Understanding the causes, risks and practical ways to manage electrostatic hazards in pharmaceutical and industrial manufacturing.
Static electricity is an often-overlooked challenge in powder processing. Whether handling pharmaceutical ingredients, nutraceutical formulations, food powders or fine chemicals, electrostatic charge can develop during everyday manufacturing operations.
From blending and conveying to filling, discharge and material transfer, the movement of dry particles can generate electrical charge. If not properly assessed and controlled, this can contribute to powder adhesion, difficult discharge and, in certain environments, serious ignition hazards.
From blending and conveying to filling, discharge and material transfer, the movement of dry particles can generate electrical charge. If not properly assessed and controlled, this can contribute to powder adhesion, difficult discharge and, in certain environments, serious ignition hazards.
This guide explains why static electricity occurs and the steps manufacturers can consider to manage it across the complete powder handling process.
What causes static electricity in powder handling?
Static electricity develops when electrical charges are separated and accumulate on materials or equipment surfaces.
In powder processing, triboelectric charging commonly occurs as particles contact and separate from other particles, vessel walls and transfer components.
Operations where charging can occur include:
- Powder blending: Contact between particles and vessel surfaces.
- Pneumatic conveying: Repeated contact with pipelines during transfer.
- Filling and discharge: Powder falling or flowing into drums, Intermediate Bulk Containers (IBCs) and other containers.
- Sieving and screening: Particle contact with mesh and equipment surfaces.
- Manual handling: Pouring, scooping and transferring dry ingredients.
The extent of charging depends on the powder, the materials it contacts and operating conditions.
Many dry powders are poor electrical conductors, so charge may remain on particles rather than readily dissipating.
Why does static electricity matter in powder processing?
The effects of static electricity extend beyond occasional shocks or powder sticking to equipment.
Depending on the material and manufacturing environment, electrostatic charging can affect product handling, operational efficiency and process safety.
Fire and explosion risks
A combustible dust dispersed in air can form an explosive atmosphere.
Certain electrostatic discharges can act as ignition sources if their energy and the surrounding conditions are sufficient.
The hazard depends on dust properties, the type of discharge, equipment design and how the process is operated.
Material testing and a suitable dust hazard assessment may therefore be necessary.
Powder adhesion and material retention
Charged particles may adhere to vessel walls, transfer hoses and discharge components.
Depending on the formulation, this can increase cleaning requirements, reduce yield and complicate changeover procedures.
For pharmaceutical manufacturers, where controlled processing and cleaning are important considerations, unwanted powder retention can create additional operational challenges.
Inconsistent powder flow and discharge
Electrostatic forces can influence fine and cohesive powders, potentially contributing to irregular discharge or build-up.
However, static is only one possible factor. Particle size, moisture, cohesion and equipment geometry should also be investigated when diagnosing powder flow problems.
Operator safety
Electrostatic shocks may cause discomfort during manufacturing operations.
More seriously, personnel and isolated conductive objects can become ignition sources in hazardous dust atmospheres if suitable precautions are not taken.
This makes electrostatic risk management an important consideration when designing and operating powder handling equipment.
Seven practical ways to manage static electricity in powder handling
There is no single solution that eliminates every electrostatic hazard.
Effective management requires an understanding of the powder, equipment, operating conditions and wider manufacturing process.
The following seven considerations can help manufacturers assess and manage electrostatic risks.
1. Earth and bond conductive equipment correctly
Earthing and bonding are fundamental considerations when managing electrostatic hazards in powder processing.
Earthing creates a path from conductive equipment to earth, while bonding connects conductive components to minimise potentially dangerous differences in electrical potential.
Equipment requiring assessment may include:
- Powder blender frames
- Stainless steel drums
- Intermediate Bulk Containers (IBCs)
- Powder transfer pipelines
- Filling equipment
- Removable fittings and connections
Electrical continuity should be checked at removable connections and following maintenance activities.
However, it is important to recognise that earthing metalwork does not, by itself, remove electrical charge from insulating powders or non-conductive components
2. Specify suitable hoses and transfer connections
Flexible transfer components can differ substantially in their electrical properties.
Manufacturers should assess whether conductive or static-dissipative materials are required for the particular powder, operating environment and handling method.
A dust-tight seal does not necessarily provide an electrostatically safe connection.
Standard silicone hoses and flexible components should not be assumed to provide antistatic performance unless their specifications confirm this.
Selecting appropriate transfer connections therefore requires consideration of both powder containment and electrostatic protection requirements.
3. Assess transfer speed and process conditions
Particle contact during pneumatic conveying and gravity transfer can generate electrostatic charge.
Factors that may influence charging include:
- Powder conveying velocities
- Pipeline bends
- Transfer distances
- Filling arrangements
- Powder characteristics
- Equipment construction materials
These conditions should be evaluated during process design.
Reducing transfer speed may influence charging in certain applications, but it is not a universal solution and must not replace appropriate protective measures.
