Mueller Electric Blog

Static Electricity and Flammable Fluids

Posted by Mona Weiss on May 24, 2018 9:24:00 AM

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Static Electricity and Fluids

Some fluids that are flammable and combustible (like fuel and other chemicals) can be a static electricity hazard depending on how conductive they are.

As fluids move through pipes or a hose they can build up a static charge because they cannot conduct electricity unless the pipe is grounded. A spark can result if enough of a charge has built up, and an explosion can occur. Solvents that are water soluble like alcohol generally do not build up static electricity because the water is conductive. However when the liquids are transferred into a non-conductive container like glass or plastic, a charge can build up because the plastic or glass does not adequately dissipate the charge in the solvent.  Other factors are the flash point of the liquid, vapor pressure, air humidity, elevation, and temperature. For example, vapor levels in the air around the container will be higher in a hot room or on a hot day rather than on a cold day.

At high elevations the air pressure is lower and a solvent can boil and spark at a lower temperature

Some fluids that are flammable and combustible (like fuel and other chemicals) can be a static electricity hazard depending on how conductive they are.

As fluids move through pipes or a hose they can build up a static charge because they cannot conduct electricity unless the pipe is grounded. A spark can result if enough of a charge has built up, and an explosion can occur. Solvents that are water soluble like alcohol generally do not build up static electricity because the water is conductive. However when the liquids are transferred into a non-conductive container like glass or plastic, a charge can build up because the plastic or glass does not adequately dissipate the charge in the solvent.  Other factors are the flash point of the liquid, vapor pressure, air humidity, elevation, and temperature. For example, vapor levels in the air around the container will be higher in a hot room or on a hot day rather than on a cold day.

At high elevations the air pressure is lower and a solvent can boil and spark at a lower temperature.

 

Grounding and Bonding

Electric sparks can result from transferring a liquid from one metal container to another as a result of static electricity buildup.  To prevent sparks and electrostatic buildup, it is necessary to bond or ground the containers before pouring. Bonding is making an electrical connection with metal clamps and a wire between all the containers which will equalize the electrical potential between the containers. Bonding containers establishes a metal-on-metal connection between two or more containers.

Grounding is attaching a wire from the container to an already grounded object which will cause the static electricity to run into the ground. 

Both methods will guarantee that there will be no difference in electrical potential between the containers pouring and receiving the liquid. Bonding the containers and then grounding one of them will drain off the static charges from everything and will prevent static discharge and sparks.

For more information on static electricity and grounding, read our whitepaper

 

 

Topics: Static Electricity Grounding