Plasma Table Fume Extraction

We were given the rough figure of 30 CFM/ft^2 for downdraft fume extraction. So that's 1500 CFM required for our 4x10 table. It seems to me that number could be off by 50%. The blower we have seems to output less than 1500, maybe 1000. Still, I don't think 1500 will be enough. We have a much bigger blower we can try out when we get a chance. It will have to be figured out before winter, when opening the doors isn't an option.