4. Control environmental conditions appropriately
Humidity can influence how readily electrical charge dissipates from some materials.
However, the effect varies according to powder characteristics and the surrounding environment.
Increasing humidity may also be unsuitable for moisture-sensitive formulations or validated pharmaceutical manufacturing processes.
Environmental conditions should therefore be assessed alongside formulation requirements, product quality and equipment design.
Humidity control should not be treated as a blanket solution to electrostatic hazards.
5. Select powder processing equipment for the complete process
Electrostatic safety should be considered when specifying powder blending and handling equipment.
Important considerations include:
- Vessel construction
- Electrical continuity
- Removable IBC arrangements
- Powder discharge design
- Material transfer connections
- Potentially explosive atmospheres
- Containment requirements
- Mechanical handling arrangements
A correctly specified blending system should consider electrostatic safety, powder behaviour, containment and mechanical handling together.
For example, a manufacturing operation may use a stainless steel IBC for blending before transferring the material into downstream production equipment.
Although the blending vessel may be appropriately earthed, the complete transfer arrangement must also be assessed.
This includes flexible connections, removable components and receiving equipment.
6. Review DSEAR, ATEX and combustible dust requirements
Manufacturers handling combustible powders should assess the relevant hazardous-area and explosion-protection requirements.
In the United Kingdom, the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) require employers to assess and control risks associated with dangerous substances and explosive atmospheres.
ATEX requirements may apply to equipment intended for use in potentially explosive atmospheres.
Dust hazardous areas are generally classified according to how frequently an explosive dust atmosphere is expected to occur.
Zone 20
An area where an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, frequently or for long periods.
Zone 21
An area where an explosive dust atmosphere is likely to occur occasionally during normal operation.
Zone 22
An area where an explosive dust atmosphere is unlikely to occur during normal operation and, if it does occur, is expected to persist only briefly.
Appropriate protective measures depend on the hazardous-area classification, dust ignition characteristics and wider risk assessment.
It is important to understand that ATEX marking alone is not a substitute for evaluating electrostatic discharge hazards throughout the complete installation.
7. Maintain equipment and train operators
Effective electrostatic risk management extends beyond initial equipment specification and installation.
Routine maintenance procedures should incorporate appropriate checks of:
- Bonding points
- Earth continuity
- Transfer hoses
- Flexible fittings
- Removable connections
- Replacement components
Operators should also receive suitable training to recognise equipment damage and follow approved powder handling practices.
Where required by the risk assessment, appropriate clothing, footwear and other personnel controls should be implemented.
Maintaining the condition of equipment and ensuring operators understand the associated risks are important elements of ongoing electrostatic protection.
Why do powder characteristics matter?
Different powders can behave very differently when processed using the same equipment.
Two materials handled through an identical blending or transfer system may generate and retain different levels of electrostatic charge.
Factors worth investigating include:
- Particle size
- Moisture content
- Electrical resistivity
- Material composition
- Powder flow characteristics
- Ignition sensitivity
For combustible powders, suitable testing may be required to establish properties such as minimum ignition energy and other explosion characteristics.
Understanding these properties can help manufacturers make better-informed decisions about equipment specification, process conditions and protective measures.
Why is it important to consider the complete powder handling process?
Electrostatic hazards are not limited to the blending stage.
Charging can occur during multiple manufacturing activities, including loading, mixing, discharge, conveying, sieving and filling.
Each stage can introduce different charging mechanisms and associated risks.
For example, a correctly earthed blending vessel does not guarantee that a downstream flexible connection, isolated metal component or receiving container is electrostatically safe.
Manufacturers should therefore consider the complete powder handling route rather than assessing individual pieces of equipment in isolation.
This becomes particularly important when:
- Introducing new formulations
- Changing process conditions
- Scaling production
- Installing additional equipment
- Modifying existing material transfer arrangements
A process-wide assessment can help identify potential hazards before they become operational problems.
How Terriva supports safe and effective powder processing
With more than 40 years of experience in powder processing equipment, Terriva works with manufacturers to specify blending and material handling systems for a range of industrial applications.
Our equipment supports pharmaceutical, nutraceutical, food and other powder processing operations, with solutions designed around the requirements of individual manufacturing processes.
Pharmatech powder blending systems
Terriva’s Pharmatech blending range supports powder processing applications from research and development through to full-scale manufacturing.
Our blending systems can accommodate a variety of vessels, including stainless steel pharmaceutical drums, Intermediate Bulk Containers, V-Shells and Double Cone vessels.
Hazardous-area options are available according to the application and equipment configuration.
When specifying a powder blending system, our approach considers the wider manufacturing process, including material characteristics, vessel handling, powder discharge and relevant safety requirements.
Terriva Containment Systems
Alongside our blending equipment, Terriva supplies a range of containment and flexible connection components.
These include:
- Dust Cap Seals
- Flexible transfer connections
- Silicone hoses
- Associated material handling components
These products support controlled powder transfer between different stages of manufacturing.
