ATEX Radar Level Sensor UK: 9 Critical Checks for Safe Level Monitoring
An ATEX radar level sensor is one of the most practical ways to get non-contact, real-time level visibility on fuel, chemical, solvent and other hazardous-area tanks—but only when it’s specified and installed in a way that matches your site’s hazardous-area classification and ignition risk controls.
In the UK, the workplace duties for controlling fire and explosion risks from dangerous substances sit under DSEAR (Dangerous Substances and Explosive Atmospheres Regulations). HSE’s overview is here:
https://www.hse.gov.uk/fireandexplosion/dsear.htm
ATEX also appears in UK practice as the shorthand for the suitability of equipment used in potentially explosive atmospheres, and HSE provides dedicated guidance on ATEX equipment and explosive atmospheres here:
https://www.hse.gov.uk/fireandexplosion/atex.htm
This blog is written to help you avoid the common mistakes that derail hazardous-area monitoring projects: unclear zoning, vague “ATEX-rated” claims, missing paperwork, and installations that don’t match the certification conditions.
If you want to see how this integrates into a full IoT deployment (LoRaWAN or cellular) with alarms and dashboards, start with:
AQUAIOT Radar product page: https://aquaiot.co.uk/product/aquaiot-radar-smart-water-level-monitoring/
Contact AQUAIOT: https://aquaiot.co.uk/contact-aquaiot
ATEX radar level sensor basics (and why radar is popular in hazardous areas)
A radar level sensor measures distance to a liquid surface using radio waves. In operational terms, radar is popular because it is non-contact (no probe in the liquid) and can be deployed to provide continuous trend visibility and actionable alarms.
In hazardous areas, the operational drivers are usually very specific:
- You want to reduce manual dipping/inspection and site attendance.
- You want earlier warning for overfill risk, unusual inflows, or bund accumulation.
- You want reliable evidence for operational governance, incident review, and compliance.
An ATEX radar level sensor becomes the right tool when you need all of the above, and the location (or surrounding zone) means you must also control ignition risk from equipment.
9 critical checks before you specify an ATEX radar level sensor
1) Start with DSEAR controls, not the sensor
If you begin by shopping for an “ATEX sensor” you can end up with the wrong equipment for the wrong zone. DSEAR requires you to assess and control the risks of fires and explosions from dangerous substances in the workplace. HSE’s DSEAR overview is the correct starting point:
https://www.hse.gov.uk/fireandexplosion/dsear.htm
For practical compliance guidance, HSE’s Approved Code of Practice and guidance (L138) is here:
https://www.hse.gov.uk/pubns/books/l138.htm
Your selection should follow the control strategy, not the other way around.
2) Confirm hazardous area classification (zones) for where the device will sit
Hazardous area classification is the step that drives everything: where a flammable atmosphere might form and how long it might persist. HSE explains the purpose of hazardous area classification here:
https://www.hse.gov.uk/electricity/atex/classification.htm
A key practical point: the zone at the sensor location may differ from the zone inside the tank or near vents/fill points. You need the right classification for the actual intended installation position and operating conditions.
3) Match the equipment category/EPL to the zone (don’t guess)
ATEX equipment selection is not “one rating fits all”. Your zoning outcome determines the equipment protection level required. HSE’s ATEX and explosive atmospheres guidance is a useful reference point:
https://www.hse.gov.uk/fireandexplosion/atex.htm
If you’re deploying to high-risk zones (including Zone 0 areas), the specification becomes more demanding and model selection must be exact.
4) Read the Ex marking properly (it tells you what you’re really buying)
This is where most projects get sloppy. The Ex marking is not decoration: it communicates the protection concept, gas group and temperature class.
For example, some intrinsically safe devices are marked with formats such as Ex ia (intrinsic safety) and gas group/temperature class indicators. Your competent persons should interpret this in the context of site hazardous area classification and ignition risk controls.
A useful HSE page for broader electrical control expectations in explosive atmospheres is here:
https://www.hse.gov.uk/electricity/explosive.htm
5) Treat “ATEX available” as model-specific and evidence-based
A credible website statement is always specific and evidence-based. A vague claim (“ATEX-certified”) without model detail is a red flag.
As a worked example of how to do it correctly, the Milesight EM41x-RDL documentation states that ATEX Zone 0 support is model-specific, with an Ex marking stated for a particular variant. Datasheet (PDF):
https://resource.milesight.com/milesight/iot/document/em41x-rdl-datasheet-en.pdf
User guide (PDF):
https://resource.milesight.com/milesight/iot/document/em41x-rdl-lora-user-guide-en.pdf
And the Milesight product page also states ATEX availability is specific to a model:
https://www.milesight.com/iot/product/lorawan-sensor/em41x-rdl
The operational takeaway: when you specify an ATEX radar level sensor, you must specify the exact model and the exact certification/marking, and keep the manufacturer documentation on file.
6) Confirm installation conditions: mounting, thread, separation, and “what’s inside the zone”
Hazardous-area compliance is not only about the sensor—it’s the installation and the surrounding system.
Ask the practical questions early:
- Is the sensor installed above the tank, through a nozzle, or in a stilling arrangement?
- Is the process connection (thread/nozzle) compatible, and does it introduce any site constraints?
- Are there any nearby ignition sources, or conductive/earthing requirements?
- If there is a local junction box or gateway nearby, is that also inside a zone?
For many sites, it’s the “other bits” (cables, glands, power, junctions) that create the non-compliance risk, not the sensor itself.
7) Plan connectivity safely: LoRaWAN and cellular are deployment choices, not compliance shortcuts
Most radar monitoring projects want remote alerts, so connectivity matters. Typically you’ll choose between:
- LoRaWAN for estate-wide coverage and scaling across many assets
- Cellular for standalone sites or where LoRaWAN coverage is unavailable
From a hazardous-area perspective, the important point is that the overall system must remain compliant with the area classification and ignition risk controls. Don’t place non-suitable equipment inside a zone simply because it’s “convenient for signal”.
