Friction head loss calculation

The filter losses to be treated separately. There will be flow-loss characteristics for filters.

For pipe lines there are loss calculations (a few days back there was a thread on this in CR4 forum) - there are calculators on this. Wou have to consider bends, branches etc also.

The technical group for the filter manufacturers should be able to supply you with the filter loss information as well as guidelines for use.

The head loss characteristic of a sand filter is specific to the filter. As I am sure you realize a filter will behave differently for differing realize sand source & gradation, flow rate, head over the filter, configuration, etc.. The manufacturer should be able to provide some standard curves for filter behavior at different flow rate for a variety of recommended standard sand sources. Keep in mind that no. 5 sand is not the same from every source, sand is never homogeneous in size and shape, which effects differences in effective porosity, packing and pore size characteristics.