Early Streamer Emission or “ESE” air terminals (hereafter simply abbreviated “ESEAT”) were conceived by French manufacturers in the 1980’s to generate an upward streamer earlier than a traditional lightning conductor, or “Franklin Rod” (FR). This “time advance” characterises the effectiveness of such equipment according to French standard NF C 17-102.
The time advance can be measured relatively easily in a high voltage laboratory against a specific test procedure. The effectiveness of an ESEAT is defined by its “radius of protection”. The radius of protection depends on a number of factors, described below.
From a practical or market viewpoint, a study report published by INERIS by INERIS in October 2001 notes that: Certain claimed ESEAT’s are not tested in a HV laboratory although the manufacturer claims conformity with NF C17-102; Certain models of ESEAT have never been tested to ensure they can handle large lightning currents; The effectiveness of protection claimed by certain manufacturers, who refer to standard NFC 17-102, has never been verified on actual installations; and The capacity of the ESEAT to capture lightning is claimed, but superiority in the radius of protection compared to a Franklin rod is not specified. ScopeNF C17-102 is specifically written on the testing, application and installation of ESE terminals.
Since the release of the 2011 version of this standard, ESEAT protection is now deemed to be applicable to structures of any height and for the protection of open areas. Note that the previous version of the standard, first published in 1995, has been cancelled by the French standards organization UTE. Technical and legal conformity with that version ceased in September 2012.