Richard Evert, National Director of the Earthing and Lightning Protection Association (ELPA) has provided Sparks Electrical News with a comprehensive series on lightning issue. The series will cover Risk Management; Lightning Protection Design; Lightning Protection System (LPS) Installations; Surge Protection Measures; Earthing and Resistance; and more. Be sure to catch all the articles over the next six months.
RSA National Ground Flash Density Map 11 years.
As an organisation, ELPA strive for industry transparency and vested property stakeholder risk awareness to the extent that every property in South Africa will be supported by a risk assessment alongside the risk assurance electrical COC. The risk assessment will ensure that only vested property stakeholders of properties that require lightning protection solutions will require additional guidance on the risk strategies they need to adopt. This will only be possible with sustained industry support and an adopted skills development plan approved by SAQA and the QCTO in accordance with the request as tabled by the Department of Employment and Labour.
Lightning protection is an exercise in risk management. Risk management as a principle, weighs up the potential for loss or damage, the cost to avoid that loss or damage and the amount of loss or damage that can be tolerated. If the assessed loss or damage can be tolerated without any actions taken to avoid the loss or damage, then the purposes for taking the prescribed actions is deemed not critical or urgent.
Further to this consideration, the assessment may also determine that the actions to avoid loss or damage may cost more than the loss or damage itself and it would be irrational to undertake the prescribed actions.
Proactive and Reactive Risk Management and Lightning
Understanding the risk allows the risk manager to adopt either a reactive or a proactive risk management strategy or some combination of these.
* Reliable historical lightning data is required in a proactive lightning risk management strategy.
* Reliable real-time lightning data and thunderstorm reporting is required for both proactive and reactive lightning risk management strategies.
Governance, Legislation and Regulations
The information being shared here has been carefully worded such that there is neither ambiguity nor opportunity to exploit the explanations.
In the context of the explanation given above, governance cannot unilaterally enforce lightning protection on the citizens of our country in any shape or form either through legislation or regulations.
Any exploitive statements by individuals about existing law and planned changes in legislation and regulations to market their products and services are irrational and a violation of at minimum, the Consumer Protection Act.
On the other end of the spectrum, any attempts at holding our government liable for irresponsible asset management on the part of vested property stakeholders is equally irrational.
Every South African citizen, business and organisation in our country, is entitled to all the support you can get to manage the risks you face. To that end, lightning risk falls into a category where:
* Standards have been developed to offer guidance,
* Governance support exists in the context of liabilities and safety,
* The insurance industry try to factor it in to their support to property owners,
* Academia and lightning scientists study the phenomena to find more effective ways to manage this risk.
ELPA was established specifically to bring certainty to the uncertainty that has been reigning in the lightning protection industry for many years. That so much needs to be unpacked regarding legislation is indicative that exploitation and uncertainty have inflicted considerable collateral damage to our industry and associated industries.
This article and others like it shed light on the matter offering secure alternative understanding based on concrete rational reasoning. More information will be forthcoming on subjects such as "Authority Having Jurisdiction", the liabilities of service providers towards the client and the client opportunities to adopt long term responsible risk management plans.
Lightning – the culprit
There is no question that lightning is a life-threatening risk and causes tremendous losses when it terminates on assets of any value.
Lightning poses a threat even when it does not strike a person or a building directly.
* Indirect lightning is lightning occurring in the vicinity of a structure and not on it.
* Indirect lightning can cause significant damage to electrical and electronic equipment in that structure and inflict fatalities and permanent injuries.
Understanding the culprit and managing the risk
To make an intelligent assessment of the risk posed at any location and to any person, the source of the threat must be understood.
* Knowledge about the lightning that occurs on a location, is central to determining whether lightning protection is required.
* The exercise to examine lightning information to confirm whether lightning caused damage to a property is a reactionary exercise.
* Reactionary strategies do not reduce lightning related losses and are adopted when the anticipated losses are deemed to be tolerable.
