Explosive objects, such as gasoline filling stations, shall be grounded. In particular, it will focus on grounding the fuel storage and refueling islet in the Siberian Federal District.
The ZANDZ Technical Center received a request for calculating the grounding of the gasoline filling station, consider what solution has been prepared.
Initial data:
- site plan;
- soil resistivity accepted for calculations - 1000 Ohms*m.
Task:
calculate the grounding device for the refueling islet and tanks with a resistance of 4 ohms max.
A set of measures to provide the necessary requirements for the grounding device (electrolytic grounding) is presented by the following solutions:
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tanks: 4 kits of ZZ-100-102 electrolytic grounding and performing grounding contour, using a copper-plated steel strip of a 30x4 mm section, around the tank site perimeter at a distance of 1 m min. The distance from the electrodes to communications and foundations should be no less than 3 m. Deepening is 0.5 to 0.7 m.
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islet: 4 kits of ZZ-100-102 electrolytic grounding and performing grounding contour, using a copper-plated steel strip of a 30x4 mm section, around the islet perimeter at a distance of 1 m min. The distance from the electrodes to communications and foundations should be no less than 3 m. Deepening is 0.5 to 0.7 m.
Tank ground terminal resistance calculation:
The resistance set ZZ-100-102:
whereС is a dimensionless factor describing the electrolyte concentration in the surrounding soil, 0.125;
р is soil equivalent resistivity, 1000 Ohms m;
L is vertical electrode length, 2.4 m;
d is vertical electrode diameter, 0.065 m;
T - deepening is the distance from the ground surface to the ground electrode, 0.6 m;
Horizontal electrode resistance:
where p is soil resistivity, 1000 Ohm m;
b - is horizontal electrode width, 0.03 m;
h - is horizontal electrode depth, 0.5 m;
Lгор is horizontal electrode length,59 m.
Grounding impedance:
where n is the number of kits, 4 pcs.;
Kисп is utilization factor, 0.95 (electrolytic), 0.7 (strip).
Rated resistance of the grounding device is 8,96 ohms, which is less than the required value of 10 ohms.
Refueling islet ground terminal resistance calculation:
The resistance set ZZ-100-102:
where С is a dimensionless factor describing the electrolyte concentration in the surrounding soil, 0.125;
р is soil equivalent resistivity, 1000 Ohms m;
L is vertical electrode length, 2.4 m;
d is vertical electrode diameter, 0.065 m;
T - deepening is the distance from the ground surface to the ground electrode, 0.6 m;
Horizontal electrode resistance:
where p is soil resistivity, 1000 Ohm m;
b - is horizontal electrode width, 0.03 m;
h - is horizontal electrode depth, 0.5 m;
Lгор is horizontal electrode length,53 m.
Grounding impedance:
where n is the number of kits, 4 pcs.;
Kисп is utilization factor, 0.95 (electrolytic), 0.7 (strip)
Rated resistance of the grounding device is 9,1 ohms, which is less than the required value of 10 ohms.
The location of the equipment is shown in Figure 1.
Figure 1 - equipment location.
Условные обозначения - Conventional symbols
Полоса стальная омедненная 30х4 мм (GL-11075) - Copper-coated steel strip of a 30x4 mm section (GL-11075)
Зажим для соединения проводников (ZZ-005-064) - Conductor clamp (ZZ-005-064)
Вертикальный заземлитель длиной 3м - Vertical ground electrode, 3 m. long
Авар. рез-р - Dropout sump
The list of necessary materials is given in Table 1.
Таблица 1 – Перечень потребности материалов.
| № | Figure | Part number | Наименование | Description |
| 1. |  |
ZZ-100-102 | ZANDZ Electrolytic Grounding Set (horizontal; 3 meters length) | 8 |
| 2. |  |
ZZ-005-064 | ZANDZ Conductor connection terminal (up to 40 mm) | 40 |
| 3. | .png) |
GL-11075-50 | Copper-plated strip GALMAR (30*4 mm / S 120 mm²; 50-meter coil) | 3 |
| 4. |  |
ZZ-007-030 | ZANDZ Waterproofing tape | 11 |
Do you have questions or do you need to calculate the grounding system of the gasoline filling station? Send a request to info@zandz.ru.
Refer also to: