Helium detection ยท La Mirada, CA
Helium leak detection and repair in La Mirada
Helium leak detection pressurizes the pipe with inert helium gas and uses a mass spectrometer at the surface to detect concentrations as low as a few parts per billion, locating leaks too small for acoustic methods to register.
Properties in the La Mirada 90638 area generate a large share of calls for this service, typically from homes with original copper supply. For a first call, the service to book is tracer gas detection.
Some leaks are too slow to register as vibration and too small to cause a detectable pressure drop in a reasonable test window. Acoustic correlators need a flow rate large enough to generate vibration, and a pressure decay test needs a measurable drop over time. Helium leak detection bypasses both requirements. It fills the pipe with an inert tracer gas at controlled pressure, and a mass spectrometer at the surface detects the helium concentration escaping upward from the smallest opening, down to parts per billion sensitivity.
Why helium
An inert noble gas with a unique advantage
Helium is selected for this method for three reasons. First, it is a noble gas with no reactivity whatsoever, which means it will not combine with the pipe material, the soil, or any residual water in the line. Second, helium molecules are among the smallest in existence and pass through openings that water cannot, which is why it detects microscopic cracks and hairline seam failures that water has not yet found. Third, the background concentration of helium in the atmosphere is a consistent 5.24 parts per million, giving the mass spectrometer a stable baseline: any reading above that level at the surface indicates helium rising from the pipe below.
The method
Pressurize, purge, and scan
The line is isolated by closing upstream and downstream valves, drained of water, and then pressurized with helium from a regulated cylinder to a controlled fill pressure, typically between 5 and 15 psi depending on the pipe's pressure rating. The gas is allowed to dwell for a period that depends on the pipe length and depth, giving the helium time to permeate upward through the soil column above the leak. The technician then walks the pipe path with a sniffer probe connected to the mass spectrometer, reading the helium concentration at each step and noting where it peaks. The peak in concentration, corrected for wind direction and soil type, marks the leak location.
Small leak that acoustic methods cannot find?
Helium fills the line and a mass spectrometer finds the concentration peak at the surface.
Limitations
Soil depth, wind, and line access
Helium detection requires that the line be taken out of service and drained, which is a disruption acoustic methods do not require. It also needs access at two points to isolate the line and introduce the gas. In deep soil or under thick concrete, the helium concentration that reaches the surface is lower and the scan moves more slowly. Wind disperses the concentration plume at the surface, so calm conditions produce more reliable results. Because of these constraints, helium detection is reserved for situations where the leak is too slow for other methods, or where the pipe must be confirmed gas-tight before reburying after repair.
The instrument
How a mass spectrometer reads helium
The field mass spectrometer used in plumbing helium detection is a scaled-down version of the analytical instrument used in semiconductor fabrication and aerospace testing. The sniffer probe draws a sample of air from just above the surface and passes it into an ionization chamber inside the instrument, where the sample is ionized by an electron beam. The ions are then accelerated through an electric field into a flight tube, and their trajectory curves according to their mass-to-charge ratio. Helium ions, being among the lightest, arrive at the detector at a characteristic position that distinguishes them from every other gas in the sample. The readout reports the helium ion current in parts per billion, updating continuously as the probe moves along the surface.
In La Mirada
Small leaks under slabs and pavement
In La Mirada's slab-on-grade homes and paved service line paths, a leak too slow to register acoustically but large enough to cause a slowly rising water bill is the most common reason to bring in helium detection. The concrete slab or pavement over the line actually helps: it traps the helium concentration beneath the surface and concentrates the plume, improving the signal the sniffer probe reads. After a helium locating job, the repair can be made in a targeted opening rather than a search trench. call (562) 488-9614 to discuss whether helium is the right tool for what you are seeing.
A common misconception
Small leaks can wait
For a helium scenario, a pinhole losing a quart per hour translates to 5,500 gallons a year sitting in the subgrade under the foundation. The soil holds it, the concrete flexes over it, and next year runs the same math.
What to do instead
Confirm the loss at the meter first, then call. That single step separates the guesses from the diagnostics.
Questions we hear
Answered for La Mirada homeowners
How sensitive is helium leak detection?
A mass spectrometer can detect helium concentrations down to a few parts per billion, far below what any other field method achieves. This makes it effective for leaks too small to register as vibration or as a pressure drop.
Why is helium used instead of air or water?
Helium is a noble gas with no reactivity, and its molecules are small enough to pass through openings water cannot find. Its stable background concentration in the atmosphere also gives the mass spectrometer a reliable baseline to read against.
Does the pipe have to be taken out of service?
Yes. Helium detection requires the line to be isolated, drained, and filled with helium gas. Acoustic detection does not require taking the line out of service.
What is the background helium level?
Atmospheric helium is a consistent 5.24 parts per million. Any reading above that at the surface, detected by the sniffer probe, indicates helium rising from the pipe below.
When should I request helium detection?
When you have a confirmed leak by meter test but acoustic methods cannot locate it, or when a small continuous loss is raising the water bill without any surface sign. Also as a post-repair confirmation check on a line that has been relaid.
Related services
Other leak services in La Mirada
Tracer Gas Detection
The technicians who handle tracer gas detection are the same specialists you would want on acoustic leak locating.
Acoustic Leak Locating
The point at which non-invasive detection becomes cost-effective is when the third pinhole shows up. For addresses in the La Mirada 90638 area, response times and pipe profiles are on the coverage page.
A very small leak you cannot locate by sound or pressure?
The line is open every hour, every day.