Hi All,
I used to design test fixtures with scrubbers which would remove the test smoke from a small room.
The HEPA we used AirePure (Melb,Vic,Aus) AP4931212DB (Filter HEPA 305mmx305mmx70mm)
The rough rule of thumb is the L/min would need to pass the HEPA Filter 8-10 times to fully scrub the room of fine particles.
The guys there will prob know more about applications, but I guess it depends on
1) Size of the Room. Is it for a fume hood about a soldering bench/ Flux etc.
2) L/min you need to flow through the filter - Note the impendence of the Filter can turn a 200Lmin Fan down to 20L/min.
Hope this helps