Like all the rest places of mass gathering, cinemas require a reliable lightning protection. We already wrote an article about lightning protection of a shopping and leisure center and even prepared a standard plan for it.
Nowadays cinemas are rarely located in individual structures, usually they are located in shopping malls. Lightning protection of a cinema is provided at the expense of a complex lightning protection of the whole building.
Let's study lightning protection of a cinema - one of the newest projects of ZANDZ Technical Center.
Task
Calculate lightning protection and grounding of a cinema.
Solution
Calculations of lightning protection are made in accordance with the following documents:
- «Electrical Installation Code» EIC 7th ed. (hereinafter - EIC).
- «Instructions for organization of lightning protection of buildings, structures and industrial communications» IS 153-34.21.122-2003 (hereinafter IS).
- «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 lightning current into the ground without a damage for the protected object.
A cinema refers to traditional objects from the point of view of lightning protection in accordance with IS and to the third category of lightning protection in accordance with AD.
Lightning protection system description
The set of measures to provide the required lightning protection is offered by the following solutions:
- Lightning protection of the object is performed in the form of a lightning protection mesh with the help of a steel copper-bonded wire 8 mm in diameter laid with the pitch of not more than 12x12 m. The mesh is made the way so the current would have at least two different ways to the ground electrode.
- Down conductors from the mesh to the ground electrode are laid with the distance not less than 25 m along the perimeter of the building.
- Fixation of down conductors is performed (installation distance 0.6-1 m):
- on the walls by means of GL-11703A clamps;
- on a flat roof by means of GL-11711 clamps.
- To connect rolled metal over the length and in the mesh nodes, a universal clamp GL-11551A is used.
- All metal elements placed on the roof (stairs, pipes, mines, ventilation devices) must be connected to lightning protection mesh with the help of ZZ-005-064 clamps (must be foreseen separately).
The set of measures on the provision of the necessary requirements to the grounding device is presented by the following solutions:
- Installation of a grounding device consisting of a horizontal electrode (copper bonded tape 4x30 mm), 0.5 meter deep laid along the perimeter of the building 1 m from the foundation.
- In accordance with clause 2.13 of the AD, a circuit without installation of vertical electrodes is enough.
- Interconnection of horizontal electrodes is carried out by using clamp ZZ-005-064.
- The down conductor is connected to the galvanized tape protruding from the ground with the help of GL-11562A clamp.
- The structure of the grounding device corresponds to item 1.7.55 of EIC. Grounding devices for protective grounding and lightning protection grounding are common.
The layout of elements in the lightning protection system and the grounding device is shown in Figure 1.
Figure 1. Plan with the layout of lightning protection elements and grounding device
Components for lightning protection and grounding of the cinema
| № | Product item | Name | Quantity, pcs. |
| Lightning protection system | |||
| 1. | ZZ-502-008-125 | ZANDZ steel galvanized wire (D 8 mm / S 50 mm²; coil of 125 m) | 8 |
| 2. | GL-11551A | GALMAR Clamp for connecting down conductors (painted galvanized steel) | 50 |
| 3. | GL-11711 | GALMAR Clamp for down conductor on a flat roof (D8 mm; plastic, concrete) | 750 |
| 4. | GL-11703A | GALMAR Clamp to the facade / wall for a down conductor with elevation (15 mm high; painted galvanized steel) | 250 |
| 5. | GL-11562A | GALMAR Control clamp for connecting down conductors, wire + tape (painted galvanized steel) | 11 |
| Grounding device | |||
| 6. | ZZ-005-064 | ZANDZ Clamp for connecting conductor (up to 40 mm) | 17 |
| 7. | ZZ-502-304-52 | ZANDZ steel galvanized tape (30*4 mm; coil of 52 m) | 6 |
| 8. | ZZ-007-030 | ZANDZ Waterproof tape | 6 |
Do you have any questions on grounding and lightning protection of a cinema? Please contact our ZANDZ Technical center!
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