A room decontamination systems, controllers and methods for decontaminating a room. The room decontamination system may be a UV room decontamination system that uses UV radiation to perform a decontamination operation in the room. A controller may determine whether safe conditions for decontamination exist and initiate a decontamination operation on the basis of whether they exist. Determination of safe conditions for decontamination may be based on light actuation detection and/or sensor data, which may include presence detector data and door sensor data. Determination of safe conditions for decontamination may include a determination of whether sensors are functioning properly. The controller may also determine whether decontamination operations are required on the basis of the historical condition data, for example on the basis of whether the room has been occupied since the last decontamination operation.
