Powering extractor fans

[Sigurd]

Thank you all for your helpful comments. I am now in a better position to move forward.

 

[johnduffell]

That target extraction rate seems a bit high, 1800l would be over 100 air changes an hour, in normal circumstances (at least for domestic) even purge ventilation is only several air changes. And back ground would be 0.5 or less.
With 300+ people in the room, i could just about understand 1800l though. But I'm guessing not so many.

 

[Marvo]

555 litres per second would give around 10 air changes per hour. Sensibly I'd be aiming around that figure.

 

[Sigurd]

The capacity of the hall is 50 but in practice rarely more than around 30. Part of our problem has been humidity due to people breathing and heating by IR heaters - quick rise in temp, fast fall, cold walls, = condensation. The biggest part of the refurbishment, apart for sorting out roof and pointing problems, is the installation of gas fired central heating. That will provide a background temp of around 8 degrees boosting when hall is in use. That was and is done in the church which had similar condensation problems (Grade I Listed, built in 1120) That has made a big difference in there.

 

[Deleted account]

Hi Sigurd,
Once you've completed your install could you come back and let us know what you did?
Quite often we never hear from people again once advice is given. I would like to know how you resolved it.

Cheers peter

 

[Sigurd]

Will certainly do so. My simple (I thought) question seems to have stimulated quite a discussion so I will make sure I bring it to a conclusion!

 

[Marvo]

Simple questions are rarely simple and discussion is a good thing, hopefully you've got enough info to prevent money being spent on something that's not going to fulfil the brief.

If you find your extract rates are a bit shy you can set a longer overrun time on the system if you use an occupancy sensor.

Good luck.

 

[johnduffell]

The volume of the hall is around 200 c.m.

555 litres per second would give around 10 air changes per hour

good point, slight calculation, I should have said 1800 would give nearly 40 ACH.

Thanks for the correction!