Hazardous-area equipment selection
Can an ATEX Filling Machine Be Used in Zone 0?
Zone 0 describes an external area where an explosive gas atmosphere is present continuously, for long periods or frequently. Equipment for that duty requires the highest gas-atmosphere protection level and a complete application-specific review.
Direct answer
A complete filling machine is not normally assumed suitable for Zone 0; any equipment actually installed in Zone 0 must be specifically selected and evidenced for that duty.
Under the DSEAR definitions, Zone 0 is a place where an explosive atmosphere of gas, vapour or mist is present continuously, for long periods or frequently. That is a more demanding external-area classification than Zone 1 or Zone 2. Equipment selection must follow the competent area classification and address electrical and non-electrical ignition sources, gas group, temperature class, equipment protection level, interfaces and the conditions of use.
In many filling projects the engineering objective is to minimise releases and keep the external machine area out of Zone 0. A flammable atmosphere may exist inside a closed product vessel or pipe, while the external filling point is classified differently. Internal process containment and external area zoning are related but not interchangeable, so the hazardous-area drawing must define the actual boundaries.
Do not select from the word “ATEX” alone.
A generic ATEX label does not prove suitability for Zone 0. The equipment marking, protection concept, certificates or technical evidence, instructions and complete assembly must all match the declared duty.
Zone definitions
How Zone 0 differs from Zone 1 and Zone 2.
| Zone | Meaning for gas, vapour or mist | Filling-project implication |
|---|---|---|
| Zone 0 | Explosive atmosphere present continuously, for long periods or frequently. | Any equipment within the zone needs the corresponding very high level of protection; designers should also examine whether release prevention can reduce the external Zone. |
| Zone 1 | Explosive atmosphere likely to occur in normal operation occasionally. | Commonly associated with credible normal-operation releases around an open process, subject to competent classification and ventilation. |
| Zone 2 | Explosive atmosphere not likely in normal operation and, if it occurs, present for a short period only. | Often associated with secondary releases, but the actual extent and equipment category still require documented classification. |
These are regulatory definitions, not a substitute for a site hazardous-area classification. Do not assign a Zone from a generic table or container size.
Internal atmosphere
Inside a vessel is not automatically the same as the external machine Zone.
A tank, hose or container may contain flammable vapour as part of the process. The protection strategy for equipment entering or connected to that internal space can differ from the classification of the room or area outside it.
Examples include a filling lance entering a container, an instrument mounted on a product vessel, or a vapour-return connection. The specification must identify which parts are exposed internally, which are located externally and which protective concept applies to each interface.
External release
Open filling and displaced vapour can define the area around the fill point.
The grade of release, product temperature, vapour characteristics, ventilation, fill opening, extraction and foreseeable faults all influence external zoning. Reducing the release at source and capturing displaced vapour may reduce the extent of the hazardous area, but the outcome must be demonstrated by competent classification.
Engineering options
Ways a project may avoid placing the complete machine in Zone 0.
Reduce release
Use closed transfer, sealed connections, controlled venting or compatible nozzle arrangements to minimise normal-operation vapour release.
Extract at source
Capture displaced vapour close to the opening and prove the required airflow and machine response to extraction failure.
Separate equipment
Locate control panels, drives or other equipment outside the classified area where the process and installation allow it.
Use suitable interfaces
Select sensors, barriers, glands, valves and other components for the actual Zone and circuit protection concept.
Contain the process
Keep flammable atmosphere within a closed, controlled product path where practicable and manage openings deliberately.
Assess abnormal conditions
Include leaks, overfill, loss of extraction, hose failure and maintenance states rather than classifying normal production alone.
Evidence package
What the equipment supplier needs.
- Hazardous-area drawing showing Zone 0, Zone 1, Zone 2 and non-hazardous boundaries.
- Gas group, temperature class and environmental conditions.
- Release sources and the assumptions behind ventilation or extraction.
- Product SDS, operating temperature and foreseeable cleaning products.
- Equipment-location plan, cable and control interfaces and intended safe states.
- Any site standard governing EPL, equipment category, intrinsic safety or segregation.
Verification
What should be checked before acceptance.
- Marking and documentation for components and the completed assembly.
- Special conditions of use and installation instructions.
- Correct equipment location against the approved hazardous-area drawing.
- Earthing, bonding, extraction and permissive operation.
- Fault response, isolation and controlled restart.
- Site acceptance checks that cannot be completed at the factory.
Buyer questions
Questions about Zone 0 and filling machinery.
Is the inside of every flammable-liquid container Zone 0?
The internal atmosphere may meet conditions associated with a continuously or frequently present flammable atmosphere, but equipment selection must follow the actual process classification and applicable standards. Do not transfer an internal classification directly to the whole room or machine exterior.
Can Category 2G equipment be installed in Zone 0?
Zone 0 generally requires the equipment category or protection level corresponding to a very high level of protection. Category 2G is associated with Zone 1 use. Final selection must be confirmed by the competent specification and equipment documentation.
Can ventilation turn Zone 0 into Zone 1 or Zone 2?
Ventilation can affect the extent and persistence of an external explosive atmosphere, but zoning is based on the release source, ventilation availability and reliability, and the complete scenario. A fan alone does not justify reclassification.
Does intrinsically safe equipment solve the whole machine requirement?
No. Intrinsic safety is one protection concept, mainly relevant to suitable electrical circuits. The machine also contains non-electrical ignition sources, product-path equipment, mechanical parts, controls and installation interfaces that require assessment.
What is the first document to send Lancing?
Send the hazardous-area classification drawing and basis together with the product SDS and process description. The drawing should show the Zone extent around the fill point and the intended location of machinery, controls and product-transfer equipment.
Authoritative UK definitions
Use the HSE definitions and a competent site classification.
HSE defines Zone 0, Zone 1 and Zone 2 by the likelihood and duration of an explosive atmosphere. Its guidance on hazardous-area classification and ignition-source control also links the classified Zone with suitable equipment selection. The project-specific assessment remains the controlling evidence.
For the adjacent decision, review Zone 1 versus Zone 2 filling equipment and the full DSEAR and ATEX filling-equipment guide.
Classify before configuring
Send the hazardous-area drawing and process details for review.
Lancing can map the machine, controls and product-transfer interfaces to the customer’s competent Zone specification.