Hi,

I've been checking Part L1A for a a friend based in England (I'm based in Scotland). I'm very familar with Scottish Regs, but haven't constructed in England for 12 years.

The L1A doc (conservation of fuel and power) is 2013 with 2016 revisions, as per the .gov.uk website. Am I really looking at the up to date document? No revisions in 5 years?? Scottish regs are updated every 2 years, more often for things like Fire, after serious incidents.

I'm specifically looking at the Air Tightness, which seems very sparse, only saying it's got to be 10m3/m2/hr or less to pass. No mention of low levels needing additional air inputs, eg. MVHR/passive vents required below 3m3/m2/hr.

Not asking for people to do my research, just wary that I'm missing something very obvious.

Thanks Will,

I think Part F may have been what I was looking for. Can't say it's a particularly clearly worded part of the regs.

I think I get the following from my attempt at reading;

1. Part L suggests air leakage of 10m3/m2/hr or better, but SAP will pick up the consequences of the actual

2. Part F assumes you'll achieve between 5 and 3. Less than 3 and consult the BCO. More than 5 and you can have a bit less fixed ventilation.