What are the differences in test results between different detection principles?

Semiconductor sensors typically detect leaks from 0 to 10,000 PPM and are used to detect small leaks. Catalytic combustion sensors typically detect leaks from 0 to 100% LEL (the most common range), while infrared sensors typically detect leaks from 0 to 100% VOL. Laser sensors detect leaks from 0 to 50,000 PPM or 0 to 100,000 PPM and are commonly used for telemetry.