3228 EI Research report: A qualitative assessment of electrostatic risks in jet fuel handling and distribution

Overview:

This EI Research Report has been prepared for the Energy Institute’s Aviation Committee and is intended to provide information on whether a safe level of conductivity for kerosene-type jet fuel can be derived from a robust quantified risk assessment.

One of the key global disparities between kerosene-based Jet A/A-1 (ASTM D1655) and Jet A-1 (Defence Standard (DEF STAN) 91-91) fuels is the mandated minimum conductivity requirement. Where mandated, a conductivity improving additive is used to achieve the minimum level. Enhanced conductivity levels reduce the time it takes for an electrostatic charge to dissipate to the surrounding structure after it is formed by fuel flowing at speed through pipes and filtration. Conductivity improving additive does not, and cannot, prevent the creation of electrostatic charges in the first place. The use of conductivity improving additive can pose fuel handling challenges. Disagreement about the need for conductivity improving additive is an obstacle to the convergence to a single global jet fuel specification.

This report was commissioned to investigate whether a safe level of conductivity for kerosene-type jet fuel can be derived from a robust quantified risk assessment. The study reviewed a wide range of literature concerning all aspects of the introduction of conductivity improving additive, as well as a review of flammability of jet fuel and the minimum energies needed to ignite fuel:air mixtures between the lower and upper flammability limits.

The report goes on to identify four key areas within the current global jet fuel distribution network, where electrostatic discharges might occur within an ullage space, and hence where all three elements of a ‘fire triangle’ (fuel, air and ignition source) have the potential to exist.