What is BS EN IEC 62305-2:2024 - Protection against lightning risk management about?
The second in a four-part international series on lightning protection measures, BS EN IEC 62305-2:2024 outlines risk assessment for a structure or service from lightning flashes to earth. The other standards in the series are:
- BS EN IEC 62305-1 General principles
- BS EN IEC 62305-3 Physical damage to structures and life hazard
- BS EN IEC 62305-4 Electrical and electronic systems within structures
Who is BS EN IEC 62305-2:2024 - Protection against lightning risk management for?
BS EN IEC 62305-2 is essential for anyone directly or indirectly involved in lightning protection, most likely in the built environment, health and safety, risk management, and electrical engineering sectors.
Specific users will include:
- architects involved in the design and construction of large and critical buildings, including the retrofit installation of equipment in existing buildings having lightning protection;
- surveyors involved in design and construction of large and critical buildings including the retrofit installation of equipment in existing buildings having lightning protection;
- engineers involved in the design and manufacture of lightning protection components;
- builders involved in construction of large and critical buildings;
- facility managers involved in maintenance of large and critical buildings;
- electrical engineers in specialist earthing companies;
- high voltage engineers; and
- consultants and specification engineers.
What does BS EN IEC 62305-2:2024 - Protection against lightning risk management cover?
BS EN IEC 62305-2:2024 outlines risk assessment for a structure or service from lightning flashes to earth. Its purpose is to provide a procedure for the evaluation of such a risk - one that can be reduced by the protection measures employed within BS EN IEC 62305-3 and BS EN IEC 62305-4.
Why should you use the standards in the BS EN IEC 62305 series?
Efficacy: lightning discharges are an unpreventable and hazardous weather phenomenon. Protection measures are essential and the measures in the BS EN IEC 62305 series of standards are proven to be effective at reducing risk.
Assurance: the BS EN IEC 62305 series of standards give assurance that a building design provides adequate protection against lightning. It gives assurance that retrofitted equipment is sufficiently separated from lighting conductors and lightning bonded equipment, or if this isn’t possible, that appropriate bonding is performed. And it gives assurance that an appropriate maintenance cycle is adopted.
Knowledge: the BS EN IEC 62305 series of standards provide a robust, up-to-date understanding of the specific requirements of lightning earthing and, especially in Part 1, the electrical characteristics of lightning positive and negative strokes.
Empowerment: the BS EN IEC 62305 series of standards give users sufficient knowledge of lightning protection to understand the outcome of a lightning risk assessment and write specifications for installation and maintenance contracts.
What has changed?
BS EN IEC 62305-2:2024 constitutes a technical revision and includes the following significant technical changes:
- The concept of a single risk, to combine loss of human life and loss due to fire, has been introduced.
- The concept of frequency of damage that may impair the availability of the internal systems within the structure has been introduced.
- The lightning ground strike-point density NSG has been introduced replacing the lightning flash density NG in the evaluation of expected average annual number of dangerous events.
- Risk components reduction by the use of preventive temporary measures activated by means of a thunderstorm warning system (TWS) compliant with IEC 62793. The risk of direct strike to people at open areas is introduced in this edition, considering the reduction of that risk using TWS.
National Annexes to BS EN IEC 62305-2 3ED
The values assigned for certain parameters used as part of the risk evaluation process in this British Standard, are values proposed by IEC (specifically in Annexes B and C). National Annexes NB and NC contain appropriate UK interpretations. Furthermore, to undertake a risk evaluation, users will need to have knowledge of the ground strike density over the UK.
- National Annex NB (informative), Assessment of probability PX of damage
- National Annex NC (informative) Assessment of loss LX
- National Annex NG (informative) UK Ground Strike Density Maps