Falx Calculation - An innovative mounting system for every type of PV panel

Calculation of materials and ballast according to NEN-EN1991-1-4 (2011).


Terrain category
Sea or coastal area with wind coming from the open sea.
Lakes or flat and horizontal area with negligible vegetation and without any obstacles.
Area with low vegetation like grass and freestanding obstacles (trees, buildings) with an intermediate space of at least 20 obstacle heights.
Area with frequent vegetation or buildings or isolated obstacles at intervals of not more than 20 obstacle heights (such as villages, suburban area, permanent forest).
Area where at least 15% of the surface is covered with buildings with an average height above 15 m.
Wind direction
France only
Altitude above sea-level
United-Kingdom only

Building dimensions & field placement

Roof height
Minimum 1m, maximum 30m.
Maximum allowed static load/weight to add on roof [kg/m2]  

Please enter the buidling's dimensions. The minimum distance from the edges is 1m, but you can add extra distance for each side if you prefer a smaller field or need to work around obstacles.

All values in metres.


PV panel

Dimensions of PV panel (including frame)
The short side must be between 981mm and 1060mm.
The height must be between 27mm and 50mm.
Weight [kg]  
Nominal power [Wp]  
Ventilation slits between panels
Minimum value is 20mm.

Note: ©2017 Flamco B.V. The purpose of the Flamco Falx calculation tool (from here : “calculation tool”) is to provide the user of this tool (from here : “user”) with an accurate estimate of the amount of components and ballast weight needed (from here : “calculations” or “results”) for the correct use of the Flamco Falx PV mounting system. At all times the correct installation needs to comply with national and international safety rules and regulations in combination with the instruction manual supplied with the product. The minimum number of PV panels for a correct use of the Flamco Falx system is six [6*] and needs to be placed in a portrait or landscape orientation on a flat surface, having a maximum pitch of 5 degrees.
The calculations are based on (1) the NEN EN 1991-1-4:2005 with national annex for each country, (2) the Dutch norm NEN 7250:2017 in combination with the Dutch CUR 103 for wind tunnel tests.
The results presented in the calculation tool are entirely dependent on the correctness and completeness of the data supplied by the user and therefore solely indicative in nature. The user is responsible for the input and the correct interpretation of the results delivered
Please note that the calculation tool only provides a guideline. Its calculations are based on a thouroughly tested but theoretical situation. Every situation is unique and may require specific and additional calculations and measures, for which the user is responsible.
At any time the user is responsible for the correct installation of Flamco Falx and ballast distribution. Moreover the user is responsible for the proper use and implementation of all the applicable local rules and regulations.
Although Flamco has produced this calculation tool with the highest care and we believe this application to be reliable, Flamco can’t be held responsible for the completeness and correctness of the results presented by this application. The results presented by Flamco are without any guarantee. The user waives the right to hold Flamco liable for any direct, indirect or consequential damage relating to the use of the calculation tool and the application of the presented results. The user of this calculation tool may not derive any rights from the presented results.
For questions, please contact our Technical Support: +31 332991850.
Bunschoten-Spakenburg, 31-07-2013