The Rosemount 625IR fixed gas detector uses solid-state dual IR sources and dual IR receivers to provide continual cross checks and internal adjustments that maintain the factory calibration. Heaters on the optical surfaces and a range of optical protection accessories provide continual detection without unexpected downtime. The Rosemount 625IR has a standard operating temperature range of -40 to +167℉, and its ingress protection levels are IP66/67 and NEMA 4X. It is rated for use in hazardous areas, specifically North American Class 1, Division 1, Groups B, C and D, and INMETRO/ATEX/IECEx - Ex db ib IIC T5 Gb. The detector is also SIL2 rated in accordance with IEC61508, and SIL3 rated when used in a 1oo2 voting configuration.