Air raid shelter ventilation - has angled air intake tube terminating well above terrain fitted with hood-protected radial inlets

摘要

The air raid shelter is located underneath the actual building and consists of rest room (16) and air lock (18). In the rest room (16) a motor- or manually driven fan assembly is installed, which aspirates ambient air either directly via pipe (19) or indirectly through sand filter (22) via pipe (21). The sand filter is provided in pit (23) next to the rest room (16). The ambient air enters the pit through suction pipe (26) running horizontally buried in the terrain, it is anchored in concrete block (29), in which the pipe is turned into a vertical section (31), terminating above the terrain at a level well above the expected highest blanket of snow. The end of the pipe (33) is fitted with a suction hood (33) covering a set of radial inlet openings protected by a wire mesh. On top of hood (33) a flexible aerial (49) is fitted and the space between hood (33) and pipe (31) accommodates a radiation sensing element. Cables from both accessories are installed inside pipe run (26,31).