Explosive open areas must be equipped with a lightning protection system, since they represent an increased danger to the immediate environment.
ZANDZ Technical Center received a request for the development of lightning protection system for an open fuel and lubricant depot. We will see what solution was offered.
the measures of the protected area:90х70х17 m;
soil resistivity: 100 Ohm * m.
Calculate external lightning protection system.
The fuel and lubricant depot refers to "special, dangerous for immediate surrounding" in accordance with IS and to the 2 category according to AD. Required system reliability — not less than 0.95.
The set of measures to provide the required lightning protection is offered by the following solutions:
- installation of 4 catenary wire lightning protection bases with the wires hanging at the height of 22 m along the perimeter of the protected area (see fig.1);
- installation of the grounding device according to AD, item 2.2 consisting of 3 vertical electrodes 3 m long, united by the horizontal electrode (copper-bonded tape 30x4 mm). The distance from the horizontal electrode to the object should be not less than 1 m, deepening 0.5 - 0.7 meters. The distance between the vertical electrodes is at least 5 meters.
Results of the calculation carried out with the software developed by the JSC "Energy Institute to the name of G.M. Krzhizhanovsky (JSC "ENIN"):
Density of lightning strikes into the ground - 4 strikes / sq. km per year
Full number of strikes into the system – 0.17 (once in 6 years);
The number of breakthroughs into the object - 0,0042 (once in 238 years);
System reliability – 0,976;
Probability of breakthrough into all the system objects - 0.024.
Calculation of a grounding device resistance (per one mast):
The design resistance of the grounding device is 9.3 ohms.
Location of equipment is shown in figure 1.
The list of equipment and required materials is given in Table 1.
Figure 1 - Location of equipment.
Опора тросовой молниезащиты высотой 22 м – Base of catenary wire lightning protection 22 m high
Электрод – Electrode D = 14 mm, L = 3m
Полоса омедненная стальная сечением – Copper bonded steel tape with the cross-section of 30 x 4mm
Грозотрос – Ground wire
Защищаемое пространство над дыхательными клапанами – protected space over the breethe valves
Table 1 - Materials requirement list.
|№||Figure||Product item||Name||Quantity, pcs.|
|1.||ZZ-204-222-В3-Сн3-С6-Т100||ZANDZ Catenary wire lightning protection base (height of suspension 22 m; sag 2 m; length 100m; 2 pointsl 3 wind region; 3 snow region; 6 sesmic region; with embedded parts; without ground wire)||4|
|2.||ZZ-204-001||ZANDZ Galvanized steel ground wire (50 mm2)||400|
|3.||ZZ-001-065||ZANDZ Copper-bonded threaded grounding rod (D14; 1.5 m)||24|
|4.||ZZ-002-061||ZANDZ Threaded coupler||13|
|5.||ZZ-003-061||ZANDZ Starting tip||12|
|6.||ZZ-004-060||ZANDZ Driving head for a jackhammer||5|
|7.||ZZ-006-000||ZANDZ Conductive grease||2|
|8.||ZZ-008-000||ZANDZ Header for a jackhammer (SDS max)||1|
|9.||ZZ-005-064||ZANDZ Clamp for connecting conductor (up to 40 mm)||12|
|10.||ZZ-007-030||ZANDZ Waterproof tape||4|
|11.||GL-11075-50||GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 50 meters)||1|
Do you have questions or you need to calculate lightning protection and grounding for a fuel and lubricant depot? Send your request to firstname.lastname@example.org.