Glossary
Excitation time advance (ΔT) : Average excitation time saving of the ascending tracer compared to that of a simple rod lightning conductor. The setting up of the excitation time advance is performed in accordance with NFC 17-102 standard tests. This time advance is measured in microseconds (µs) and cannot exceed 60 µs.
Natural components : Protection components against lightning not installed specifically for this purpose but can fulfill the function of one or several parts of the LPS (Lightning Protection System).
Down conductor : Part of the outdoor installation assigned to convey the lightning current from the capture device to the earthing system.
Dart (“streamer”) : The dart (“streamer”) is the electrical discharge line growing over distances of up to some tens of centimeters and generated by the rise of the electrical field. The dart enables the shaping of the low ionized channel through which the lightning current will be conveyed.
Lightning density : It stands as the number of strikes per year per square kilometer. This value is an important factor in the assessment of lightning risk.
Capture device : Part of the metallic outdoor installation to intercept lightning.
Separation distance : Distance between two conductive parts for no dangerous gateway to appear.
Lightning flash : Electric download from the atmosphere which may occur within the cloud or between clouds.
Lightning : Electric download from the atmosphere between the thunder cloud and the earth.
LEMP (Lightning Electromagnetic Pulse) : Electromagnetic effects of lightning current.
Lightning equipotential link : Interconnection of the lightning protection system to the conductive parts of an installation by conductors of surge protectors reducing potential differences caused by the lightning current, and thus the risk of dangerus spark.
Keraunic level : Number of days per year when thunder is heard within some place.
Level of protection : Figure associated with a set of parameter values of lightning current in the probability that the maximum and minimum associated design values will not be exceeded when lightning occurs naturally. 4 main levels of protection were determined by standard (from I to IV), I which is the most important level of protection.
Surge protector : Device designed to limit temporary surges and evacuate shock currents.
Early Streamer Emission lightning conductor (ESE) : Lightning conductor equipped with an air ionization system generating excitation time advance compared to a simple rod set in the same conditions.
Simple rod : Lightning capture device placed in the upper part of the structure to be protected, exceeding 2m at least. The angle of protection (or radius of protection) depends on the level of protection and is defined in EN 62305-3 standard.
Earthing : Part of the external lightning protection system to convey and clear lightning current to the earth.
Foundation earthing : Foundation steel armor or conductor embedded in the concrete foundations of the structure, used as a ground electrode under some conditions.Also called foundation loop, it can made of a bare copper little earth cable buried around the concerned structure.
Meshed cage protection : Protection for setting up conductors surrounding the structure. The size between roof and down conductors depend on the level of protection.
Tight strand protection : it consists of avoiding the protection of a structure to come into contact with it. The setting up of one or several conductors is required.
R risk : Measuring the probable annual loss (people and property) of the object to protect.
TR tolerable risk : Maximum risk value that can be tolerated by the protected object.
Protective system against lightning : Whole system enabling to protect a structure against lightning direct and indirect effects.
Glossary
Excitation time advance (ΔT) : Average excitation time saving of the ascending tracer compared to that of a simple rod lightning conductor. The setting up of the excitation time advance is performed in accordance with NFC 17-102 standard tests. This time advance is measured in microseconds (µs) and cannot exceed 60 µs.
Natural components : Protection components against lightning not installed specifically for this purpose but can fulfill the function of one or several parts of the LPS (Lightning Protection System).
Down conductor : Part of the outdoor installation assigned to convey the lightning current from the capture device to the earthing system.
Dart (“streamer”) : The dart (“streamer”) is the electrical discharge line growing over distances of up to some tens of centimeters and generated by the rise of the electrical field. The dart enables the shaping of the low ionized channel through which the lightning current will be conveyed.
Lightning density : It stands as the number of strikes per year per square kilometer. This value is an important factor in the assessment of lightning risk.
Capture device : Part of the metallic outdoor installation to intercept lightning.
Separation distance : Distance between two conductive parts for no dangerous gateway to appear.
Lightning flash : Electric download from the atmosphere which may occur within the cloud or between clouds.
Lightning : Electric download from the atmosphere between the thunder cloud and the earth.
LEMP (Lightning Electromagnetic Pulse) : Electromagnetic effects of lightning current.
Lightning equipotential link : Interconnection of the lightning protection system to the conductive parts of an installation by conductors of surge protectors reducing potential differences caused by the lightning current, and thus the risk of dangerus spark.
Keraunic level : Number of days per year when thunder is heard within some place.
Level of protection : Figure associated with a set of parameter values of lightning current in the probability that the maximum and minimum associated design values will not be exceeded when lightning occurs naturally. 4 main levels of protection were determined by standard (from I to IV), I which is the most important level of protection.
Surge protector : Device designed to limit temporary surges and evacuate shock currents.
Early Streamer Emission lightning conductor (ESE) : Lightning conductor equipped with an air ionization system generating excitation time advance compared to a simple rod set in the same conditions.
Simple rod : Lightning capture device placed in the upper part of the structure to be protected, exceeding 2m at least. The angle of protection (or radius of protection) depends on the level of protection and is defined in EN 62305-3 standard.
Earthing : Part of the external lightning protection system to convey and clear lightning current to the earth.
Foundation earthing : Foundation steel armor or conductor embedded in the concrete foundations of the structure, used as a ground electrode under some conditions.Also called foundation loop, it can made of a bare copper little earth cable buried around the concerned structure.
Meshed cage protection : Protection for setting up conductors surrounding the structure. The size between roof and down conductors depend on the level of protection.
Tight strand protection : it consists of avoiding the protection of a structure to come into contact with it. The setting up of one or several conductors is required.
R risk : Measuring the probable annual loss (people and property) of the object to protect.
TR tolerable risk : Maximum risk value that can be tolerated by the protected object.
Protective system against lightning : Whole system enabling to protect a structure against lightning direct and indirect effects.