The Rosemount 936 is an open-path toxic gas detector designed for continuous monitoring of hydrogen sulfide (H2S) or ammonia (NH3) in harsh environments where dust, fog, rain, snow, or vibration can cause signal reduction. It utilizes ultraviolet flash technology, which provides high immunity to false alarms, with a detection range up to 200 ft (60 m).

The detector features user-programmable communication via HART or RS-485 Modbus protocols, a built-in data logger (100 events), and heated optics to eliminate condensation and icing. The 316L stainless steel housing is rated for hazardous areas, and the device is not influenced by solar radiation, hydrocarbon flames, or other IR sources. It carries worldwide approvals including ATEX, IECEx, FM/FMC, INMETRO, TR CU, and SIL 2 (TÜV). Applications include offshore platforms, petrochemical plants, gas terminals, agriculture, food and beverage, waste management, and water treatment.