API RP 545 - Lightning Protection for Above Ground Storage Tanks Status Update of Ongoing Tests Per NFPA 780 (Lightning Protection Code), shunts are required to be installed on floating roof tanks above the seal at 3 meter (10 feet) spacing around the tank perimeter. The purpose of these shunts is to provide a conductive path from the tank roof to the tank wall. Tests conducted for the API RP 545, "Lightning Protection for Above Ground Storage Tanks", task group have shown that these shunts can generate showers of sparks during lighting strikes. If there is a gap between the seal and the tank wall during a lightning strike and if a flammable mixture is present, a tank fire may result. Since the best defense against lightning is a tight seal, this reinforces the need to conduct routine seal inspections and maintenance. Also, access to tanks should be restricted when there is a potential for lightning. The API RP 545 task group is planning to conduct additional tests in order to evaluate alternative methods of providing a conductive path between the tank roof and the tank wall to meet the intent of NFPA 780. The test results and recommended mitigation measures will be included in a new RP 545 - "Lighting Protection For Above Ground Storage Tanks" (expected publication date: mid 2008). The test results with bonding conductors should be available in early Fall 2006 and the test results for under-liquid shunts should be available in early 2007. For more information, please contact Gordon Robertson at API, 1220 L Street NW, Washington, DC, by telephone at 202-682-8190 or through email at [email protected] .

API RP 545 Lightning Protection for Above Ground Storage Tanks

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Page 1: API RP 545 Lightning Protection for Above Ground Storage Tanks

API RP 545 - Lightning Protection for Above Ground Storage TanksStatus Update of Ongoing Tests

Per NFPA 780 (Lightning Protection Code), shunts are required to be installed on floating roof tanks above the seal at 3 meter (10 feet) spacing around the tank perimeter. The purpose of these shunts is to provide a conductive path from the tank roof to the tank wall. Tests conducted for the API RP 545, "Lightning Protection for Above Ground Storage Tanks", task group have shown that these shunts can generate showers of sparks during lighting strikes. If there is a gap between the seal and the tank wall during a lightning strike and if a flammable mixture is present, a tank fire may result.

Since the best defense against lightning is a tight seal, this reinforces the need to conduct routine seal inspections and maintenance. Also, access to tanks should be restricted when there is a potential for lightning.

The API RP 545 task group is planning to conduct additional tests in order to evaluate alternative methods of providing a conductive path between the tank roof and the tank wall to meet the intent of NFPA 780. The test results and recommended mitigation measures will be included in a new RP 545 - "Lighting Protection For Above Ground Storage Tanks" (expected publication date: mid 2008). The test results with bonding conductors should be available in early Fall 2006 and the test results for under-liquid shunts should be available in early 2007. For more information, please contact Gordon Robertson at API, 1220 L Street NW, Washington, DC, by telephone at 202-682-8190 or through email at [email protected].

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