Consulting Services

Rolling Sphere Method Modelling for Complex Facilities

3D protection zone analysis that optimises air termination placement and verifies coverage.

Modern facilities present complex protection challenges — multiple roof levels, elevated equipment, architectural constraints, and operational restrictions on conductor placement. Standard prescriptive approaches can leave gaps or result in expensive over-design.

Aetheric applies 3D Rolling Sphere Method analysis using XGSLab's Lightning module integrated with CAD-based tools to determine precisely where protection is needed and where it isn't — optimising coverage while controlling cost.

How RSM Works

The Rolling Sphere Method models the lightning attachment process by conceptually rolling a sphere over and around a structure. Any point the sphere contacts before touching a protection conductor represents a potential strike point requiring additional protection.

  • Sphere radius correlates with the lightning protection level (LPL) defined in IEC 62305 and AS/NZS 1768
  • Smaller radii (higher LPL) require more comprehensive air termination
  • Facility geometry imported from AutoCAD DWG/DXF, Revit, Navisworks, and other BIM formats
  • The sphere is applied systematically to identify all unprotected surfaces and equipment

Protection Level Selection

IEC 62305 and AS/NZS 1768 define four lightning protection levels with corresponding sphere radii:

LPL I — 20m

Highest protection. Critical infrastructure and high-consequence facilities.

LPL II — 30m

Enhanced protection. Data centres, hospitals, and essential services.

LPL III–IV — 45/60m

Standard protection. Commercial and general industrial facilities.

We model coverage for multiple LPL options based on risk assessment results, enabling informed decisions balancing protection effectiveness against budget.

Complex Geometry Analysis

Our modelling handles the challenges standard methods miss:

  • Multiple roof levels and height variations between structures
  • Elevated equipment — HVAC systems, telecom antennas, rooftop solar
  • Architectural and aesthetic constraints on conductor placement
  • Access restrictions and structural limitations
  • Iterative optimisation of conductor layouts for cost-effectiveness

Integration with Protection Design

RSM analysis feeds directly into the broader protection system design:

  • Identified air termination points inform down conductor routing and current dissipation paths
  • Protection zone boundaries guide SPD placement on connected services
  • Results integrate with XGSLab electromagnetic analysis for fault current distribution and ground potential rise
  • Complete documentation for construction teams and compliance verification

Industry Applications

What You'll Receive

3D RSM analysis report with visualisations of protection zones and unprotected areas
Optimised air termination layout recommendations for the selected protection level
Multi-LPL comparison if requested — coverage vs. cost for each option
CAD-compatible output files integrating with your project documentation
Standards compliance documentation per IEC 62305 and AS/NZS 1768:2021

Related Services

Need Protection Zone Analysis?

Whether you're designing new protection or verifying existing coverage, our 3D modelling delivers the precision your facility requires.

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