Read Aloud the Text Content

This audio was created by Woord's Text to Speech service by content creators from all around the world.

Text Content or SSML code:

External Lightning Protection System or LPS is designed to protect the structures from damages due to External Lightning Strikes. Design of External Lightning Protection System depends on Lightning Protection Level. The lightning protection system is classified into different levels based on the risk factor assessment. The design criteria are adopted from IS/IEC 62305. A detailed risk assessment should be made prior to the design, in order to provide the right level of lightning protection. As the risk assessment is a complex procedure, NBC 2016 recommends lightning protection levels or LPL for different structures. for example, most risky areas like Military applications, Nuclear Power Stations, computer data centers, high rise buildings or hotels, are categorized under LPL1. LPL 2 comprises the areas such as fuel retail outlets, gas stations, and compressor stations etc. Residential buildings, schools, banks, such other structures are classified into either LPL 3 or 4 depending on the severity of damages. There are 3 different methods that used in designing the air termination of LPS. The method of design is chosen according to the rooftop structure. • Mesh method: This method is suitable for flat or plain roofs. A mesh is formed above the rooftop using wires or flat. Mesh size should be selected as recommended as per IS/IEC 62305 • Rolling Sphere method: It is the most suitable method for all complex buildings. In this method, an imaginary sphere with a particular radius is assumed to be rolled over the structure in all possible directions. Air terminals are placed at each point of contact. The radius of the rolling sphere differs for each class of LPS as shown in the table. • Protective angle method: This method is selected to protect simple structures. Vertical air terminals can be placed at suitable points, especially in the projected parts to ensure maximum protection. The radius of coverage depends on 2 major factors, base height of the air terminal and the class of LPS. As you understand from the table, with increase of height of air terminal, the radius of coverage gets improved. Moreover, for the same height of air terminal, the radius of coverage will be different for each class of LPS.