Cooker Hood ducting max length

[Russell692]

Does anyone have experience of a practical maximum length of horizontal extraction ducting for a cooker hood?
Mine would need to be 3.7m. Is this likely to work or should I just resign myself to a recirculating filter (would rather go for extraction)?
Thanks.

 

[rexel]

3.7 metres is to long max length 1,5 metre

 

[jj4091]

What ever you do , do not use a recirculator. I would suggest you try a conventional extractor & if it does not work efficiently, put an inline fan half way along your ducting, never tried a duct that length, but I cannot really see it being a problem for a decent extractor.

 

[NoPoke]

4metres should be okay if you use the right fan. a quick search found the folowing unit. http://www.tlc-direct.co.uk/Technical/DataSheets/SolerPalou/CK25.htm

140+m^3/hr flow

No idea if that is sufficient ventilation to meet building regulations.

 

[Russell692]

Thanks very much jj4091 & NoPoke. I'll use the uPVC soil pipe as well to improve the flow which will also be easy to cut into if I need to add an inline fan as well.