Lightning empirical data – The real threat
To afford us the opportunity to make our own informed choices between proactive and reactive strategies, we must have some idea of the actual lightning activity that can be anticipated at the location.
* Historical records provide evidence of what has taken place in the past.
* Supplementary evidence will confirm to what extent the past lightning behaviour will continue to exist in the future.
* If there is no supplementary evidence showing that the lightning behaviour will change, then losses can be determined on the basis that the future lightning behaviour is mirrored by the historical evidence.
As with any risk, we answer some questions about its existence based on evidence we have at our disposal: When, How, Why and Where – the order of these have been purposely placed out of sequence.
No lightning
Firstly, does lightning exist at the location?
When there is no lightning, the following answers are given to the questions:
* When? Never.
* Why? The circumstances required to produce lightning do not exist.
* Where? In each specific instance, this was answered as part of the scope of work.
* How? This question is no longer relevant with regard to lightning. It may be useful to answer this question with regard to how the conditions can occur where lightning will not exist.
In conclusion:
* If there has been no lightning recorded in any shape or form, and
* If there is no evidence to suggest that there will be lightning in the future, then
* There is no lightning threat.
* End of assessment.
For all other instances, the assessment requires sound scientific, engineering and business rationale to conclude with an effective lightning risk management strategy, irrespective of the size of the location, the property use or the commercial value.
When?
When does this lightning occur? The answers provide input to consider a variety of different risk management phases:
* If it occurs when nobody is present, there is no threat to humans.
* If it occurs in significant volumes with a particular start date and a particular end date, a strategy can include preparation phases, reactionary phases and a phase of consolidation.
* If the losses can be quantified as a progressive phenomenon in a repetitive manner annually, the effectiveness of the risk management strategy can be tracked in each year as the storm season progresses, allowing for an intervention phase for years when the thunderstorm activity exceeds expectations or failures exceed the expected levels for that portion of the year.
How?
How does this lightning occur, and how often? Lightning frequency forms part of the information gathered about when.
* If it occurs once every 20 years (that would be very low lightning density), you may be able to tolerate it when it occurs.
* If the location is in or near Piet Retief or Paulpietersburg then you will experience lightning either visually or audibly on a regular basis every month during the storm season and in some months at least every week.
The magnitude of lightning currents will influence the extent of damage inflicted on the structures and the amount of loss suffered.
* The risk manager of a nuclear power station in a very low lightning density area may determine the risk of one very large magnitude lightning strike in 20 years is more than the power station can tolerate.
* If the subsequent damage results in nuclear fallout, the communities within 100km of that nuclear facility would agree with that risk assessment.
* As a consequence, the communities who would suffer terribly from the consequences of such damage, would have great difficulty to comprehend how the power station could have resolved otherwise.
It is in this context that the SANS 62305-2 determines that the tolerable loss of life or permanent injury is one such incident in 100 000 years.
Even then, the subject matter experts resolved that such a figure is subject to the local "Authority Having Jurisdiction" because the supplementary measures to prevent loss of life must complement the lightning protection standards.
How of storm behaviour
The lightning threat is fundamentally linked to the threat of storms which in itself brings with it other environmental threats such as high winds, hail and flooding.
Some reactive lightning risk management strategies include early storm warning solutions and adopting standard operating procedures when such warnings are issued. These measures are considered to be reactive since they have no influence on the behaviour of the lightning terminating on the ground. Such measures on their own will not prevent damage to structures nor will they reduce damage to electronic and electrical equipment.
By understanding the historical behaviour of storms at the location of interest, effective early warning solutions can offer more time during which the vested property stakeholder can enforce changes to minimise possible damage.
By example, proactive early storm warning measures offer the stakeholder the opportunity to move people on the property, to areas that are considered to be safe facilities free from the threat of injury by lightning.
Why?
Why does lightning occur?
Thunderstorms:
* Lightning occurs predominantly in thunderstorms.
* Since thunderstorms are seasonal in our country we can understand why lightning also has a seasonal trend.
Air gap – spatial clearances:
* Lightning to earth is the balancing of electrical discharge between two bodies at different electrical potentials.
