Lightning Protection Design for a Railroad Terminal and Station

Задание:

Facility: dead-locked railroad terminal.
Soil: sand clay, sand.
Soil resistivity at the site: 150 Ohm/m.
The structure comprises a metal frame, concrete, roll roofing in the main building, metal steel coating over the access-way (station).
Ventilation and air conditioning equipment is located on the roof.
It is required to perform calculation and develop a lightning protection and grounding design while meeting the requirements of the effective regulatory documents.

Solution:

According to SO 153-34.21.122-2003 (Table 2.1), the railroad terminal building is classified as a conventional facility in terms of lightning protection. Protection level - III, and reliability of protection against direct lightning strikes (DLS) is 0.99.
To protect building and equipment, lightning protection using ZANDZ lightning rods and a lightning grid with the spacing at least 10 m comprising natural and artificial elements are provided on the railroad terminal roof.

The lightning protection of the cover over the access-ways is made according to Category II as per item 2.11-2.13 of RD. The steel cover is used as a natural lightning rod, and metal building columns and metal frame connected to the natural ground terminal, namely reinforced concrete foundation, are used as current collectors.

The facility provides for:

1. Installation of two lightning rods, article No.: ZZ-201-014-3, 14 m high. Lightning rod ZANDZ ZZ-201-014-3 is intended to install on the flat roof of the protected building. The support structure allows providing for the required stability of the lightning rod without using heavy weights, which in turn allows reducing load to the roof.

The ZZ-201-014-3 delivery set includes all components required to assemble and install the lightning rod:

a tripod support;
a base part of the rod;
a set of metalware.

2. The lightning arrester grid is a steel copper-plated wire having a diameter of 8 mm (GL-11149) and a natural lightning rod represented by steel aprons above the rampart and projecting roof structures.

3. A grid on flat surfaces is secured using clamp GL-11711, and clamp GL-11703A on the vertical surfaces. The clamp spacing is 0.8 to 1.0 m.

4. Universal clamp GL-11551A is used for securing rolled metal along the distance, as well as in the grid nodes.

5. Current collectors are connected to the lightning rods using a clamp included in the rod set.

6. All metal elements located on the roof shall be connected to the lightning grid using clamps GL-11545A.

7. Metal elements (aprons) at various levels and a steel coating over the access-ways are interconnected using a steel copper-plated wire having a diameter of 8 mm and flange clamps thus forming a continuous metal connection.

8. A natural ground terminal, i.e. building foundations, are used as a ground terminal. The resistance of the ground terminal does not exceed 10 Ohm.

9. Metal columns of the building structure and covers over the access-ways are used as current collectors from the lightning grid.

10. Protection from secondary lightning effects and high voltage is provided by connection of metal utility pipes, cable sheaths at the building entry to the building frame.

11. To protect the equipment and electrical utilities inside the building, we recommend employing a set of measures which allow preventing dangerous overvoltage. DDI contains the surge protection device SDP Class I+II+III PP BCB TNS 25/100 selected according to a three-phase input to the building and power system TN-C-S or TN-S.

List of required materials:

Item #	Fig.	Designation	Name	Quantity	Unit weight, kg
1		ZZ-201-014-3	ZANDZ 14 meter lightning rod for installation on the roof	2	325
2		GL-11149	GALMAR Steel copper-plated wire (D 8 mm/S 50 mm2)	1500	0,41
3		GL-11551А	GALMAR Multi-purpose clamp	60	0,07
4		GL-11545A	GALMAR Flange clamp	54	0,112
5		ZZ-007-030	ZANDZ Waterproof tape	6	0,442
6		GL-11706	GALMAR Holder for D 8 mm current collectors (for attaching; plastics) to the flat roof	1860	0,1