Ashen Gomes

Hierarchy of hazard control to minimize lightning risk

This paper presents analysis of various potential lightning risk scenarios, especially in less developed communities. We identify that there is no uniform safety promotion module that may be applicable to all communities with success. Hence we develop a hierarchy of hazard control mechanism that may be applicable to any given community with uniform professional or social practices. The hierarchy of control ladder has been integrated with the responsibility distribution network that runs from government level to the potential victim. The mechanism could be adopted by designers of lightning safety promotional programs in many parts of the world by appropriately determining the tools of implementation at various societal and professional levels. It is expected to minimize deaths and injuries as well as property damage due to lightning in vulnerable parts of the world.

Lightning; Gods and sciences

This paper gives an account on the historical and regional social concepts on the natural atmospheric phenomenon of the lightning phenomenon. It explores the divine concepts induced on lightning by various communities. The investigation also looks into the mythical beliefs with the objective of analysing how such conceptual aspects affect the promotion of scientific rationales of lightning safety and protection in such societies. The facts presented explain the reasons that prevent some communities from developing logical thinking and analytical skills in the field of lightning science.

Lightning hazard mitigation in Uganda

This paper addresses a concurrent burning issue in Uganda; the mitigation of rapidly increasing lightning hazards in the country. By analyzing various economic, technical and social factors a feasible hazard mitigation module has been proposed. The module essentially needs government intervention for providing facilities and coordination of various contributors and stakeholders for channeling expertise and possible funding. Several lightning disaster mitigation strategies have been proposed whereas practicality and limitations of applying them in Uganda are discussed in detail. Proposed modules are applicable in many countries having similar socio-economic environment.

Lightning current and voltage distribution of large axially symmetric buddhist stupa in Sri Lanka

This is one of the first scientific investigations on lightning current and voltage distribution along Buddhist Stupa in Sri Lanka and elsewhere. Such distribution provide vital information on lightning safety concerns of people and objects outside the structure as the building is totally sealed. The metal casket of which the block of quartz is installed at the pinnacle of the Stupa, may act as the point of interception with lightning stepped leader. Large hemi-spherically symmetric outer structure of the Stupa causes uniform distribution of current over its surface. Such distribution yields very low current density thus possibilities of side flashing or localized heating are minimized. Structure of the Stupa was analyzed as a collection of lumped circuit elements using MatLab and SimuLink software to show that there will be no dangerous potentials developed within possible arcing range to the surrounding, in the application of impulse current. Thinly distributed current, driven into the deeply laid foundation of the structure, prevents development of significant step potentials in the vicinity that could pose danger to the devotees.

Evaluation of lightning protection systems proposed for small structures by electromagnetic simulation

This paper validates the performance of low-cost lightning protection systems for small structures proposed by researchers in the past. Such structures have an acute demand in the countries with very high lightning ground flash density, yet the affordability of the mass public is quite limited due to the struggling economies of the countries. The protection systems for small housing structure, and a standalone protection structure for one or few people have been investigated by implementing the structures in HFSS/ANSYS software which employs finite element method. By applying current waveforms to represent first negative return stroke, subsequent negative return stroke and positive return stroke, the electric field and potential gradient of the entire space and the current density and the thermal profile of the protective structure have been computed. The objectives were to find whether the voltage distribution in the wake of a lightning strike could initiate side flashes, generate touch potential and step potentials that exceed dangerous levels, drive current densities due to which the structure collapse under thermal effects. It has been found that the proposed protective structures could suppress side flashes and harmful effects due to step potential while the structure will be able to withstand the heat generated. However, the touch potential could still be beyond the human injury thresholds, thus a minimum separation from the lightning current passage should be advised to the occupants.

Concerns of the application of lightning protection risk assesment for small structures

International Standards on lightning protection risk assessment (IEC 62305-2: 2010) are well accepted and applied in many parts of the world. During the last few years a large number of lightning related accidents, especially due to direct strikes, have been reported from Asia and Africa where the lightning struck objects are small structures. Information gathered from several investigations done on these cases have been used to determine the level of protection needed for these structures as per the standard risk assessment. In many cases the outcome was the none-requirement of any LPS for such structures or a risk factor for direct strike probability which is less than the critical value. As there are millions of similar structures in these regions, we propose the development of a separate risk assessment algorithm for such structures, especially in underdeveloped countries.

Lightning safety psyche

How is lightning protection ranked in the field of safety science? What is the general perception of the public with regard to the risk of receiving a lightning strike to their building? How do business entities manipulate the psyche of the public in upsizing financial gains? What is the true risk of public adopting lightning protection techniques that have not been included in major international standards? Is the research presented so far in condemning the lightning protection systems rejected by the scientific community, well-conducted? Is tabooing of some lightning protection technologies a productive strategy in driving the public to adopt protection systems recommended by international (IEC) standards? This paper makes comprehensive attempts to answer these questions.

Characteristics of fulgurite-like structures under HV conditions: Effects on electrical earthing systems

Fulgurites are natural tubes of glass formed by the fusion of silica sand or rock from a lightning strike. The fulgurites have been produced artificially in HV conditions in the past. Recent studies have found that fulguritic structures can be formed in some other materials, such as bentonite and cement, as well. These fulgurites can change the overall physical and electrical properties of the original materials. Thus, formation of fulgurites can modify the performance of electrical earthing systems, both ordinary and those improvised with backfill materials. This study investigates the fulgurite formation under alternating, direct and impulse current application. Bentonite and sand were tested under high voltage conditions. The type of fulgurites and their effects on electrical earthing systems were studied by analyzing the resistivity and permittivity of original materials and fulgurites. It has been found that fulgurites formation has a severe effect on the earth resistance of grounding systems.

Analysis of Lightning Occurence in Zambia

This paper presents analysis of human observations on thunder days in five regional centers in Zambia. The regions covered are specifically of interest to aviation industry. The variation pattern of monthly thunder days show that the lightning activity has well-detectable oscillatory pattern over the year. However, the pattern varies from region to region thus, as a single country Zambia experiences lightning almost throughout the year. We strongly recommend the installation of automated lightning detection system in the country to provide more accurate lightning ground flash and cloud flash density mapping. Such information will play a vital role in lightning safety and protection planning.