In previous publications, much attention was paid to the grounding of healthcare facilities. Customers often demand to calculate a grounding arrangement for a specific resistance, but they do not request to install the lightning protection system.
In this news item, we will tell you how the lightning protection of the building of a maternity welfare center is made. We had to pay special attention to the lightning catch to avoid its striking at some point of the building. To do this, 4 m lightning rods were arranged in the building corners. As a result, the entire structure area was covered by the protection zone.
Read to learn more about the used solution for lightning protection of the maternity welfare center.
Task
To calculate the lightning protection for the maternity welfare center.
Solution
Calculations of the lightning protection for the maternity welfare center are made in accordance with the following regulatory 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 maternity welfare center is classified as Category 3 according to RD and as a special facility with the limited hazard in terms of lightning protection according to SO.
Description of the lightning protection for the maternity welfare center
A set of arrangements ensuring compliance with the lightning protection requirements is based on the following solutions:
- Installation of 6 x 4 m lightning rods on the wall. It is considered that 0.7 m of the rod length is used for securing.
- Two current collectors are arranged from each lightning arrester using a zinc-plated wire D = 2 mm. Six downdrops to the grounding arrangement are used. The main conductor cables are mounted (with mounting step 0.6-1 m):
- to the walls using clamps GL-11703A.
- Connection and branching of current collectors are made using clamps GL-11551А.
A set of measures to ensure the requirements for the grounding arrangement is based on the following solutions:
- Installation of a grounding arrangement consisting of a horizontal electrode (steel zinc-plated strip having cross-section 4 x 30 mm), depth 0.5 m, laid as a circuit around the building, and 6 x 3 m vertical electrodes (rods made of zinc-plated steel having diameter 16 mm).
- The connection of vertical and horizontal electrodes between each other is made using clamp ZZ-005-064.
- The connection of the current collector with the terminal of the zinc-plated ground bar is performed using control clamp GL-11562A.
- The design of the grounding arrangement corresponds to clause 1.7.55 of EIC Grounding arrangements for protective grounding and grounding for lightning discharges are common.
The location of the elements of the lightning protection system and the grounding arrangement is shown in Figure 1. The depicted protection area corresponds to area B, constructed as per Appendix 3 of WD.
План кровли - Roof plan
Условные обозначения - Key
стержневой молниеприемник - Lightning rod
Горизонтальный заземлитель - Horizontal grounding arrangement
Токоотвод - Current collector
Зажим для подключения проводника - Clamp for connecting conductor
Зажим для соединения токоотводов - Clamp for connecting current collectors
Вертикальный заземлитель длиной 3 м - 3 m vertical grounding arrangement
Зона защиты - Protection zone
На отм. - at elevation
РД - RD
Picture 1. Layout of elements of the lightning protection and grounding arrangement of the maternity welfare center
Components used for lightning protection of the maternity welfare center
Do you have any questions regarding the calculation of the lightning protection and grounding for a maternity welfare center? Please, contact the ZANDZ Technical Center!
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