For commercial projects the minimum allowable width is 300mm.
Box gutter sump.
Choose an available size or any other size and enter that for the calculation of the sump.
Down pipe must be.
For the associated box gutter outlet.
The outlet must be no further than the diameter of the outlet to the centre of the outlet.
The theoretical down pipe diameter is shown for reference purposes only.
It is easier to mark and cut the spigothole prior to fitting the sumpinto the box gutter.
The spigotcan also be fitted from inside the sump this allows the downpipe to be fitted up to the sump.
Must have a constant slope between 1 40 and 1 200.
Sides must be vertical.
Code box gutter requirements the minimum width allowed for domestic projects is 200mm.
Sump with a side overflow device sumps do require an increase in the depth of flow in the box gutter and gutters are to be fitted with either.
This is a good size for the required flow.
Overflow devices need to discharge to the atmosphere in such a way as to prevent damage to buildings and property.
Box gutters must be straight no bends.