STATIC ELECTRICITY – Operations and Machines Generating Static Charge and Its Safety Measures

Introduction: The Invisible Electrical Hazard

Static electricity is something most people experience without giving it much thought.

You walk across a carpet and touch a metal door handle—you get a small shock.

You remove a synthetic sweater and hear tiny crackling sounds.

You see your hair stand up after removing a cap.

These everyday examples may seem harmless. In an industrial environment, however, static electricity can become a serious safety hazard.

A static charge can accumulate on a person, machine, product, container, conveyor belt, pipe, hose, or other object. When the accumulated charge suddenly finds a path to ground, it can discharge as a spark.

In an ordinary environment, that spark may simply cause a small shock.

But if flammable gas, vapor, mist, or combustible dust is present, the same spark can potentially become an ignition source.

This makes static electricity particularly important in industries such as:

Oil and gas
Petrochemicals
Chemical manufacturing
Pharmaceuticals
Paint and coatings
Food processing
Plastics
Textiles
Packaging
Printing
Powder handling
Grain processing
Solvent handling
Fuel storage and transportation

Understanding where static charge comes from, how it accumulates, and how to safely control it is therefore an important part of EHS and process safety.

What Is Static Electricity?

Static electricity is an imbalance of electrical charge accumulated on the surface of a material.

Unlike the continuous flow of current through a conductor, static charge can remain accumulated until it finds a suitable discharge path.

Static charge can be positive or negative.

It can develop when two different materials:

Come into contact
Separate
Rub against each other
Flow past each other
Move rapidly
Break apart
Are sprayed or atomized

The process can transfer electrons from one material to another.

When the charge has nowhere to dissipate, it accumulates.

Eventually, if the electrical potential becomes sufficiently high and a suitable discharge path exists, the charge may jump across an air gap.

That sudden transfer is known as electrostatic discharge (ESD).

Why Is Static Electricity Dangerous?

Static electricity becomes particularly dangerous when three conditions come together:

A combustible or flammable material + oxygen/air + an ignition-capable discharge

For example, imagine a solvent being transferred from one container to another.

During the movement of the liquid, static charge may develop.

If the container or transfer system is not properly grounded or bonded, charge can accumulate.

A spark may then occur.

If flammable vapor is present around the container, that spark could potentially ignite the vapor.

The result could be:

Flash fire
Explosion
Burns
Equipment damage
Production loss
Serious injury or fatality

The important lesson is:

Static electricity itself is not always dangerous. Uncontrolled static discharge in the presence of an ignitable atmosphere can be extremely dangerous.

How Is Static Charge Generated?

Static electricity is commonly produced through contact and separation of materials.

Several industrial operations naturally generate static charge.

The amount of charge generated depends on factors such as:

Material properties
Surface condition
Speed of movement
Contact area
Separation rate
Humidity
Temperature
Equipment design
Grounding arrangements

Some materials allow charge to dissipate easily.

Others are good electrical insulators and can hold charge for long periods.

1. Liquid Transfer and Filling Operations

One of the most important industrial sources of static electricity is the movement of liquids.

Static charge can be generated when liquids flow through:

Pipes
Hoses
Pumps
Filters
Valves
Nozzles
Filling systems

This is particularly important when handling liquids with relatively low electrical conductivity, including certain hydrocarbons and solvents.

The faster the liquid moves and the more turbulence or mixing occurs, the greater the potential for charge generation under some conditions.

Examples include:

Filling drums with solvents
Loading tank trucks
Fuel transfer
Pumping hydrocarbons
Filling chemical containers
Transferring paints and coatings

Appropriate bonding, grounding, equipment design, and operating procedures are essential.

2. Pumping Operations

Pumps can contribute to static generation during liquid transfer.

Static charge may develop as liquid passes through:

Pump components
Pipes
Filters
Valves
Restrictions

The risk may increase when the liquid contains suspended particles, multiple phases, or has low conductivity.

Operators should therefore ensure that the transfer system has appropriate grounding and bonding arrangements and that operating procedures are followed.

3. Pipeline Flow

Liquid flowing through a pipeline can generate electrostatic charge.

This is particularly relevant when:

Flow velocity is high
The liquid has low conductivity
Filters are installed
The system contains restrictions
Two phases are present
Turbulence occurs

Pipeline systems should be designed and operated with appropriate controls based on the material and process.

