Example of lightning protection calculation of a public bath in the Crimea

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:

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.

Roof plan of a public bath

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.

№	Picture	Code	Name	Q-ty
1.		GL-21121	GALMAR Air-terminal mast (4,0 m; on 3 concrete bases; one-stage wire support; galvanized steel)	4
2.		GL-11149-50	GALMAR Copper-bonded tape (D 8 mm / S 50 mm²; coil of 50 meters)	2
3.		GL-11149-20	GALMAR Copper-bonded tape (D 8 mm / S 50 mm²; coil of 20 meters)	1
4.		GL-11149-10	GALMAR Copper-bonded tape (D 8 mm / S 50 mm²; coil of 10 meters)	1
5.		GL-11551A	GALMAR Clamp for connecting down conductors (painted galvanized steel)	7
6.		GL-11711	GALMAR Clamp on a flat roof for down conductor (plastic, concrete)	90
7.		GL-11703A	GALMAR Clamp to the façade for down conductor with its elevation over the clamp to 15 mm (painted galvanized steel)	40
8.		GL-11562A	GALMAR Control clamp for connecting down conductors wire + tape (painted galvanized steel)	2
9.		GL-11075-20	GALMAR Copper-bonded tape (30*4 mm / S 120 mm²; coil of 20 meters)	1
10.		GL-11075-10	GALMAR Copper-bonded tape (30*4 mm / S 120 mm²; coil of 10 meters)	1
11.		ZZ-001-065	ZANDZ Copper-bonded threaded grounding rod (D14; 1,5 m)	4
12.		ZZ-002-061	ZANDZ Threaded connecting coupler	3
13.		ZZ-003-061	ZANDZ Starting tip	2
14.		ZZ-004-060	ZANDZ Driving head for a breaker hammer	1
15.		ZZ-005-064	ZANDZ Clamp for connecting conductor (up to 40 mm)	3
16.		ZZ-006-000	ZANDZ Conductive grease	1
17.		ZZ-007-030	ZANDZ Hydro-insulation tape	1
18.		ZZ-008-000	ZANDZ Head for a breaker hammer (SDS max)	1

Do you have questions on lightning protection of a public bath or other objects?

Contact ZANDZ Technical Center!