Editor’s note: The following is a question-and-answer conversation between Chemical Engineering magazine senior editor Scott Jenkins and Sean Carpenter, solutions analyst at Lightning Eliminators & Consultants, Inc. (LEC), a leading provider of lightning protection solutions. Chemical Engineering’s questions appear below in bold font; LEC answers are regular font.
Q: Can you outline the risks associated with a lightning strike at a chemical process facility, and differentiate between the impacts of a direct strike on equipment, versus a strike nearby?
A: Chemical plants are highly vulnerable to lightning strikes due to the constant presence of flammable and volatile materials. A direct strike, spark, or even an occurrence miles away can trigger fires, explosions, equipment failures, or widespread process disruptions. Even in areas with infrequent thunderstorms, severe lightning events can still occur, leading to catastrophic damage, injury, downtime, fines and negative impact to corporate reputation.
There are additional interrelated factors that contribute to the vulnerability of chemical plants to lightning strikes. Sites are often located in open or elevated areas, such as flat plains and gulf coasts, which naturally increases their exposure to lightning. The presence of tall steel structures, including towers, tanks, piping and electrical transformers further heightens the risk, as these installations are more likely to attract electrical discharges. Compounding the hazard is the presence of flammable gases and liquids, which can create explosive atmospheres, particularly around storage tanks, vents, or during transfer operations. A lightning strike in such conditions can easily trigger fires or explosions.
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Modern chemical plants also rely on complex electrical and control systems, which are sensitive to voltage surges. Even indirect lightning strikes up to a mile away can result in equipment failure or operational disruption. When these events arise, the financial consequences can be devastating. This is leading many chemical plants to adopt lightning defense strategies designed to protect structures, equipment and personnel.
Most industrial applications inherently meet lightning protection requirements due to the structural thickness of vessels, stacks and tanks, which are typically greater than 3/16 in. However, in chemical processing environments, damage to the structure itself is not the primary concern. The greater risk lies in the potential for a lightning event to ignite flammable vapors or cause significant harm to low-voltage instrumentation and control lines. For this reason, mitigating and preventing lightning activity should be a priority, as the secondary effects of a strike can lead to far more serious operational and safety consequences.
Q: Are there particular types of equipment that would be more or less vulnerable than others to a lightning strike? Could you “rank” the equipment types in terms of highest risk to lowest?
A: In a chemical process facility, large storage tanks represent one of the highest-risk assets when it comes to lightning exposure. Their height, geometry and composition make them natural collection points for direct strikes. A lightning event on a tank can introduce extremely high currents into the structure, creating an ignition source for flammable vapors. In addition, tanks often have roof-mounted instrumentation, such as level transmitters, pressure switches, or temperature probes. A strike in the area of these units can introduce surge energy to a plant’s control network.
Risk ranking for equipment types (highest to lowest vulnerability)
- Storage tanks containing flammable liquids
- Distributed control systems (DCS), programmable logic controllers (PLCs), input/output (I/O), marshaling cabinets
- Field instrumentation and signal lines
- Variable-frequency drives (VFDs), motor control centers (MCCs), electrical distribution equipment
- Communications equipment and supervisory control and data acquisition (SCADA) equipment
- Steel structures containing inert material with a thickness greater that 3/16 in.
Q: From your experience, can you tell us about specific instances where lightning damaged an industrial process facility, and what were the outcomes?
A: Recently, a lightning strike caused a hydrogen stack at a chemical plant to ignite. According to incident records, the strike made direct contact with the stack during a severe storm, delivering enough electrical energy to ignite the hydrogen. The resulting fire was quickly contained by on-site safety systems, and no injuries were reported, but the event underscored the inherent vulnerability of hydrogen-handling equipment during lightning activity. The incident prompted a broader review of the plant’s lightning protection strategy, emphasizing the need for preventive technologies and improved grounding. While the damage was minimal, the event served as a clear reminder of how rapidly a lightning strike can escalate into a hazardous situation when flammable gases are involved.