4. Spraying and Atomization

Spraying liquids can generate substantial static charge.

Examples include:

Spray painting
Solvent spraying
Chemical spraying
Agricultural spraying
Coating operations
Cleaning operations

Atomization creates very small droplets with a large total surface area.

The resulting charge can create electrostatic attraction, sparks, or other hazards.

Spray systems should therefore be assessed for electrostatic risk, particularly when flammable liquids or solvents are involved.

5. Powder Handling

Static electricity is not limited to liquids.

Powders can generate significant electrostatic charge when they:

Flow through pipes
Fall through air
Pass through conveyors
Enter silos
Move through pneumatic systems
Are mixed
Are sieved
Are poured into containers

Industries handling combustible powders should take electrostatic ignition hazards seriously.

Examples include certain:

Pharmaceutical powders
Food powders
Flour
Sugar
Plastics
Chemical powders
Metal powders

In these environments, static discharge can potentially ignite a combustible dust cloud.

6. Pneumatic Conveying Systems

Pneumatic conveying can generate substantial electrostatic charge because particles move rapidly through pipes and contact the pipe walls.

This is particularly relevant to:

Plastic pellets
Powders
Pharmaceutical materials
Food products
Chemical materials

The movement of particles creates repeated contact and separation.

Appropriate grounding and bonding of conductive components, suitable equipment selection, and process-specific controls are therefore important.

7. Conveyor Belts

Conveyor belts can generate static electricity through friction and repeated contact with:

Rollers
Pulleys
Product
Support structures

This can be especially noticeable with synthetic or polymeric belt materials.

Static charge can accumulate if the belt or associated components are electrically isolated.

Where static presents a hazard, appropriate antistatic belt materials, grounding arrangements, and equipment design should be considered.

8. Textile Machines

Textile manufacturing is another area where static electricity can become significant.

Fibers continuously rub against:

Rollers
Guides
Needles
Combs
Belts
Other fibers

This repeated friction and separation can create electrostatic charge.

Static can cause:

Fibers sticking together
Product-quality problems
Material attraction
Operator shocks
Ignition hazards in certain environments

Humidity control, antistatic materials, grounding, and appropriate machine design can help control the problem.

9. Plastic Film and Sheet Processing

Plastic films are generally good electrical insulators.

When plastic film passes rapidly over rollers or through processing equipment, significant static charge can develop.

This can result in:

Film sticking to machine components
Dust attraction
Operator shocks
Product handling problems
Unexpected discharges

In some manufacturing environments, static neutralizers or ionization systems may be used to reduce charge accumulation.

10. Printing and Packaging Machines

Printing presses and packaging machinery can generate static charge through the movement of:

Paper
Plastic films
Foils
Labels
Packaging materials

High-speed movement increases the opportunity for contact and separation.

Static charge can cause sheets to:

Stick together
Repel each other
Misalign
Attract dust

It can also create shocks for operators.

Where flammable inks, solvents, or vapors are present, electrostatic ignition must also be considered.

11. Mixing and Agitation

Mixing operations can generate static electricity when different materials move rapidly against each other.

This may occur in:

Chemical mixers
Blenders
Powder mixers
High-speed agitators
Pharmaceutical processing equipment

The risk depends heavily on the material and process.

If flammable materials are being mixed, the possibility of static ignition should be evaluated as part of the process hazard assessment.

12. Filtration

Filters can be an important source of electrostatic charge generation.

Liquid flowing through a filter can experience:

Turbulence
Separation
Friction
Charge transfer

Similarly, powder passing through filtration systems can generate electrostatic charge.

Filter systems handling flammable materials should therefore be designed with appropriate static-control measures.

13. Rubber and Polymer Processing

Rubber and polymer materials can generate significant static electricity during:

Extrusion
Rolling
Cutting
Conveying
Mixing
Film production

These materials can retain charge because many polymers are electrical insulators.

Operators may experience shocks when touching machine frames or nearby conductive objects after becoming charged.

14. Human Body as a Static Charge Generator

People can also generate static electricity.

Walking across floors, especially when wearing insulating footwear, can cause the human body to accumulate charge.

Synthetic clothing and dry environmental conditions can increase static buildup.

A person may then discharge the accumulated energy when touching:

Metal equipment
Electrical panels
Containers
Machinery
Another person

In an ordinary environment this may simply be uncomfortable.

