Face mask strap securing tongues - includes removal of roof, and internal walls, consolidation of site, and rebuilding with prefabricated rooms or panels

摘要

The breathing mask which covers the face from forehead to chin has a lower part fitting over the chin, above which is the mouth opening. This opening is approximately triangular in shape, with its point downwards. Two attachment points (4) for securing straps are located about half way down the sides of the triangle. Two more points (4) are at each corner of the triangle, and one more is centrally located above the triangle, in the forehead region. These points are trapeze shaped, with rounded corners terminate in rounded regions, or edges tangential to the rounded corners.