In an observation tower, the personnel may be present 24/7 at any season, which means that, to protect their life and health, the personnel has to leave the tower during the storm. One would think that if the work schedule at the observation tower is correct, then we do not need to protect it against lightning. However, the observation tower should be provided with the lightning protection system.
Any high-rise structure attracts lightnings. If it is not protected and grounded, the lightning path across the facility and in the ground around it will be unpredictable. This presents danger for the nearby people, which may be affected by the current from the main channel and by the significant step voltage, if the lightning current flows along the ground in a chaotic manner.
We are going to consider how to properly perform lightning protection for the observation tower so that it would not present any danger for the people around.
Task
To calculate the lightning protection and grounding systems for the observation tower.
Solution
Solutions for the observation tower lightning protection are made according to the following documents:
- "Electrical Installations Code" (hereinafter referred to as the EIC), 7th edition.
- "Instructions for the installation of lightning protection of buildings, structures, and industrial communications" SO 153-34.21.122-2003 (hereinafter referred to as SO).
- "Instructions for mounting the lightning protection of buildings and structures" Working Documentation 34.21.122-87 (hereinafter referred to as the RD).
The lightning arresters are used to protect the buildings against lightning strokes. The lightning arrester consists of an interception rod, intercepting a lightning discharge, the main conductor cable, and the ground electrode. All these elements let us divert lightning current into the ground safely, without any damage to the protected facility.
The observation tower is classified as a conventional facility in terms of lightning protection according to SO and to Category 3 according to RD.
Description of the lightning protection system for the observation tower
Lightning protection of the 20 m tower is made by installation of a 4 m lightning rod. It is considered that 0.5 m of the rod length is used for securing.
A set of measures to ensure the requirements for the grounding arrangement of the observation tower is based on the following solutions:
- Laying a horizontal grounding electrode for current spreading in three directions with an angle of 90 degrees between them. Length of each ground electrode is 5 m. The ground electrode is made of a corrosion-resistant steel copper-plated strip with a cross section of 4x30 mm, the laying depth is 0.5 m.
- At the end of the horizontal ground electrode, one vertical electrode with the length of 3 m is installed in each directions.
- The connection of vertical and horizontal electrodes between each other is made using clamps ZZ-005-064.
The location of the elements of the lightning protection system and the grounding arrangement is shown in Figure 1. The indicated protection zone corresponds to zone B according to RD.
Условные обозначения: - Key:
Вышка - Tower
Вертикальный заземлитель длиной 3 м - 3 m vertical grounding electrode
Горизонтальный заземлитель - Horizontal grounding electrode
Зажим для подключения проводника - Clamp for connecting conductor
Figure 1. Layout of elements of the lightning protection and grounding arrangement
Components for lightning protection and grounding of the observation tower
| № | Part number | Name | Quantity, pcs. |
| Lightning Protection | |||
| 1. | ZZ-201-004 | ZANDZ Tower interception rod, 4 m (stainless steel) | 1 |
| Grounding arrangement | |||
| 2. | ZZ-005-064 | ZANDZ Conductor connection terminal (up to 40 mm) | 5 |
| 3. | GL-11075-20 | GALMAR Copper-plated strip (30*4 mm/ S 120 mm²; 20-meter strip bundle) | 1 |
| 4. | ZZ-001-065 | ZANDZ Copper-clad threaded grounding pin (D14; 1,5 m) | 6 |
| 5. | ZZ-002-061 | ZANDZ Threaded coupling | 4 |
| 6. | ZZ-003-061 | ZANDZ Termination | 3 |
| 7. | ZZ-004-060 | ZANDZ guide head for jackhammer attachment | 2 |
| 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 relating to calculation of the lightning protection and grounding of the observation tower? Please, contact the ZANDZ Technical Center!
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