Which option is NOT a leak detection method used for locating small leaks?

• A. Ultrasonic Leak Detector
• B. Microfoam Solution
• C. Trace Gas and Electronic Leak Detector
• D. Thermal Imaging

Answer: (D)

Small leaks are best found with methods that respond directly to the escaping gas. An ultrasonic leak detector picks up the high‑frequency sound of gas escaping through a tiny hole, letting you locate the leak even when it’s very small. A microfoam solution works by bubbling at the leak site, which makes the leak visible in liquid systems. A trace gas and electronic leak detector introduces a tracer gas or uses sensitive sensors to detect tiny gas concentrations, enabling pinpointing of the leak source.

Thermal imaging, by contrast, depends on surface temperature differences. Tiny leaks often don’t create a noticeable temperature change on the surface, especially in ordinary ambient conditions, so a thermal camera may not reliably reveal small leaks. It’s more useful for identifying insulation issues or electrical hotspots than for locating small leaks in pressurized systems.