Lightning protection of buildings of educational or health-improving institutions is very important, since, first of all, it is the safety of children. Recently, our ZANDZ Technical Center received a request for lightning protection of one of the bedroom buildings of the children's camp. We offer you to get familiarized with the project details and calculation example:
Calculation of lightning protection for the children's camp building
Object: Children's camp building.
Figure 1 - Object plan.
Task: Perform calculations of the lightning protection system of the building of the children's camp.
Protection of buildings and structures against lightning discharges is ensured by lightning rods. A lightning rod is a device rising above the facility that diverts lightning current into the ground without entering the facility. It consists of a lightning rod which directly takes the lightning discharge upon itself, a down conductor and a ground electrode.
Solutions to ensure the requirements for the lightning protection system of the camp building:
1. Lightning protection is carried out in accordance with EIC 7th edition., IS 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures and industrial communications" (hereinafter IS) and AD 34.21.122-87 "Instructions for lightning protection of buildings and structures" (hereinafter AD).
2. The object refers to category 3 of lightning protection. System reliability must be not less than 0,9.
3. Lightning protection of the object is performed using 2 vertical lightning rods 2 m high on the roof ridge (GL-11521SS) and 4 vertical elevations of the down conductor to a height of 1 m from the edge of the roof of the building;
4. Installation of down conductors is carried out with the help of clamp GL-11564A - on a ridge, GL-11747A -on horizontal surfaces, GL-11545A- on a gutter, GL-11514 on a rain-pipe. Distance between the clamps- from 0.8 up to 1.0 meter;
5. A universal clamp GL-11551A is used for connection of the rolled metal along the length and in the nodes;
6. All metal elements, placed on the roof, must be connected to down conductor with the help of clamps GL-11545A, stairs, railings are connected with the use of clamp GL-11514;
7. Installation of a grounding device consisting of 4 vertical electrodes of 3 m in length united by a horizontal electrode (copper-bonded tape of 30x4 mm). The distance from the horizontal electrode to the object should be not less than 1 m, deepening 0.5 - 0.7 meters;
8. In case of presence of the existing grounding device, they should be united into one grounding device in accordance with EIC p.1.7.55.
Results of the calculation carried out with the software developed by the OJSC "Energy Institute to the name of G.M. Krzhizhanovsky (JSC "ENIN"):
Density of lightning strikes into the ground - 4 strikes / sq. km per year;
Full number of strikes into the system – 0.027 (once in 7 years);
The total number of breakthroughs is 0.0023 (every 435 years);
The reliability of the system is 0.915;
Probability of a breakthrough into all the system objects - 0.085.
Grounding device resistance calculation:
The design resistance of the grounding device is 24,94 Ohm.
Figure 2 shows the arrangement of equipment.
Table 1 gives the list of the required equipment and materials.
Условные обозначения – Type Codes
Молниеприемник мачта коньковый, высотой 2 м – Ridge air terminal mast 2 m high
Вертикальное возвышение токоотвода на высоту 1 м – vertical elevation of down conductor to 1 m
Электрод - Electrode
Полоса омеденная стальная диаметром 8 мм – Copper-bonded steel tape 8 mm in diameter
Опуск токоотвода – down conductor down drop
Figure 2 - Location of equipment for lightning protection of the camp building.
Table 1 - List of need in materials.
Do you have any questions about lightning protection for children's camps? Please contact our ZANDZ Technical center!