Individual components and equipment configurations must be assessed for the intended process and electrostatic protection requirements.
Our team can work with manufacturers to discuss these considerations during equipment specification and system design.
Conclusion: Managing static electricity requires a process-wide approach
Static electricity is a common consequence of powder movement, but the hazards vary considerably according to the material and manufacturing process.
Effective management goes beyond simply earthing equipment.
It requires consideration of powder characteristics, equipment surfaces, transfer arrangements, environmental conditions, hazardous-area requirements and ongoing maintenance.
A process-wide assessment during the design and specification stages can help manufacturers make more informed decisions about equipment selection and protective measures.
For pharmaceutical and industrial manufacturers, understanding these factors is an important step towards developing safer and more effective powder handling processes.
Discuss your powder handling requirements with Terriva
Are you planning a new manufacturing facility, upgrading existing powder processing equipment or reviewing your material transfer arrangements?
With more than four decades of experience in powder processing equipment, Terriva can help you explore suitable blending and material handling solutions for your application.
Contact Terriva to discuss your powder processing requirements and discover how our Pharmatech blending and containment solutions can support your manufacturing operations.
Frequently Asked Questions
What causes static electricity during powder blending?
Static electricity during powder blending is primarily caused by triboelectric charging, which occurs when powder particles repeatedly contact and separate from each other or equipment surfaces.
As powders move inside a rotating blending vessel, electrical charges can accumulate, particularly when processing dry, fine or poorly conductive materials.
The level of electrostatic charging depends on factors including particle size, moisture content, equipment materials and operating conditions.
Understanding these characteristics is important when designing pharmaceutical powder blending systems and selecting appropriate equipment.
How can manufacturers reduce static electricity in powder handling equipment?
Manufacturers can reduce electrostatic hazards in powder handling equipment through appropriate earthing and bonding, suitable material transfer connections, controlled operating conditions and regular equipment maintenance.
Key considerations include ensuring conductive components are correctly earthed, assessing the electrical properties of flexible hoses and reviewing the complete powder handling process.
However, earthing alone does not eliminate static electricity from insulating powders or non-conductive materials.
Effective electrostatic protection requires a risk assessment covering the powder, equipment and manufacturing environment.
Can static electricity cause explosions in pharmaceutical powder processing?
Yes. Static electricity can create an ignition hazard during pharmaceutical powder processing when combustible dust forms an explosive atmosphere and an electrostatic discharge provides sufficient energy to ignite it.
The level of risk depends on the characteristics of the powder, the surrounding atmosphere, the equipment design and the type of electrostatic discharge.
Manufacturers handling combustible powders should assess relevant requirements under the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) and applicable ATEX legislation.
Suitable equipment selection, electrostatic protection measures and appropriate dust hazard assessments are important considerations when managing these risks.
Does an ATEX-certified powder blender prevent static electricity?
No. An ATEX-certified powder blender does not automatically eliminate static electricity or every electrostatic ignition hazard.
ATEX equipment is designed and assessed for specified potentially explosive atmospheres, but electrostatic charging can still occur as powders move within vessels and transfer systems.
Manufacturers must also consider earthing, bonding, material characteristics, flexible connections and downstream powder handling equipment.
Terriva’s Pharmatech powder blending systems are available with hazardous-area options, subject to the requirements and configuration of the individual application.
What is the difference between conductive and antistatic powder transfer hoses?
Conductive and antistatic powder transfer hoses are designed to manage electrostatic charge, but their electrical properties and suitability can differ.
Conductive hoses provide an electrically conductive path that may allow charge to dissipate when correctly connected to an appropriate earthing system.
The term antistatic is broader and may describe materials designed to reduce charge accumulation or promote charge dissipation.
However, antistatic does not necessarily mean conductive, and the terminology alone does not establish that a hose is suitable for use in an explosive dust atmosphere.
Manufacturers should verify the electrical specifications and suitability of transfer hoses and flexible connections for their powder, process and hazardous-area requirements.
How can manufacturers choose a powder blending system that considers electrostatic safety?
Choosing a powder blending system requires consideration of the material being processed, its electrostatic characteristics, the manufacturing environment and the complete powder handling process.
Important factors include vessel construction, electrical continuity, powder discharge arrangements, containment requirements and any applicable ATEX or DSEAR considerations.
Manufacturers should also assess how powder enters and leaves the blending system, including connections to upstream and downstream equipment.
With more than 40 years of experience in powder processing equipment, Terriva works with pharmaceutical, nutraceutical and industrial manufacturers to specify blending and material handling solutions.
Terriva’s Pharmatech powder blending systems accommodate a variety of vessels, including stainless steel drums, Intermediate Bulk Containers (IBCs), V-Shells and Double Cone vessels, with hazardous-area configurations available for suitable applications.
Contact Terriva to discuss your powder blending requirements and the electrostatic safety considerations relevant to your manufacturing process.
