Abstract: The present invention relates to a high-strength panel used as flooring in a clean facility, such as a semiconductor clean room. The high-strength panel comprises rim ribs, each having a tapered surface, formed at a respective rim portions of the panel. A main reinforcing rib divides an interior space defined by the rim potions into a plurality of square lattice sections. A plurality of auxiliary reinforcing ribs is arranged in each of the square lattice sections to divide the lattice sections into sub-sections, wherein a plurality of circular recesses is diagonally arranged in each sub-section, Each circular recess is surrounded by a circular rib. Accordingly, a supporting force for resisting a vertical load and an eccentric load is enhanced. Thus, the strength of the panel for resisting a concentrated load is increased by distributing the load downwardly concentrated at a specific location of the panel throughout the entire panel.

Abstract: A floorboard for clean rooms is disclosed. The floorboard has a support unit (110) and a tile unit (120). In the support unit (110), a plate part (111) has a plurality of engaging holes (114) on its upper surface. A support part (112) is vertically and integrally formed along the edge of the lower surface of said plate part. A plurality of reinforcing ribs (113) linearly, regularly and integrally extend on the lower surface of the plate part in a way such that the ribs are integrated with both the plate part and the support part. In the tile unit (120), a cover part (121) engages with the upper surface of the plate part. A plurality of engaging projections are (122) formed on the lower surface of the cover part at positions corresponding to the engaging holes (114) of the support unit, thus engaging with the engaging holes of the support unit. Each of the engaging projections has a ventilation hole (123) at its central portion.FIG. 4 shows the most relevant embodiment.