The most recent version of the DIN standard 1946-4: 2018 requires hospitals to do a positioning analysis in order to determine the size of the clean zone that will be needed for surgery. Previous such analyses resulted in too large clean zones for current LAF ventilation systems, which meant that the staff had to work in a smaller zone than they actually required. This is not allowed anymore. Thus, very large LAF systems (i.e. 4.3×4.3m with more than 15.000 m3/h) are anticipated. This will be very expensive. An option is the smaller, cost-effective and proven Opragon system, which has been scientifically proven to make the whole OR ultra-clean.
Read a background article here (in German): DIN article