Explosion protection in everyday operations: Safe processes when handling bulk materials

Bulk goods come in a wide variety of colours and shapes. (Image source: NürnbergMesse / Thomas Geiger)

In industrial processes involving bulk materials such as flour, sugar, cement, lime, plastic granules, or metal powder, explosion protection is one of the key safety tasks. Fine, combustible dusts can form explosive mixtures when combined with oxygen and a suitable ignition source. Even small amounts of dust dispersed in the air are sufficient to cause considerable damage when ignited. The protection of people, machines, and infrastructure therefore requires a holistic concept that includes design, organizational, and technical measures.

The challenges in handling dusty bulk materials lie in their physical properties. The finer the material and the drier the process, the greater the risk of an explosive atmosphere. The same basic principles apply across all industries – from food processing to chemicals and pharmaceuticals to the building materials industry: minimize dust generation, eliminate ignition sources, and use explosion-proof components.

Despite economic challenges, the global market for bulk material handling equipment is expected to grow by 2025. (Image source: AdobeStock / IM Imagery)

An explosion occurs when the so-called “explosion pentagon” is complete: combustible material, oxygen, ignition source, sufficient concentration, and a closed space. In practice, mechanical friction, electrostatic discharge, and hot surfaces are particularly underestimated as potential ignition sources. It is therefore crucial that all components used—from the screw conveyor to the shut-off valve to the seal—comply with the requirements of the European ATEX Directive 2014/34/EU.

Technical prevention and constructive decoupling

In modern plant engineering, explosion protection is increasingly seen as an integral part of process design. The aim is not only to prevent explosions, but also to limit their effects. This includes pressure-resistant enclosures, non-return valves, explosion decoupling devices, and conductive materials for dissipating electrostatic charges. Safe zone separation is particularly necessary at transfer points between different pressure or Ex zones to prevent the spread of an explosion.

A proven principle is “structural decoupling”: this ensures that in the event of an explosion in one part of the plant, no flames or pressure waves can spread to adjacent areas. This is achieved, for example, by means of lock systems with two gas-tight fittings and an intermediate chamber that can be specifically vented or inerted. Such systems ensure that at least one of the two fittings is always closed, preventing the transmission of pressure and flame fronts.

Optimal bulk material handling is crucial, especially in the pharmaceutical industry. (Image source: AdobeStock / YURY YUTY)

Fittings and seals as safety-related components

Industrial valves not only perform control tasks in bulk material processes but also fulfil key safety functions. Butterfly valves, gate valves, and sluice valves must be designed to function reliably in potentially explosive atmospheres. The selection of suitable materials—such as conductive elastomers in seals—plays a key role in this regard, as it allows electrostatic charges to be dissipated in a controlled manner.

The mechanical robustness of the components is also crucial: pressure shock-resistant designs in accordance with DIN EN 14460 ensure that valves can withstand even internal overpressure. Complete grounding of all conductive components—including drives and housings—is one of the essential measures of primary explosion protection.

Explosion protection in bulk solids technology requires more than just compliance with legal requirements. (Image source: EBRO ARMATUREN)

In practice, pneumatic or electric actuators are often used directly in potentially explosive areas. They must therefore be ATEX-compliant, as must the associated positioners, limit switch boxes, or sensors. Due to increasing integration into automated systems, secure electrical and communication connections are another aspect to consider in the overall system.

Normative principles and operational responsibility

European regulations define clear requirements for explosion protection: In addition to the ATEX Directive 2014/34/EU for equipment and protective systems, EN ISO 80079-36/-37 is authoritative for non-electrical components. Operators are obliged to carry out a risk assessment and document suitable protective measures. The principle of prevention over control applies here. Only when an explosive atmosphere cannot be technically ruled out do structural protective measures such as relief, decoupling, or pressure resistance come into play.

However, everyday operations show that safety cannot be achieved through technology alone. Regular training, maintenance concepts, and consistent dust management are just as important as choosing suitable valves. The trend toward digital condition monitoring is also gaining in importance: Sensors for leak detection, temperature monitoring, or switching cycles can indicate deviations at an early stage, thereby reducing the risk of uncontrolled ignition events.

Balancing cost-effectiveness and safety

Explosion protection is not an isolated issue, but an integral part of economical plant management. Downtime, repairs, and production losses resulting from dust explosions cause enormous costs. At the same time, regulatory requirements are increasing—especially in sensitive industries such as pharmaceuticals and food, where product safety is just as important as operational safety.

Manufacturers of valves and sealing systems are responding to this with modular, adaptable design concepts that can be flexibly integrated into existing systems. This allows safety, ease of maintenance, and energy efficiency to be harmonized. The use of conductive materials, flow-optimized geometries, and low-dead-space designs also helps to prevent deposits and ignition risks.

Conclusion

Explosion protection in bulk material handling is an interdisciplinary task that combines design safety, material technology, and organizational responsibility. In addition to precise dosing and conveying technology, valves and seals play a central role, as they determine tightness, conductivity, and pressure resistance.

EBRO Armaturen GmbH provides an example of application-oriented solutions with shut-off and lock systems specially developed for hazardous areas, which ensure zone separation and material transfer. Such systems demonstrate that explosion protection is not an isolated safety module, but an integral part of modern bulk material processes – with a direct influence on plant availability, product quality, and employee protection.