Lightning & Static Risks To Facilities

Oil production and salt water disposal sites often report incidents of fire, equipment damage and control system failure due to lightning & static discharges.

Petro Guardian’s experienced engineering team works collaboratively with your operations and engineering group to co-develop a standardized approach to protecting your facilities from lightning and static discharge ignitions caused by lightning strikes and static discharge and from lightning induced control system failures. Our plan incorporates recommendations from standards for lightning protection and static mitigation, including NFPA, IEEE, API, and IEC. Contact us for a coordinated protection plan.

THIEF HATCH FIRE

The thief hatch enables continuous operation by releasing vapor to maintain an optimal pressure in fiberglass and lined steel tanks. Sudden separation of the thief hatch lid from its base can generate a static discharge if the lid and base are inadequately bonded and grounded. This static discharge in a flammable environment can start a fire which can ignite a tank battery or injure a pumper opening the thief hatch for maintenance or metering.

FIBERGLASS TANK FIRE

Fiberglass tank fires at production and salt water disposal (SWD) facilities are often caused by a static current discharge. The flow of volatile fluids in and out of an insulated tank generates static charge that accumulates on the fluid surface and on the walls of the insulated tank. If the flow rate of the fluids is not controlled, often the rate of static generation exceeds the rate of its relaxation. This results in accumulation of static charge on the surface of the fluid. As the surface charge density increases, the risk of it arcing over to grounded metal structures such as the tank stick or bull plug also increases. This static discharge can ignite the flammable vapors within the tank.

TRUCK LOAD OUT FIRE

The loading and unloading process of tank trucks transporting large quantities of flammable semi-conductive fluids generates static electricity. If this static charge is not grounded appropriately, it can result in a static spark in a vulnerable location. Often truck operators carry their own static bonding clamp, however, that hardware can be damaged or not function properly. If the grounding stations are not available at the truck load-out stations, truck operators do not know where to make the grounding attachment, and will sometimes connect to non-grounded or isolated grounds.

TANK BATTERY FIRE

During developing lightning storms, voltage stress on ground structures attain high values as the air gap between the storm cloud and ground structures ionizes and prepares to neutralize the voltage difference. Upward leaders (also known as streamers) initiate from the ground structures as the initial phase of a lightning strike. These streamers are high energy electrical events associated with high temperatures and they are capable of igniting flammable vapors over a tank battery.

ELECTRICAL & ELECTRONIC EQUIPMENT FAILURE

Lightning events induce voltage and current surge into power and control cables that damage electrical, electronic equipment, and instrumentation at the facility leaving operations paralyzed. Lightning surge voltages and current can reach a facility not only by direct strike, but also indirectly by coupling to utility services and entering via ground potential rise. Automatic transfer switches, variable frequency drives, pumps, UPS, power supply units, PLC control cards and field instrumentation are ar risk of damage. Such events are associated with equipment replacement cost and production downtime.

COMMUNICATION & CONTROL EQUIPMENT FAILURE

Supervisory Control and Data Acquisition (SCADA) is a system that uses coded signals over communication channels to transmit and receive data that controls process equipment. Induced voltage from lightning electromagnetic fields often damage PLC control cards and the PLC power supply. Communication antennas are generally mounted on a tower. Lightning poses a risk of direct attachment to the tower which could induce surge voltages into the communications equipment. Lightning also often damages solar battery charge circuits.