Abstract: System to detect coking in at least one component of refinery equipment is provided. The system includes a fiber optic assembly having at least one optical fiber operably coupled with the component, the fiber optic assembly further including a light source to transmit light having a known parameter through the optical fiber and a receiver to receive the light from the optical fiber, and a processor in communication with the fiber optic assembly to identify a shift in the parameter received by the receiver, the shift corresponding to an operating characteristic of the component. Method also provided for detecting coking using the system to detect coking disclosed herein.