Gas detectors designed to help comply with ASHRAE 15 and 34, EN 378, and CSA B52 are to protect someone from entering a mechanical room with refrigerant concentrations that could be harmful to their health. These protection levels are outlined in the safety standards to be about 1000ppm, 8-hour TWA depending on the type of refrigerant being used in the equipment. The alarm set points, location and number of detection points outlined in the safety standards are typically insufficient for finding the more common, smaller leaks that add up to large annual refrigerant emissions, decreased efficiency and overall safety.

	Small Leaks	Moderate Leaks	High Level
Leak Probability	Very Likely	Less Likely	Extremely Unlikely
Safety Gas Detector 100 ppm MDL Detector	WILL NOT DETECT A safety gas detector will not detect smaller leaks	MAY NOT DETECT Depending on the airflow and placement in a refrigerated room, a safety gas detector may not detect a moderate leak until the concentration grows over time.	WILL DETECT TO MEET SAFETY STANDARDS Will detect large leaks with annual calibration at each detection point and routine visual inspection to ensure a clear diffusion path.
Ultra-Sensitive Sampling System 1 ppm MDL Detector	WILL DETECT AND MEET SAFETY STANDARDS With properly located sampling tubes and a superior MDL, the aspirated system can detect leaks no other commercial detector can. Early leak detection allows maintainers to fix leaks early and prevent Moderate and High Level leaks altogether.	WILL DETECT AND MEET SAFETY STANDARDS It is very likely that any leak reaching an OEL level would have been detected early by the aspirated system.  Nevertheless, a moderate leak reaching the OEL level would easily be detected and alarm.	WILL DETECT AND MEET SAFETY STANDARDS A properly designed aspirated system will detect high level leaks with a system response time comparable to a diffusion style monitor. Ultra-sensitive sampling systems additionally have self-diagnostics.