The case seems simple: a drum, a sack truck, and a pump.
A sealed metal drum containing a flammable liquid is moved through a production hall on a sack truck. The drum was filled by an external supplier, sealed, and appears harmless. There is no leakage, no visible vapour formation, and no obvious abnormal condition. It looks like a routine task in an environment where flammable substances are part of daily operations.
After arriving at its destination, the drum is placed next to a process installation. The area is not classified as a hazardous area. The risk assessment refers only to occasional vapour formation during open handling. The drum is opened. Shortly afterwards, the liquid is transferred into a mixing vessel through a hose connection. Everything appears to follow the normal work method. There is no visible mechanical damage, no obvious ignition source, and no apparent defect in the pumping system.
And yet ignition occurs just as the liquid flow starts.
The installation is made safe and the investigation begins. The liquid has a flash point well below the ambient temperature. During transport, the drum was moved across an industrial floor on a sack truck. Before opening, no explicit bonding or earthing connection was made between the drum, the receiving system and the surrounding installation. When the drum was opened, a vapour-air mixture formed in and around the filling opening. The pump was electrically driven and correctly installed in accordance with EN IEC 60079-14. The hazardous area classification had been prepared in line with EN IEC 60079-10-1.
The ignition source was not found in the fixed electrical installation.
When conductive metal containers are filled or emptied with low-conductivity flammable liquids, electrostatic charge separation can occur. During movement, handling, hose connection, opening and transfer, different conductive parts may be at different electrical potentials. If those parts approach each other or make contact without controlled bonding, a spark discharge can occur. For some vapour-air mixtures, the minimum ignition energy is so low that a very small amount of transferred energy can be sufficient to initiate ignition.
This is where the analysis moves away from equipment certification and towards system behaviour.
Under the European ATEX workplace requirements, and under the UK DSEAR framework, the employer or operator must assess and control explosion risks arising from dangerous substances during normal operation, maintenance, filling, emptying, cleaning and foreseeable abnormal situations. The ATEX equipment requirements and the UK Equipment and Protective Systems Regulations address the suitability of equipment placed on the market, but the safe use of that equipment depends on the complete work process in which it is applied.
IEC 60079-32-1 provides the relevant guidance for electrostatic hazards, including material properties, process conditions, bonding, earthing and operational controls. EN IEC 60079-14 addresses the design, selection, installation and initial inspection of electrical installations associated with explosive atmospheres. EN IEC 60079-10-1 provides the framework for classifying gas and vapour hazardous areas. EN ISO 80079-36 and EN ISO 80079-37 are relevant where non-electrical ignition sources and mechanical equipment must be assessed.
The key question is therefore not whether the pump was certified or whether the fixed installation was correctly installed. The key question is whether the full handling sequence was assessed as one integrated system.
Was the movement of the drum included in the explosion risk assessment? Was the sack truck considered as part of the operation? Was the interaction between the floor, the wheels, the metal drum, the hose, the receiving vessel and the pump assessed? Was bonding applied before opening the container? Was the area immediately around the drum opening controlled during transfer? Was the liquid conductivity known? Was the filling and emptying rate compatible with electrostatic safety principles?
These transition zones between logistics and process operation are often underestimated. The activity is not seen as production, but it is also no longer simple storage. It is an open handling operation involving a flammable liquid, a vapour-air mixture, movement, transfer, material contact and potential charge separation.
The case seems simple: a drum, a sack truck, and a pump.
But the real weakness is not necessarily in the component that is easiest to see. It may be in the missing link between hazardous area classification, electrostatic assessment, work instruction, bonding practice and operational supervision.
For a competent technical assessment, the primary design error or organisational gap is therefore likely to be this:
the complete handling route was not treated as an ignition-source scenario.
That is where explosion safety often fails.
Not in the certified pump.
Not in the drawing.
Not in the label.
But in the unassessed interaction between people, materials, movement, electrostatics and process conditions.
The discussion is open.
https://exquintia.com/
#ATEX #DSEAR #ExplosionSafety #ProcessSafety #Electrostatics #IEC60079 #HazardousAreas #FlammableLiquids #IndustrialSafety #ChemicalIndustry #SafeHandling #RiskAssessment #Exquintia