L - Average crack width is < 10 mm ( 3/8 in.).

M - One of the following conditions exists: average crack width is ≥ 10 and < 40 mm (≥ 3/8 and <1- ½ in.); or the area around the crack is moderately spalled, or surrounded with secondary cracks.

H - One of the following conditions exists: the average crack width is > 40 mm (1-½   in.) or the area around the crack is broken into easily removed pieces.