There are no special requirements to lightning protection of a public path in accordance with the regulatory documents. It is important to ensure the required reliability of lightning protection. Recently, ZANDZ technical Center received a request to protect a public bath by lightning rods. Let’s consider our solution we offered in more detail.
Calculation of lightning protection of a public bath in the Crimea
Object: public bath.
Figure 1 – Object plan.
Task: Perform calculations of lightning protection for a public bath.
Protection of buildings and structures from lightning strikes is carried out by using lightning rods. A lightning rod is a device towering above the protected object through which a lightning current, bypassing the protected object, is diverted to the ground. It consists of a lightning rod, directly taking on the lightning discharge, down conductor and ground electrode.
Solutions on provision of requirements to lightning protection system of a public bath:
- Lightning protection is carried out in accordance with EIC 7th ed., IS 153-34.21.122-2003 «Instruction on lightning protection of buildings, structures and industrial communications» (hereinafter IS) and AD 34.21.122-87 «Instruction on lightning protection of buildings and structures» (hereinafter AD).
- It is necessary to perform a grounding device (GD) with the resistance not more than 10 Ohm.
- Soil resistivity taken for calculations - 100 Ohm*m.
- The object refers to the III according to AD. The system reliability must be at least 0,9.
- Lightning protection of the object is carried out using 4 lightning air-terminals masts 4 m high on 3 concrete bases (GL-21121) placed on the roof.
- Steel copper-bonded (the thickness of the copper bonding is not less than 70 mcm) wire d8 mm is used (GL-11149).
- Installation of down conductors is carried out using a clamp GL-11711 – on a flat roof, GL-11703A – on vertical surfaces. Installation pitch of the clamps is 0,8-1,0 m.
- A universal clamp GL-11551A is used for the connection of the rolled metal along its length and in the nodes.
- 2 vertical copper-bonded steel electrodes 3 m long are used as a grounding device. A copper-bonded steel tape with a cross section of 30x4 mm, uniting vertical electrodes, is used as a horizontal ground electrode. The distance to the foundation of the facility is not less than 1 m. The depth of the tape burial is 0.5 - 0.7 m.
- According to EIC-7 ed., p.1.7.55 - Grounding devices of protective grounding of electrical installations of buildings and structures and lightning protection of the 2nd and 3rd categories of these buildings and structures, as a rule, should be common.
- If there are reinforced concrete structures, they must be connected to down conductors / grounding device.
- Connection to the grounding device is carried out with the help of ZZ-005-064 clamps.
Calculation of the grounding device resistance:
The rated resistance of the grounding device is 8.22 ohms.
Figure 2 shows the location of the equipment.
Table 1 lists the required equipment and materials.
- План кровли – roof plan
- Зона защиты на уровне –protection zone at the level of +12,400
- Условные обозначения – Type Codes
- Молниеприемник- мачта высотой 4 м на 3 бетонных основаниях – Air-terminal mast 4 m high on 3 concrete bases
- Проволока стальная омедненная диаметром 8 мм – Steel copper-bonded tape 8 mm in diameter
- Универсальный зажим-соединитель для проволоки – universal connecting clamp for wire
- Полоса стальная омедненная сечением 30*4 мм – copper-bonded steel tape with the cross-section of 30* 4mm
- Зажим для подключения проводника – clamp for connecting conductor
- Опуск токоотвода – down conductor downdrop
- Вертикальный заземлитель длиной 3 м – vertical ground electrode 3 m long
Table 1 – List of material needs.
Do you have questions on lightning protection of a public bath or other objects?
Contact ZANDZ Technical Center!