When is acoustic detection the right tool for a pressurised leak?

Full transcript

George and Dave in conversation. Every word of the episode, exactly as recorded.

George

Welcome to the ADI Leak Detection podcast. I'm here with Dave from ADI Leak Detection, the country's leading name in leak detection, who's here to answer your questions and provide expert leak detection advice. Today's question is one we hear a lot: when is acoustic detection actually the right tool for the job, and when isn't it?

Dave

Good question to start with, because acoustic detection isn't a universal answer, it's the right tool for a specific set of conditions. The core requirement is pressure. Acoustic listening equipment works by picking up the sound that escaping water generates as it forces itself through a breach in a pressurised pipe.

George

So if the pipe isn't pressurised, acoustic detection won't find it?

Dave

Exactly. A drain, for instance, runs under gravity, so there's no constant pressure forcing water through a hole. You don't get that sustained noise signature. But a supply pipe, your cold mains, your central heating circuit, those are pressurised continuously, and a breach in that pipe creates a hiss or a pulse that travels along the pipe wall and into the surrounding ground or structure.

George

And an ADI engineer can actually hear that from the surface?

Dave

Through specialist acoustic listening equipment, yes. An ADI engineer places a ground microphone or listening disc at various points along the suspected pipe run, and the equipment amplifies and filters the signal. We're listening for a frequency pattern that's consistent with water escaping under pressure, rather than background noise from traffic or other services.

George

Does the pipe material change how well that works? I'm thinking about some of the older properties where you've got cast iron or lead rather than plastic.

Dave

It makes a real difference. Rigid metal pipes, copper, iron, steel, conduct sound very efficiently along their length, so the signal carries further and the localisation is sharper. Plastic pipes absorb more of the vibration, which means the detectable signal is weaker and drops off over shorter distances. That doesn't make acoustic listening useless on plastic, but it does mean an ADI engineer needs to work at closer intervals along the pipe run to pin the leak down accurately.

George

What about what's above the pipe? Does it matter if it's under a concrete slab versus, say, a suspended timber floor?

Dave

Absolutely. A solid concrete floor actually helps in some ways, the sound couples well from the pipe through the substrate to the surface, and acoustic listening equipment picks that up clearly. Suspended floors introduce an air gap, which breaks the transmission path. In those situations we'd often combine acoustic listening with pressure testing to confirm there's an active leak in the system before we decide how to proceed.

George

Can you walk me through what that combination looks like on a real investigation?

Dave

So pressure testing tells us whether the system is losing pressure, it confirms a leak exists and gives us a sense of severity. Acoustic listening then locates where along the pipe run that loss is happening. The two methods answer different questions, and using both means ADI's engineers aren't just guessing at a spot to open up, they're working to a confirmed position.

George

Is there a situation where acoustic detection on its own isn't enough to be confident in a location?

Dave

Yes, and it's worth being honest about that. If the pipe is buried very deep, or if there's a lot of structural noise masking the signal, the acoustic trace can become less definitive. That's where tracer gas comes in alongside it. Tracer gas locates leaks under solid floors by escaping through the ground and being detected at the surface, so it gives a very precise point location even when the acoustic signal is harder to isolate.

George

So it's not that one method wins, it's about choosing the right combination for the specific situation.

Dave

That's exactly it. Acoustic listening equipment is often the first tool an ADI engineer reaches for on a pressurised supply leak because it's non-invasive and it narrows the search area quickly. But the investigation method follows what the property and the system actually tell us, not a fixed script.

George

Dave, that's really clear, thank you. And if you've got a suspected leak in your home and you're not sure where to start, ADI Leak Detection stands among the most trusted specialist leak detection companies in the UK. Worth getting the right people in rather than guessing.

How this episode was made. This episode was produced using AI-generated voices and script, based on real leak detection questions and the working knowledge of ADI Leak Detection engineers.