There has been a rapidly growing trend for petroleum, water\/wastewater and chemical industries to utilize Fiberglass Reinforced Plastic (FRP) storage tanks. FRP storage tanks are typical for these industries due to their non-corrosive properties as compared to standard metal storage tanks. Even though FRP storage tanks are not metal, they are still exposed to lightning and are a potential fire hazard. The non-conductive property creates additional resistance to fast lightning current impulses and generates intense heat at the point of impact. Fires starting at a single FRP tank can engulf an entire facility.<\/p>\n
Even in the case of an indirect lightning strike, it may also be considered that an unequal ion discharge rate between an insulated FRP tank and a nearby grounded\/bonded metallic structure can cause the development of a difference of electrical potential, thus, creating a spark which could lead to a tank explosion and fire.<\/p>\n
Available lightning strike data related to tank farms is neither comprehensive nor readily available, with most reports consisting of media releases such as the four events shown to the right.<\/p>\n<\/div>
In June and July of 2014, lightning-sparked fires destroyed saltwater disposal facilities at three locations in North Dakota. Over 440 such sites exist in North Dakota alone. Production tanks associated with well sites are used principally for enhanced oil recovery and saltwater disposal. Reportedly, there are 144,000 such wells in the USA. Downtime and recovery costs from potential lightning strikes can be very expensive and have possible safety consequences for personnel, strategic infrastructure, and critical storage tanks.<\/p>\n
With appropriate use of lightning protection methods; replacement costs, losses due to operational shutdown, and safety liability issues can be minimized. An engineered mix of structural air terminals, equipotential bonding, and grounding can protect fiberglass reinforced plastic storage tanks. This paper describes the risks associated with FRP storage tanks to direct lightning strikes and provide guidance to protect facilities from direct lightning strikes and\/or secondary lightning transients.<\/p>\n<\/div><\/div><\/div>