At Lightning Master® https://lightningmaster.com/ we get a lot of questions about the different systems available for lightning & static protection for production tanks. We offer a complete static and lightning protection system for steel and fiberglass production tanks. LMC’s system addresses dissipation of static and bound charge (potential) on the stored product, direct lightning attachment to the tank or tank battery, and bonding of all masses of inductance on the tank and battery. Alternative solutions offered do not address all three problems, and offer partial solutions of only limited effectiveness. I’ve decided to re-post the below discussion about the alternatives available, their design intent, and performance limitations, and a brief summary of the Lightning Master® system and philosophy. We hope this may clarify some of the confusion, but we are always available to discuss and explain our research & products in more detail.
LMC’s In-Tank Static Drain (ITSD)
Carbon veil is a conductive strip woven into a fiberglass tank with a grounding lug provided near the base of the tank. The intent is to dissipate static charge from the stored product onto the strip. The drawback of this system is that it presents a flat surface to the stored product. Charge more readily dissipates into a liquid off small radius electrodes than off flat surfaces, limiting the effectiveness of the veil. If adjacent wraps of the veil do not overlap, it presents the possibility of arcing between wraps during a lightning strike or ground fault. The carbon veil does not provide bonding to miscellaneous masses of inductance on the tank. Neither does it provide air terminals (lightning rods) or a full- size conductor to ground.
Chain or Carbon Fiber Rope Type Product in tank is also intended to dissipate static charge from the stored product onto the chain or other appliance. The drawback of this system is that it presents a flat (curved) surface to the stored product. Charge more readily dissipates into a liquid off small radius electrodes than off flat surfaces, limiting the effectiveness of the appliance. The chain or other appliance does not provide bonding to miscellaneous masses of inductance on the tank. Neither does it provide air terminals (lightning rods) or a full-size conductor to ground.
Conductive paint only coats the outside of the tank. Therefore, it cannot dissipate static charge from the stored product. Conductive paint may help by providing a path for energy from a direct lightning strike down the bank exterior. However, this division of current over the face of the painted surface is compromised, as there is only one or two ground lugs providing a path to ground at the base of the tank. Additionally, the painted surface will be only marginally effective in serving as a lightning attachment point. If lightning attaches to the tank, the paint will probably not be thick enough to prevent melt-through of the fiberglass, as it does not meet lightning protection code requirements (NFPA 780- 220.127.116.11).
Catenary system consists of grounded masts or poles supporting a wire or wires over the site. This type of system is primarily intended to protect electric power utility company transmission and distribution lines by intercepting what would otherwise be direct strikes to the phase conductors. The overhead wires have no effect on streamer formation from the tanks, and therefore do not affect the likelihood of a direct strike to the tanks. They are merely intended to “get in the way” of a direct strike, intercepting and conveying it to ground. When used to protect tanks or other structures, this system cannot mitigate secondary effect arcing, the primary cause of ignition. In fact, if a catenary system performs exactly as designed and intercepts a direct strike, it maximizes the likelihood of secondary effect arcing across the tank and appurtenances by bringing the lightning energy to ground near the base of the tank. The catenary system also has no effect on the static charge on the stored product, does not provide bonding to miscellaneous masses of inductance on the tank, and does not provide purpose-designed air terminals on the tank or tank battery.
Conventional Lightning Rod system uses Franklin-type lightning rods arranged on the tanks and battery. The conventional lightning protection model is based on attracting lightning to the lightning rod, then conveying it to ground. While this is fine on a wooden house or barn, the type of structure the system was designed to protect, it is not appropriate for use on tank batteries. Lightning attachment is not the primary cause of ignition at your sites. Secondary effect arcing is the primary cause of ignition. As these systems attract lightning to themselves, they actually cause maximum secondary effect current flow right at your site, introducing, not preventing, the primary cause of ignition.
Early Streamer Emitting system uses a small number of air terminals, usually a single air terminal, to protect an extended area. This type of air terminal works by emitting a streamer early in the streamer formation phase of a lightning strike. This assures that its streamer will reach the downward reaching stepped leaders before any other, thereby becoming the preferred lightning attachment point. They often are labeled with names inferring that they protect the area by keeping away direct lightning strikes. Actually, the opposite is true. They attract lightning to themselves and to your site. Therefore, lightning will tend to attach to the ESE air terminal rather than to your tanks and other structures. However, lightning attachment is not the primary cause of ignition at your sites. Secondary effect arcing is the primary cause of ignition. As these devices attract lightning to themselves, they actually cause maximum secondary effect current flow right at your site, introducing, not preventing, the primary cause of ignition.
Lightning Master Solution. The Lightning Master system, on the other hand, provides a total solution. The in-tank static drain (ITSD) provides thousands of small radius points at various elevations throughout the stored product to dissipate static and bound charge on the product. The bonding system brings all masses of inductance to the same potential, reducing the likelihood of arc-caused ignition. The purpose-designed streamer-delaying air terminals delay the formation of lightning- completing streamers from the tanks, thereby reducing the likelihood of a direct strike.
Lightning Master – we wrote the book on lightning and static protection for SWD tanks.