A properly designed air-termination device will significantly reduce the possibility of lightning strikes requiring lightning protection spaces. Only when the design of the lightning protection device and the structural design of the building are carried out at the same time, the optimal combination of technology and economy can be obtained. Especially when designing buildings, the metal objects of buildings should be fully utilized as parts of lightning protection devices.

IEC1024-1:1990 The air-termination arrangement is suitable when the requirements in the table below are met. Arrange the air-terminations according to the protection level. Protection angle method: the positions of the lightning conductor, lightning rod, lightning protection tower and lightning protection line should be such that each part of the protected building is in the shape formed by the points on the conductor of the lightning protection device with the "angle projected to the ground in all directions". within the track surface. The protective angle method has geometric limitations.

Rolling ball method: For buildings with complex geometric shapes, or when the protective angle method is excluded from Table 1 of IEC1024-1, the rolling ball method shall be used to determine the area of the building and the protective space of each part. The radius of the "rolling ball" should be in accordance with the selected level of protection of the lightning protection system.

The rolling ball method is to use a ball of radius "R" on a building to roll around the building until it hits the ground level, or any permanent structure or object that is in contact with the ground level and can be used as a lightning conductor until. It is possible to be struck by lightning in places where rolling contact with buildings. At such points and locations, lightning protection by lightning conductors is required.

The protected space of a lightning protection system is the volume of space that the "rolling ball" does not pass through when it contacts the conductor and acts on the building. The level of protection and the installation cost of the lightning protection system increases with the size of the ball selected.

Mesh method: Air-termination conductors or roof conductors shall form a closed polygon with the perimeter laid close to the edge of the roof. This polygonal air-termination device shall be completed by the addition of interconnected transverse air-termination conductors to form a grid complying with the requirements of Table 1 of IEC 1024-1.