Buildings and structures are exposed to lightning during a thunderstorm and it does not depend on their height, construction materials and assignment. For the security of the facilities and their safety, it is necessary to carry out a complex of measures on lightning protection. The complex of such measures, in turn, will allow to protect farm buildings from fire, mechanical damage, and protect living of humans and animals. Let's consider a real example of calculation of lightning protection for an agricultural buildings for breeding chickens!
Agricultural building for chickens, Leningrad region, Priozersk district.
- Width (along the roof): 7 m.
- Length (overall along the roof): 23 m.
- Height of the walls: 4.05 m.
- Ridge height: 5.75 m.
Agricultural building for chickens
Agricultural building for chicken, side view
As usual, we use the following regulations for the calculations:
- EIC 7th ed (Hereinafter - EIC);
- IS 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures and industrial communications" (hereinafter - IS)
- AD 34.21.122-87 "Instructions for lightning protection of buildings and structures" (hereinafter AD)
Agricultural buildings refer to ordinary constructions in terms of lightning protection in accordance with the IS and to category 3 according to the AD.
Protection of buildings against lightning strikes is carried out by lightning rods. A lightning rod presents itself a device rising above the protected facility to divert the lightning current into the ground without entering the protected facility. It consists of a lightning rod directly perceiving the lightning discharge, down conductor and ground electrode system.
Complex of measures:
- Installation of two lightning rods 4 meters high at the edges of the roof (see. Fig. 1).
- The arrangement of down conductors with the use of copper-bonded wire D = 8 mm, so all lightning rods are interconnected to provide two current drainers.
- Assembly of a grounding device, consisting of two vertical electrodes 3m long, united by a horizontal electrode (copper-bonded wire with the diameter of 10 mm). The distance from the electrode to the walls of the building is not less than 1 m, penetration of 0.5 - 0.7 meters. Connection of the grounding device to the input shield is carried out with the help of wire ZZ-500-105.
Figure 1 - Arrangement of lightning protection and grounding equipment. Protection zone.
The list of necessary equipment:
If you have any further questions on the selection and calculation of grounding, contact us and we will help!