The loading and unloading of tank trucks containing flammable or combustible products has long been recognized as one of the most serious fire and explosion risks for hazardous industry operations. A study conducted by the American Petroleum Institute in 1967, for example, identified static discharges as being responsible for more than 60 incidents in tank truck loading operations. Since then more stringent preventive standards have been developed and significant advancements have been made in the technology of static electric discharge prevention. Yet accidents traced to static electric discharges still occur, with sometimes tragic results.
The natural presence of static electricity during product transfer operations, combined with its associated ignition hazards, ensure that regulators take static control precautions for tank trucks very seriously. The primary guidelines are detailed in three primary standards: NFPA 77, API RP 2003 and CLCTR: 50404. An understanding of these standards and of current technology in static discharge prevention can contribute greatly to preventing tank truck load transfer incidents.