MVHR supply and extract rates (Scotland)

[newbuild upnorth]

good morning.

 

Im working to Scottish building regs and finding it difficult to determine exactly what the building regs requirements are - actual documented standards, not just what building control may or may not want to see.

approved document F is fairly clear for England, BRE398 is not much help, CIBSE guide B2 and I keep seeing passive house standard but that's not really what everyone works too either.

does Scottish regs pin down exactly what they need anywhere or is it just as vague as it reads.

[JohnMo]

You need to go into the guidance notes (attached) page 23 on

 

Basically 0.5 ACH based on house volume. I would also use passivhaus advise on minimum room flow rates especially for bedrooms. Then go there.

 

If your house is large you will need to trim flow rates to closer to 0.3 once house is signed off, as 0.5ach is a bit over ventilated and humidity levels can dive in winter once house has dried out 

 

Building+standards+domestic+ventilation+guidance%2C+November+2017.pdf

[ProDave]

I commisioned mine to English regs that clearly state requirements for each room.  Scottish BC never showed an interest in or asked for any documentation.  I now run at a lower rate and it all works fine.