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An RGA, or Retractable Grounding Assembly, is a device used on floating roof tanks to maintain a permanent, reliable and low-impedance electrical connection between the floating roof and the tank shell.
Its objective is to reduce the risk of sustained electrical arcs and fires during lightning events or other electrical phenomena, providing a controlled path for the discharge of currents between the roof and the tank body.
SETI provides RGA systems for API storage tanks in hydrocarbon terminals, refineries, industrial plants and fuel terminals, supporting technical specification, supply, installation and after-sales support.
The RGA system, patented and ATEX-certified according to the applicable model, substantially reduces the risk of fire in floating roof tanks by limiting the formation of sustained electrical arcs during lightning events or other electrical phenomena. The RGA does this better than other traditional methods for bonding floating roofs because the retractable cable always has the shortest possible length. The resulting low resistance and impedance produce a voltage too low to sustain the arc, meaning no fire. For any questions, please contact us via WhatsApp or through our form. We will be glad to help you. in floating roof tanks by limiting the formation of sustained electrical arcs during lightning events or other electrical phenomena.
The RGA does this better than other traditional methods for bonding floating roofs because the retractable cable is always at the shortest possible length. The resultant low resistance and impedance results in too low of a voltage to sustain the arc, meaning no fire.
If you have any questions, please contact us via Whatsapp or our contact form. We will be glad to help you.
There are There are known to be between 15 and 20 floating roof tank fires per year. EFR tanks are especially vulnerable to the direct and indirect effects of lightning. A direct or nearby lightning strike will cause electrical currents to flow through the tank shell and roof. When these lightning currents arc across the roof/shell interface, they can ignite any flammable vapor that may be present. Therefore, it is necessary to bond the roof and the shell to prevent arcing at the roof/shell interface.
To substantially reduce the risk of sustained arcs, a reliable, full-time, low-impedance and low-resistance connection is required between the tank shell and the roof. In addition, the connection must operate independently of the condition of the tank.
The RGA is not affected by the condition of the tank because the RGA and the cable are bolted and sealed in optimal locations on the tank shell and the floating roof. When properly applied, multiple RGAs on each tank provide low-impedance paths to safely discharge lightning currents.
The RGA is designed to be easily adapted to any existing tank, even tanks in service, and is also easy to inspect and built to be low-maintenance.
The new RGA 750 uses stronger springs to retract the cable.
The use of the retractable grounding device is also recommended with internal floating roofs.
To combat the risk of fires in fuel storage tanks, the industry has been using metal strips called “shunts” that electrically bond the shell and roof of the tank.
Unfortunately, the bond established by shunts is not reliable and creates a higher risk of sustained arcs:
API testing showed that shunts arc under all conditions, even if the tank wall and the shunts are new and clean.
Unlike conventional shunts, the RGA maintains a permanent retractable connection between the floating roof and the tank shell, with the shortest possible cable length during operation.
This makes it possible to reduce the impedance of the system, improve electrical continuity and reduce the risk of sustained arcs at the interface between the floating roof and the tank shell.
The system also facilitates inspection, reduces maintenance needs and can be installed on both new tanks and existing tanks.
An RGA is a retractable grounding system that maintains a permanent, low-impedance electrical connection between the floating roof and the tank shell.
It is used to reduce the risk of sustained electrical arcs and fires during lightning events or other electrical phenomena in floating roof tanks.
Traditional shunts depend on physical contact with the tank shell and can be affected by corrosion, paint, deposits or roof misalignment. The RGA uses a retractable cable that maintains a more reliable, low-impedance connection.
Yes. The RGA system can be installed on both new tanks and existing tanks, depending on the tank conditions and the project requirements.
Yes. The use of retractable grounding systems can also be recommended in tanks with internal floating roofs, depending on the tank design and the corresponding technical evaluation.
RGA systems are specified considering applicable recommendations and requirements from standards such as API 545 and NFPA 780 for lightning protection and bonding in storage tanks.
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