In a hazardous atmosphere, however, a person could potentially become an ignition source.

This is why personal grounding and appropriate antistatic measures may be important in specific industrial environments.

Factors That Increase Static Charge

Several factors can make static electricity more likely.

Low Humidity

Dry air generally allows charge to remain on surfaces for longer.

This is one reason static shocks are often more noticeable in dry conditions.

High Speed

Faster movement can increase charge generation in many processes.

Examples include:

Fast liquid transfer
High-speed belts
Rapid film movement
Pneumatic conveying

Insulating Materials

Materials such as many plastics and synthetic polymers do not readily allow charge to dissipate.

Friction

Repeated rubbing and contact can generate charge.

Separation

Contact followed by separation is a major mechanism for electrostatic charge generation.

What Is Grounding?

Grounding provides a conductive path for electrical charge to dissipate to earth or an appropriate reference system.

In static-control applications, grounding helps prevent charge from accumulating to hazardous levels.

Equipment that may require grounding can include:

Storage tanks
Transfer vessels
Pipes
Pumps
Process equipment
Filling equipment
Structural components

However, simply connecting a wire somewhere does not automatically guarantee effective grounding.

The grounding system must be properly designed, installed, maintained, and periodically verified according to applicable requirements.

What Is Bonding?

Grounding and bonding are related but different concepts.

Bonding connects conductive objects together so that they remain at substantially the same electrical potential.

This reduces the possibility of a dangerous potential difference developing between two objects.

For example, during liquid transfer between two conductive containers, bonding may be used to connect the containers electrically before transfer begins.

The system can then be appropriately grounded as required.

A useful way to remember the difference is:

Bonding = connect objects together.

Grounding = provide a path to earth/reference.

Both can be important for static control.

Static Electricity Safety Measures

1. Ground Conductive Equipment

Conductive equipment that can accumulate hazardous static charge should be appropriately grounded.

Examples include:

Tanks
Vessels
Pipes
Pumps
Filling equipment
Metal containers

Ground connections should be maintained in good condition.

2. Bond Containers Before Transfer

When transferring flammable liquids between conductive containers, appropriate bonding and grounding procedures should be followed.

This helps minimize potential differences that could result in an electrostatic spark.

Where required by the process, bonding should be established before the transfer operation begins.

3. Control Flow Velocity

Excessively high flow rates can increase electrostatic charge generation in certain liquid-transfer operations.

Operating procedures should specify appropriate flow conditions based on the material, equipment, and process design.

The objective is not simply to transfer material as quickly as possible.

Safe transfer is more important than fast transfer.

4. Reduce Splash Filling

Splashing and turbulence can increase electrostatic charge generation and vapor formation during liquid transfer.

Where appropriate, filling arrangements should minimize unnecessary turbulence and free-fall of flammable liquids.

Engineering controls should be selected based on the properties of the liquid and the process.

5. Use Appropriate Antistatic Materials

Where static accumulation is a known hazard, materials designed to dissipate electrostatic charge may be appropriate.

Examples include:

Antistatic flooring
Conductive containers
Antistatic conveyor belts
Conductive hoses
Antistatic footwear
Static-dissipative work surfaces

The material must be suitable for the specific application.

Simply calling something “antistatic” does not automatically make it appropriate for every hazardous environment.

6. Control Humidity Where Practical

Increasing humidity can sometimes reduce static accumulation on certain materials.

This is particularly relevant in:

Textile operations
Plastic processing
Packaging
Electronics manufacturing

However, humidity control is not a universal solution.

In hazardous chemical or process environments, grounding, bonding, equipment design, and ignition-source control remain critical.

7. Use Static-Elimination Devices

Industrial processes may use devices such as:

Ionizing bars
Static eliminators
Ionizing blowers
Antistatic brushes
Charge neutralizers

These devices can help neutralize static charges on materials.

They should be selected, installed, and maintained according to the application.

8. Maintain Grounding Systems

Grounding systems can deteriorate due to:

Corrosion
Loose connections
Mechanical damage
Paint or coatings
Improper modifications
Broken conductors

Therefore, grounding should not be treated as a one-time installation.

Periodic inspection and testing should be incorporated into the site’s maintenance program where required.

