To determine the box gutter depth is the first and foremost step for sizing components and materials for the roof drainage system which includes the rain heads and the box gutters.
Box gutter sump depth.
The depth shown of the box gutter is the depth at the upstream end.
Deviations from the gradient must be smooth and prevent towards the outlet without a proportional permanent ponding.
The theoretical down pipe diameter is shown for reference purposes only.
Box gutter gradients shall not be flatter than 1 200 for sole widths equal to or less than 600mm wide.
The suggested down pipe diameter is shown for reference purposes only.
Here is a step wise guide for you to help.
The depth shown of the box gutter is the depth at the upstream end.
The minimum size of a sump is 400mm x 200mm minimum width of box gutter and 150mm deep.
Sump with high capacity overflow device.
Choose an available dp size or any other size and enter that for the calculation of the sump.
The outlet must be no further than the diameter of the outlet to the centre of the outlet.
This is a good size for the required flow.
The line will correspond to a minimum box gutter depth.
Choose an available size or any other size and enter that for the calculation of the sump.
The minimum depth required for the box gutters that make up this roof drainage system is 125 mm.