(41q) Understanding Ignition Risks from Electrostatic Sources Involving Plastic Containers

The greatest and most common hazard resulting from static electricity arises because the small sparks that are simply annoying in our everyday world can easily ignite many flammable vapors that are found in industry. Even sparks that are far too small to be felt by people can readily ignite many common industrial substances, which can lead to fires and explosions causing injury to people, destruction of plant, and loss of business.

Plastic containers present unique challenges in flammable liquid service, as most plastics are highly electrically insulating, cannot be grounded, and can easily accumulate electrostatic charges. These electrostatic charges result in elevated risks of electrostatic ignitions where the potential for ignitable mixtures exists, including unique and different exposures on the inside and outside surfaces of plastic containers.

This paper and presentation will overview the industrial hazards presented by static discharge, and provide practical insights to evaluate these risks, including background principles related to Charge Generation, Charge Accumulation, Discharge Energy Level, and Sensitivity of the Atmosphere to Ignition. The risk evaluation processes contained in NFPA 77 (2024), considered a globally applicable Recognized and Generally Accepted Good Engineering Practice (RAGAGEP) on Electrostatics, and NFPA 30 (2024), a RAGAGEP related to Flammable & Combustible Liquids Safety, will be overviewed.

Learning Objectives:

1. Attendees will become aware of the basic principles for how static electricity is generated.
2. Participants will understand the basic hazard principles related to static electricity ignition scenarios, including (1) Charge Generation, (2) Charge Accumulation, (3) Discharge Energy Level, and (4) Sensitivity of the Atmosphere to Ignition.
3. Participants will become aware of the unique electrostatic hazards presented by plastic containers used in flammable liquid service, including common methods to identify critical risk factors.
4. Participants will become aware of the most common US sources of information for conducting electrostatics evaluation, namely NFPA 77 (2024), Recommended Practice on Static Electricity.