Tracer Gas (Helium) Leak Detection

Tracer gas leak detection uses helium, or a helium-nitrogen mixture, introduced into a pipe system to locate leaks that are difficult or impossible to find with acoustic or thermal methods. Helium is chosen because it is inert, non-toxic, non-flammable, and the lightest element, which allows it to migrate through soil, concrete, and other porous materials faster and farther than liquid water. When helium is pressurized into a leaking pipe, it escapes through the same breach that water uses, migrates upward through the surrounding soil or concrete, and reaches the surface at or near the leak point. A calibrated helium detector held at the surface identifies the concentration peak that marks the leak location.

How Tracer Gas (Helium) Works

The tracer gas detection procedure involves draining the pipe section to be tested, pressurizing it with helium or a helium-nitrogen mix to a controlled test pressure, and then scanning the surface above the pipe path with a sensitive helium sniffing probe. Helium that escapes through the pipe breach migrates through the surrounding material and concentrates at the surface directly above the leak. The helium detector meter reading increases as the probe approaches the leak surface exit point and reaches a maximum directly above the breach. This gives a surface location for the leak that is not subject to the lateral signal scatter that affects acoustic methods in clay soil.

How We Apply This in Smyrna and Cobb County

Tracer gas detection is particularly valuable in Smyrna for two reasons related to local conditions. First, Georgia's red Piedmont clay soil produces lateral scatter in acoustic signals that can offset the surface signal peak from the actual pipe location by a foot or more. Helium migrating upward through clay soil reaches the surface in a tighter column than an acoustic signal travels through the same soil, giving a more spatially precise surface indication of the underground leak point. Second, Smyrna's high annual rainfall keeps the clay soil saturated for extended periods, and saturated clay transmits acoustic signals differently than dry clay. Tracer gas migration is less affected by soil moisture content than acoustic signal propagation.

We use helium tracer gas as the confirmation method after acoustic scanning has narrowed a service line leak to a zone in a Smyrna yard, particularly when the acoustic signal peak position is not clearly defined or falls in a location where excavation confidence matters, such as under a concrete driveway or under established landscaping where unnecessary digging is costly.

Tracer gas detection locates the surface exit point of a leak rather than the acoustic signature at the pipe level, which distinguishes it fundamentally from both acoustic and electronic detection methods. It is the most spatially precise surface location method available for underground leaks and is used specifically in situations where acoustic and electronic methods produce uncertain or conflicting results.

When We Use This Method in Smyrna

We deploy helium tracer gas detection in Smyrna for service line leaks under driveways or paved surfaces where excavation confidence is critical, for underground pool plumbing leaks in sealed pipe sections that are not accessible to acoustic surface scanning, for leaks in pipes embedded in walls where the helium can migrate through the wall material to a surface detector, and as a confirmation method when acoustic results are inconclusive due to clay soil scatter or high ambient noise. The method requires pipe access at both ends for gas introduction and is not applicable to drain or sewer systems.

Frequently Asked Questions