9. Avoid Insulating Connections

A conductive system can become electrically isolated by:

Plastic sections
Non-conductive gaskets
Coatings
Rubber components
Insulating hoses

These components may interrupt the intended static-dissipation path.

Where static control is important, the complete system should be evaluated—not just the main metal equipment.

10. Use Suitable Hoses

Hoses used for flammable liquid transfer should be selected based on the material, pressure, compatibility, and electrostatic requirements of the application.

Where static accumulation is a concern, suitable conductive or static-dissipative hoses may be necessary.

A hose should never be assumed to be electrically safe simply because it looks like a normal industrial hose.

11. Control Combustible Dust

Where combustible dust is present, static-control measures should be combined with effective housekeeping.

Avoid allowing combustible dust to accumulate on:

Machinery
Electrical equipment
Floors
Beams
Ducts
Cable trays

Dust deposits can create additional fire and explosion hazards.

Cleaning methods should also be selected carefully to avoid creating hazardous dust clouds or ignition sources.

12. Control Ignition Sources

Static electricity should be considered alongside other ignition sources.

These may include:

Open flames
Hot surfaces
Welding
Grinding
Electrical arcs
Smoking
Mechanical sparks
Lightning
Hot work

The goal is to prevent any credible ignition source from contacting an ignitable atmosphere.

13. Conduct Risk Assessments

Static electricity should be addressed during:

HAZOP
Job Safety Analysis
Risk Assessment
Process Hazard Analysis
Permit-to-Work planning
Management of Change

Ask:

Where can static charge be generated?

Where can it accumulate?

Where could it discharge?

Could a flammable atmosphere be present?

What controls prevent ignition?

This approach makes static electricity a visible part of the safety discussion.

Static Electricity Safety Checklist

Before operating equipment that may generate static charge, consider the following:

Equipment

Is the equipment suitable for the process?
Are conductive components appropriately grounded?
Are required bonding connections in place?
Are hoses suitable?
Are grounding connections free from visible damage?

Process

Is the transfer speed appropriate?
Is excessive turbulence controlled?
Is splash filling minimized where necessary?
Are flammable materials being handled safely?

Environment

Could a flammable atmosphere exist?
Is combustible dust controlled?
Is ventilation adequate?
Are other ignition sources controlled?

Personnel

Are workers trained?
Is suitable PPE being used?
Is appropriate antistatic footwear/clothing required?
Are workers aware of static-discharge hazards?

Maintenance

Are grounding systems inspected?
Are bonding connections maintained?
Are static-control devices functioning?
Are defects reported and corrected?

Common Mistakes That Increase Static Electricity Risk

1. Assuming Small Sparks Are Harmless

A tiny spark can become a serious ignition source in the right atmosphere.

2. Ignoring Grounding

Metal equipment does not automatically mean it is properly grounded.

3. Forgetting Bonding

Two conductive objects can develop a potential difference even when both appear to be metal.

4. Transferring Flammable Liquids Too Quickly

High-speed transfer can increase electrostatic generation under certain conditions.

5. Using Ordinary Plastic Containers

Insulating containers may allow charge to accumulate.

6. Ignoring Synthetic Clothing

Synthetic materials can contribute to electrostatic charge accumulation.

7. Assuming Humidity Solves Everything

Humidity can help in some applications but should not replace proper engineering controls.

8. Ignoring Combustible Dust

Static electricity can become an ignition source for combustible dust clouds.

9. Failing to Inspect Grounding Connections

A disconnected or corroded grounding conductor may not provide the intended protection.

10. Making Unauthorized Equipment Modifications

Modifications can compromise grounding, bonding, or hazardous-area protection.

Static Electricity in Hazardous Areas

The risk becomes particularly serious when static-generating operations take place in a hazardous area.

Examples include:

Fuel loading
Solvent transfer
Tank filling
Chemical processing
Powder handling
Spray painting
Gas processing
Pharmaceutical powder handling

In these environments, static electricity must be treated as a potential ignition source.

The controls may involve a combination of:

Grounding + Bonding + Equipment Selection + Process Control + Atmospheric Control + Ignition-Source Control

No single control should automatically be assumed to eliminate the hazard.

The Role of EHS Professionals

EHS teams can help organizations manage electrostatic hazards through a structured program.

Identify

Determine which operations and equipment generate static charge.

Assess

Evaluate whether accumulated charge could produce an ignition-capable discharge.

