Over 90 percent of damages to electrical items or machinery can be averted:"

Precautions against lightning hazards - Prof. Chandana Jayaratne

By Ranil WIJAYAPALA

The high intensity of lightning incidents and the number of deaths due to lightning incidents in the country has once again rung alarm bells to the people to take precautionary steps to avoid becoming a lightning victim and to protect their properties from getting damaged from lightning.

To give more in-depth knowledge to the public, the Sunday Observer interviewed Professor in Physics at the Colombo University Prof. Chandana Jayaratne, who is also the Ex Group Leader, Atmospheric Physics and Lightning Research Group, Department of Physics, University of Colombo. Prof. Jayaratne was also involved in preparation of Sri Lanka Standards for Lightning Protection Systems for Sri Lanka Standards Institute and was also a Member of the Committee to Investigate Safety Against Lightning Hazards formulated under the directive of Parliament Committee. He is also currently the principal trainer on lightning protection under the Ministry of Science and Technology VIDARTHA program of the Arthur C Clarke Centre for Modern Technologies, Katubedda, Moratuwa.

Following are excerpts of the interview the Sunday Observer had with Professor Chandana Jayaratne:

Q: These days we very frequently hear about lightning incidents and deaths due to lightning. Some people are of the opinion that this is a normal situation and some of the opinion that this situation is unusual. As a person who has experience in this subject and who has conducted research on this issue what are your observations about this situation?

A: I have done an analysing of lightning activities in the past 1958 onwards. According to these analysis data, lightning incidents were not that intense in the past. There were high activities in the years like 2008. But we cannot depend on these data as we have collected these from newspaper reports of the National Archives because we don't have such data at the moment.

At the Disaster Management Centre the recent data are there. Now we get more lightning. That is happening on an annual basis and also if there is a weather anomaly we may get it. This may also be a part of global warming. The number of lightning incidents also can be increased due to other reasons. The population density is also high at present and also that lightning strikes not only from outside but also when we use electrical appliances we get indirect lightning which is lightning that will hit a tower or telecommunication line coming through the television and or through a power cord main switch which can strike somewhere. There are various reasons for the increase of reported deaths. In the past we have not got enough media reports like today.

There have been years in the past where there had been a lot of lightning incidents. 2008 was such a year where we got a lot of lightning incidents. But in the recent past we have had a lot of lightning incidents with over 60 deaths per year.

Q: Have you identified specific areas where more lightning incidents are reported?

A: There are certain areas like Horana, Avissawella and Ratnapura where we get more lightning than other areas. When we consider the map of Sri Lanka we have the mountain region, dry zone and wet zone. We get more lightning in the wet zone. The lightning incidents are very rare in the dry zones like Hambantota and Eastern part of the country and in Jaffna. But still we get lightning deaths but not like in the wet zone.

If we consider deaths due to lightning effects we have to consider Western, Sabaragamuwa and Southern provinces. They are the areas where you get more lightning damages. Even in those areas you get pockets where increased lightning strikes.

Q: What are the reasons for these areas getting intense lightning incidents?

A: The reason for this may be due to the conductivity in the ground. It may be due to metallic component and it also due to acidity, or else there can be geological dislocation. Geological dislocation is due to the plate underneath which we cannot see. Such plates move very slowly in a period of decades or so.

Q: Is this situation unique to Sri Lanka or common to other parts of the world as well ?

A: Lightning injuries and casualties are common all over the world. However, the more intense lightning is around the equatorial belt. Sri Lanka is located in an equatorial belt.

There are countries like Indonesia, Congo (and Sri Lanka) where you get very high lightning activities. We are getting very high lightning incidents as we get two inter monsoon conditions also.

In Sri Lanka lightning is very intense during the inter monsoon period.

You don't get monsoons in all countries. And in some countries you don't get two monsoons like us. So therefore we are more vulnerable for lightning.

And we should not look at the European countries and other countries to come here and talk with us. This is a very important factor. Nevertheless we have not got involved in the protection part of it.

Sri Lanka is located in the intense lightning belt. Usually all the countries do not have Lightning Location and Positioning Instrument. So they have a different system to identify the thunderstorm activity. If thunder is heard they call it a thunder day. When a BOI company comes to Sri Lanka they used to ask how many thunder days exists per year. In the world map the number of thunder days are very high in tropical forest areas. Lightning hot spots are identified in Florida, USA as we get a climate exactly similar to this part. The number of thunder days in the western province is 160 per year. That is almost half of the year. When it goes to Hambantota and Kataragama it is around 40 thunder days per year.

Q: Why are inter monsoon periods vulnerable for lightning?

A: Inter monsoon periods are from March to April and October to November. Actually what happens in Sri Lanka is, when North East and South East monsoons come they meet and go up very high creating tall clouds. When there is monsoon we get rain but no clouds. But during the inter monsoon period we get a towering structure like 10 to 12 km long clouds. This length is important for charge generation.

Q: Have you observed a change in the pattern of lightning incidents in Sri Lanka?

A: In certain years due to weather anormality in the past this high lightning activities existed but not that frequently. For example, every ten years you get very high thunder activity. But, now it is more frequent. Now you get intense thunder and lightening every other year. Since 2008 we experience such a situation. This is an area we have to investigate - why we get more intensed lightning and more thunderstorms.

Q: Are there systems to predict thunderstorms to give early warnings to the public?

