Robert Stephen Morton
Mr Unity. We lowly Plumbers in Oz work on a rating system for vents, that is :-
Size of Fixture units Vent rating
vent pipe discharging to
DN drain
40 >1 <10 .5
50 >10 <30 1
65 >30 <175 2
80 >175 <400 3
100 >400 6
If there are other vents on the line they can be used as credits. ie 12 40mm vents off a stack could be equivelent to a 100mm vent venting more than 400fu, However we have to get the sewage to run uphill.
