Not long time ago we published a news of lightning protection of a hotel. It doesn't mean we will repeat ourselves, because a hotel we will be talking about is located in Syria, that's why its operation conditions are special, climatic at least.
First of all, the hotel is located on the sea shore, and it means the installed lightning protection equipment must be counted for operation in the salty sea climate. Secondly, the concentration of salt in the ground is immense, which puts some restrictions on the material of ground electrodes.
Taking these facts into consideration, it is necessary to use corrosion-resistance metals. Copper-bonded and copper equipment was chosen for the project. Copper has a high resistance to salt, that is why ground electrodes, down conductors and clamps will last for a long time.
Get familiarized with the lightning protection calculation example of a hotel in Syria from the text below.
The solution on lightning protection of the hotel
The calculations are made in accordance with the following documents:
- "Electrical Installation Code" EIC 7th ed. (hereinafter - EIC).
- "Instructions for organization of lightning protection of buildings, structures and industrial communications" IS 153-34.21.122-2003 (hereinafter IS).
- "Instructions for lightning protection of buildings and structures" AD 34.21.122-87 (hereinafter - AD).
Lightning rods are used for protection of structures from lightning strikes. The lightning conductor usually consists of a lightning rod, intercepting the lightning strike, a down conductor and a ground electrode. All these elements allow to safely drain lightning current into the ground without a damage for the protected object.
The hotel refers to traditional objects from the point of view of lightning protection in accordance with IS and to the third category of lightning protection in accordance with AD.
Hotel's lightning protection system description
The set of measures to provide the required lightning protection is offered by the following solutions:
- Lightning protection of the object is performed in the form of a lightning protection mesh with the help of a steel copper-bonded wire with the diameter of 8 mm laid with the distance of not more than 12x12 m. The mesh is made the way so the current would have at least two different ways to the ground electrode.
- Lightning protection of the bottom floors is provided by the building itself, which creates protection zone B of AD, the bottom part is the part of this zone. Protection zone is showed in the diagram.
- Down conductors from the mesh to the ground electrodes are laid with the distance not less than 25 m along the perimeter of the building.
- Fixation of down conductors (installation distance 0.6-1 m):
- To connect rolled metal over the length and in the mesh nodes, a universal clamp GL-11551M is used.
- All metal elements placed on the roof (reservoirs for heating water) must be connected to lightning protection mesh with the help of ZZ-005-064 clamps.
The set of measures to ensure provision of the necessary requirements to the grounding device is offered by the following solutions:
- Installation of a grounding device consisting of a horizontal electrode (copper bonded tape 4x30 mm), 0.5 meter deep laid along the perimeter of the building 1 m from the foundation.
- In accordance with clause 2.13 of the AD, a contour without installation of vertical electrodes is enough.
- Interconnection of horizontal electrodes is carried out by using ZZ-005-064 clamp.
- The down conductor is connected to the copper-bonded tape protruding from the ground with the help of GL-11562M clamp.
- Construction of the grounding device corresponds to item 1.7.55 EIC. Grounding devices for protective grounding and lightning protection grounding are common.
Расположение элементов системы молниезащиты и заземляющего устройства показано на рисунке 1.
Figure 1. Plan with the layout of lightning protection elements and grounding device
Components for lightning protection and grounding of the hotel
|Lightning protection system
|GALMAR Copper- bonded steel wire (D8 mm; coil of 50 meters)
|GALMAR Clamp for connecting down conductors (copper)
|GALMAR Clamp to the facade / wall for down conductor (height 15 mm; copper)
|GALMAR Clamp for down conductor on a flat roof (D8 mm; plastic, concrete)
|GALMAR Control clamp "wire+tape" (D8+T<35; copper)
|GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 50 meters)
|ZANDZ Clamp for connecting conductor (up to 40 mm)
|ZANDZ Waterproof tape
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