Electrostatic hazards with underground plastic pipes at petrol stations

The paper analyses some ignition incidents that have been reported with insulating, (non-conductive) underground plastic pipes in retail petrol stations. The occurrence of the incidents is compared with voltage measurements, observations of the typical spread of streaming currents recorded in gasoline handling and theoretical estimates of the voltages on the pipes. The comparisons suggest that neither incendive sparks from unbonded conductors nor incendive brush discharges from insulating pipe surfaces can be ruled out although both are expected to be rare. The hazards can be prevented by using pipes with earthed conductive or dissipative inner linings.