* The smaller the gap is between the bodies, the lower the charge build-up required to initiate the discharge between them.
* Since areas of higher altitude have a smaller air gap between ground and the base of clouds, there will be more lightning on the South African highveld than other parts of the country.
* The Drakensberg mountain range and its associated ridge across towards Swaziland/Eswatini demonstrate the most pronounced regions affected by this phenomenon and is visible in the national lightning ground flash density (GFD) map.
Time and space correlation:
* By analysis of our own empirical data we can identify the greatest areas of risk either by way of timing in the year or by regional exposure.
* The risk posed by lightning can be measured by the annual toll on business performance, quantifying their historical losses with the historical lightning information at that location.
* By example, industries such as insurance companies and the power utilities, can identify, annually, increased claims and damage at locations coinciding with changing volumes of lightning before, during, and after the thunderstorm season.
* Establishing that link provides evidence for, and therefore more certainty about, the effectiveness of any proposed risk management strategy.
Where?
Where does this lightning occur?
* The questions of when, how often, how big, and why, need to be repeated for every location of interest across South Africa
* The lightning ground flash density map published by SAWS (South African Weather Service) clearly demonstrates the frequency of lightning activity spatially throughout South Africa.
Lightning Data - South African Weather Service (SAWS)
Lightning has been tracked by means of the Southern African Lightning Detection Network (SALDN) owned and operated by SAWS since January 2006.
SALDN – Credibility
The SALDN system has been independently audited and has achieved service excellence comparable to the best lightning detection networks across the world. The SALDN has produced the longest history of consistently reporting and archiving lightning activity, to the detail required to manage power system assets, in Africa.
SALDN and risk parameter GFD
The lightning ground flash density (GFD) report published by SAWS in 2017 is consistent with the CSIR maps produced in the 1980s.
* Regional association of values are proportionally consistent.
* Variances in values are consistent with the measurement limitations of the CIGRe singular manual flash counters as opposed to the networked and automated modern wide-area lightning sensors under controlled operating conditions.
* SAWS GFD values in regions of high lightning exposure are considerably higher than reported in the CSIR studies and are consistently proportional to the behaviour of thunderstorms over those regions.
The SAWS SALDN GFD lightning data has proven to be a reliable replacement of the lightning risk parameter for all lightning risk assessments in South Africa.
* The details of the new data offers far greater resolution (4 square kilometres across the entire country).
* The details pinpoint localised areas of elevated topology, affording the lightning protection designer more specific input for the risk analysis.
Therefore, lightning risk no longer needs to be the vague exercise that it currently is.
The SAWS by means of the SALDN, offers South African vested property stakeholders:
* Lightning GFD data,
* Lightning ground stroke density (GSD) data,
* Historical lightning stroke and flash data, and
* Lightning data for incident investigations analysis.
The information offered by the lightning ground flash density map is the first step in the review of historical lightning data analysis and is available from SAWS.
Lightning Mitigation Instruction
While lightning protection cannot be enforced by legislative or regulatory means, the national standards of our country provide guidelines for vested property stakeholders who may adopt those standards as minimum requirements for their properties.
* Reputable Standards.
* Reliable Subject Matter Experts.
Reputable standards – South African National Standards (SANS)
The SABS is the custodian for South African Standards and their duties are legislated by South African law. They are therefore liable and accountable to the South African citizen and all our industries to uphold best practices and maintain guidelines that are compliant with South African Competition Law and enable an open international trade environment in the best interests of all South Africans.
In addition to the electrical and grounding/earthing standards, SABS maintain numerous standards pertaining to lightning and lightning protection.
Lightning Risk Management SANS 62305-2
The theoretical lightning risk analysis procedures to follow in 2023 are still governed by the 2011 publication of SANS 62305-2.
This document does not bridge the scientific details of lightning and the adoption of suitable lightning protection designs to the recognised principles of risk management as covered in ISO/SANS 31000 which describes 'risk management' as the process of identifying and controlling risks facing an organisation.
