Overfill protection and leak detection are essential safety measures in industrial plants, including chemical, pharmaceutical, water management and energy applications. This article highlights the regulatory requirements – from WHG to VLAREM and FM – and explains when certified level and point level systems are required to reliably protect plants, people and the environment.
What is meant by overfill protection and leak detection?
Overfill protection prevents tanks or containers from exceeding their maximum capacity. When a defined limit level is reached, the measurement system sends a signal to the control unit or automatically stops the filling process. This ensures that liquids do not unintentionally escape into the environment and helps avoid potential environmental damage.
Leak detection serves to identify leaks at an early stage – for example in double-walled tanks, pipelines or containment spaces. Modern systems continuously monitor the interstitial space and trigger visual and/or audible alarms in the event of a fault.
The CN 7120 monitors the interstitial space, the RF 8100 safeguards the maximum level for overfill protection, and the NR 8300 provides continuous level measurement
The NR 7 measures the fill level, the CN 7121 safeguards the maximum level, and the CN 7150 reliably detects leaks
Where are such approvals required?
Approvals or legally compliant designs of level and point level systems are required whenever water-hazardous, flammable or toxic media are stored, processed or transported.
Typical applications include:
Chemical and petrochemical plants, where aggressive or hazardous liquids such as acids, alkalis or solvents are handled.
Tank farms and refineries, where overfill protection systems are legally mandated.
Water and wastewater management, to protect bodies of water from contamination.
Food and pharmaceutical production, where installations must comply with strict hygiene and safety regulations.
Industrial facilities with heating oil or diesel tanks, which must meet national safety standards.
Agricultural storage tanks for manure, slurry and silage effluent: For these applications, the Vibranivo® VN 7 tuning fork is approved as a leak detection probe – a specific certification for use in environments with high environmental protection requirements.
In all these cases, the regulations aim to ensure operational safety, environmental protection and legal compliance.
Typical applications
Certified or legally compliant overfill and leak detection systems are used wherever water-hazardous, toxic or flammable substances are handled. This includes:
- Storage tanks and process vessels
- Fuel and heating oil tanks
- Dosing and reaction vessels
- Collection and clarification tanks
WHG, VLAREM, FM & more – what’s behind these standards?
WHG / AwSV (Germany):
The Water Resources Act regulates the handling of water-hazardous substances. The associated AwSV ordinance mandates the use of overfill protection and leak detection systems for specific types of installations. Only approved components may be used.
VLAREM (Belgium, Flanders region):
VLAREM is not a certification body but a legally binding environmental regulation for the Flanders region. It defines the technical and safety requirements that installations must meet – including provisions for overfill protection, leak detection and the handling of water-hazardous liquids.
FM Approvals (USA):
This is not a law but a testing and certification body. FM-approved devices meet high safety standards and are widely required worldwide, particularly in North America.
International Standards
In addition to WHG, VLAREM and FM, there are several other guidelines that define requirements for overfill protection and leak detection systems:
API 2350 (USA): Standard for preventing overfills in tanks used in the oil and gas industry
Prawo Wodne & Ustawa Prawo Ochrony Środowiska (Poland): National environmental and technical safety laws such as Prawo Wodne and Ustawa Prawo Ochrony Środowiska define the requirements for overfill protection and leak detection. Technical rules for fuel and chemical tanks mandate protective devices, leak monitoring and periodic inspections by UDT to ensure safe operation and environmental protection.
PGS guidelines (Netherlands): National safety regulations for the storage and handling of hazardous substances, including overfill protection.
KVU implementation aids and TRCI guidelines (Switzerland): KVU implementation aids and TRCI guidelines (Switzerland): These define requirements for tank farms, containment areas and overfill protection systems, serving as practical guidance for operators and authorities.
The aim of all these regulations is to ensure the highest possible level of plant safety and environmental protection.
UWT sensors meet the latest VLAREM II requirements
With the ongoing development of the Belgian environmental regulation VLAREM, the demands on reliable overfill protection and leak detection in sensitive installations continue to increase. UWT sensor solutions such as the Vibranivo® VN 7 meet these requirements and are approved for use in agricultural storage tanks for manure, slurry and silage effluent, as well as in biogas plants. For existing installations, a transition period applies until the end of 2027.
UWT is among the manufacturers whose point level sensors comply with the applicable specifications for overfill protection and leak detection systems. The Capanivo® CN 71xx and Vibranivo® VN 7 product ranges provide legally compliant and future-proof solutions for operators in Belgium and beyond — delivering maximum operational safety and proven measurement performance.
Whether in chemical tanks, heating oil systems or water treatment facilities: Reliable level, point level and leak monitoring is essential for the safe operation of any plant. UWT sensors make a significant contribution to this — with robust materials, internationally recognized approvals and solutions that can be flexibly adapted to different regulatory requirements.
UWT sensors certified for overfill and leakage control
| WHG Overfill protection | WHG Leak detection | VLAREM Leak detection | VLAREM Leak detection | |
| VN 7 | ||||
| CN 71xx | x | x | x | x |
| CN 8 | x | -- | x | -- |
| RF 8 | x | -- | x | -- |
| NC 8 | -- | -- | x | -- |
| NR 4/7 | x | -- | -- | -- |
