The ZANDZ Technical Centre has received a request to calculate the lightning protection system for the logistics centre. Let's consider the solution offered by our specialists.
Facility: logistics center
30 m illumination supports are installed along the perimeter.
Soil resistivity: 100 Ohm*m.
The activities have been performed according to:
- EIC, Rev. 7;
- SO 153-34.21.122-2003 Instructions for Mounting Lightning Protection for Buildings, Structures, and Industrial Utilities (hereinafter referred to as SO);
- RD 34.21.122-87 Instructions for Mounting Lightning Protection for Buildings and Structures (hereinafter referred to as RD).
The protected facility is classified as a conventional facility in terms of lightning protection according to SO and to Category 3, Protection Zone B according to RD.
A set of arrangements ensuring compliance with the lightning protection requirements for the logistics center is based on the following solutions:
- installation of 1 x 14 m standalone lightning protection;
- existing 30 m illumination supports are used as lightning arresters;
- protection radius and heights based on which protection zones B according to RD are generated, are shown in Fig. 1.
For a standalone lightning arrester, the grounding arrangement is installed as:
- a horizontal grounding electrode for the current flowing in two directions at 90 degrees between them. The grounding arrangement is made of a corrosion-resistant steel zinc-plated bar 5 x 40 mm, installation depth 0.5 m;
- in each direction, at the distance of about 5 m from the lightning arrester, one vertical electrode 3 m long is installed, and as a third vertical electrode, an embedded part of the lightning arrester foundation is used;
- interconnection of horizontal electrodes, with vertical electrodes and with lightning arresters is performed using clamps ZZ-202-012.
Ground terminal resistance calculation:
Vertical grounding arrangement resistance:
Верт - Vert
Экв - Eq
Ом - Ohm
ρ is equivalent soil resistivity, 100 Ohm*m;
L is vertical electrode length, 3 m;
d is vertical electrode diameter, 0.014 m;
T is depth;
t is distance from the ground surface to the grounding electrode, 0.5 m;
м - m
Horizontal electrode resistance:
Гор - Hor
ρ is soil resistivity, 100 Ohm*m;
b is horizontal electrode width, 0.04 m;
h is horizontal electrode depth, 0.7 m;
Lгор is horizontal electrode length, 10 m.
Electrical impedance of the grounding arrangement:
ЗУ - GA
n is number of vertical electrodes, 2 pcs; horizontal electrode, 1 pc;
kисп is a set utilization ratio, 0.81;
estimated resistance of the grounding arrangement is 9,75 Ohm.
Мачта освещения H30 м - Illumination mast H = 30 m
Условные обозначения - Legend
- отдельно стоящий молниеприемник - standalone lightning arrester
- проектируемый горизонтальный заземлитель - horizontal grounding electrode to be designed
- зажим для подключения проводника - clamp for wire connection
- проектируемый вертикальный заземлитель длиной 3 м - 3 m vertical grounding electrode to be designed
Figure 1. Layout of grounding arrangement parts.
Table 1. List of materials.
|№||Part number||Name||Quantity, pcs.|
|Lightning protection system|
|1.||ZZ-201-014||ZANDZ 14 m vertical lightning arrester (galvanized steel; with parts embedded under the foundation)||1|
|2.||ZZ-502-405-6||ZANDZ Steel zinc-plated bar (40 * 5 mm; 6 m bundle)||2|
|3.||ZZ-202-012||ZANDZ Clamp for circular wire and bar (D14-20 mm; up to 40 x 6; zinc-plated steel)||4|
|4.||ZZ-001-065||ZANDZ Copper-plated threaded grounding rod (D14; 1,5 m)||4|
|5.||ZZ-002-061||ZANDZ Threaded coupling||3|
|7.||ZZ-004-060||ZANDZ Guide head for jackhammer attachment||1|
|8.||ZZ-006-000||ZANDZ Conductive grease||1|
|9.||ZZ-007-030||ZANDZ Waterproofing tape||1|
|10.||ZZ-008-000||ZANDZ Attachment to the hammer (SDS max)||1|
Do you have any questions about lightning protection of the logistics center or other facilities? Please, contact the ZANDZ Technical Center!