LIGHTNING PROTECTION OF A WAREHOUSE FOR EXPLOSIVES

There are such types of objects that require an increased level of reliability of lightning protection. So, the ZANDZ Technical Center was given the task of calculating lightning protection of a warehouse of explosive materials used for blasting in mining activities.

It was required to protect three sites with containers in which explosives, UTS and DES are stored. In accordance with the standard IS 153-34.21.122-2003, the objects refer to special ones that pose a danger to the immediate environment, therefore, the required reliability of lightning protection is 0.99. Reliability of 0.9 is enough to protect UTS and DES.

Having examined the location of objects in the warehouse, technical experts came up with the optimal solution - to use two separate lightning rods with the height of 28 m, which protect the warehouse of explosive materials from lightning with the required reliability. Since UTS and DES were located at some distance from the containers and did not enter the protection zone, another 12-meter-high free standing lightning rod was used to protect them.

Learn about the solution for lightning protection of the explosive materials warehouse from the news text.

Task

To calculate lightning protection of a warehouse of explosive materials.

Solution

To calculate lightning protection, the following regulatory documents were used:

1. "Electric Installation Code" EIC 7th ed. (hereinafter - EIC).
2. "Instructions for organization of lightning protection of buildings, structures and industrial communications" IS 153-34.21.122-2003 (hereinafter IS).
3. "Instructions for lightning protection of buildings and structures" AD 34.21.122-87 (hereinafter - AD).

Lightning arresters are used for protection of structures from lightning strikes. A lightning arrester usually consists of a lightning rod, intercepting the lightning strike, a down conductor and a ground electrode. All these elements allow to safely drain the lightning current into the ground without a damage for the protected object.

Description of an external lightning protection system for an explosive storage facility

The measures providing the necessary requirements for the lightning protection system are presented by the following solutions:

1. Installation of two vertical lightning rods for installation in soil with the height of 28 meters to protect containers with a reliability of 0.99 IS.
2. Installation of one high for the protection of UTS and DES and electrical installations with a reliability of 0.9 IS.

The grounding device of each vertical lightning rod is implemented in the form of:

1. A horizontal ground electrode, the current from which flows in three directions, the angle between each beam is 90 degrees. The length of each beam is 5 m. The ground electrode is made of copper-bonded stainless steel with the cross-section 4x30 mm (GL-11075), laying depth - 0.5 m.
2. At the end of each beam there is a horizontal ground electrode, one vertical electrode 3 m long is installed.
3. Horizontal and vertical electrodes are connected by clamps ZZ-005-064.

Расположение элементов системы молниезащиты показано на рисунке 1.

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