Q: Can you talk about the different approaches for lightning defense, explaining the difference between “lightning avoidance” and “lightning protection”?
A: Lightning defense is a specialized body of knowledge that has accumulated for over 200 years. Broadly speaking, lightning defense encompasses two key approaches: lightning protection and lightning avoidance, such as charge-transfer technologies. Proper grounding and surge protection are also critical.
NFPA 780 and UL 96A are the accepted lightning collection standards in the United States. UL 96A was first published in 1916. In the last 50 years, lightning prevention systems have proved valuable in uptime critical industrial applications.
Rather than offering a one-size-fits-all solution, lightning protection and mitigation recommendations should be tailored to a facility’s unique vulnerabilities, whether that involves bonding solutions for storage tanks, direct strike avoidance, secondary damage caused by a nearby strike or grounding improvements.
The most effective defense is to prevent a lightning strike from occurring. This is a far superior solution than a lightning rod-based system that attracts lightning to the protected site and then attempts to manage the strike.
Lightning occurs when the difference in potential between storm clouds and the earth reaches a critical level, triggering an electrical discharge. For lightning to strike, it requires a connection between a downward leader from the cloud and an upward streamer from the ground.
Products designed to prevent direct lightning strikes within a designated protection area are available. The approach is to lower the electric field to levels below those required for lightning to form. These systems prevent these connections by using point discharge technology, which neutralizes the charge differential before a strike can occur. Through a system of well-grounded points, this approach facilitates the exchange of ions between the air and the ground, disrupting the conditions necessary for a lightning strike.
Each lightning protection system is customized as each structure and application has its own needs. Some installations may only require lightning rods as structural integrity is the primary concern. Uptime critical applications with hazardous material or complex control systems require surge protection and a lightning prevention system that utilizes dissipation technology.
Q: What are differences in risks of lightning strikes for facilities in different climates, geographic regions, elevations, proximity to coast, and so on?
A: In most cases, the inherent risk posed by a lightning strike is the same regardless of location. The difference lies in the frequency of events and the concentration of industrial activity.
For example, lightning occurs far more often along the Gulf Coast — from Florida to Texas — than in the Pacific Northwest. A strike in Seattle would cause damage comparable to one on the Gulf, but it is simply less likely to happen. Additionally, the Gulf region has a much higher density of chemical plants, refineries, process facilities, and pipeline infrastructure, which naturally leads to a greater number of lightning-related incidents and operational disruptions.
The risk of a lightning strike in a specific location can be determined with isokeraunic maps that determine lightning days per year in geographic areas. States along the Gulf have higher isokeraunic numbers which equate to higher lightning activity and higher probability of lightning problems. From these maps, it is determined that West Africa is the lightning capital of the World, and the Tampa area of Florida is the lightning capital of the U.S.
Q: Are floating-roof storage tanks considered to be in their own class, in terms of risk?
A: Storage tanks should be treated as their own category because traditional lightning protection systems are not appropriate for these applications. Due to the explosive nature of the materials involved, allowing the high currents from a lightning strike to enter the structure can lead to the ignition of flammable vapors. In any environment involving the production, handling, or storage of ammunition, explosives, or flammable liquids or gases, only a lightning prevention system that uses dissipation technology should be employed.
At chemical plants, one of the most significant and well-documented risks is storage tank fires. The most common types are fixed and floating roof, but there are also spherical, “Horton sphere,” bullet, and cryogenic tanks.
The most common type of fire in floating roof tanks is a seal fire, which results from a lightning-induced spark or a buildup of static charge igniting vapors near the tank’s rim seal. While there are systems that are designed to manage a seal fire, the consequences can be significant. The affected tank must be taken offline, cleaned, and have its seals replaced, creating downtime and operational disruption for the terminal. Larger tank fires are less common but can burn for days, causing severe damage and making recovery much more difficult.
