Sports facilities, in which many people gather, must be protected from lightning and grounded. The ZANDZ Technical Center often receives requests for the development of such facilities. This time it was required to make a calculation of lightning protection and grounding of a football arena.
The arena is used as a training ground and base for one of the leading teams of the Russian Football Premier League. It has smaller dimensions than the stadiums where official matches are held, but nevertheless, designers and builders are simply obliged to provide reliable lightning protection of the arena.
Neither weather factors nor equipment malfunctions should interfere training process of the team. A well-organized lightning protection system will help protect against the former, and grounding must guarantee the normal operation of the electronics in any conditions.
Find out about the lightning protection and grounding solution of the football arena from the ZANDZ Technical Center from our latest news, which is written before the upcoming World Cup!
To calculate lightning protection and grounding of a football arena.
Calculations of lightning protection and grounding are made in accordance with the following documents:
- "Electric Installation Code" EIC 7th ed. (hereinafter - EIC).
- "Instructions for organization of lightning protection of buildings, structures and industrial communications" IS 153-34.21.122-2003 (hereinafter IS).
- "Instructions for lightning protection of buildings and structures" AD 34.21.122-87 (hereinafter - AD).
Lightning protection of buildings from lightning strikes is carried out with the help of 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 directly perceiving the lightning discharge, down conductor and ground electrode system.
A football arena refers to traditional objects from the point of view of lightning protection in accordance with IS and to the third category of lightning protection in accordance with AD.
Description of the external lightning protection system and grounding of the football arena
The set of measures to provide the required lightning protection is offered by the following solutions:
- Installation of two composite masts on back legs 12 m high and four 8 m high.
- Protection zones corresponding to the reliability of 0.9 IS are shown in Figure 1.
- The metal frame of the building is used as a down conductor in accordance with clauses 1.6 and 2.12 of the AD.
- Down conductors are laid from copper-bonded wires with the diameter of 8 mm, which are mounted on the roof to vertical surfaces using GL-11747A clamps and connected to a metal frame using ZZ-005-064 clamps.
- In accordance with clauses 1.8 and 2.13 of the AD, a natural grounding conductor- the foundation of the building, is used as a grounding conductor.
According to AD, it is recommended to use the conductive structures of the building as down conductors: a metal frame, reinforcement mesh of reinforced concrete structures, glass unit fittings, etc. ensuring electrical contact over the entire height of the building.
It is also recommended to use a natural ground electrode system - a reinforced concrete foundation as a grounding device. To connect down conductors, it is necessary to perform valve outlets or to provide continuous communication with structures that play the role of down conductors. When using polymer compositions for waterproofing the foundation, the foundation cannot be used as a ground electrode system.
Figure 1. Plan with the layout of lightning protection elements and grounding device
Calculation of the grounding device resistance of a football arena
The estimated value of the soil is taken to be 400 Ohm ∙ m.
Warning. In case of difference between the ground resistivity from the calculated grounding, it is necessary to carry out calculation with the real value. If necessary, if the resistance of the charger is exceeded, changes should be made to the design of the ground electrode.
In accordance with the reference of Karyakina R.N. "Grounding devices of electrical installations" chapter 3.10, the resistance to spreading of reinforced concrete foundations of the foundations of an industrial building is determined by the formula:
where p - soil resistivity, Ohm*m;
S - area bounded by the building perimeter, m2.
Do you have any questions on calculation of lightning protection for a data processing center? Please contact our ZANDZ Technical center!