Details on “Siphonic Drainage” in the “Settings” (Wastewater/Roof Drainage)
Information about the Siphonic Drainage tab in the Settings dialog of the Pipe Network Calculation Waste Water and Roof Drainage.
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Methods and Limit values
Method
Drop-down list for selecting the method for calculating the siphonic drainage. Depending on the selected method, certain limit values are specified by the standard. These values are deactivated and cannot be changed. Selecting the general method, all options are available.
Kinematic Viscosity
Determines the kinematic viscosity of the water, which directly influences the flow resistance.
Density of the Water
Specifies the density of water.
Operation Roughness
Specifies the roughness of the pipe's inside surface. High roughness levels lead to higher pressure loss, among other things, and may require more powerful pumps or larger pipe diameters to achieve the same performance.
Minimum Velocity
Sets the limit value for the minimum velocity in all sections except downpipes.
Minimum Velocity (down pipe)
Sets the limit value for the minimum velocity in downpipes.
Maximum Velocity Tension Release Pipe
Sets the limit value for the maximum velocity in release pipes.
Checking the Start-up Conditions Starting from Down Pipe Length
The length from which on a vertical pipe is supposed to be defined as a down pipe. Depending on the selected method, the system checks whether all down pipes meet the start-up condition.
Safety Supplement to Design Flow Rate
Sets the percentage safety supplement for the design volume flow rate. The supplement helps you ensure that the siphonic drainage system continues to function reliably even under unforeseen loads, which increases the operational safety of the system.
Permissible Residual Pressure Deviation
Depending on the selected calculation method, you can specify the percentage or absolute deviation from the permissible residual pressure here. If the specified value is exceeded, a corresponding error message is displayed in the reports of the calculation.
Other Settings
| Option | Explanation |
|---|---|
| Zeta Values | Enabled: If stored by the selected manufacturer, real, measured zeta values are used for the calculation. If no values are defined, zeta values from the standard are used. Disabled: Zeta values from the standard are used in the calculation. |
| If possible, dimension for positive residual pressure. | Enabled: Setting this option active will dimension the drains in such a way that the particular volume flow rate of each drain is at least equal to the previously dimensioned volume flow rate. This is done in order to dimension those drains that are predominantly located in local troughs (sinks). |
| Apply alternative drain outlet capacity | Enabled: If stored by the selected manufacturer, the values for alternative drainage capacities are used in the calculation of the siphonic drainage. |
| Display nominal diameter changes graphically | Enabled: Changes of nominal diameter in the drawing are shown graphically. Color/Symbol factor If the graphical display of changes of nominal diameter is activated, you can define the color and the symbol factor here. |
Transfer to open drainage
Maximum from Q(targ) and Q(act)
The target volume flow rate is compared to the actual volume flow rate. The higher value of both will be transferred to the open drainage system that is connected behind.
Only Q(targ)
Only the target volume flow rate is transferred to the connected open-channel drainage pipe network.