Control

Implement grounding, bonding, equipment design, process controls, and other appropriate measures.

Inspect

Verify that static-control systems remain functional.

Train

Teach workers why static electricity matters and how to recognize unsafe conditions.

Review

Reassess the hazard whenever processes, materials, equipment, or operating conditions change.

A Simple Way to Remember Static Electricity Safety

For workers, the following five-step approach is easy to remember:

GENERATE → ACCUMULATE → DISCHARGE → IGNITE → PREVENT

Generate

Identify where the process creates static charge.

Accumulate

Determine where the charge could build up.

Discharge

Identify possible paths through which the charge could jump.

Ignite

Determine whether a flammable gas, vapor, mist, or dust could be ignited.

Prevent

Use grounding, bonding, suitable equipment, process controls, and other safeguards.

This simple thought process can make an invisible hazard much easier to understand.

Final Thoughts: Don’t Wait for the Spark

Static electricity is invisible.

You cannot always see it building up.

You may not hear it.

You may not feel it.

And you certainly cannot rely on the absence of a previous incident as proof that the process is safe.

That’s what makes electrostatic hazards particularly important in industrial environments.

A liquid flowing through a pipe, powder moving through a conveyor, plastic film passing over a roller, or a worker walking across an insulating floor can all create electrostatic charge.

Most of the time, nothing happens.

But when the right conditions come together, a small discharge can have serious consequences.

The safest approach is to identify the source of static generation and prevent the charge from accumulating to hazardous levels.

That means:

Ground conductive equipment.

Bond conductive components.

Control transfer and process conditions.

Use appropriate hoses and equipment.

Control combustible dust and flammable atmospheres.

Maintain static-control systems.

Train workers.

Never ignore a spark in a hazardous environment.

Most importantly, remember:

Static electricity may be invisible, but the consequences of an uncontrolled static discharge can be very real.

Good EHS management means recognizing the hazard before the spark occurs.

When static electricity is properly understood and controlled, many seemingly mysterious shocks, sparks, fires, and process problems can be prevented.

Control the charge before it controls the outcome.

Frequently Asked Questions

What is static electricity?

Static electricity is an imbalance of electrical charge that accumulates on the surface of a material. It can remain stored until it finds a path through which it can discharge.

How is static electricity generated in industries?

It can be generated through contact and separation, friction, liquid flow, powder movement, conveyor belts, plastic-film processing, spraying, mixing, pumping, filtration, and movement of people.

Why is static electricity dangerous in hazardous areas?

A static discharge can potentially provide an ignition source when flammable gases, vapors, mists, or combustible dust are present.

What is the difference between grounding and bonding?

Grounding provides a path for charge to dissipate to earth or an appropriate reference. Bonding electrically connects conductive objects to reduce potentially hazardous differences in electrical potential between them.

Does grounding eliminate static electricity?

Grounding can provide a means for accumulated charge to dissipate, but its effectiveness depends on proper system design, installation, continuity, and maintenance. It is one part of a broader static-control strategy.

Can plastic generate static electricity?

Yes. Many plastics are insulating materials and can readily accumulate electrostatic charge when they contact and separate from other materials or undergo friction.

Can humans generate static electricity?

Yes. Walking, clothing movement, and contact with insulating materials can cause a person to accumulate electrostatic charge.

How can static electricity be reduced?

Depending on the application, controls may include grounding, bonding, antistatic materials, humidity control, ionization, suitable equipment, controlled flow rates, and process design.

Is static electricity only a fire hazard?

No. It can also cause electric shocks, product contamination, material-handling problems, equipment malfunction, production issues, and ignition hazards.

Is a small static shock dangerous?

In many ordinary situations, a small static shock is mainly uncomfortable. However, in an environment containing an ignitable atmosphere, even a small electrostatic discharge can potentially become an ignition source.

Important Safety Note

This article is intended for general EHS and industrial safety awareness. Static-electricity hazards are highly dependent on the materials, process conditions, equipment, environmental conditions, and presence of flammable or combustible substances.

For industrial operations, appropriate controls should be established through a competent engineering assessment, applicable regulations and standards, manufacturer’s requirements, process-safety studies, and site-specific procedures.

Grounding, bonding, flow control, static-dissipative equipment, atmospheric controls, and other measures must be selected based on the actual process rather than applied as generic solutions.