More work is required by our subject matter experts to bring the two areas of science and theory closer to the business of risk management.
Reliable subject matter experts
When considering lightning as a threat, the subject matter is not limited to lightning. In fact, the central subject of interest is the business of the vested property stakeholder.
In the case of insurance companies, the subject of interest is actuarial science. The standards attempting to qualify the respective tolerance levels that a vested property stakeholder must adopt, defer to the "Authority Having Jurisdiction" in the respective countries who adopt the standard.
The insurance industry adopts certain practices based on product pricing and risk. The final values they decide upon, are influenced by many parameters. The more reliable the data for those parameters, the more certain the company is of being able to offer a sustainable product to their clients.
Lightning exposure is one such parameter and the possible solutions offered by technical subject matter experts is another. Technical subject matter experts themselves offer services either to their employers or to the South African citizen directly as a specialist consultant. During the SABS standardisation processes, these subject matter experts have to set aside their own affiliation with other entities and set about finding the best practices for our country to meet the needs of all stakeholders despite their own vested interests.
Appointed standardisation committees who represent the national interests of every organisation or body impacted by a particular standard, rely on those subject matter experts to contribute efficiently such that we as representatives, can convey the content of new standards to our industries for approval.
In summary, our standards are a reflection of the consolidated efforts of our subject matter experts and the organisations deemed to be stakeholders pertaining to the field the standard applies to. Both our subject matter experts and the organisations that represent our national interests, MUST apply their minds to the development of standards that uphold quality of life at a reasonable cost.
Risk averse: Lightning
To ensure that lightning does not cause damage to a structure, a lightning protection system (LPS) offers the lowest uncertainty of risk.
A lightning protection system (LPS) by local and international standards definition (to avoid tedious debate and ambiguous misinformation) is the electrically conducting system installed on a structure to safely divert lightning current:
* Away from a specific point of contact, and
* Into a controlled electrical path, of adequately low impedance, into the ground.
The desired outcome will be that the lightning will have terminated to ground at the property of interest, with no damage to the structure it has terminated on.
Risk averse: Over-voltage
To ensure that lightning does not cause damage to electrical or electronic equipment in a structure, lightning protection surge protection measures (SPM) together with an LPS offer the lowest uncertainty of risk.
The terminology here regarding lightning protection surge protection is somewhat clumsy due to the obvious repeat of the word 'protection'.
The word "protection" is repeated since 'lightning surge protection' conveys a different and incorrect message than what is intended in the context of surge protection under lightning conditions. For the purposes of avoiding the clumsiness we will refer to this subject as 'LP surge protection' measures.
Why is this important and why is this not simply being pedantic?
* Lightning current poses the most severe threat in any installation.
* Suitable LP SPM does not transfer lightning current at any point in the scheme.
* Lightning current causes over-voltage surges as a secondary and equally dangerous threat.
* The threat is towards electrical and electronic equipment due to the designed voltage restrictions of that equipment.
* This concept of surge protection must not be confused with protection against other sources of over-voltage.
* Hence, I have elected to stick with this LP SPM format for the scope of the articles shared in this publication.
Reliable lightning risk assessments
Risk assessments must be repeatable and must produce the same results no matter who does the calculations.
This is only possible when the method of assessment is applied in the same manner and with the same empirical data and using the same calculation assumptions.
It is important to understand that a risk assessment determines:
* Whether an LPS is required,
* Whether SPM are required, or
* Whether an LPS AND SPM are required.
The list above is not in error. There are instances when a site does not require an LPS but does require SPM.
A reliable risk assessment may confirm that:
* You do not need lightning protection and save money.
* You do need lightning protection but not a much as you were told, and save money.
* You do need lightning protection but more than you were told, and you save money.
The difference in these scenarios is simply when you save the money.
* Without an assessment, the vested property stakeholder has no basis to determine the extent of the risk,
* Know your systems, understand your tolerance limits and manage your risk.
Enquiries: www.elpasa.org.za