Rehabilitation center is an organization providing physical, psychological, social, and moral restoration of people (rehabilitants) who have suffered from debilitating diseases of nervous and locomotor systems, sensory organs, etc., as well as those having psychic and behavioral disorders. The need for rehabilitation services has been increasing worldwide. Such centers require lightning protection and grounding. The facility is conventional according to regulatory documents and does not imply any specific requirements for the lightning protection, but it is important to protect the structure. The ZANDZ Technical Center has received a request to calculate the lightning protection system for the rehabilitation center in Irkutsk. Let us continue with more detailed review of our offered solution.
Calculation of lightning protection for the rehabilitation center in Irkutsk
Facility: rehabilitation center in Irkutsk
Figure 1. Facility plan.
Task: to calculate the lightning protection system for the rehabilitation center in Irkutsk
Solutions to meet the requirements to the lightning protection system of the rehabilitation center in Irkutsk:
- The lightning protection is made in accordance with Electrical Installations Code (EIC), Rev. 7, SO 153-34.21.122-2003 "Guidelines for the lightning protection of buildings, structures and industrial infrastructure (hereinafter referred to as SO) and RD 34.21.122-87 "Guidelines for the lightning protection of buildings and structures (hereinafter referred to as the RD).
- This facility is classified as category IV of lightning protection according to SO. The system's reliability should be at least 0.8.
- The facility lightning protection is made via 4 x 1.5 m lightning rods installed on roof ridges (103 410).
- A copper-plated steel wire (copper coating thickness of 70 μm min.), d8 mm (GL 11149) is used as a down conductor.
- Current collectors are installed using holder GL-11564A on the roof ridge, using holder GL-11545A on the roof pitches, using holder GL-11703А on the vertical surfaces. The accepted pitch of terminals is 0.8-1.0 m.
- The universal terminal GL-11551A is used to connect rolled products along the length and in joints.
- All metal elements located on the roof must be connected to the main conductor cable with the terminals GL-11545. Stairs, railings are attached using the terminal-clamp GL-11514N.
- The vertical copper-plated steel electrodes with the length of 3 m are used as the grounding devices at the downdrops of the current conductors. The copper-plated steel strip with a cross-section of 30x4 mm, combining all vertical electrodes is used as a horizontal ground electrode. The distance to the facility foundation is at least 1 m. Strip deepening is 0.5 to 0.7 m.
- According to EIC-7 issue, par.1.7.55 - Grounding devices for protective grounding of electrical installations for buildings and structures and the 2nd and 3rd categories lightning protection of these buildings and structures, as a rule, shall be common.
- If there are concrete-steel constructions, they shall be connected to down conductors/grounding device.
- Connection to the grounding device is carried out using ZZ-005-064 clamps.
Results of calculation performed using the software developed by the Krzhizhanovsky Energy Institute (OAO ENIN):
lightning discharge density into the ground is 4 strikes/sq. km per year.
Total number of strikes into the system is 0.2 (once every 25 years).
Total number of blowouts is 0.0058 (once per 172 years).
The probability of a blowout into the system's facilities is 0.14.
The system reliability is 0,86.
Ground terminal resistance calculation:
Ом - Ohm
Верт - Vert
Гор - Hor
ЗУ - GA
The design resistance of the grounding arrangement is 1,62 Ohm.
Figure 2 shows hardware layout.
Table 1 includes the list of required hardware and materials.
Условные обозначения - Key
Молниеприемник-мачта высотой 1.5 м на конек - 1.5 m lightning rod on the roof ridge
Универсальный зажим-соединитель для проволоки - Multipurpose connecting clamp for wire
Фальцевая клемма для крепления к металлическим конструкциям - Flange terminal for securing to metal structures
Зажим-хомут - Clamp holder
Опуск токоотвода - Downdrop
Полоса стальная омедненная сечением 30 х 4 мм - Steel copper-plated bar having cross-section 30 x 4 mm
Вертикальный заземлитель длиной 3 м - 3 m grounding electrode
Figure 2. Hardware layout for the lightning protection of the rehabilitation center in Irkutsk
Table 1. List of materials needed for all building sections.
Do you have any questions about lightning protection of the rehabilitation center or other facilities? Please, contact the ZANDZ Technical Center!
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