How does leak detection work in double-walled pipes?
In a double-walled piping system, an interstitial space exists between the inner pipe and the outer pipe. When the inner pipe leaks, fluid flows into this space. A sensor — positioned at the lowest point of the compartment — measures electrical conductivity. Once the measured value exceeds the threshold (500 mS, corresponding to a resistance below 500 kO), the system triggers a leak alarm.
The control unit manages up to 99 sensors via a two-wire cable. Each measurement point has its own ID, so the system indicates exactly where the leak is located. After cleaning the pipe and performing a reset, the system is immediately operational again — no sensors or cables need to be replaced.
The system performs periodic self-checks on:
- the number of connected detectors
- the status of each individual detector
- corrosion of the measurement probes
- cable integrity across the entire measurement string
In case of deviations, the control unit generates an alarm: leak, short circuit, cable break, corrosion, or power failure.
Leak detection on floors: when to apply?
On floors in process rooms, storage areas, or server rooms, leak detection is used when early fluid detection is essential. Examples include:
- drip trays beneath tanks or pumps
- floor surfaces near process instruments or connections (see also our pressure sensors and level sensors)
- cooling water pipes beneath raised floors in utility buildings
The sensor is positioned at the lowest point of the floor or drip tray, so fluid always flows toward the measuring probe.
What components does a leak detection system consist of?
A complete system consists of the following components:
| Component |
Function |
| DF1000i control unit |
Central processing, display, alarm and MOD-bus communication |
| DF1030i detector |
Collects sensor data, determines conclusion: leak / corrosion / OK |
| DF1020i sensor / measuring head |
Conductivity measurement with Hastelloy C probes, including 5 m cable |
| DF1037i end unit |
Terminates cable string, monitors end voltage and temperature |
| DF/OG cable |
Two-wire, shielded, suitable for underground and above-ground installation |
A turn-key version is available (DF1000Ti series), delivered fully pre-wired and configured. Installation is then limited to positioning and connecting via pre-assembled cables with connectors — no on-site software configuration required.
Selection guide: which system suits your situation?
Choose based on your application:
- Double-walled pipe, multiple measurement points over long distances ? DF1000i system with multiple DF1030i detectors, cable length up to 4 km (8 km with correct distribution)
- Single measurement point, limited installation ? DF1030i with DF1020i sensor as standalone version
- Installer available for configuration ? standard DF series
- No technical expertise on-site ? turn-key DF-Ti series, fully pre-configured
- Integration with SCADA or BMS required ? system with MOD-bus connection (standard on DF1000i)
Unsure about the right configuration for your piping system? Provide us with the details of your installation — number of measurement points, medium, cable length and mounting location — and we will recommend the correct setup.
Standards and certification
The system is manufactured in accordance with ISO 9001 and ISO 14001, CE certified and RoHS/REACH compliant. Electromagnetic compatibility meets EN 61000-6-4 (emission) and EN 61000-6-2 (immunity), including testing for electrostatic discharge, fast transients, and voltage dips.
For applications in the chemical or petrochemical industry, water treatment, or food production, this provides the required level of reliability and traceability. Browse our full range of
instrumentation for additional measurement and monitoring solutions.
Select the right leak detection configuration based on the number of measurement points, your medium, and the desired communication interface — or request a quote directly for the DF1000i series.
Frequently asked questions
How long can the cable string of a DF1000i system be?
The maximum cable length is 4 km. With the correct distribution of measuring heads along the string, a length of 8 km is possible. This makes the system suitable for long pipe runs in infrastructure projects or industrial sites.
How do I position a sensor correctly in a double-walled piping system?
Always position the sensor at the lowest point of the compartment. In the event of a leak, fluid flows toward this point, ensuring reliable and timely detection. For double-walled systems, several mounting options are available: via a T-piece, a butt-weld fitting, or a tapping saddle.
Can the system be connected to a SCADA or BMS?
Yes. The DF1000i control unit is equipped as standard with a MOD-bus connection. All measurement data and alarm statuses can be read via this interface, and parameters can be configured from a central management system.
