Part F outdoor ventilation rates?

[SusBE Mike]

 
Does anyone know why the outdoor ventilation rate went up to 10l/s from 8l/s ?

Trying to get my head around it and it'd be nice to know if there was a specific intervention or reason for this change.

Cheers

[David OLIVIER]

I can't see a reason

Some people have designed for 8 l/s.cap for years or even lower if the occupation at that density is intermittent.

If you design a system with poor ventilation efficiency you need more than 8, it's regrettable if this has been factored into Part F.

[SusBE Mike]

Thank you David.

I assume that CIBSE Guide A has fallen in line with part L then? As CIBSE B seems to suggest 8 l/s is suitable!

Still can't understand the motivation behind it mind 

[Mark Siddall]

EN 15251 suggests a range of ventilation standard depending upon desired IAQ. The range covers 4 l/s/person to 10l/s/person for domestic and non-domestic. The change may also be supported by the BRE studies into indoor VOC emissions. Could this have influenced matters? who knows?