Floating-roof tanks are particularly susceptible to fires resulting from lightning strikes. Electrical currents from such strikes can traverse the tank’s shell and roof, potentially arcing across the roof-shell interface. This arcing can ignite flammable vapors present near the floating roof seal, leading to catastrophic fires. Traditional bonding methods such as metal strips, known as “shunts,” have proven unreliable due to factors like corrosion, misalignment, and inherent design flaws, thereby increasing the risk of sustained arcs. Proper bonding and grounding solutions are critical for prevention.
Even non-metallic and internally lined storage tanks can accumulate static electricity during regular operations. This accumulation poses a significant risk, as static discharge or external factors like nearby lightning strikes can ignite flammable vapors within the tank, leading to catastrophic events.
Q: Can you explain the roles of grounding and surge protection in the context of lightning strikes?
A: Grounding and surge protection are inseparable, with each relying on the other to function effectively. Surge protection serves as the first line of defense against the secondary effects of a lightning strike, clamping over voltages and directing them safely to ground before damage occurs.
Grounding provides the actual pathway for that surge energy to flow; without a low-impedance grounding system, a surge protector cannot operate as intended. Lightning is opportunistic and lazy. It is always looking for the path of least resistance, so both the grounding system and surge protection must be designed to offer a clear, low-resistance path to ground.
When these elements work together, a solid grounding network paired with properly installed surge protection, they form a coordinated system that limits overvoltage, protects sensitive equipment, and reduces the risk of failures during lightning events or electrical transients.
Q: What are the considerations for installation of lightning protection technologies?
A: Due to the wide range of available technologies, mounting an effective defense against lightning-related threats typically requires a tailored strategy that integrates multiple solutions, each having its own specific purpose for minimizing damage or avoiding it altogether. The optimal combination depends on the specific site conditions and the nature of the operation.
While the proper combination of component technologies is crucial, having a single source oversee the installation of these systems can also be a key aspect of effective implementation.
Traditional lightning protection methods typically involve engaging separate vendors for system design, material procurement, and installation. This fragmented approach often results in miscommunication, extended project timelines, and increased costs.
A turnkey provider that consolidates all project phases under a single expert team ensures unified accountability, accelerates execution through streamlined coordination, improves system performance through integrated component design, and lowers overall costs by reducing errors, rework, and inefficiencies caused by misaligned vendor efforts.
Edited by Scott Jenkins
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Editor’s note: Answers here were provided by Sean Carpenter, solutions analyst at Lightning Eliminators & Consultants, Inc. (LEC; 6687 Arapahoe Rd. Boulder, CO 80303, USA; Phone: 303-447-2828; Email info@lecglobal.com; Website: lightningprotection.com). LEC’s solutions protect critical operations and structures for some of the world’s most recognized companies, including Federal Express, UPS, Marathon Petroleum, Chevron, ExxonMobil, Telluride Ski Resort, and thousands more. LEC is the maker of the patented Dissipation Array System (DAS), which can be integrated with a wide range of structures, including buildings, towers, tanks, and stacks. DAS is designed specifically to the site it is meant to protect. Through consulting with the customer, it is determined what has been affected by lightning using empirical data, maintenance records, atmospheric reports with timelines and others to first determine the issues. Then with the customers’ assistance, LEC determines the critical processes, structures and assets (both physical and financially) that are at risk and how best to protect them. A lightning protection system is then designed and tailored to the specific site making sure that all the critical concerns are included in the solution. The effectiveness of DAS is enhanced when combined with a comprehensive lightning protection system that includes a low-impedance grounding system, transient voltage surge suppression, and modular strike prevention devices. Together, these components ensure optimal protection against both direct strikes and secondary electrical surges. LEC is also the developer of the Retractable Grounding Assembly (RGA), designed to safeguard floating roof storage tanks from lightning-induced fires. This patented and ATEX-approved solution ensures a permanent, low-impedance bond between the tank’s floating roof and shell, preventing dangerous arcing and subsequent ignition of flammable vapors.