Special Guest Blog
Kingsmill would like to thank María López from PSR Pararrayos (Spain) for the contribution to our blog page.
PSR Pararrayos located in Spain develops, manufactures and distributes products against lightning and have done since 1976.
Their core product is the Early Streamer Emission Device (a capture device) and Kingsmill are proud to be a distributor for these products. View the range by clicking here
LIGHTNING PROTECTION SYSTEM/EARLY STREAMER EMISSION DEVICE: THE BASICS
What is a lightning bolt? What are its effects?
Many of us think that lightning bolts are one of Nature’s wonders and beauties, yet so few are conscious of to how dangerous they could be to both people and properties.
Lightning can be considered a disruptive electrical discharge due to the dielectric breakdown of the air between the clouds and the earth. When it reaches the earth it generally impacts on natural elements such as trees, hills or even water but it also does impact on buildings or even worst, people.
When a lightning strike occurs, we face two different types of undesirable effects:
- Direct effects
These are due to the circulation of an intense current (several tens of thousands of amperes) which heats materials and causes calcination, melting down of some metal elements, destruction of roofs, antennae etc. and, of course, electrocution when a person receives such an impact.
- Indirect effects
These are not so “spectacular” but, since they are due to over voltages produced by induction, conduction and so forth, they may damage electrical or communication devices such as computers, switchboards etc.
Protecting ourselves from lightning bolts
Over the centuries, protecting people and structures from the effects of lightning has been a major concern.
- In 1752 Benjamin Franklin invented the first protection device – called “Franklin rod” after the American politician and scientist- which consists of one or more tips and down conductors. These are connected to the earth of the installation by means of one or more grounding electrodes.
- A derivation of this device is the meshed cage (also known as a Faraday cage) which consists of a network of tips and down conductors which literally encage the structure on which they are installed. This network is also connected to grounding electrodes.
The problem here is that both rods and cages offer just a mechanical protection. The lightning strike will probably impact on them because they are the highest structure over a rooftop – but it might not do so, and impact elsewhere.
Early Streamer Emission Device
When a way of directing the lightning downward leader was sought, a new type of protection device was developed – the one that is still manufactured nowadays, and very successfully so: the Early Streamer Emission Device.
Early Streamer Emission Devices – such as the ones manufactured by PSR are capture devices based on the electrogeometric (or imaginary sphere) model, which defines the spherical volume protected by a lightning conductor.
The importance of grounding
Grounding is key, this is why we, at PSR, are always insisting on the importance of good grounding when installing a lightning conductor. The earth – which is the ultimate ground – has the ability to absorb an unlimited amount of electrical charge.
When measured, the value of a well done grounding should never be more than 10 Ω. If it is higher, some additional measures are to be taken (such as burying copper plates or using a soil conditioning agent) to improve the resistance of the earth.
Which is the ideal level of protection?
A consistent protection should take into consideration the dimensions of the structure to be protected as well as other parameters such as the keraunic level (the activity of lightning in a given area), the materials of which the structure is made and even the level of human occupation of the building.
All these factors will determine the level of protection of the lightning conductor to be installed. This level of protection also defines the model of the lightning conductor to be selected for a given installation.
View the range by clicking HERE.