# EXAMPLE OF GROUNDING CALCULATION FOR CHEMICAL REAGENTS WAREHOUSE

The protection of industrial buildings and structures is always given increased attention, especially when it comes to electrical safety. The organization of grounding is a mandatory event during the construction or reconstruction.

The material will describe the decision to organize a grounding device for the storage of chemical reagents. Let’s consider the solution, using the calculation example performed by the ZANDZ Technical Center according to one of the requests.

Data provided for calculation:

• horizontal grounding length: 60 m;
• equivalent ground resistance: 466 Ω*m.

Task:

It is necessary to make a grounding device with a resistance of not more than 4 ohms for grounding the warehouse of chemical reagents.

A set of measures to ensure the necessary requirements for the grounding system of a chemical reagent warehouse is represented by the following solutions:

• mounting 4 kits of electrolytic grounding (vertical, 3 m);
• electrodes are connected using a strip of galvanized steel with 30x4 section. Depth of the strip is 0.6 m;
• the distance from the foundations of buildings to the electrode is at least 3 m.

Ground terminal resistance calculation:

ZZ-100-102МВ kit resistance:

where С is a dimensionless factor describing the electrolyte content in the surrounding soil, 0.125;

Lверт is ground electrode length, 3 m;

d is the diameter of the ground electrode, 0.065 m;

p is soil resistivity, 466 Ohm m.

Horizontal electrode resistance:

where p is soil resistivity, 466 Ohm m.

b - is horizontal electrode width, 0.03 m;

h - is the depth of the horizontal electrode, 0.6 m;

Lгор is horizontal electrode length, 60 m.

Grounding impedance:

where n is the number of kits;

kисп is utilization rate.

The rated resistance of the grounding device is 3,46 ohms, which is less than the required value of 4 ohms.

The list of necessary materials is given in Table 1.

Table 1 - A list of necessary materials for organizing the grounding of a chemical reagents warehouse.

 № Figure Part number Name Quantity 1. ZZ-100-102МВ ZANDZ Electrolytic Grounding Kit (vertical; 3 meters) 4 2. ZZ-005-064 ZANDZ Conductor connection terminal (up to 40 mm) 10 3. ZZ-502-304-52 ZANDZ strip steel galvanized (30 * 4 mm; coil 52 m) 2 4. ZZ-007-030 ZANDZ Waterproofing tape 3

Do you have questions or do you need to calculate grounding for a chemical warehouse? Send a request to info@zandz.ru.

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