Lightning Shielding

GENERAL DESCRIPTION

SHIELD is a powerful full 3D graphical application for the evaluation of the protection of structures from direct lightning strokes using the Rolling Sphere and the Eriksson methods. SHIELD is based on a numerical model that consider vertical direct lightning strokes, and is then suitable for structures up to 60 m high.

The Rolling Sphere Method is considered by many standards (EN, IEEE, NFPA, AS …) and is an universal method for shielding design, and particularly recommended for complex geometry.
Alternative methods like the protection angle or mesh method are suitable for simple-shaped buildings or for buildings where plane surfaces are to be protected.
The Rolling Sphere Method can be applied to the structure to be protected. In such case, SHIELD can identify the parts of the structure exposed to a direct lightning stroke, that are the points where is more effective to install the air termination system.
Then the Rolling Sphere Method can be applied to air termination + down conductor system. In such case SHIELD generates a 3D surface corresponding to the protected volume.
The protected volume is then superposed to the structure to be protected. The parts of the structure to be protected that protrudes over this surface are not protected.
The Rolling Sphere Method has been implemented taking into account a numerical models based on a geometrical scan over a calculation grid, suitable for structures up to 60 m high. The advanced module SHIELD_A is based on an analytical model and evaluates the surfaces generated by the intersection of the rolling spheres in the 3D space and suitable for general purposes.
The numerical model will consider essentially vertical lightning strokes while the analytical model will be able to consider also lateral lightning strokes.
When the Eriksson Method is set, SHIELD generates the collection area of air termination + down conductor system and structure to be protected.
The lightning protection system is effective when collection area of air termination + down conductor system includes collection area of structure to be protected.
The User can modify the lightning protection system and generate again the protected volume or collection areas. This iterative process allows to get an effective shield.

Lightning shielding is an increasing important topics. In many areas the flash density is growing and on the other side the values to be protected (people, buildings, systems …), are also increasing. A good lightning shielding design is the first step for a good lightning protection system installation.