Keep Your Storage Tanks Protected

Dairyland decouplers are often associated with common indus­try applications such as AC mitigation and isolation joint protection, however they can also provide significant performance improvements for cathodic protection (CP) systems in a wide variety of other applications, including on storage tanks.

Facility Grounding Systems Can Compromise Your Tank CP

Typical storage tanks are electrically bonded to local grounding systems to provide lightning protection. In addition, most tanks have electrical equipment such as motor-operated valves and pumps that must be grounded for AC fault protection as well as instrumentation that is grounded for signal integrity. Since the facility ground­ing systems are electrically bonded to the tank by way of these grounding connections, they are also protected by the CP system and thus consume CP current well in excess of what would otherwise be required to protect the tank alone.

As a result, operators can have difficulty achieving sufficient CP potentials on the protected tank structure, which could lead to an expensive, oversized design and possibly cause interference with other structures.

Dairyland Decouplers Provide Simultaneous Overvoltage Protection and CP Isolation

Dairyland products such as the PCR and SSD address tank facility CP problems by acting as an isolation device for DC current in the affected bonds and grounds, while also meeting overvoltage safety requirements. When installed in series in the grounding conductor of AC-powered equipment and in other bonds between the tank and the facility grounding system, Dairyland products block passage of direct current from CP systems while providing safety grounding in the event of an AC fault or lightning strike. Sim­ilarly, decouplers should also be applied to other potential paths for CP current such as conduit and instrumentation shielding that is bonded to the protected tank. Dairyland decouplers and overvolt­age protectors are UL and C-UL certified for providing an “effective ground-fault current path” as defined by the U.S. National Electrical Code, and other codes. The result is an effective CP system that is unaffected by the site grounding systems.

Protect Isolation Joints

Most tanks also have piping that may create a bond to other tanks or pipelines, unless isolation joints are utilized. Although very effective at blocking CP current, isolation joints can be dam­aged by AC faults and lightning. Dairyland decouplers can be used to protect isolation joints during these events while maintaining isolation of CP current.


Properly applied Dairyland decouplers and over-voltage protectors can dramatically improve the performance of CP systems in tank facilities


Don’t Forget About Hazardous Locations!

Many tank facilities are formally classified as hazardous loca­tions and appropriate decoupler products must be selected based on these classifications. The most common hazardous location desig­nations are Division 2 or Zone 2, where explosive gases or vapors are not typically present, and Division 1 or Zone 1 locations, where such gases may be commonly present. Dairyland’s products are the only solid-state decoupling devices in the world certified for use in areas classified as Division 1 or Zone 1, and an array of Division2/Zone 2 certified products are also offered. Dairyland maintains an audited ISO 9001 quality system and extensive international product certifications.


For more details on using decouplers with storage tank applications download the application guide found at Decoupling Tank Grounding Systems or contact us.


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