Calculation bases (Waste water options wizard)

On the Calculation bases tab in the Rainwater options area, properties are defined for determining the rainfall donations and the runoff coefficients for determining the rainwater runoff.

Selection of rainfall events

  • In the Selection of rain events area, use the Rain event drop-down menu to select the duration of the rain event and the annuality for property drainage, roof drainage and emergency drainage.
    Note:
    The default setting for roof drainage areas and property areas is always 5 minutes.
  • The corresponding rainfall yield is displayed in the Rainfall yield (l/(s*ha)) column.
    Note:
    The rainfall amounts displayed are derived from the data from the German Weather Service. It is therefore mandatory to enter the postcode in the project editor.
  • If an exceptional level of protection is required for a building (see DIN EN 12056-3, Table 2), the entire centennial event should be drained via the emergency drainage system in accordance with DIN 1986-100. In this case, the Emergency drainage exceptional level of protection checkbox must be activated.

Reservoir height

  • In the Maximum permissible accumulation height on the roof input field, you define the accumulation height in mm that must also be taken into account for the maximum permissible surface load for the roof structure. You can adjust this accumulation height by entering it in the input field.
  • In the Maximum permissible stowage height on open areas input field, define the stowage height in mm that must also be taken into account for the maximum permissible surface load for the open areas. You can adjust this water level by entering it in the input field.

Standard roof area runoff coefficient

Standard open space runoff coefficient