be hard pressed to find a tile with an no lippage.
However the measurement at right shows that the ceramic tile lippage is less than 1 6 mm 1 16 in which is within standards.
In the days before isostatic presses warpage was more common.
02 standards say that acceptable lippage for floor tiles with a grout joint width of 1 16 to less than 1 4 is 1 32 plus the allowable inherent warpage of the tile.
This is described in as 3958 1 1991 ceramic tiles part 1.
5 4 6 tile finish and joints a when measured with a straightedge the finished surface of the tiling should be flat and true to within a tolerance of 4mm in 2m from the required plane.
For ceramic tiles which includes porcelain tiles they are allowed to have 1 mm of lippage plus the actual warpage in the tile which is normally about 1 mm for grout joint widths between 2 to 7 mm.
Guide to the installation of ceramic tiles on page 53.