I am going to sacrifice 120x120 mm of my overhead and back wall panels to some PC fans to extract smoke.
I have found the most silent, not a bad price at 14 UKP each, but i worry its not strong enough.
Its about 700 RPM..
NF-S12B ULN Ultra Low Noise 120mm Cooling Fan, 500/700 RPM
well if anyone has somthing to say about it i am all ears, if not, i will go with this one.
Cheerz
john