Severity Levels

L - Minimal loss of surface paste that poses no FOD hazard. No FOD potential.

M - The loss of surface paste that poses some FOD potential including isolated fragments of loose mortar, exposure of the sides of coarse aggregate (Less than ¼ of the width of coarse aggregate), or evidence of coarse aggregate coming loose from the surface.

H - The high severity is associated with low durability concrete that will continue to pose a high FOD hazard; normally the layer of surface mortar is observable at the perimeter of the scaled area, and is likely to continue to scale due to environmental or other factors. Indication of high severity FOD is that routine sweeping is not sufficient to avoid FOD issues.