Check these sites out:
http://www.fansandspares.co.uk/shop/cat ... trial-fans
They are not so clever over the phone mind but online are all the specs & data for everything they sell.
http://www.airtradecentre.com/AA/EN/doc ... ion/I-Fans
These guys were more helpful over the phone & the website has a better range of fans.
I've found that the cheaper the fan for the volume shifted the noisier they are.
The inline bathroom extraction fans are pretty quiet & shift a lot of air and should be well sealed against moisture but their intake area is small.
If you have a commercial kitchen canopy maker nearby then they might have an old fan knocking around or lookout for takeaways/restaurants being gutted/renovated as one might lying about..but it'll be manky. Speed controllers are available for all these fans too.
I can get this stuff from time to time & have lots of smaller cooling fans but I bought the Jet AFS 500 recently & am very happy with it. It is very quiet & I've not sneezed or coughed since I got it.
