Article on “ Natural Component as a LPS Conductor”

Metallic Roofing:

• LPS conductors and rods should be mechanically secured so that they are capable of withstanding stress due to wind or weather and work carried out on the roof surface.
• Metal covering provided for mechanical protection of outer walls parapet capping may be used as a natural component of the air-termination, if there is no risk of fire ignition by melting metal.
• The combustibility depends on the type of material under the metal cladding. The combustibility of the material employed should be confirmed by the contractor.

• The roof sealing arrangement on metallic roofs, as with other types of roof, can be perforated by a lightning flash.

• In such a case, water can penetrate and leak through the roof at a point far from the striking point. If this possibility is to be avoided, a separate air-termination system should be installed.

• Roof coverings of conductive sheet which do not conform to condition in standard may be used as air terminations where melting at the striking point of lightning can be accepted.

• If this is not acceptable, the conductive roof sheeting should be protected by an airtermination system of sufficient height.
• Non-conductive as well as conductive supports are allowed. When conductive supports are used, the connection to the roof-sheet should withstand partial lightning current.
• Flush-mounted and protruding structures on the roof surface should be protected by means of air-termination rods. Alternatively, extraneous metalwork should be bonded to the LPS.

Natural Components:

1. The metal of the electricallycontinuous reinforced concrete framework of the structure;

• With prefabricated reinforced concrete, it is important to establish interconnection points between the reinforcing elements.

• It is also important that reinforced concrete contains a conductive connection between the interconnection points. The individual parts should be connected on-site during assembly.

• In the case of pre-stressed concrete, attention should be paid to the risk of causing unacceptable mechanical consequences, due either to lightning current or as a result of the connection to the lightning protection system.

2. The interconnected steel framework of the structure;

Ring conductors are not necessary if the metal framework of steel structures or the interconnected reinforcing steel of the structure is used as down-conductors.