A: In countries like America when a thunderstorm comes towards a certain city they have a warning system so that people can prepare for it. We are also trying to install such lightning location system in future. That needs hundreds of millions of rupees. If that equipment is available it is easy to inform the people. With that instrument you can see a thunder cloud moving and can warn the people, and if there is damage you can say this damage is due to lightning. Because it indicated the pointer location as well as the time that lightning struck over the map of that country. That instrument is available in many countries.

Q: Has Sri Lanka initiated any program to install such equipment here?

A: It is very expensive and we have to create interest among the authorities to get these things to minimise the damages due to lightning. We can also locate the damages due to lightning because that particular instrument has direction and sensors at least in three places in the country. It will sense any lightning inside the country and also within 200 km from the centre location. Sometimes it can be extended up to 1,000 km so that even the ocean or southern part of India can be covered from that instrument. The Met Department tried to purchase one but it is still in the pipeline.

Q: People are now more concerned about the lightning protection systems. Is there any necessity for each and every house to have lightning protection systems?

A: Having lightning protection system for every house is not necessary. There is an equation from which you can calculate whether you need a lightning protection system or not. Those buildings with a large number of people, places concerned with the maintenance of public assistance, where you get more lightning incidents and houses located in very tall and isolated structures or those with historic and cultural heritage there is weight for each criteria and depending on those factors people can decide whether to have lightning protection systems or not.

Q: Despite having lightning protection systems also we hear about damages from lightning. Why do such incidents occur? What are the standards that a lightning protection systems should have?

A: Unfortunately in Sri Lanka though we have lightning protection systems, they also get affected from lightning. This is why we are going to have regulatory mechanism to check them. According to Lightning Protection Standards in Sri Lanka, these Sri Lankan Standards for Lightning Protection safety Standards were prepared according to the requests from Insurance operators.

You need a National Lightning Safety Centre to make protective systems compulsory or to register the vendors or the people or the organisation who install lightning protection systems according to these guidelines. Now anybody can do anything and people don't know whether the lightning protection system they have is good or bad. The other reason is that when you have lightning protection system installed, the conductivity should be good. The ground must be very highly conductive. In many places of the country you don't get this high conductivity in the ground. The conductivity of the ground should be less than 10 ohms. Less than 7 ohms is much better. When the inter-monsoon period comes or the lightning starts we start installing the lightning protection systems and in that weather the conductivity of the ground is always good. But now we observe most of the lightning injuries and accidents taking place at the beginning of the inter monsoon also. Because at the beginning of the inter-monsoon you don't get much rain. When lightning thunder storms come early the soil is dry and the necessary optimum conductivity is not there. Therefore the Sri Lanka standards now recommends that anybody who had install a lightning protection system to check the conductivity at least twice a year.

Q: We can estimate the damages to the people by the number of deaths and injuries. What about the cost of the damages to property?

A: Cost of the property damages due to lightning though there is no proper calculations, can vary from Rs.300 million to Rs.1 billion per year.

That cost is less than what we are going to spend on lightning location and positioning system.

A survey conducted in 2011 the electrical damages are basically on electrical items. The damages from the direct hits are only one percent. More than 99 percent is from indirect hits. From that also 82 percent comes from the power lines. About one percent from the SLT lines. About 8 percent are from SLT plus power lines.

Q: Are there systems available to avoid such damage to the properties?

A: More than 90 percent of the damages to the electrical item or the machinery can be avoided by having surge diverters. Many people are unaware that surge diverter or surge arrestors can be fixed in front of your house before the main switch. It costs Rs.10,000 to 12,000.

The price may change from single phase to three phase current. Once you fix it in front of the main switch that high voltage current coming from the electrical power supplies will go to ground and the instruments will be safe. This is something that is going to be implemented in this country. Right now there is no law but in many countries they have. In Sri Lanka also some people have done this. People should be aware of it and diverters are available in the market and technicians can do it. What we have emphasised is that lightning protection systems should be installed at household level in vulnerable areas. If it is a burden to the Ceylon Electricity Board that can be deducted from the electricity bill.

The second one is that even in front of the important instruments you can have surge diverters.

Q: Are mobile phones vulnerable for lightning?

A: You should not answer the phone from land lines. There was perception that mobile phones are safe. But now we advise not to use mobile phones even. Because there are reported cases where mobile phone battery get exploded due to lightning and the person gets injured. It may be due to low quality batteries or the mobile phones. So we cannot say which is good and which is bad. It is the induced current that cause the battery to explode.

Q: What are the main causes for deaths due to lightning?

A: A research conducted in Sri Lanka by myself and my colleague found that 85 percent of deaths due to lightning have taken place when they are outside. That is very important because if you want to get protected you should not be outside.

Out of the deaths due to lightning, 80 percent of the lightning deaths in this country could have been avoided by giving proper first aid, artificial respiratory and taking the victim to the nearest hospital. People are scared to touch that person. That has to be avoided. Direct hits will not kill people immediately, and 80 per cent can be saved.

Q: How can we get protected from lightning inside a house?

A: The current may come to the floor from a nearby tree. Therefore wearing rubber slippers is not enough. We advise you to be in a bed or in an easy chair keeping your legs closer and you should be away from the window and the main switch. You should not take showers or cooking because inside the house a lightning may strike a light bulb and flash in to your head. Television has to be removed from the electrical power supply and in addition it is better to remove your antenna cable and put it outside the house. We also recommend to put a small cellophane or rubber cover because water can go into it.