3D Software Implementation of Air Terminal Placement Methods

To protect a structure or site from lightning, lightning protection rods or air terminals are positioned at suitable locations on or near the structure or site. There are several methodologies that direct the positioning these air terminals, specifically guiding the number of terminals, their location on the structure or site, and their height above the structure or site. These methodologies include Rolling Sphere Methodology (AS/NZS 1728:2021), Leader Inception Theory (IEEE 998-2012), Early Streamer Emission methodology (NF C 17-102:2011), and Collection Volume Method (IEEE 998-2012). Each of these methodologies provides different guidance about the positioning of the lightning protection. The lightning protection required for any particular structure or site will likely differ as a result of which methodology is being applied. Each of these methodologies is similar in one respect, however: its guidance is relatively straightforward to apply when considering a simple rectangular structure and gets complicated when considering realistic structures. For each methodology, a hand analysis of required lightning protection may suffice when considering a simple structure but, for a realistic structure, advanced methods are required for efficient analysis.

Thus, a variety of software applications have been developed to assess the lightning protection requirements of realistic structures and sites. These applications have been integrated into AutoCAD and use AutoCAD’s inherent 3D solid modelling capabilities to assess a structure or site’s particular requirements for lightning protection, and to guide a user to position lightning protection appropriately for that unique structure or site. The computational ability of AutoCAD allows for analysis of structures that are beyond merely simple geometries. Additionally, the lightning protection requirements stemming from different methodologies can be compared with relative ease due to the common software platform.

This presentation provides an overview of the lightning protection software’s capabilities and provides various examples of lightning protection of realistic complex structures.