Tracer gas detection is our go-to method for leaks that thermal and acoustic can't find. This guide explains the science, applications, and equipment.
How tracer gas works
A safe mixture of 5% hydrogen and 95% nitrogen is introduced into a drained or depressurized pipe system. The gas mixture escapes through any leak and rises to the surface. A sensitive gas detector (ppm-level) traces the gas concentration gradient to pinpoint the leak source.
When to use tracer gas
Best for: low-pressure or gravity systems, complex piping with multiple branches, small leaks that don't produce enough sound for acoustic detection, sensitive environments (heritage buildings, hospitals, cleanrooms), and confirming acoustic or thermal findings.
Safety
The 5% hydrogen / 95% nitrogen mixture is non-flammable, non-toxic, and safe for occupied buildings. Hydrogen is used because it's the lightest gas — it escapes through the smallest openings. We use this in hospitals, schools, and heritage buildings regularly.
Sensitivity
Tracer gas detection is sensitive to leaks as small as 1 PPM (part per million). It can find microscopic leaks that waste a few litres per day — far smaller than what thermal or acoustic can detect.
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