Every year, lightning strikes buildings millions of times worldwide. Public buildings and the service sector—offices, healthcare facilities, schools, hotels, shopping centers—are particularly vulnerable. bothlarge numbers of occupants and sensitive electronic equipment, the failure of which can have serious consequences.
Thus, the international standard IEC 62305 provides a structured framework for assessing lightning risk and sizing appropriate protection systems. Therefore, understanding its requirements is essential for any project owner, engineering firm, or installer involved in protecting commercial buildings internationally.
Why are commercial buildings and public access buildings exposed to lightning?
Numerous occupants and high security rods
Public access buildings (ERP) by definition bring together many people simultaneously. A hospital in full operation, a school in class, a shopping center on a Saturday afternoon — in all these contexts, a direct or indirect lightning strike can cause injuries, critical breakdowns or fires.
In concrete terms, the consequences of insufficient protection are numerous:
- Fire safety and alarm system failures
- Destruction of medical or computer equipment
- Risk of fire due to electric arc
- Prolonged business interruption and financial losses
- The manager's responsibility is being called into question
Increasingly sensitive electronic equipment
Furthermore, the accelerated digitization of commercial buildings increases their vulnerability. Servers, access control systems, building management systems (BMS) and IoT equipment are extremely sensitive to power surges induced by lightning.
Furthermore, even a lightning strike several hundred meters away can induce dangerous power surges through electrical or telecommunications networks. Therefore, protection is not limited to lightning rods: it also includes surge protection devices (SPDs/surge arresters).
IEC 62305: the international reference standard
In countries applying IEC 62305, lightning protection is based on a structured approach in four complementary parts. First, Part 1 (IEC 62305-1) defines the general principles. Then, Part 2 introduces the risk assessment method.
- IEC 62305-1 : General Principles
- IEC 62305-2 : Risk management — Calculation of lightning density Nsg and assessment of losses
- IEC 62305-3 : Physical harm and human risks — design of the protection system (LPS)
- IEC 62305-4 : Electrical and electronic networks — Surge protection (SPD)
Thus, the lightning risk assessment (LRA) according to IEC 62305-2 is the foundational step. It notably takes into account the lightning strike density Nsg (number of ground lightning strikes per km² per year, official notation IEC 62305-2:2024), the equivalent collection area and the building characteristics.
LPL protection levels I to IV
Depending on the ERF, the standard defines four levels of lightning protection (LPL), from the most demanding to the most flexible:
- LPL I : maximum protection — 98% effectiveness — for very high risk sites (ATEX, critical level hospitals, strategic infrastructure)
- LPL II : 95% efficiency — high-risk buildings (large-capacity public access buildings, data centers, schools)
- LPL III : 90% efficiency — typical buildings with moderate risk (offices, hotels, shopping centers)
- LPL IV : 80% efficiency — low residual risk buildings
However, it is important to emphasize that the LPL level is not chosen arbitrarily: it is systematically derived from the risk calculation. Therefore, an ERF (Environmental Risk Factor) is mandatory before any protection system design.
What are the obligations for commercial buildings and public access buildings?
Lightning risk assessment (LRA): an essential step
In countries where IEC 62305 is transposed into national standards (Europe, Africa, Latin America, Asia), commercial and public buildings are required to carry out a lightning protection assessment (LPA). This assessment determines whether lightning protection is necessary and, if so, at what level.
Furthermore, certain categories of establishments — hospitals, buildings housing vulnerable people, critical infrastructure — are systematically subject to a requirement for enhanced protection, regardless of the local Nsg value.
The periodic general inspection (VGP)
Furthermore, IEC 62305-3 mandates periodic inspections of lightning protection systems. Specifically, these inspections must be carried out:
- After each known lightning strike on the installation
- After work modifying the structure or equipment
- According to a periodicity defined according to the LPL (generally 1 to 4 years)
These checks must be carried out by qualified technicians and documented in a report. However, manually managing these deadlines is complex for a multi-site fleet manager.
Lightning protection solutions for commercial buildings
Early streamer emission (ESE) lightning rod: Paraton@ir and Ellips
For large commercial buildings or buildings of significant height, the early streamer emission (ESE) lightning rod is the most suitable solution. A single ESE can cover large areas thanks to its protection radius, calculated according to IEC 62305 or NF C 17-102.
LPS France offers, in particular:
- The Paraton@ir : a connected IoT PDA lightning rod, compatible with Contact@ir System for real-time remote diagnostics
- TheEllips : a high-performance PDA lightning rod for demanding sites
Therefore, these solutions make it possible to significantly reduce the number of capture points required, thus simplifying installation and maintenance on the roof terraces of commercial buildings.
As an illustration, here is how the installation of a ESE lightning rod takes place:
Grounding, down conductors and Equipotential Spark Gap
However, a lightning rod alone is not sufficient. IEC 62305-3 requires a complete protection system including:
- conductors down Properly sized and positioned
- A grounding system that complies with the requirements of the intended LPL
- links Equipotential bonding all the metallic masses
- Surge protectors (SPDs) on the electrical and telecom networks entering the building
Towards connected and centralized management of your facilities
Once your lightning protection installation has been brought into compliance with IEC 62305, the question of its ongoing monitoring arises. Indeed, general periodic inspections (VGP), the replacement of worn components, and the management of alerts after an impact require rigorous organization.
Furthermore, for managers of commercial building portfolios with multiple sites, management complexity increases considerably. This is why LPS Manager was designed: this cloud platform centralizes all lightning incident reports, schedules periodic checks, and sends automatic alerts after a strike.
Thus, LPS Manager allows installers and managers to control their entire fleet of lightning protection devices from a single interface — in real time, from any device.
Conclusion: Act before the storm, not after
Ultimately, lightning protection of commercial and public buildings relies on a methodical approach: risk assessment according to IEC 62305-2, design of the system adapted to the required LPL, then regular monitoring of the installations.
In summary, each building is a unique case that deserves a personalized study. LPS France supports project owners, engineering firms, and installers at every stage—from the initial risk assessment to the selection of the appropriate lightning rod.
Do you have a lightning protection project for a commercial building or a public access building? experts LPS France for a personalized study.
