Understanding the New Lightning Protection Standards — BS EN IEC 62305:2024

In 2024, the lightning protection world received a major update with the release of BS EN IEC 62305:2024 the latest standard for protecting structures and people from lightning-related hazards.

At Osiris Group, we pride ourselves on being ahead of the curve —
so here’s what you need to know, and why it matters more than ever.

Previous standards often used flash density — the total number of lightning flashes in a region — to calculate risks.

The new 2024 update shifts focus to strike density meaning the number of actual ground strikes that pose real risks to structures and electrical systems.

Why does this matter?

• Ground strikes are what actually impact your building, your people, and your systems.
• Flash density could overestimate or underestimate real risk depending on atmospheric conditions.
• Strike density provides more accurate, targeted, site-specific risk assessments.

Osiris Group has long championed this approach — focusing on real, on-the-ground risks rather than just ticking boxes.

One of the biggest silent risks in lightning protection is not direct strikes —
it’s the surge currents entering through external services like:

• Rooftop plant and HVAC systems
• External lighting columns
• CCTV and security systems
• Renewable energy installations (PV arrays)

The updated 2024 standard emphasises:

This matches Osiris Group’s long-standing philosophy:
Start with coordinated surge protection to safeguard human life and operational continuity, not just structural survival.

If your system was installed or last reviewed under 2008 or earlier versions of the standard,
there’s a high probability it is no longer compliant.

We recommend system reviews for:

A Lightning Protection System (LPS) must now be part of an integrated, multi-layered protection strategy —
not just isolated rods and tapes.