Early Streamer Emission Devices
An early streamer device is powered by storing energy from the naturally occurring ambient electrical field, which builds up considerably, (as much as several thousand volts per metre) – when a storm approaches. This electrical energy is collected and stored within the device. Just before a lightning strike occurs there is a rapid increase in the electrical field and this is detected by the ESE Head. This in turn triggers the device to release the stored energy in the form of an ionization at the tip of the air terminal. This encourages the formation of rising discharge (upward leader) from the ESE Head in advance of the naturally occurring upward leaders from other points on the structure being protected. The principle being that should a lightning strike occur it would be attracted to the streamer provided by the ESE Head and then would be conducted safely to earth by the down conductors/earth.
Basic Installation Guide:
A detailed evaluation should be made before the installation; the ESE Head should always represent the highest point of the building requiring protection. The air terminal should always be sited at least 2 metres above the area it is intended to protect. When making an assessment, consideration must be given to any of the vantage points. These may include any outbuildings on the roof, the buildings gables, metallic or brick chimneys.
The ESE Head may also be mounted on a free standing pole/tower to provide protection for an open area of ground, eg recreational areas. If more than one ESE Head is required to protect a single construction, then it is necessary to inter-connect each device by a conductor conforming to relevant standards. Examples of this are: if the horizontal length of the building is greater than the vertical drop or the height of the building is greater than 28 metres. All conductors should take the shortest and most direct route to earth, avoiding sharp angles and curvatures. The radius of any curvature must be greater than 20cms. Each down conductor will be linked to its own earth, usually copperbond earth rods.