Example of calculating lightning protection of a gunpowder mill in the Central Federal District

Example of calculating lightning protection of a gunpowder mill in the Central Federal District

Gunpowder plants require particularly reliable lightning protection. The reason is clear: a direct lightning strike into the object at which the gunpowder is produced can instantly lead to fire and explosion.

Recently, the ZANDZ Technical Center received a task of calculating lightning protection of such an object, ensuring a system reliability of at least 0.99. We have proposed a solution that we will consider below.

An example of calculating lightning protection of a gunpowder plant in the Central Federal District 

Object: powder mill.

Object plan
Figure 1 – Object plan.

 

Task: Perform calculations of lightning protection system of a gunpowder plant.

Buildings are protected against lightning strikes using freestanding lightning rods.

Solutions to meet the requirements for the gunpowder mill lightning protection system:

  1. Lightning protection was carried out in accordance with  EIC 7-th ed., IS 153-34.21.122-2003 «Instructions on lightning protection of buildings, structures and industrial communications» (hereinafter IS) and AD  34.21.122-87 «Instructions on lightning protection of building and structures» (hereinafter AD).
  2. The object refers to category I of lightning protection. The reliability of the system must be at least 0.99.
  3. Lightning protection of the facility is performed using 2 vertical freestanding air-terminal masts with a height of 22 m and 2 vertical freestanding lightning rods-masts with a height of 12 m.
  4. 2 vertical copper-bonded steel electrodes of 3 m length are used, connected by a horizontal ground electrode (copper-bonded steel tape with a cross section of 30x4 mm) are used as a grounding device.
  5. If there are reinforced concrete structures, they must be connected to down conductors / grounding device.
  6. Connection to the grounding device is carried out using the terminals ZZ-005-064.

The results of the calculation carried out using software developed by JSC “Energy Institute named after G.M. Krzhizhanovsky "(JSC" ENIN "):

The density of lightning strikes into the ground is 4 strikes / sq. Km per year.

The total number of strikes in the system is 0.092 (once every 11 years).

The total number of strikes is 0,00051 (once every 1961 years).

The probability of a breakthrough into system objects is 0.0056.

The reliability of the system is 0.9944.

 

Figure 2 shows the location of the equipment.

Table 1 lists the required equipment and materials.

Location of equipment for lightning protection of a gunpowder mill

  • Условные обозначения – Type Codes
  • Молниеприемник мачта высотой 22 мм – Air-terminal mast 22 m high
  • Молниеприемник мачта высотой 12 м - Air-terminal mast 12 m high
  • Полоса стальная омедненная сечением 30*4 мм – Copper-bonded steel tape with the cross-section of 30 * 4 mm
  • Зажим для подклюения проводника – clamp for connecting conductor
  • Вертикальный заземлитель длиной 3 м  - vertical ground electrode 3 m long

Figure 2 – Location of equipment for lightning protection of a gunpowder mill 

 

Table 1 – List of material needs

Picture

Product item

name

Q-ty

1.

ZZ-201-022

ZZ-201-022

ZANDZ Vertical lightning rod 22 m (galvanized steel; with embedded details for foundation)

2

2.

ZZ-201-012

ZZ-201-012

ZANDZ Vertical lightning rod 12 m (galvanized steel with embedded details for foundation)

2

3.

GL-11075-20

GL-11075-20

GALMAR Copper-bonded steel tape (30*4 mm / S 120 mm²; coil of 20 meters)

2

4.

ZZ-001-065

ZZ-001-065

ZANDZ Copper-bonded grounding rod (D14; 1,5 m)

16

5.

ZZ-002-061

ZZ-002-061

ZANDZ Threaded connection coupler

9

6.

ZZ-003-061

ZZ-003-061

ZANDZ Starting tip

8

7.

ZZ-004-060

ZZ-004-060

ZANDZ Driving head for a breaker hammer

4

8.

ZZ-005-064

ZZ-005-064

ZANDZ Clamp for connecting conductor (up to 40 mm)

17

9.

ZZ-006-000

ZZ-006-000

ZANDZ Conductive grease

1

10.

ZZ-007-030

ZZ-007-030

ZANDZ Hydro-insulation tape

4

11.

ZZ-008-000

ZZ-008-000

ZANDZ Head for a breaker hammer (SDS max)

1

Do you have questions on lightning protection of gunpowder mills? Contact our ZANDZ Technical Center!