A large hotel is most often a building of several structures with the height of more than 50 m. Usually, such tall buildings actively attract lightning.
The hotel can simultaneously accommodate hundreds of guests. In order to protect them from fire and other dangerous effects of atmospheric discharges, a reliable lightning protection system should be put into the project of the hotel. Let's study the solution that the engineers of the ZANDZ Technical Center offered for one of the hotels.
Task
To make the choice of the lightning rods necessary for lightning protection of a hotel. The building under protection is an ordinary structure in terms of lightning protection in accordance with the IS and is in Category 3 according to the AD.
The solution to lightning protection of hotels
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).
Protection of buildings from lightning strikes is carried out with the help of lightning rods. A lightning rod is a device rising above the facility that diverts lightning current into the ground without entering the facility. It consists of a lightning rod which directly takes the lightning discharge upon itself, a down conductor and a ground electrode.
Lightning protection system description
Measures to ensure compliance with the requirements for hotel lightning protection system:
- Installation of 3 rods 7 m high, fixed to the wall. It is taken into account that 1 m of the lightning rods height is used for fixation.
- Installation of 2 rods 4 m high, fixed to the wall. It is taken into account that 0.7 m of the lightning rods height is used for fixation.
Location of the lightning rods at the hotel is shown in Figure 1. You can see protection zone B of the AD.
Calculation of reliability of lightning protection of the hotel when calculating the probability of a lightning strike to an object
The following source data are taken for the calculation:
The density of lightning strikes into the ground - 4 strikes / sq. km per year.
The results of lightning protection calculation performed by the software, developed by OJSC "Energy Institute to the name of Krzhizhanovsky" (OJSC" ENIN ") are given in table 1.
Table 1 - Results of lightning protection calculation
|
№ |
Object |
Lightning rod height, m |
Protection reliability |
Number of strikes into an object, year-1 |
Number of breakthroughs into the object, year-1 |
|
Period of srikes, year |
Period of breakthroughs, year |
||||
|
1 |
Hotel |
7 and 4 m |
0,944 |
0,3 |
0,017 |
|
once in 3 years |
once in 59 years |
Figure 2. Lightning rods location planв
Components for the hotel's external lightning protection system
|
№ |
Fig. |
Product item |
Product |
Quantity |
|
Lightning protection system |
||||
| 1. |  |
ZZ-201-007-3 | ZANDZ Vertical air-terminal mast 7 m high with a set of 2 fastenings to the wall (stainless steel) | 3 |
| 2. |  |
ZZ-202-002 | ZANDZ Clamp to the lightning rod D42 mm for down conductors (stainless steel) | 3 |
| 3. | |
ZZ-201-004 | ZANDZ Vertical air-terminal -mast 4 m (stainless steel) | 2 |
| 4. |  |
ZZ-203-001 | ZANDZ Fastening for lightning rod to the wall (stainless steel) | 2 |
| 5. | |
GL-20022 | GALMAR Clamp to lightning rods for down conductors (stainless steel) | 2 |
Do you have any questions about hotel lightning protection? Please contact our ZANDZ Technical center!
See also: