The walls, including nonsupporting partitions, wall coverings, and
ceilings, of walk-in refrigerating units, food preparation areas,
equipment washing and utensil washing areas, toilet rooms and vestibules
shall be:
(1) Light colored, smooth, nonabsorbent, and easily cleanable; and
(2) If constructed of concrete or pumice blocks, finished and sealed
to provide a smooth, nonabsorbent, easily cleanable surface.