EXAMPLE OF CALCULATION OF LIGHTNING PROTECTION OF A LOADING AND UNLOADING RACK

Railway loading and unloading racks require particularly reliable lightning protection. The reason is clear: a direct lightning strike into an object on which the loading and unloading of fuels and lubricants is carried out can instantly lead to fire and explosion.

Recently, the ZANDZ Technical Center received the task of calculating the lightning protection of a loading and unloading rack, ensuring a system reliability of at least 0.95. Our technical experts offered a solution, which we are sharing with you.

 

See also: Project in AutoCAD "Lightning protection of a railway loading and unloading rack (equipment for discharge and loading operations"

 

Example of calculation of lightning protection of a loading and unloading rack

Object: loading and unloading rack.

Figure 1 - Plan of the object.

 

Task: Perform calculations of a lightning protection system for a loading and unloading rack.

 

Buildings are protected against lightning strikes using freestanding lightning rods.

 

Solutions to ensure the requirements for a lightning protection system for a loading and unloading rack:

1. Lightning protection is carried out in accordance with EIC 7th edition., IS 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures and industrial communications" (hereinafter IS) and AD 34.21.122-87 "Instructions for lightning protection of buildings and structures" (hereinafter AD).

2. The object refers to category 2 of lightning protection. System reliability must be not less than 0,95.

3. Lightning protection of the object is made with the help of 2 vertical free-standing air-terminal masts 20 m high (ZZ-201-020).

4. Installation of a grounding device for each mast, consisting of 2 vertical electrodes with a length of 3 m, connected by a horizontal electrode (copper bonded tape of 30x4 mm). The distance from the horizontal electrode to the foundation of the building is not less than 1 m, the laying depth is 0.5 - 0.7 meters;

 

Results of the calculation carried out with the software developed by the JSC "Energy Institute to the name of G.M. Krzhizhanovsky (JSC "ENIN"):

Density of lightning strikes into the ground - 4 strikes / sq. km per year;

The total number of strikes into the system - 0.075 (once in 13 years);

The total number of breakthroughs is 0.0034 (every 294 years);

System reliability - 0.955;

Probability of a breakthrough into all the system objects - 0.045.

 

Figure 2 shows the arrangement of equipment.

Table 1 gives the list of the required equipment and materials.

условные обозначения – Type Codes
Молниеприемник мачта высотой 20 м – Air-terminal mast 20 m
Электрод - Electrode
Полоса омедненная стальная сечением 30 на 4 – Copper bonded steep tape with the cross section of 30 * 4mm

Figure 2 - Location of equipment for lightning protection of a loading and unloading rack.

 

Table 1 - List of need in materials.

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