Foul Runoff can only be defined in Phases.
Industrial Flow – Tick to include industrial flow.
Industrial Flow – The amount of industrial flow per unit area.
Industrial Peak Flow Factor – A factor to apply to the industrial flow to account for the peak flow.
Domestic Flow – Check to include domestic flow.
Domestic Flow – The amount of domestic flow per unit area.
Domestic Peak Flow Factor – A factor to apply to the domestic flow to account for the peak flow.
Calculation Method – The method used to calculate flow. Available options are Discharge Unit and Main Drainage.
Discharge Unit
- Total Discharge Units – The total of all discharge units. Editable manually or via the Total Discharge Units Calculator.
- Frequency Factor – Factor applied in calculating flow.
Main Drainage
- Flow per Dwelling – The total flow for a single dwelling. Editable manually or via the Flow per Dwelling Calculator.
- Number of Dwellings – The total number of dwellings.
Resulting Flow Rate – The total flow calculated.
Analysis
The resulting flow from the foul runoff is made up of three parts: Industrial flow runoff from the catchment area, Domestic flow runoff from the catchment area and Foul flow from dwellings.
Resulting Flow = Industrial flow rate + Domestic flow rate + flow rate from either Discharge Unit or Main Drainage.
The flow from the industrial portion of the development is calculated by:
Industrial flow rate = Catchment Area x Industrial Peak Flow Factor x Industrial Flow
The flow from the domestic portion of the development is calculated by:
Domestic flow rate = Catchment Area x Domestic Peak Flow Factor x Domestic Flow
Foul flow from dwellings can be calculated using either the Discharge Unit method or the Main Drainage method.
Discharge Unit foul flow calculation:
Foul flow rate = SQRT( Total Discharge Units) * Frequency Factor
Main Drainage foul flow calculation:
Foul flow rate = (Flow Per Dwelling * Number of Dwellings) / 86400