Fibre-optic leak detection for pipelines and district heating networks
Where is the leak, before the road sinks? Hot water, cold water or gas.
Where is the leak, before the road sinks? Hot water, cold water or gas.
A leak changes the ground temperature around the pipe and makes a noise. One fibre along the route reports both, every half metre, and two independent signatures at the same chainage is a leak, not an artefact. The alarm goes to your control room with the chainage attached.
- A per-metre temperature baseline for the route, with every persistent deviation located to the half metre.
- With the acoustic tile, persistent acoustic sources on the same chainage axis, so a leak confirms itself twice.
- Severity levels, temperature only, acoustic only, both, with the growth rate of each anomaly.
- Alarms over Modbus, MQTT or a relay, straight into SCADA.
The event, and the signal
- A pipe in the ground, the fibre beside it.
- A leak starts. The ground around it changes temperature, and the leak makes a noise.
- Both appear at the same chainage. Two signatures at one place is a leak, not an artefact, and the alarm carries the position.
Setup
| Fibre | The fibre laid with the pipe, or a telecom fibre in the same trench. Single-mode for acoustics; single-mode or multimode for temperature. New sensing cable can be laid with new pipe. |
| Length | Tens of kilometres of route per instrument for temperature; forty kilometres for acoustics. |
| Power | Mains or power over Ethernet at the substation or cabinet. |
| Integration | Modbus TCP and MQTT to the control system; relay outputs for the simplest sites; the existing alarm-wire system can be read into the same record. |
| Term | A leak survey campaign on a suspect section, or continuous monitoring on a service contract. |
The measurement
Every half metre of fibre is compared with its own baseline over the previous week, with the season taken out. A deviation that persists for longer than a set time becomes an anomaly, sign-aware because hot water warms the ground and cold water or expanding gas cools it. With the acoustic tile, a persistent rise in band energy at the same place raises the severity. Valve operations and traffic are excluded by site rules, and in the first months an analyst reviews each alarm before it goes to the operator.
Deliverables
- Route map with anomalies by severity and the two traces around each event
- Alarm table with chainage, start, temperature change, acoustic rise, duration, trend
- Live dashboard for the control room, plus the same alarms over Modbus and MQTT
- Monthly report of events and false alarms
On the dashboard, through the API, and as files. All three, always.
Asked before
- Does it work on plastic district-heating pipe with no alarm wire?
- Yes. The fibre senses the ground around the pipe, not the pipe itself, so the pipe material does not matter.
- How small a leak shows?
- It depends on burial, soil and flow. A leak that changes the ground temperature by a few tenths of a degree for half an hour is detectable; the acceptance measurement on your route tells you the figure for your case.
- Can it use the telecom fibre in the same trench?
- Yes, a dark fibre in the same duct works for temperature and for acoustics. The farther the fibre is from the pipe, the slower the thermal response.
Other things the same box does
- Wells
Where is the injected fluid going, and is the well behaving?
You get Time-lapse temperature profiles against the pre-injection baseline, with injection and shut-in periods marked.
Read more - Dark-fibre seismology
Can the telecom fibre under the road become a seismic array?
You get Quantitative strain rate on every channel, not event flags.
Read more - Geothermal
What is the ground made of, layer by layer, and is the field slowly cooling?
You get Thermal conductivity and borehole resistance per depth interval, with uncertainty, from one test.
Read more
Put your fibre to work.
Tell us about your fibre and your question. You get a call, a plan for your site and a monthly price.