Every year, many buildings and electrical equipment suffer from the effects of lightning. To protect structures from such natural phenomena, a lightning protection system should be installed.
Lightning protection in a private house is a set of measures and means that ensure the safe operation of a ground facility during thunderstorms. This is a necessary attribute of any structure that provides protection for explosive, fire hazardous, technological, material assets, as well as people from primary and secondary manifestations of lightning.
Features of choice
If there are no lightning protection devices on the structure, a lightning strike can cause a fire, destruction of an object or injury to a person.
The main lightning rod is the same, but different materials are used for construction. When choosing this design, the following parameters should be taken into account:
- Design features of the structure.
- The intensity of thunderstorms per year in a certain area.
- Desired degree of security.
Quality lightning protection
Calculation of lightning protection zones should be based on information about the width, length and height of the building, forwhich the protective structure will be built.
In addition, the average annual number of lightning strikes in a certain area of the territory should be taken into account.
In the process of preparing the project, specialists independently calculate the protection zones of the structure. Based on these data, lightning protection is being built. The calculation is simple, you can use many online calculators for this.
Purpose of the structure and lightning rod
Thinking about lightning protection, you should make a lightning protection project.
Today, there are three types of lightning rods, which differ from each other in design features and operating requirements.
The first category includes facilities that handle and store explosive chemicals. In such rooms, mixtures of dust, vapors and gases with air are constantly present. They pose a great danger to human life.
The second category includes facilities where explosive substances are stored in hermetically sealed metal containers. Under such conditions, only in an emergency can dangerous explosive mixtures arise, which consist of vapors, gases and dust with air. As a result of the explosion, the destruction will be partial.
The third category includes premises in which explosive mixtures cannot form.
It should be remembered that the installation of lightning protection systems that prevent direct strikes, secondary impacts and the introduction of high potentials is necessary for structures thatbelong to the first and second categories. Buildings belonging to the third category need to install a lightning rod to prevent a direct lightning strike and the introduction of high potentials.
Views
Let's consider a lightning protection device using the example of a multi-storey building. It can be both external and internal. Each has a specific purpose. Both the first and second types are very important. They ensure the safety of not only your property, but also the he alth of your loved ones.
External lightning protection in a private house is quite simple. It consists of the following elements:
- Down conductor.
- Lightning rod.
- Earthing.
Interception of lightning directly above the roof, and after passing the charge through a safe channel and diverting it to the ground - this is lightning protection. The calculation of the necessary materials for the construction of the structure should be given in the design documentation. Installation of the device can be carried out by each person independently.
But the scheme of the internal lightning rod is much more complicated. This is a whole range of measures that allow you to ensure the safety of electrical appliances and wiring throughout the house. It is better to entrust this work to specialists. After all, only they can choose the right equipment for your home, which will help protect the premises from damage.
Let's consider the functions of each element of the external lightning rod.
Sink
Sink is a specific conductor that connectsground electrode and lightning rod with each other. For its manufacture, galvanized or black rolled steel with a diameter of more than 6 mm is used. This element is connected using a metal clamp with nuts and bolts by welding to ground. It must be laid in such a way that there is as little distance as possible between the lightning rod and the earth electrode. The outer part of this element must be accessible. This eliminates the possibility of weakening the damage or tensioning the down conductor.
Sink can also be metal elements of the structure (pipes, fire escapes, etc.). The main thing is that there is a reliable electrical contact between all elements of the lightning protection system.
Lightning rod
A lightning rod is designed to intercept an electric discharge. Its role can be played by a metal mesh, rod or cable.
A metal lightning rod in the form of a mesh is installed directly on the roof of the building. For the manufacture of this element, rolled steel with a circular cross section or strips of this material are used. If you decide to install this type of lightning rod, then you should create conditions for constant removal of ice or snow from the roof. You also need to take care of the unhindered flow of precipitation. In no case should liquid remain on this part of the structure. The maximum cell size is 5 x 5 m.
A lightning rod in the form of a metal rod is traditional for our country. It began to be used in the 18th century. Most often itinstalled in private homes. Attach the rod to the roof. It is made from profiled rolled metal.
A lightning rod in the form of a cable has the form of a metal rope, which is suspended on supporting structures. Horizontal lightning rods are located on two grounded supports. Most often they are installed on technical structures that are characterized by a significant length (overhead power lines). This type is very rarely used to protect buildings from lightning strikes.
Lightning protection of structures directly depends on this element of the system.
Grounding conductor
He is a metal conductor that must be in contact with the soil. Most often, rolled metal products act as a grounding conductor: an angular profile, a strip or a pipe.
Making a lightning rod with your own hands allows the use of substandard or used gas or water pipes. Remember that the ground electrode must be cleaned of corrosion. The best option is to use galvanized steel. If there are people near the ground electrode during a thunderstorm, then its resistance should not exceed 10 Ohm.
Project
Before proceeding with the construction, a lightning protection project should be created. It is better to entrust it to specialists. The project should provide for the construction of a lightning rod of a structure, taking into account its main purpose, that is, the category. For example, a residential building belongs to category III.
The following must be indicated in the project:
- Type of lightning rod (fromwhat material is made, cell pitch).
- Features of the down conductor (what it is made of, wire diameter, method of attachment to the lightning rod, grounding).
- Features of grounding (location, depth, what material it is made of).
Mounting the lightning rod
You should choose the highest point on the roof. Here you need to fix the mast on which the lightning rod will be installed. Its height causes controversy even among experts. Some argue that tall masts can catch lightning that could bypass the house. Others believe that the higher it is, the better lightning protection will be. The height of the lightning rod is not calculated, since this issue is controversial. Therefore, experts do not indicate the exact length of the mast.
It is better to make a mast from a wooden bar. The air terminal must be securely attached to the top of the mast. Most often, firmly tightened metal clamps are used for this purpose.
A conductor should be connected to the lightning rod. It is attached to the mast with plastic clamps. A cable is often used as a conductor, which is easy to pass down the drain. So you can protect it from gusts of wind, ice and snow.
Lightning protection and grounding are closely related to each other. After all, it is the correct location of the last element that contributes to the safe removal of electric charge.
Dig a hole at a distance of 3 meters from the house. It is better to choose a place where people rarely go and there are no cars. The depth of the pit depends on the levelgroundwater deposits. It is advisable to lay the ground rods in moistened ground. A grounding conductor is laid in the dug hole, to which a down conductor is attached. After the hole is carefully buried.