If you want the IoT deployment overview for radar monitoring, see:
https://aquaiot.co.uk/product/aquaiot-radar-smart-water-level-monitoring/
8) Keep the paperwork: declarations, certificates, site records, and change control
An ATEX project without paperwork is a liability.
For the UK market and how explosive atmosphere equipment regulations apply in Great Britain, GOV.UK provides guidance linked to the 2016 Regulations here:
https://www.gov.uk/government/publications/equipment-and-protective-systems-intended-for-use-in-potentially-explosive-atmospheres-regulations-2016/equipment-and-protective-systems-intended-for-use-in-potentially-explosive-atmospheres-regulations-2016-great-britain
And the underlying legislation is here:
https://www.legislation.gov.uk/uksi/2016/1107
In practice you should be able to show, at minimum:
- the manufacturer datasheet/user guide for the exact model
- relevant certification/marking evidence for the hazardous area requirement
- installation records and commissioning checks
- any change control notes (if mounting position, tank configuration, or operating conditions change)
9) Make alerting operational: thresholds, rate-of-rise, escalation, and evidence
The best ATEX radar level sensor projects do not stop at “we can see the level”. They define what decisions the data must support.
For fuel and chemical assets, the most useful alert patterns are usually:
- High-level alarms (overfill risk)
- Bund level alarms (secondary containment accumulation)
- Rate-of-rise alarms (abnormal filling/inflow)
- Persistence rules (reduce nuisance alarms and escalate real risk)
When alerting is designed properly, you reduce site attendance, cut wasted call-outs, and improve response times—all while building a defensible evidence trail.
If you want to discuss practical alarm set-up and response playbooks, speak to AQUAIOT here:
https://aquaiot.co.uk/contact-aquaiot-enquiries/
Where an ATEX radar level sensor fits best (UK use cases)
Fuel storage tanks and remote depots (petrol, diesel, heating oil, aviation fuels)
A radar sensor supports remote visibility for:
- stock awareness (where relevant)
- high-level alarms for overfill prevention
- trend evidence for operational governance
- reduced need for manual attendance
Where the environment is classified as hazardous, selection must align with DSEAR, zoning and appropriate equipment marking.
Key references for UK duty and equipment context:
- DSEAR overview: https://www.hse.gov.uk/fireandexplosion/dsear.htm
- ATEX equipment guidance: https://www.hse.gov.uk/fireandexplosion/atex.htm
- Tank storage governance: https://www.hse.gov.uk/pubns/books/hsg176.htm
Bunds and secondary containment (spill prevention and compliance evidence)
Bund monitoring is a practical win: it reduces the chance that accumulation goes unnoticed and becomes a larger incident. Bund level alarms are typically straightforward to act on and easy to justify operationally.
Chemical tanks, solvents and process liquids
For chemical sites, the combination of non-contact measurement and remote alarm capability supports:
- safer operations with fewer manual checks
- earlier warning of abnormal inflows/outflows
- clearer “what happened when” records in incident reviews
Industrial wastewater, interceptors and oily water separators
Many industrial wastewater assets sit in awkward locations and are costly to check routinely. If the environment is hazardous or potentially explosive, an ATEX radar level sensor may be required depending on zoning and ignition risk assessment.
How AQUAIOT typically deploys radar level monitoring safely
AQUAIOT deployments are designed around three practical pillars:
- the right sensor and mounting approach for the asset
- telemetry that suits the site (LoRaWAN or cellular)
- alarms and dashboards that drive action, not noise
Start with the radar product overview here:
https://aquaiot.co.uk/product/aquaiot-radar-smart-water-level-monitoring/
If your project spans drainage and industrial sites, these pages also provide context for joined-up monitoring:
- Sewer Monitoring: https://aquaiot.co.uk/service/sewer-monitoring/
- Water Quality Monitoring: https://aquaiot.co.uk/service/water-quality-monitoring-uk/
For hazardous-area deployments, the scoping conversation matters: zoning, installation position, equipment suitability, and the operational response model must all be aligned.
FAQs: ATEX radar level sensor projects
Is ATEX the same as DSEAR in the UK?
Not exactly. DSEAR is the UK workplace regulation framework for controlling fire and explosion risks from dangerous substances. ATEX is often used as shorthand for equipment suitability and requirements for potentially explosive atmospheres. HSE provides both in its guidance:
- DSEAR: https://www.hse.gov.uk/fireandexplosion/dsear.htm
- ATEX equipment: https://www.hse.gov.uk/fireandexplosion/atex.htm
What does “Zone 0” mean in practice?
Zone 0 refers to areas where an explosive gas atmosphere is present continuously or for long periods. Equipment selection for Zone 0 is therefore more demanding and must be model-specific and properly evidenced.
Where can I find UK guidance on placing explosive atmosphere equipment on the GB market?
GOV.UK provides a guide linked to the Equipment and Protective Systems regulations as they apply in Great Britain:
https://www.gov.uk/government/publications/equipment-and-protective-systems-intended-for-use-in-potentially-explosive-atmospheres-regulations-2016/equipment-and-protective-systems-intended-for-use-in-potentially-explosive-atmospheres-regulations-2016-great-britain
Next step
If you’re planning an ATEX radar level sensor deployment for fuel tanks, chemical storage, bunds, interceptors or hazardous-area process assets, the fastest route to a safe, defensible project is a short scoping session: confirm zoning, installation approach, connectivity, and the alarm model that operations will actually use.
Contact AQUAIOT: https://aquaiot.co.uk/contact-aquaiot-enquiries/