passed the acs which was fine. just wondering about something which i just never enquired about. how come you are not allowed a drop of gas of say 4mb on u6 meter on pipework but with appliances connected (no smell_)you are allowed this leak/drop?? seems amazing you can have 4mb leak with cooker connected (no smell)but not on pipe!!!this is puzzling to say the least. there must be alot of engineers who come across 4mb drops on pipework but leave since a cooker can be kleaking the same but still be deemed ok!!!