I did quite a lot of reading about air filters a few months ago.
The AC400 has two layers of filters and the inner one is quoted as 85% effectiveness at trapping particles of 1 micron and below. Its big brother the AC2 has three layers of filters and claims 91% effectiveness on particles of 1 micron and below.
In the end I went for the MC760.
I use MDF quite a lot, so as it only comes as standard with a G4 single filter quoted as 65% effective for particles of 1 micron and below I've added an F9 filter from Jasun (Part number UPC911212) behind that to give 95% effectiveness at particles of 0.6 microns and below.
The MC760 has the capacity to filter 760 cubic metres of air per hour and Acrol, the manufacturers of Microclene air filters state that the MC760 is suitable for rooms up to 76 cubic metres. This is erring on the side of caution compared to COSHE advice to change the air in a dusty workshop 6 times an hour.
It looks like your workshop is about 44 cubic meters so you need 440 cubic meters per hour air flow to change the air 10 times.
When I spoke to Ron at Acrol he estimated that air flow would be around 400 cubic metres per hour with both G4 and F9 filters fitted, or 460 cubic metres per hour with only the F9 filter fitted.
He didn't really see the point of using the G4 as well, but I retained it to improve the life of the F9 and because my workshop is only 2.5m x 3m x 2m. I think if I had a bigger workshop I'd probably leave off the G4 to ensure the air flow isn't too marginal.
There's some more information in this post on my blog and a couple it links to -
http://aggravatedwoodbutchery.wordpress.com/2012/05/28/upgrading-the-microclene-mc760/
Hope this helps
John
