The New Fire Prevention Rules entered into force with Regulation 28/2011 (6 September) has resulted in significant changes (also) in the field of lightning protection. The lightning protection of the individual facilities has to be established in accordance with standards MSZ EN 62305-1-4:2006 created with an essentially new approach instead of Standard MSZ 274 enacted with previous Regulation 9/2008 (22 February) ÖTM. Previously established lightning protection devices must be inspected in accordance with the requirements of Standard MSZ 274, while the requirements of Standard MSZ EN 62305-1-4:2006 are applicable for new facilities.
Extreme attention must be paid to protection against lightning strokes in facilities and plants that may contain explosive atmospheres. The lightning protection of such system must be designed and developed so that a lightning stroke in the direct vicinity of or at a certain distance from the object cannot cause an explosion. A lightning stroke has different harmful effects: heat effect, mechanical force, electric effect.
The lightning protection of a facility can be divided into two parts:
+ Primary lightning protection (primary lightning protection, external lightning protection)
+ Protection against the secondary effect of lightning stokes (secondary protection, internal lighting protection)
The purpose of the primary lightning is to avoid direct lightning stroke to the object to be protected. This can be achieved with lighting protection devices that capture and conduct the lightning current towards the ground in a controlled way where it dissipates without harmful effects. The three basic components of a lightning protection device:
The design of primary lightning protection is determined by the lightning protection classification of the given building, industrial equipment (e.g. tank). Basic aspects of classification: function, geometry, environment, roof structure, materials of surrounding walls, air composition, consequences of secondary effects. The facility must be provided with a lighting protection device of efficiency grading in accordance with the classification.
As a secondary effect of a lightning stroke occurring in the vicinity of a facility, the short-term but very high pulse-like lightning current induces high voltage pulses in the neighbouring metal devices and wires which passes through the wire system as an attenuated wave and causes short-term (decaying) overvoltage on certain sections. This overvoltage may cause electric rupture and electric arc discharge at points with the weakest electric strength, and the ignition of the explosive gas mixture in explosive atmospheres. The internal lightning protection system is intended to conduct these pulses created as a secondary effect in a coordinated way without causing ignition sparks.
The adequacy of the lightning protection devices must be guaranteed by proper planning during establishment and reconstruction on the one hand. The lightning protection devices must be checked and inspected during the use of the facility at the intervals specified in the requirements on the other hand. The lightning protection inspection is a complex procedure specified in a standard and subject to authorisation. The result of the inspection is recorded in the Lightning Protection Inspection Report.
Previously, lightning protection was covered by Standard MSZ 274 in Hungary. Currently, the relevant requirements for this field are given in set of EU harmonised standards MSZ EN 62305.
In accordance with the valid Hungarian legislation, only designers registered in the Hungarian Chamber of Engineers, authorised to design EN-T and V-T and also highly qualified in the field of Vn may be appointed to plan lightning protection.