Optimum distances from the wheel to other components: Distance at the inlet side LA ≥ 0,5 x DSa* Distance at the outlet side LD ≥ 1 x DSa Housing wall distances A ≥ 1,8 x DSa A = B In box section with unequal side lengths, a reference surface F (equivalent parameter) consisting of side-width A and side-high B can be calculated as an iteration when there is a minimum clearance of 0,3 x DSa between the impeller and the wall. F = √AxB In the case of disturbance fl ow (for example curved pipe at the inlet, fl aps etc) LA ≥ 1 x DSa Nominal wheel size Real wheel size (ØDSa) 225 256 250 284 280 319 315 360 355 404 400 455 450 505 500 566 560 636 630 716 710 806 800 909 900 1010 1000 1140 48