The ACME REF-IR-ST Sensor/Transmitter is designed to detect the presence of refrigerant leaks in enclosed areas. The REF-IR-ST series employs a high-precision NDIR sensor ideal for gas-specific and accurate measurements of the most commercially used refrigerants. With its 1PPM resolution, 0 to 1000PPM measuring range and operating temperature and humidity characteristics, the REF-IR-ST far exceeds the current ASHRAE 15 requirements. The diffusion-based sensing method eliminates the use of filters and moving parts such as pumps, solenoid valves, etc. found in sample-draw systems and renders virtually maintenance-free operation.