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.
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:
- 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).
- The object refers to category I of lightning protection. The reliability of the system must be at least 0.99.
- 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.
- 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.
- If there are reinforced concrete structures, they must be connected to down conductors / grounding device.
- 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.
- 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 |
ZANDZ Vertical lightning rod 22 m (galvanized steel; with embedded details for foundation) |
2 |
|
2. |
|
ZZ-201-012 |
ZANDZ Vertical lightning rod 12 m (galvanized steel with embedded details for foundation) |
2 |
|
3. |
|
GL-11075-20 |
GALMAR Copper-bonded steel tape (30*4 mm / S 120 mm²; coil of 20 meters) |
2 |
|
4. |
|
ZZ-001-065 |
16 |
|
|
5. |
|
ZZ-002-061 |
9 |
|
|
6. |
|
ZZ-003-061 |
8 |
|
|
7. |
|
ZZ-004-060 |
4 |
|
|
8. |
|
ZZ-005-064 |
17 |
|
|
9. |
|
ZZ-006-000 |
1 |
|
|
10. |
|
ZZ-007-030 |
4 |
|
|
11. |
|
ZZ-008-000 |
1 |
Do you have questions on lightning protection of gunpowder mills? Contact our ZANDZ Technical Center!