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LIGHTNING AND STATIC PROTECTION |
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Salt water separation, distillate, frac, storage
and similar tanks, particularly fiberglass tanks, have a history of
susceptibility to catastrophic damage from lightning and static
discharges. To address these phenomena, Lightning Master has
developed a tank protection system. This system addresses both
problems: static and lightning strikes to the tanks. The wild card in tank protection has always been equalizing the bound charge on the stored product. Charge dissipates from a liquid onto points and edges. Even in a steel tank, there are none to help dissipate the bound charge on the stored product. The liquid simply lies against the side if the tank, and the charge must inductively couple onto the flat surface. This takes time for the potential to relax. Lightning Master has designed an in-tank static drain consisting of a stainless steel cable with stainless steel electrodes inserted into the wind of the cable. This drain, installed through the thief hatch, introduces thousands of electrically sharp points into the stored product, offering a low-resistance path for bound charge to leave the liquid and vapor space. It “sucks the charge” out of the product, allowing it to relax much more quickly. |
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This in-tank static drain is then electrically bonded (grounded) to the tank. On a steel tank, the only additional bonding required is a jumper between the thief hatch and collar (if it is loose enough to rattle, it is loose enough to arc). |
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| On a fiberglass tank, a conductor system is installed, bonding the top vent pipe or manifold, the in-tank static drain, thief hatch collar, walkway handrail system, and tank conductive elements such as a carbon veil, and the drain pipe at the base of the tank.. |
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The bonded mass of the tank system is then electrically bonded (grounded) to the injection well, truck load-out, and site electrical service ground, bringing all site components and structures to the same potential and to ground potential, thus reducing the possibility of arcing. |
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To complete the lightning protection function of
the system, streamer delaying air terminals (lightning rods) are
installed atop the tank, vent or vent manifold piping and handrail
structure to retard the formation of lightning-completing streamers
from the tanks and battery, thereby reducing the likelihood of a
direct lightning attachment. These
systems are simple, lightweight, and easy to install, and have been
employed successfully on hundreds of steel and fiberglass tanks
throughout the US and overseas. |
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Static Drain - Click Image For Larger View
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Structural Lightning
Protection Layout
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STATIC AND LIGHTNING PROTECTION FOR STEEL AND FIBERGLASS SWD TANKS AND TANK BATTERY Lightning Master offers a complete static and lightning protection system for steel and fiberglass saltwater disposal (SWD) tanks. The 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. Below is a discussion of the alternatives available, their design intent, and performance limitations, and a summary of the advantages of the Lightning Master system and philosophy. 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. The carbon veil does not provide bonding to
miscellaneous masses of inductance on the tank. Neither does it
provide air terminals (lightning rods) or full-size conductor to
ground. Chain or other appliance suspended 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 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 ground lug providing a path to ground. 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- 3.6.1.3). Catenary system consists of grounded masts supporting a wire or wires over the site. This type of system is primarily intended to protect power company transmission and distribution lines by intercepting what would otherwise be direct strikes to the phase conductors. When used to protect tanks or other structures, the overhead wires have little or no effect on streamer formation from the tanks. They are intended to “get in the way” of a direct strike, thereby intercepting it. 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. Lightning Master Solution. The Lightning Master system, on the other hand, provides a total solution. The in-tank linear dissipater provides thousands of small radius points at various elevations throughout the stored product to dissipate static and bound charge. The purpose-designed streamer-delaying air terminals (lightning rods) delay the formation of lightning-completing streamers from the tanks, thereby reducing the likelihood of a direct strike, and full-size conductors to convey to ground any direct strike that does occur. The Lightning Master system bonds all masses of inductance (or conductance) to the unified system, reducing the likelihood of arcing within and on the tank. Click here to see Our Petroleum industry clients
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These systems are simple, lightweight, and easy to install, and have been employed successfully on hundreds of steel and fiberglass tanks throughout the US and overseas.
Lightning Master. We wrote the book on static and lightning protection for petroleum storage tanks.
© 2009 Lightning Master Corporation
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