Standardise lightning systems

NEXT month, the Malaysian lightning protection standard, MS-IEC62305, will mark the 10th anniversary of its approval by the Science, Technology and Innovation Ministry (Mosti). The standard was adopted from the IEC62305:2006 standard published a year earlier by the International Electrotechnical Commission (IEC) for its 100-plus member nations around the globe.

This standard has been helping engineers throughout the world to design highly effective lightning protection systems for buildings using conventional air terminals (simple lightning rods), metallic strips and cables. The system is highly effective as long as the engineers strictly adhere to all the relevant design clauses stated in the standard.

The standard was developed by expert members of the IEC Technical Committee No. 81 (TC81) who spent more than five years studying the latest research findings on building lightning protection from around the world. Many of the experts are professors of engineering from world-renowned universities that conduct research on lightning.

The standard also contains a new design clause that predetermines the positions of the air terminals on the roof. These positions are based on a new three-dimensional (3D) design method. Known as the Collection Surface Method (CSM), it can predict with very high precision the locations on complex building structures that are at risk of lightning strikes.

This clause will enable the engineers to easily place the lightning rods where the lightning strikes are likely to occur and hence prevent those parts of the buildings from being struck and damaged.

Before this, the standard had relied on an older 2D design method known as the Rolling Sphere Method (RSM), which was invented more than 60 years ago by Hungarian professor Tibor Horvath. The RSM, which could only determine where lightning would strike a building but did not give any information about the probability of the occurrences, was applied in many national lightning protection standards since then.

Two other design methods in the existing standard are the Protective Angle Method (PAM) and the Mesh Method (MM) invented by French scientist Gay Lussac in 1823 and English scientist James Clerk Maxwell in 1876 respectively. Although more than a century old, these design methods are still being used to protect simple structures.

What most Malaysians do not realise is that the CSM was invented in Malaysia by two local electrical engineers in 1995. They have been documenting and analysing damage caused by lightning strikes to tall buildings in the country and Singapore for nearly three decades. The massive amount of data they collected enabled them to model the behaviour of lightning strikes to complex buildings in 3D which corresponded with the damages they observed.

Their research work attracted the attention of an Australian member of the TC81 committee, Professor Mat Darveniza of the University of Queensland. The professor first applied the CSM in the revision of the Australian lightning protection standard, AS1768, which was published in 2003. He also introduced the CSM to the IEC TC81 committee when the IEC standard was revised in 2000.

After evaluating the CSM thoroughly for several years, the TC81 committee adopted the method in the IEC62305 standard which was published in 2006. This made the two Malaysian engineers the first Asians in scientific history to have invented a new lightning protection design for worldwide application.

Although the CSM is not mentioned directly in the IEC standard, reference to it has been made by European experts in many lightning protection conferences held around the world since then. In 2008, Jozef and Marek Dudas of the Czech Republic mentioned that a lightning protection system designed according to the CSM can intercept up to 98% of lightning strikes to the building.

A few years later, German Professor Kern and his colleagues confirmed the value through their independent studies. This figure suggests that practically all lightning strikes to a complex building can be intercepted if air terminals are located according to the CSM.

Unfortunately, most buildings in Malaysia were designed and installed with lightning protection systems that did not fully comply with the MS-IEC62305 standard because most local engineers are unaware of the CSM and how to implement it in their design work. Consequently, these buildings have been struck and damaged by lightning. Many buildings have had their roofs damaged or burnt after being struck by lightning while falling debris have damaged cars and structures on the ground and lower floors.

This problem appears to be related to the fact that local universities still teach only the 2D RSM in their engineering curriculum. In some cases, these universities even installed the non-conventional lightning protection systems, such as the early streamer emission (ESE) air terminals, that the Malaysian and IEC standard rejected more than two decades ago. One local university even conducted research funded by the Government in order to be the first to invent a new ESE lightning protection system.

To overcome this serious safety problem, the relevant government ministries should ensure that the teaching and application of all lightning protection systems in this country fully comply with the recognised international industry standard, the MS-IEC62305.