Internal Cold Mains Leak Detection in Oxford

Symptoms

With moisture present in the corridor and no obvious visible source, internal leak detection was the appropriate course of action to systematically identify which circuit was responsible and precisely where the leak was occurring. The age of the pipework — approximately 40 years old — made a pipe failure a credible cause from the outset.

Methods Used

With damp present in two areas, the heating system was drained and pressurised with tracer gas introduced to test for escapes at the damp locations — none were detected. Pressure tests were then carried out separately on the hot feed, the heating circuit, and the cold feed.

The hot feed and heating circuit both held pressure, but the cold feed failed its pressure test. Acoustic equipment was then deployed over the bathroom floor, where an anomaly was detected, guiding the decision to open the floor at that specific point.

Investigation Process

1. 1
   Initial assessment

   Upon arrival, the engineer was informed of dampness on the corridor wooden floor. Thermal imaging was carried out to map pipework runs and identify any thermal anomalies beneath the floor.

2. 2
   Thermal anomaly and damp meter readings

   A thermal anomaly was detected on the corridor floor. High damp meter readings were recorded at that anomaly and also on the bathroom floor.

3. 3
   Tracer gas test

   The heating system was drained, an air compressor was used to clear it, and tracer gas was introduced. No gas was detected at the damp areas, ruling out the heating circuit as the source.

4. 4
   Pressure test — hot feed

   A pressure test was carried out on the hot feed pipework. The test passed, indicating no leak on that circuit.

5. 5
   Pressure test — heating system

   A pressure test was carried out on the heating system circuit. The test passed, indicating no leak on that circuit.

6. 6
   Pressure test — cold feed

   A pressure test was carried out on the cold feed. The test failed, confirming a leak was present on the cold feed pipework.

7. 7
   Acoustic detection

   Acoustic equipment was deployed over the bathroom floor. An acoustic anomaly was detected, identifying the precise area where the leak was located beneath the floor.

8. 8
   Floor excavation and leak found

   Bathroom tiles and the concrete floor were opened up. A leaking 15 mm copper pipe was found beneath the bathroom floor.

9. 9
   Repair carried out

   The leaking section of 15 mm copper pipe was replaced using new copper pipe and fittings.

10. 10
    Post-repair pressure test

    On completion of the repair, the pipework was pressure tested at 4 bar for 20 minutes. The test passed, indicating no further leaks at the time of testing.

Result & Outcome

The engineer noted that the pipework is approximately 40 years old and has now leaked on two separate occasions. A recommendation was made to replace the pipework in full, as further failures on pipework of this age are a realistic prospect.