ESICS: Wind Parameter Maps
The ESICS Wind Parameter map is a useful tool to help the user define and asses the geographical conditions of the project site. Depending on which National Annex is detected, different features will be prompted to the user in the Wind Parameter Maps section which will be further explained in the following sections.
Base Wind Velocity Map
This map will be available to the user once automatic wind velocity is activated. With the help of this map, the user can validate the location of the MAFI system while observing the base wind velocity contours in blue. Figure 3 demonstrates the base wind velocity of a project located in Canterbury, Kent, UK (left Image) and Figure NA 1. from the BS EN1991-1-4 (right image). As seen in Figure 3, the pin indicates the location of the project and the blue contour lines are the wind base velocity contours.
Figure 3. Comparison of the ESICS Base Wind Velocity Map with Figure NA 1. from the BS EN1991-1-4
Distance Upwind to Shoreline
The interactive distance upwind to the shoreline map is prompted to the user only in the UK locations. This feature allows the user to determine the shoreline boundaries of their project location within a 100 Km radius in twelve directions as denoted by the UK NA. These distances are further used to determine the roughness factor Cr(z), according to BS EN 1991-1-4:2005, 4.3.2 (1). Figure 4 demonstrates the graph used to find Cr(z) retrieved from BS EN 1991-1-4.
Figure 4. Schematic Dispaly of figure NA.3 from BS EN 1991-1-4.
Note that the distance upwind to the shoreline map shown in ESICS is semi-automatic. meaning that any green dot seen in the maps is the automatic selection of shoreline boundary in that specific direction. However, if the automatic selection is not correct the user can move the dots closer or further from the centre of the circle to correctly define the edge of the shoreline. The red dots indicate that no shoreline has been detected within the 100 km distance. Whereas white dots indicate distances that have been modified by the user. Figure 5. is an example of the distance upwind to the shoreline map of a project located in Canterbury, Kent, UK.
Figure 5. ESCIS Distance Upwind to Shoreline Map for a Project located in Canterbury, Kent, UK.
Inside Town Boundary
In addition to Distance Upwind to Shoreline, the interactive "Inside Town Boundary" map is prompted to the user only in the UK locations and if the terrain category is defined automatically or manually as Town. This feature allows the user to determine the town boundaries of their project location within a 20 km radius in twelve directions as denoted by the UK NA. According to BS EN 1991-1-4:2005, 4.3.2 (1), for sites in town terrain, the roughness factor Cr(z) given in Figure 4 should be multiplied by the roughness correction factor Cr,T for which can be obtained from the graph demonstrated in Figure 6.
Figure 6. Values of Correction Factor Cr,T for Sites in Town Terrain
Note that ESICS automatically detects the edge of the town, however, manual override is possible and, in most cases, modifications are required. In an instance where the town boundaries are incorrectly detected, the user can manually override by moving the dots closer or further from the centre of the circle to correctly define the edge of the town. As mentioned in section 2.2, The red dots indicate that no town boundary has been detected within the 20 km distance, whereas the white dots indicate distances have been modified by the user. Figure 7 is an example of the town boundary map of a project located in Canterbury, Kent, UK.
Figure 7. ESICS Inside Town Boundary Map for a Project located in Canterbury, Kent, UK.